Ecology Notes Winter & Spring 2024 PDF

Equations: Sulfur Deposition: SO2 → Sulfuric Acid (H2SO4). Oxidization: SO2 + O2 - SO3. SO3 + H2O → H2SO4 (Sulfuric Acid). H2SO4 → SO4^2- (sulfate ion). Reduction: SO4^2- → H2S (hydrogen sulfide gas). H2s → elemental sulfur or sulfur compounds under anaerobic conditions in wetlands. Assimilation: Pl...

Equations: Sulfur Deposition: SO2 → Sulfuric Acid (H2SO4). Oxidization: SO2 + O2 - SO3. SO3 + H2O → H2SO4 (Sulfuric Acid). H2SO4 → SO4^2- (sulfate ion). Reduction: SO4^2- → H2S (hydrogen sulfide gas). H2s → elemental sulfur or sulfur compounds under anaerobic conditions in wetlands. Assimilation: Plants absorb sulfate ions and conver them to organic sulfur compounds. Decomposition: Organic sulfur compounds are decomposoed and sulfate ions released back into the soil and H2O. This sulfate can also reduced to hydrogen sulfide. Volcanic: Volcanic eruptions release sulfur dioxide into the atmosphere and weathering in rocks releases sulfate ions into the soil.pr QUICK REF: Atavism: reappearance of traits or characteristics in a species that had previously disappeared in its evolutionary history. This can sometimes lead to individuals w/in a pop showing ancestral features that are considered vestigial. Allochthonous/Autochthonous Inputs: Allochthonous: Energy or nutrients that enter an ecosystem from external sources, like leaf litter in streams. Autochthonous: Energy/nutrients produced w/in an ecosystem, like algae in a pond. Anastomosing Rivers: Complex river systems w/ multiple interconnected channels that split and merge. These are stable over geological time and create diverse habitats for aquatic life. Apparent Competition: An indirect interaction where two species are negatively affected because they share a common predator or parasite, rather than competing directly for resources. Alpha/Beta/Gamma: Alpha diversity w/in a certain area/ecosystem and is usually expressed by of species (richness) in that area, Beta: comparison of diversity between ecosystems, measuring the rate of change in species composition across different habitats or areas, Gamma: total diversity across all ecosystems w/in a large region, essentially representing the overall diversity for a group of ecosystems. Aposematism: The use of toxins or chemicals by organisms to deter predators, often combined w/ warning signals like bright colors (aposematism), Adaptive Landscapes: conceptual model showing how different genotypes have different fitness levels, w/ peaks representing high fitness and valleys low fitness, Adaptive Radiation: The rapid evolution of diversely adapted species from a common ancestor in response to new ecological niches, such as Darwin’s finches. Anthropogenic Biomes (Anthromes): Biomes significantly modified by human activity, such as urban and agricultural lands, reshaping ecological dynamics and biodiversity. Analogy: Similarity in function but not in evolutionary origin (e.g., wings of birds and insects). Allelopathy: A biological phenomenon where one organism releases biochemicals that influence the growth, survival, and reproduction of other organisms. Common in plants (e.g., black walnut trees releasing juglone). acclimation vs. adaptation: acclimation: short-term/reversible/response to environment, adaptation: long-term/evolution/passed thru generations. allelopathy chemical interactions between plants, where certain plants release biochemicals that can inhibit the growth/development of other plants (allelochemicals- secondary metabolites that can affect germination/root growth/nutrient uptake/physiological functions). Phenolic Compounds Caffeic acid, ferulic acid, p-hydroxybenzoic acid: Common in many plants, including sunflowers & sorghum- acids can inhibit seed germination and reduce root elongation in neighboring plants. Terpenoids Catechin: Released by spotted knapweed (Centaurea maculosa), catechin is known to affect nearby plant roots. α-Pinene, β-Pinene: conifer species like pine trees, where they inhibit seed germination and soil microbial activity. Alkaloids Sanguinarine, chelerythrine: Found in poppies, these alkaloids can have strong inhibitory effects on the growth of neighboring plants. Nicotine: tobacco plants, nicotine can leach into soil, affecting other plants' growth. Flavonoids Quercetin, luteolin: Released by many plants (clovers/legumes, these flavonoids have been observed to suppress the growth of nearby plant roots Quinones Juglone: black walnut trees (Juglans nigra), inhibits the growth of many surrounding plants by affecting root respiration and H2O uptake. Saponins Avenacin: oats (Avena species), inhibit the growth of fungal pathogens, which can indirectly affect other plant communities. Glucosinolates Sinigrin: mustard plants and other members of the Brassicaceae family. When sinigrin is hydrolyzed, it forms allyl isothiocyanate, which has herbicidal properties and can suppress weed growth. Coumarins Scopoletin: Found in plants like sweet clover and lavender, scopoletin can inhibit the growth of fungi and competing plant species. Benzoquinones Plumbagin: Found in Plumbago species (leadwort), this chemical is known for its antifungal and antibacterial properties, which can also suppress the growth of nearby plants. Tannins Gallotannins, ellagitannins: Found in many tree species, including oaks and eucalyptus, tannins can reduce the growth of other plants by inhibiting root elongation and nutrient uptake. Balancing Selection: Natural selection maintaining genetic diversity by keeping multiple alleles in a pop, Biocapacity/Ecological Footprint: Biocapacity- ability of ecosystems to produce resources and absorb waste. Biomagnification: (polychlorinated biphenyls or DDT) + heavy metals (such as mercury/arsenic). Biodiversity genetic diversity (adaptability + survival), species diversity (helps ecosys. stability), + ecosys. diversity (ensures ecological functions). Critical Thermal Limits: temperature range w/in which an organism can survive and function, beyond which it experiences stress or death, Critical Thermal Maximum (CTmax)- Ectotherms: highest temperature at which ectothermic animals (e.g., reptiles, amphibians) can maintain physiological function before experiencing failure. Character Displacement: Evolutionary divergence of species' traits, like morphology or behavior, due to competition, reducing niche overlap and allowing coexistence, Corridors & Habitat Connectivity: Natural or artificial pathways that connect fragmented habitats, allowing wildlife movement and gene flow, Co-evolutionary Arms Race: A cycle of adaptations and counter-adaptations between interacting species, such as predators evolving better hunting methods and prey developing better defenses, Character Displacement: Occurs when species that live in the same geographical area evolve to reduce competition by diverging in traits (such as beak size or feeding habits), leading to resource partitioning and coexistence. Corridors and Connectivity: Structures or natural areas that connect fragmented habitats, facilitating movement, gene flow, and survival of species in fragmented landscapes. Climatic Refugia: Areas where species survive during unfavorable climate periods, like ice ages. Refugia act as reservoirs of biodiversity, supporting recolonization once conditions improve. Dormancy (Hibernation, Estivation): A state of reduced metabolic activity to survive unfavorable conditions; hibernation occurs during cold periods, and estivation during hot, dry periods, Evil Quartet: Habitat Destruction, Overexploitation: Unsustainable harvesting of species- food/medicine/trade. Invasive species, Coextinction: extinction of one species leads to the extinction of another dependent species Extinction Vortex: A downward spiral where small pops face increasing genetic, demographic, and environmental pressures, leading to extinction, Ex-situ vs. In-situ Conservation: Ex-situ involves conserving species outside their natural habitat (e.g., zoos, seed banks), while in-situ conservation preserves species w/in their natural habitat, Energy Budget: balance between the energy an organism consumes, stores, and expends for activities like growth, reproduction, and maintenance, Ecosystem Engineers: Organisms that modify, create, or maintain habitats, significantly affecting the ecosystem (e.g., beavers building dams). Ecological Debt/Planetary Boundaries: The concept of overshooting the earth’s ecological limits and thresholds, indicating environmental sustainability limits. Extinction debt: number of species likely to become extinct. Environmental Heterogeneity: Variability in environmental conditions across a landscape. This variation supports biodiversity by providing different niches for species to exploit. Ecesis: successful establishment and growth of a plant or animal species in a new habitat. This involves not just arriving at a location but adapting to environmental conditions and starting to reproduce. Ecological Footprint: The measure of human demand on Earth's ecosystems, indicating the amount of land and resources needed to support a person's lifestyle, Ecological Release: when a species expands its niche or pop.in response to a decrease in competition. ecotone: transition between 2 biological communities & show high species diversity b/c mix of species. eutrophication: nutrient enrichment in aquatic systems (usually runoff containing nitrogen/phosphorus), leading to algal blooms. Facilitation: A positive interaction between species where one species benefits another, such as by improving environmental conditions or providing resources, Functional Redundancy: Multiple species performing similar ecological roles. This redundancy enhances ecosystem resilience, as other species can fill gaps if one is lost. Guilds: Groups of species that exploit the same resources in similar ways, regardless of their taxonomic classification (e.g., seed-eating birds and mammals form a guild), Gene Flow: Movement of genes between pops, increasing genetic diversity, Genotype Curves: represent distribution or frequency of different genotypes in a pop across a specific trait or multiple traits, often used in genetic studies to visualize variation w/in pop. Allelic Frequency Distribution: Shows the relative frequencies of different alleles of a gene in a pop. Phenotype Curve: Distribution of observable traits w/in a pop. Selection Curve: Shows how certain genotypes are favored or disadvantaged under selection pressures. Fitness Landscape: A conceptual model mapping genotype or phenotype against reproductive success. genetic drift: random changes in allele frequency that occur in small pops- variation among individuals. Hysteresis: A delayed response in an ecosystem, where returning to the original conditions does not necessarily restore the original state of the system, as seen in phase shifts in coral reefs. Haplodiploidy: A genetic system where males are haploid (one set of chromosomes) and females are diploid (two sets), common in certain insects, Hybrid Zones: Geographic regions where interbreeding occurs between different species, leading to hybrids. Hox Genes/Evo-Devo: Hox genes are a group of related genes that control the body plan of an embryo along the anterior-posterior axis; evo-devo (evolutionary developmental biology) studies how evolutionary changes in development lead to diversity in form and structure. Demography: statistical study of pop changes over time; Factors Affecting: pop Size, pop Density, Sex Ratio, Age Structure. Habitat Fragmentation: The breaking up of habitats into smaller, isolated patches, often leading to reduced biodiversity and genetic exchange. Heterozygote Advantage: Condition where heterozygous individuals have a survival or reproductive advantage over homozygotes, Homology: similarity in structures or genes between species due to shared ancestry (ex. forelimbs of mammals (like humans/bats) are homologous structures, as they share a common evolutionary origin despite different functions). Hardy-Weinberg: The Hardy-Weinberg equilibrium- principle used to describe the genetic makeup of a pop that is not evolving, equation helps predict the expected frequencies of genotypes (and alleles) in a pop. p^2 + 2pq + q^2 = 1: p = frequency of the dominant allele (A), q = frequency of the recessive allele (a), p^2 = frequency of the homozygous dominant genotype (AA), 2pq = frequency of the heterozygous genotype (Aa), q^2 = frequency of the homozygous recessive genotype (aa) Conditions to be in the HW equilibrium (not evolving): No mutation: No new alleles are introduced into the pop. Random mating: Individuals pair by chance w/out any selective mating. No gene flow: No migration of individuals into or out of the pop. Infinite pop size: The pop must be very large to avoid genetic drift. No selection: All alleles confer equal reproductive success (no natural selection). Habitat Loss conversion: changing the environment for human use - fragmentation: the environment is split up (farming, construction) - simplification: removing natural debris from an area intrusion: interfering w/ other species (dams, telephone wires). heritability: proportion of variation in a trait due to genetic factors (can be acted on by natural selection). High heritability indicates much of the variation seen in a trait is inherited Inclusive Fitness and Kin Selection: Inclusive fitness combines an individual's own reproductive success w/ the success of relatives due to altruistic behavior; kin selection is the process favoring this altruistic behavior towards close relatives. Indicator species: evidence that an ecosystem is going through some change or condition Lichen: Symbiotic Organism (close, long-term interaction) made out of a fungus (body, algae (provides food), + Cyanobacteria (food thru photosynthesis). Roles: They provide habitat, food, + shelter (birds using a nesting material), Landscape Connectivity: The degree to which landscapes facilitate or impede movement of organisms. Connectivity is critical for species migration, gene flow, and pop viability. Metabolic Rate (Basal vs. Field Metabolic Rate): Basal Metabolic Rate (BMR) is the energy used at rest in a neutral environment, while Field Metabolic Rate (FMR) is the energy expended in real-life conditions, including activity and environmental factors, Mimicry: Mullerian: Two well defended species look the same (ex: monarchs and viceroys) - Batesian: A weaker animal mimics another species w/ better defenses (ex: hover flies and bees) Emsleyan/mertensian: A deadly prey mimics something less dangerous, very rare (ex: coral/milk snakes) - Peckhamian/Aggressive: a predator mimics its prey or something harmless (ex: snapping turtles) - Vavilovian mimicry: weeds resemble plants Automimicry: An organism that mimics its own species (ex: Monarch caterpillars have tentacles on both sides of their body). Mate Guarding: individual protects their mate from rivals to ensure reproductive success and prevent infidelity. Matrix pop Models: A tool used to study pop dynamics by modeling the life stages (e.g., juveniles, adults) and the rates of growth, survival, and reproduction w/in each stage, Microhabitat Selection: preference and adaptation of organisms to specific small-scale habitats w/in a larger ecosystem. Mutation Accumulation: Gradual buildup of mutations in a pop, potentially leading to evolutionary changes, Nutrient Cycling: exchange of energy/matter between biotic/abiotic parts of the environment- ex. fossil fuels are burned emitting CO2 into the atmosphere so it can be used for photosynthesis. Nestedness: species composition in smaller, less diverse habitats is a subset of larger, more diverse habitats. Niche Construction: The process by which organisms actively modify their environment or niche, influencing the selection pressures on themselves and other species. Nutrient Spiraling: In streams, nutrients undergo a cycling process along the flow path, moving and cycling between different organisms and inorganic forms. Osmoregulation: process by which organisms regulate H2O and solute balance to maintain proper hydration and electrolyte levels, Optimal Foraging Theory: model that predicts how animals maximize energy gained while minimizing energy spent and risks during food searching and acquisition. Outbreeding Depression: Reduced fitness in offspring resulting from mating between genetically distant individuals, Orthology: Homologous genes separated by a speciation event. Paradox of Pesticides: may increase pop of a pest when the pest has a natural predator. Paradox of Enrichment: as K increases, the equilibrium of the dynamical system becomes unstable. Phylogenetics (Cladistics, Phylograms): Phylogenetics: study of evolutionary relationships among species. Cladistics classifies species based on shared derived characteristics, while phylograms are tree diagrams that represent the evolutionary relationships (branch lengths indicating time or genetic change; Pleistocene Rewilding: conservation strategy aiming to restore large animals to landscapes, inspired by species that existed during the Pleistocene epoch, to enhance ecosystem functioning. Photoperiodism: response of organisms to seasonal changes in day length, influencing behaviors like flowering, migration, or breeding, Patch Dynamics: An approach focusing on the dynamic interactions w/in a habitat matrix, where patches undergo cycles of disturbance and succession. Phreatophyte: Deep-rooted plants that access groundH2O, often influencing local hydrology and H2O availability in arid ecosystems. Phenological Mismatch: Occurs when timing changes in one species’ life cycle (e.g., flowering or migration) misalign w/ those of another due to climate change, disrupting mutualistic relationships. Photoinhibition: A decrease in photosynthesis at high light levels. In some aquatic plants, this can impact productivity and carbon cycling in freshH2O and marine ecosystems.Prezygotic Isolation of Species: Habitat Isolation: Species live in different environments, so they do not meet to mate. Behavioral Isolation: Species have different mating rituals or behaviors that prevent them from recognizing each other as potential mates. Temporal Isolation: Species breed at different times (e.g., different seasons or times of day), so they do not overlap during mating periods. Mechanical Isolation: Physical differences in reproductive structures prevent successful mating between species. Gametic Isolation: Even if species mate, their gametes are incompatible, and fertilization does not occur. Punctuated Equilibrium: Theory that evolution occurs in rapid bursts, separated by long periods of stability, pop Atrophy: decline/shrinking of a pop- resource scarcity, disease, predation- reduction in size/genetic diversity, potentially leading to extinction. Paralogy: Homologous genes that result from gene duplication w/in a species. Paradox of Enrichment: Predicts that increasing the availability of a limiting resource (e.g., nutrients) in an ecosystem can destabilize pops and lead to the extinction of predators or oscillations in prey-predator dynamics. Ring Species: connected series of pops, where neighboring pops interbreed, but the ends of the series cannot, illustrating gradual speciation. Reinforcement (Hybrid Breakdown): speciation where natural selection increases the reproductive isolation (further divided to prezygotic isolation and postzygotic isolation) between two pops of species. Runaway Selection: Extreme evolution of traits b/c sexual selection, where exaggerated traits increase reproductive success, Resource Pulses: Occurs when ecosystems experience temporary but substantial increases in resource availability (e.g., sudden nutrient influxes, mast seeding in trees), leading to short-term pop booms in species that exploit the resources, followed by eventual crashes. Redfield Ratio: carbon to nitrogen to phosphorus (106:16:1); found in phytoplankton and deep oceans- indicates balance of nutrients needed for optimal growth in marine ecosystems/dissolved nutrient pods. Reaction norm: describes how the phenotype changes in response to varying environment. ReclamationHelps to restore disturbed land to a useful state Advantages: - Helps produce oxygen, especially near urban areas - Re-provides habitats for organisms, increasing biodiversity Disadvantages: - Expensive/Takes long time (100+ yr). Reintroduction of Species Types: Translocation: moving wild-caught animals to another location - Reintroduction: Moving captive-born animals into their former range - Important practice for conservation Advantages: - Increases biodiv - Reduces the need to capture wild individuals - Helps restore species pops Disadvantages: - Loss of learned behavior in captive animals - Some species are difficult to breed in captivity - Initial stocks could further endanger wild pops. Species Distribution Models (SDMs): Models used to predict the geographic distribution of species based on environmental variables and species occurrence data, Sky islands are isolated mountain ecosystems surrounded by contrasting lowlands, creating biodiversity hotspots w/ species adapted to cooler, wetter climates. Examples include the Madrean Sky Islands in North America and Africa's Eastern Arc Mountains, both hosting rare species due to long-term isolation. Threatened by climate change, deforestation, and habitat loss, these ecosystems are vital for studying evolution and require conservation efforts to maintain connectivity and protect unique flora and fauna. Shifting Baseline Syndrome: A gradual change in accepted norms for ecosystem health, where each generation perceives the degraded ecosystem as “normal.” Stoichiometry; the balance of multiple chemical elements in ecological interactions. For example, the nutrient composition of plants influences herbivore diets and pop dynamics. Stable Age Distribution: proportions of individuals in each age group remain constant over time, often due to consistent birth and death rates. It is an equilibrium state seen in pops under stable environmental conditions. Source-Sink Dynamics: "source" habitats have a surplus of individuals- can migrate to other areas- while "sink" habitats depend on immigration from source areas to maintain their pops because local reproduction alone is insufficient for survival. Species evenness the commonness/rarity of a species. Species Richness is how many species. Torpor: In some desert regions, certain animals escape the rigours of summer drought by entering a torpid state, estivation, that is similar in many ways to hibernation. Taxis: Directed movement toward/away from stimulus: Light (phototaxis), Chemical signals (chemotaxis), Gravity (geotaxis), Positive taxis: towards stimulus, Negative taxis: away from stimulus. Thermoregulation (Endotherms vs. Ectotherms): Endotherms regulate body temperature internally (e.g., mammals), while ectotherms rely on external sources for temperature regulation (e.g., reptiles), Territoriality:defense of a specific area by an individual or group to secure resources such as food, mates, or shelter, Tolerance: later successional species are less affected by conditions set by earlier species and can establish independently. Transgressive Overyielding: phenomenon where diverse plant communities produce more biomass than expected based on the growth of individual species, often due to complementary resource use. Trophic/Ecological Efficiency: The percentage of energy transferred from one trophic level to the next in a food chain. Top-down vs. Bottom-up Control: Top-down refers to predators controlling the structure of ecosystems, while bottom-up refers to resource availability (e.g., nutrients) driving ecosystem dynamics, Trophic Cascades: Ripple effects in ecosystems caused by the addition or removal of top predators, affecting lower trophic levels, Tragedy of the Commons: ecological/economic phenomenon where individuals acting in their own self interest overexploit a resource- depleting it and harm community. Umbrella Species: Species whose protection indirectly benefits many other species and ecosystems, due to their large habitat needs. Vernalization: requirement of a period of cold weather for certain plants to flower. Vernalization influences plant distributions and adaptations to climate. Zoogeomorphology: Study of how animals influence landscape formation (e.g., elephants creating H2O holes), w/ implications for understanding ecosystem engineering across evolutionary timescales. EVOLUTION: Anagenetic (Anagenesis): phyletic evolution, gradual evolutionary change w/in 1 lineage where a species accumulates new traits over time w/o branching into different species- can lead to a new species over long periods- does not increase biodiversity (orig. species is replaced). Cladogenetic (Cladogenesis): lineage splits into 2 or more distinct species, increasing biodiversity- triggered by geographical isolation/different environmental pressures, leading to diverging evolutionary paths. Divergent Evolution: 2 or more species evolve in different directions from a common ancestor- leads to homologous structures—traits inherited from a shared ancestor but adapted to different functions. Convergent: unrelated species independently develop similar traits due similar environmental pressures or ecological roles- leads to analogous structures (traits serve similar functions; do not come from a shared ancestor) Parallel: 2 related species evolve in similar ways after diverging from a common ancestor- response to comparable selective pressures; closer evolutionary relationship. Adaptive: single ancestral species rapidly diversifies into multiple new forms to fill various niches; isolated ecosystems- adaptive radiation leads to high species diversity in a short evolutionary time. Coevolution: reciprocal evolutionary process where 2 or more species exert selective pressures on each other, leading to mutual adaptations. Horizontal Gene Transfer (Lateral Evolution): transfer of genetic material between organisms that are not parent and offspring, often seen in prokaryotes like bacteria. This allows for rapid adaptation and evolution. Example: Antibiotic resistance spreading among bacterial species. Mosaic Evolution: Different traits evolve at different rates and times w/in the same organism. Example: In human evolution, bipedalism evolved earlier than larger brain sizes. Saltational Evolution: Evolution occur in large, sudden steps, rather than gradual changes over time. Example: Polyploidy in plants, where chromosome duplication leads to new species. Punctuated Equilibrium: Evolutionary change occurs in rapid bursts, separated by long periods of stability w/ little or no change. Example: Fossil records showing sudden appearance of new species after mass extinctions. Reticulate Evolution: The combination of two lineages through processes like hybridization, often seen in plants. Example: Modern wheat, which originated from hybridization events. Peripatric Evolution: A small pop becomes isolated at the edge of a larger pop and evolves into a new species due to genetic drift and selective pressures. Example: Darwin's finches on the Galápagos Islands. Epigenetic Evolution: Changes in gene expression rather than the DNA sequence itself influence evolution. These changes can sometimes be inherited. Example: Stress-induced epigenetic changes in plants that prepare offspring for similar conditions. Dollo's Law (Irreversible Evolution): Once a complex trait is lost in a lineage, it is unlikely to re-evolve in the same form. Example: Loss of limbs in snakes. Major Points/Key Figures: Natural Selection (Charles Darwin & Alfred Russel Wallace)- on the Origin of Species by Darwin (1859). Inheritance of Acquired Traits (Jean-Baptiste Lamarck)- proposed that traits acquired during an organism's life could be passed to offspring. This idea was later disproven but initiated discussions about evolution. Mendelian Genetics (Gregor M.)- demonstrated patterns of inheritance through experiments w/ pea plants, forming the basis of modern genetics. Neutral Theory of Molecular Evolution (Motoo Kimura)- proposed that most evolutionary changes at the molecular level are not driven by natural selection but by genetic drift. Punctuated Equilibrium (Stephen Jay Gould/Niles Eldredge)- suggested evolution occurs in rapid bursts of change followed by long periods of stability. Gene-Centered View of Evolution (Richard Dawkins)- emphasized the role of genes in driving evolution, The Selfish Gene. Symbiogenesis (Lynn Margulis)- role of symbiosis in evolution, particularly in the origin of eukaryotic cells through endosymbiosis. Extended Evolutionary Synthesis,(2000s-Present)- incorporates additional like epigenetics, niche construction, and cultural evotion.Parallel Evolution: Similar evolutionary changes occurring in related species in similar environments, Divergent Evolution: Evolution of different traits in closely related species, leading to speciation, Group Selection: idea that natural selection operates on groups, favoring traits that benefit the group over individual survival. Antagonistic Coevolution: A reciprocal evolutionary struggle between two species, where adaptations in one drive counter-adaptations in the other (predator-prey or host-parasite relationships), SPECIATION: Allopatric: divided into two or more geographically isolated groups, over time, genetic differences accumulate due to mutation, natural selection, & genetic drift- isolated pops become separate species. Peripatric: a small pop becomes isolated at the edge of a larger pop, leading to divergence due to genetic drift and selection. Parapatric: pops are adjacent but not completely isolated, w/ limited gene flow leading to divergence, Polyploidy: new species due to a duplication of the entire genome, common in plants, Hybrid: hybrids between two species become reproductively isolated and form a new species, Sympatric: Speciation occurring in the same geographic area, thru mechanisms like ecological niche differentiation or sexual selection,Parallel: Similar species evolve independently in separate locations due to similar environmental pressures. SUCCESSION: Facilitation: process in succession where early colonizers modify the environment in ways that benefit subsequent species, often enhancing soil fertility or shade. Inhibition: A process in succession where early-established species make the environment less suitable for other species, slowing down or preventing succession.Allogenic Succession: caused by abiotic factors or geography, Autogenic Succession. SERE/SERAL COMMUNITY: Hydrosere: plant succession in aquatic (ponds/lakes), beginning w/ phytoplankton and progressing through submerged plants, floating plants, marshes, and eventually terrestrial forests.. Phytoplankton Stage: Microscopic algae/bacteria dominate open H2O, Submerged Plant Stage: Rooted aquatic plants (pondweeds) establish as sediment accumulates, Floating Plant Stage: Plants (H2O lilies) grow, reducing open H2O, Reed-Swamp Stage: Emergent plants (reeds/cattails) colonize shallow H2O, Sedge-Meadow Stage: H2O levels drop; sedges and grasses replace reeds, Woodland Stage: Shrubs and trees grow as soil develops. Xerosere: Succession in arid/dry environments, Bare Rock Stage: Pioneer colonize rock surfaces, Lichen Stage: Lichens weather rock into soil, allowing mosses to grow, Moss Stage: Mosses improve soil depth and moisture retention, Herb Stage: Grasses/herbaceous plants establish, Shrub Stage: Drought-tolerant shrubs grow as soil improves.Lithosere: Succession on bare rock surfaces, Pioneer Stage: Lichens colonize bare rock, Moss Stage: Mosses grow in the developing soil, Herb Stage: Small herbs/grasses establish as soil deepens, Shrub Stage: Woody plants and shrubs replace smaller plants. Psammosere: Succession on sandy environments, such as coastal sand dunes, beginning w/ pioneer plants like marram grass that stabilize the sand, followed by more complex vegetation as soil develops. Embryo Dune Stage: Pioneer plants (marram grass) colonize loose sand, Yellow Dune Stage: Marram grass stabilizes dunes, forming semi-fixed dunes. Grey Dune Stage: Organic matter accumulates; lichens and mosses grow. Dune Slack Stage: Low-lying areas between dunes host moisture-loving plants. Halosere: Succession in saline conditions, such as salt marshes or mangroves, Pioneer Stage: Halophytes (glasswort/cordgrass- salt tolerant) colonize saline mud. Low Marsh Stage: Salt-tolerant grasses/sedges establish, trapping sediment. High Marsh Stage: Salinity decreases; diverse vegetation like sea lavender grows. Climatic Climax: last stage of succession determined by regional climate- deciduous forest in temperate zones or a tropical rainforest in equatorial regions. Edaphic Climax: stable community determined by soil conditions, such as nutrient-poor soils favoring heathlands over forests, regardless of climate. Subseres: Intermediate stages w/in a sere, such as a swamp in a hydrosere or a grassland in a xerosere, which may persist for extended periods before progressing further. Polyclimax: The concept that multiple stable endpoints (climaxes) can exist in a region due to factors like soil type, fire regimes, or human impact, rather than a single climax community. Plagioclimax: A stable community maintained by external disturbances, such as grazing, mowing, or controlled burning, which prevent natural progression to the climatic climax. FEEDBACK LOOPS: processes where ecosystems' outputs return to influence their inputs, either amplifying or stabilizing changes w/in the ecosystem- regulate species pops/nutrient cycling/energy flows/climate processes. Types of Feedback LoopsPositive: amplify changes in an ecosystem- rapid transformations or potential destabilization. An increase in an ecosystem component triggers further increases, creating a self-reinforcing cycle (ex. vegetation loss) Negative: promote stability by counteracting changes. When an ecosystem component increases or decreases, negative feedback often works to return it to an equilibrium (ex. predator/prey; CO2 absorb). Mechanisms: Nutrient Cycling feedback, biogeochemical cycle feedback, evolutionary feedback, trophic cascade feedback, climate feedback. Implications on Stability: Negative: ecosystem resilience by keeping variables w/in stable ranges; Positive can lead to tipping points. When positive dominate (ex. ice melting in Arctic), an ecosystem can shift to a new potentially irreversible state- often lose biodiversity, making recovery difficult. HYPOTHESES/THEORIES: MODERN SYNTHESIS Evolutionary theory- combines Darwinian natural selection w/ Mendelian genetics- explains evolution as a change in allele frequencies w/in a pop over time, driven by factors like mutation, genetic drift, migration, and natural selection. Scientists: Sewall Wright: adaptive landscape, Ernst Mayr: biological species concept, Darwin Lewotin paradox: genetic diversity increases w/ pop size, yet observed levels of diversity across metazoans vary only two orders of magnitude while pop sizes vary over several- unexpectedly narrow range of diversity Gaia Hypothesis: Suggests that organisms interact w/ their inorganic surroundings on Earth to form a self-regulating, complex system that helps maintain and perpetuate the conditions for life on the planet. Evolutionary Time Hypothesis: biodiversity in a region increases w/ the amount of evolutionary time available, assuming no major disruptions like glaciation. Resource Ratio Hypothesis: assumes each plant is the superior competitor for a particular proportion of a limited resource. Island Biogeography Theory: Developed by MacArthur and Wilson, this theory explains species diversity on islands based on factors like island size and distance from the mainland- mainly for large/close. Dynamic Stability Hypothesis: longer food chains = less stable than short b/c pop fluctuations at lower tropics amplify as it moves up- higher trophics = more vulnerable to disturbances. Energy Limitation/ Energetic Hypothesis: length of food chains is limited by energy availability, as energy decreases at each trophic, leaving not enough energy to support additional levels. Red Queen Hypothesis: Species must continuously adapt and adapt (not just to gain repro. advantages), but to maintain relative fitness in response to co-evolving species (esp. In pred/prey & parasite/host). Intermediate disturbance hypothesis: ecosys. experiencing moderate levels of disturbance (fire,storms) tend to have higher species diversity compared to ecosystems w/ low or high disturbance levels. Janzen-Connell Hypothesis: high local species diversity in tropical rainforests is maintained by specialized natural enemies (pathogens/herbivores) that prevent one species from dominating. Green World Hypothesis: Suggests that predators are crucial in keeping herbivore pops in check, which in turn prevents herbivores from overconsuming vegetation, allowing the "green world" of plants to thrive. Overcompensation Hypothesis: Suggests that some prey pops can actually increase their pop growth rate when subject to moderate levels of predation, as reduced density can free up resources and reduce competition. Molecular Clock Hypothesis: A method for estimating the time of evolutionary events based on the mutation rates of biomolecules, w/ the assumption that genetic changes accumulate at a relatively constant rate over time. Intermediate Host Hypothesis: explains that many parasites require an intermediate host (an organism in which the parasite develops but does not reach maturity) to complete their life cycle. Changes in the pop dynamics of these hosts can significantly affect parasite transmission. Selfish Herd Theory: The idea that individuals reduce their predation risk by positioning themselves close to others in a group, using them as shields. Neutral Theory of Biodiversity: A theory suggesting that species diversity patterns can be explained by random processes of speciation, extinction, and dispersal, rather than niche differences. Game Theory (Hawk-Dove Game): A model in behavioral ecology where individuals adopt aggressive (hawk) or passive (dove) strategies, w/ outcomes depending on the strategies of others, Random Process Theory: stochastic events (e.g., chance dispersal or random extinctions) in shaping community structure and biodiversity. Unlike deterministic theories like ETIB, it suggests that randomness can significantly impact: Which species colonize a habitat, The composition of ecosystems over time, especially in small or isolated pops- acknowledges the role of unpredictable events, such as natural disasters, in driving ecological and evolutionary outcomes. Shifting Mosaic: maintain resilience by undergoing small, localized changes. Intermittent Voluntary Lethargy: reduce activity due to stress conditions. Redundancy hypothesis: ecosystems can maintain function despite loss of some species, as long as redundant species w/ similar functions are present. Rivet Hypothesis: species loss- few may be okay, but beyond a certain threshold, the ecosystem becomes dysfunctional. Green World Hypothesis: Predators maintain balance by consuming herbivore pops. Selfish Gene Theory (Dawkins): altruistic behaviors may evolve because they help genes (through relatives) survive. Neutral Theory of Molecular Evolution: rate of nucleotide substitution is highest at the third position of a codon, nonfunctional proteins experience faster rates of evolution, + correlation between molecular weight of a protein and polymorphism. EFFECTS: Spillover Effects: effects from protected areas to non-protected areas (increased biodiversity). Albedo Effect: The measure of how much solar energy is reflected by a surface, impacting local and global climate; changes in vegetation cover can alter albedo. Allee Effect: Phenomenon where individuals in a pop. have reduced fitness at low pop. densities, leads to difficulties in survival/repro. as pop. size decreases. Bottleneck: a sharp reduction in the size of a pop due to environmental events (natural disasters/human activity)- results in loss of genetic diversity/can affect the pop's ability to adapt to future changes. Dilution: increased biodiversity reduces spread of certain diseases b/c higher number of non-host species decrease likelihood of parasites encountering a suitable host. Edge: changes in pop/community structures that occur at the boundary of 2+ habitats- often leads to more biodiversity at the edges b/c of mixing of species. Founder: when a new pop is established by a small number of individuals from a larger pop, leading to reduced genetic variation and potentially different evolutionary paths compared to the original pop. Rescue: when pops in declining/isolated areas receive new individuals from other pops (can prevent local extinction). Refugium: Describes the phenomenon where certain areas (refugia) provide shelter or favorable conditions that allow species to survive during periods of adverse environmental change, such as glaciations or habitat degradation. Laws and Rules Lindeman’s 10%, Competitive Exclusion Principle (Gause’s Law): No two species can coexist indefinitely in the same niche if they are competing for the same resources. One species will eventually outcompete the other. Allen's Rule: Organisms adapted to cold climates tend to have shorter appendages than those in warmer regions to minimize heat loss. Bergmann’s Rule: Warm-blooded animals tend to have larger body sizes in colder climates and smaller sizes in warmer climates. Rapoport’s Rule: The geographic range of species tends to increase as latitude increases, meaning species in polar regions typically have larger ranges than those in the tropics. Fosters/Island Rule: species on islands tend to evolve toward smaller sizes if they are large animals or larger animals if they are small; influence from limited resources/fewer predators or competitors. Self-Thinning Rule: describes how plant pops decrease in density as individuals grow larger, due to competition for resources like light, H2O, and nutrients. Hamilton's rule asserts that a trait is favored by natural selection if the benefit to others, multiplied by relatedness, exceeds the cost to self. Bateman’s Principle: males have higher variable success in reproduction. Van Valen’s Law: constant arm’s race and rate of extinction, Liebig’s Law: several factors are involved in development of organism/one is available in only small quantities: that will determine success/failure. Cope’s Rule: In evolution, species bodies tend to get larger. Shelman’s Law of Tolerance: Species survival/distribution is based on tolerance limits for environmental factors. SELECTIVE PRESSURES: predation, disease, availability of resources, evolutionary force that causes phenotype to be favorable in certain conditions. Aka selective forces/agent. THERMS: Temp. Regulation: Poikilotherm: body temperatures that vary w/ the ambient environment. Homeotherm: maintain a constant internal body temperature regardless of external conditions. Ectotherm: rely on external environmental heat sources to regulate body temperature. Endotherm: produce internal metabolic heat to maintain body temperature. Mesotherm: regulate their body temperature through a mix of metabolic heat production and environmental heat absorption. Tolerance Stenotherm: tolerate only a narrow range of temperatures. Eurytherm: tolerate a wide range of temperatures. Temp. Range and Environmental Preference: Cryotherm: adapted to extremely cold environments, often below freezing. Psychrotherm (or Psychrotolerant): can grow and survive in cool temperatures, but not necessarily extreme cold. Thermophile: thrive at high temperatures, typically between 41–122°C. Hyperthermophile: thrive in extremely high temperatures, often above 80°C. Mesophile: moderate temperatures, usually between 20–45°C. Xerotherm: adapted to high temperatures and arid conditions. Hygrotherm: prefer warm/humid conditions. Temperature -Dependent Behavior Heliotherm: rely on direct sunlight to warm bodies. Thigmotherm: absorb heat from contact w/ warm surfaces. ATMOSPHERIC CIRCULATION: Easterly trade winds E->W, Quasi-Biennial Oscillation: quasiperiodic oscillation of the equatorial zonal wind between easterlies and westerlies in the tropical stratosphere w/ a mean period of 28 to 29 months. Orographic Effect: Mechanism: As moist air rises up a mountain slope, it cools adiabatically. When the air cools to its dew point, condensation occurs, forming clouds and precipitation on the windward side. The air loses moisture as it ascends, resulting in drier air descending the leeward side, creating a rain shadow effect. Examples: The Himalayas: Heavy rainfall on the southern slopes but arid conditions in northern regions like Tibet. The Sierra Nevada: Lush forests on the western slopes, deserts like the Great Basin on the eastern side. Adiabatic Cooling and Warming: Rising air expands and cools w/out exchanging heat w/ its surroundings (adiabatic cooling). Descending air compresses and warms (adiabatic warming), contributing to dry conditions on the leeward side. Katabatic Winds: Dense, cold air descends rapidly from elevated areas, often affecting local climates. Examples: Mistral winds in France, Santa Ana winds in California. Foehn Winds: Warm, dry winds on the leeward side of mountains, caused by the adiabatic warming process. Examples: Chinook winds in North America, Foehn winds in the Alps. Monsoonal Effects: Mountains enhance monsoonal rainfall by forcing moist monsoon winds to rise and cool, causing heavy precipitation. Example: The Western Ghats in India receive significant monsoon rainfall. Altitudinal Zonation: Variations in climate/ecosystems w/ elevation due to changes in temperature and precipitation. Example: Andes mountains transitioning from tropical forests to snowcaps. Barrier Jet Phenomenon: Strong winds deflected parallel to a mountain range when the atmospheric pressure gradient forces air against it. Common near the Rockies or the Andes. LAKES: Pycnocline/ Thermocline: pycnocline is both the halocline (salinity gradients) and the thermocline (temperature gradients) refers to the rapid change in density w/ depth.Epilimnion: warm, upper layer of a lake that is well-mixed and exposed to sunlight, leading to warmer temperatures and higher oxygen levels. Metalimnion: middle layer of a stratified lake, where temperature changes sharply w/ depth. This layer includes the thermocline. Hypolimnion: cold, deep layer of a lake below the thermocline, where H2O temperature is relatively stable and cooler. Chemocline: layer in some lakes where there is a sharp change in chemical composition, typically due to the presence of different salinity or oxygen levels. Halocline: layer where there is a significant gradient in salinity, often found in lakes influenced by salty inflows or in lakes near the ocean. Oxycline: layer where oxygen levels drop sharply, often coinciding w/ the thermocline or chemocline. Littoral Zone: shallow, nearshore area of a lake where sunlight can reach the lake bottom, allowing rooted plants to grow. Limnetic (Pelagic) Zone: open H2O area away from the shore, extending from the surface down to the depth where sunlight can still penetrate. Profundal Zone: deep, dark region of a lake below the limnetic zone where sunlight does not reach. Benthic Zone: bottom, including sediments and the organisms living in or on them. Photic Zone: surface layer of a lake that receives sufficient sunlight for photosynthesis, usually encompassing the epilimnion and sometimes part of the limnetic zone. Aphotic Zone: deeper H2O layer below the photic zone, where light does not penetrate enough for photosynthesis Oligotrophic: low nutrient levels (nitrogen and phosphorus), clear H2O, high oxygen levels, and low primary productivity. Eutrophic: high nutrient levels, leading to high primary productivity and often dense growth of algae and aquatic plants. Mesotrophic: moderate nutrient levels, an intermediate productivity between oligotrophic and eutrophic. D (or Humic): high levels of organic matter, often from surrounding bogs or peatlands, giving them a brown or tea-colored appearance. Meromictic: do not fully mix, creating distinct layers that remain stable over time due to density differences (due to salinity or temperature). Monomictic: mix (turn over) once a year, typically in regions w/ mild winter temperatures. Dimictic: mix twice a year, once in the spring and once in the fall, common in temperate climates.Polymictic: mix frequently, sometimes even daily, usually in shallow or tropical lakes w/ little temperature stratification. Amictic: never mix, usually found in polar regions w/ ice cover year-round. Endorheic: Lakes that do not drain into rivers or oceans, often located in closed basins where H2O evaporates or seeps into the ground. Anadromous: fish migrate from sea to rivers to spawn, Catadromous: fresh to seaH2O, Diadromous: both. Mixolimnion: The upper, mixed layer of a meromictic lake where active mixing occurs due to wind and temperature changes. Monimolimnion: The bottom, dense, non-mixing layer of a meromictic lake, usually rich in salts and lacking oxygen. Secchi Depth: A measurement of H2O transparency, often used to determine the depth of the photic zone in a lake. Thermal Bar: A zone of temperature discontinuity in large lakes during spring and fall, separating colder offshore H2O from warmer nearshore H2O. Circulation and Mixing Dynamics: Holomictic: A term used to describe lakes that completely mix from top to bottom during a specific season (e.g., monomictic, dimictic, polymictic lakes fall under this category). Langmuir Circulation: A series of shallow, spiral currents on the surface of a lake caused by consistent winds, visible as streaks of debris or foam on the H2O surface. Seiche: A standing wave oscillation in a lake caused by changes in atmospheric pressure, wind, or seismic activity, leading to fluctuations in H2O levels on opposite shores. Chemical and Biological Gradients: Redoxcline: A layer w/in a stratified H2O body where there is a sharp redox potential gradient, usually due to the presence or absence of oxygen. Methanocline: A layer where there is a rapid increase in methane concentration, often found in anaerobic, nutrient-rich hypolimnia. Nutrient Limitation: Refers to whether nitrogen, phosphorus, or another nutrient primarily limits primary production in a lake; often varies w/ trophic status. Lake Classifications: Lotic vs. Lentic: Lotic refers to flowing H2O systems (streams, rivers), while lentic refers to still H2O systems (lakes, ponds). Tectonic Lakes: Lakes formed by tectonic activity, such as rift valleys or faulting (e.g., Lake Baikal). Glacial Lakes: Lakes formed by glacial activity, such as kettle lakes or fjords. Volcanic Lakes: Lakes formed in volcanic craters or calderas (e.g., Crater Lake). Artificial (Reservoirs): Man-made lakes used for H2O storage, hydroelectricity, or recreation. Hydrology and Hydrodynamics: Thermohaline Circulation: Refers to the mixing driven by temperature and salinity differences, often more pronounced i → → → → → → → → → → → → → → N.A. Deserts: Great Basin: Temperate desert, between the Sierra Nevada and the Wasatch range. Spans across Nevada, Utah, and some of Eastern CA. Has varying ecosystems according to altitude. Over 600 vertebrates and over 800 plants live in this desert. Climate: Temps= days over 90 °F (32 °C) and nights near 40 °F (4 °C). Coldest desert in N.A. Has hot, dry summers and cold, snowy winters. Most precipitation comes in the form of snow. The G.B. Desert gets little precipitation bc of the Sierra Nevada, which blocks most precipitation. Any prec. that gets in cannot drain into the ocean due to the fact that this desert is in a basin. Instead, prec. Drains into lakes, get evaporated, or is absorbed into the soil. Flora/Fauna: Sagebrush is the dominant plant. Has the least cactus species of the 4 deserts. Flora includes shrubs and some fir trees. Fauna includes bats, mountain lions, dune lizards, and small to medium mammals. Mojave: 54,000 square miles, known as “high desert,” distinctive basin and range topography (parallel mountain ranges/valleys), has Death Valley, (lowest point in North America- 282 ft. below sea level)- bordered by the S. Andreas Fault (southwest) & Garlock Fault (north). Surface rivers are scarce, but have major underground rivers (Mojave River and Amargosa)- Shallow lakes such as Manix, Mojave, Little Mojave, and saline Soda Lake. Endemic plant species: Joshua tree, ironwood, blue palo verde, spiny menodora, desert senna, California fan palm, California dalea, and goldenhead. Winters are freezing w/ strong winds, and mountainous areas occasionally receive rain or snow. Summers are extremely hot, w/ temperatures frequently exceeding 100°F (38°C), esp. in lower elevations like Death Valley. Sonoran Desert: approximately 100,000 square miles, spanning southern Arizona, southeastern California, and parts of Mexico, low-elevation basins and rugged mountains- bordered by the Colorado River (west) and the Mojave Desert (northwest): region features several prominent rivers (Gila River and Santa Cruz River), many are intermittent/underground. Shallow, seasonal lakes like Salton Sea exist, fed by surrounding rivers. Common flora includes the saguaro cactus, ocotillo, palo verde, creosote bush, ironwood, and brittlebush, w/ fauna such as desert tortoise, Gila monster, bobcat, coyote, javelina, kangaroo rat, and Gambel’s quail. Winters are mild w/ sporadic rainfall, while summers are extremely hot, w/ temperatures regularly exceeding 100°F (38°C). The desert’s biodiversity is supported by two rainy seasons: the winter rains and the monsoons in late summer. This desert experiences double the maximum annual precipitation. Chihuahuan: Largest N.A. desert, spans over 200,000 square miles, covering parts of northern Mexico, southern New Mexico, western Texas & parts of Arizona- varied topography (basins, plateaus, rugged mountains), bordered by Sierra Madre Occidental (west) and Sierra Madre Oriental (east). Rio Grande: primary river, intermittent streams/arroyos that flow seasonally. Vegetation: creosote bush, lechuguilla, mesquite, tarbush, ocotillo, yucca, and agave. Fauna: Mexican wolf, kit fox, pronghorn, burrowing owl, roadrunner, black-tailed jackrabbit, desert cottontail, cougar, and western diamondback rattlesnake. Winters are cooler, w/ occasional frost, while summers can reach 100°F (38°C) or higher. Rainfall is minimal, primarily during summer monsoons and occasional winter storms. More arid than the Sonoran Desert, but known for its high biodiversity, esp. its large variety of succulent plants. Highest variety of cacti species out of the 4. Colorado Plateau: approximately 130,000 square miles, parts of Colorado, Utah, Arizona & New Mexico- elevated flatlands & deep canyons, bordered by Rocky Mountains (east) & Great Basin (west). Major rivers: Colorado River, carves canyons like Grand Canyon, & intermittent streams that flow through the region. Vegetation: pinyon pine, juniper, sagebrush, cottonwood, & various grasses. Fauna: bighorn sheep, mule deer, coyotes, mountain lions, desert tortoises, red-tailed hawks, and reptiles like Gila monster. Climate varies, cold winters bring snow at higher elevations & hot summers exceed 90°F (32°C). Rainfall is low, occurring during monsoon season in late summer. Mammalian Desert: Fennec Fox (Vulpes zerda): large ears dissipate heat/detect prey underground, Desert Kangaroo Rat (Dipodomys deserti): survive w/o direct H2O intake by metabolizing moisture from its food. Dromedary Camel (Camelus dromedarius): long treks across arid regions, storing fat in its humps for energy. Desert Cottontail (Sylvilagus audubonii): conserve H2O. Black-tailed Jackrabbit (Lepus californicus): large ears for heat dissipation- active during cooler parts of the day. Addax (Addax nasomaculatus): A critically endangered antelope species well-adapted to the Sahara Desert, capable of surviving for long periods w/out H2O. Meerkat (Suricata suricatta): deserts of Southern Africa, known for living in groups and using burrows for temperature regulation. Kit Fox (Vulpes macrotis): adapted for hunting at night and finding moisture in prey. Jerboa (Jaculus jaculus): small hopping rodent found in African and Asian deserts, long legs and tail that aid in escaping predators. Bighorn Sheep (Ovis canadensis): Found in North American desert mountains, adapted for scaling rocky terrain and w/standing arid conditions. G. Adaptations: American Bison (Bison bison): grazing and living in herds. Pronghorn (Antilocapra americana): one of fastest land mammals, adapted to open grassland habitats.Black-tailed Prairie Dog (Cynomys ludovicianus): burrowing rodent, living in large colonies for protection. Cheetah (Acinonyx jubatus): African savannas, unparalleled speed, adapted for chasing down prey in open spaces. African Elephant (Loxodonta africana): Commonly found in the savannas of Africa, adapted for foraging large areas for food and H2O. PHOTOSYNTHESIS: C3 (Calvin): Process: C3 photosynthesis is the most common pathway, where carbon dioxide is fixed into a three-carbon compound (3-phosphoglycerate) using the enzyme RuBisCO, efficient under cool, moist conditions w/ moderate sunlight. Common Plants: Grassland Plants: temperate grasses and forbs, such as wheat (Triticum aestivum), rye (Secale cereale), and clover (Trifolium). Examples: Kentucky bluegrass (Poa pratensis), big bluestem (Andropogon gerardii), Desert Plants: Some shrubs and annuals that grow during cooler seasons or in shaded areas (Creosote bush (Larrea tridentata)). Advantages: Energy-efficient when H2O is not limiting. Disadvantages: Less efficient in hot, dry conditions due to photorespiration (RuBisCO reacts w/ oxygen instead of carbon dioxide). C4: Process: fix carbon dioxide into a four-carbon compound (oxaloacetate) in mesophyll cells. This compound is then transported to bundle-sheath cells, where it enters the Calvin cycle- reduces photorespiration and increases H2O-use efficiency. Common Plants: Grassland Plants: Common in tropical and subtropical grasses, particularly in warm-season grasses- Maize (Zea mays), sugarcane (Saccharum officinarum), and switchgrass (Panicum virgatum). Desert Plants: Some desert grasses and drought-tolerant species use C4 photosynthesis to survive high temperatures- Blue grama (Bouteloua gracilis), saltbush (Atriplex spp.). Advantages: High H2O-use efficiency and reduced photorespiration. Disadvantages: Requires more energy (ATP) than C3 photosynthesis. CAM (Crassulacean Acid Metabolism): Process: CAM plants open their stomata at night to fix carbon dioxide into organic acids (e.g., malate). During the day, stomata close, and the stored acids are converted back to CO2 for the Calvin cycle- pathway minimizes H2O loss by separating carbon fixation and the Calvin cycle temporally (night vs. day). Common Plants: Grassland Plants: Rare in grasslands but may occur in some drought-prone species. Desert Plants: Common in succulents, cacti, and other xerophytes. Examples: Saguaro cactus (Carnegiea gigantea), agave (Agave spp.), and jade plant (Crassula ovata). Advantages: Extremely H2O-efficient, allowing survival in arid environments. Disadvantages: Slower growth Enzymes: Glutamine Synthetase (GS): Catalyzes the ATP-dependent conversion of glutamate and ammonia into Global Warming Potential (GWP)- measures their warming effect relative to carbon dioxide (CO₂) over a glutamine, which is a central process in nitrogen assimilation. Glutamate Synthase (GOGAT): Works w/ glutamine specific time period- (~100 years). Sulfur Hexafluoride (SF₆) GWP (100-year): 23,500, Lifetime: ~3,200 synthetase in the GS-GOGAT pathway to assimilate ammonia, producing glutamate, which is used to generate various years, Potency: The most potent greenhouse gas regulated by the Kyoto Protocol, primarily used in the nitrogen-containing compounds. Nitrate Reductase: reduces nitrate (NO₃⁻) to nitrite (NO₂⁻) in the initial step of nitrate electrical industry for insulation. Perfluorocarbons (PFCs) GWP (100-year): ~7,000–12,000 (varies by assimilation in plants, fungi, and bacteria. Glutamate Dehydrogenase: Facilitates the reversible amination of type), Lifetime: Up to 50,000 years, Potency: Highly potent/ long-lived, electronics industry/byproduct of α-ketoglutarate to form glutamate, which can serve as an amino group donor in various metabolic processes. Alanine aluminum production. Hydrofluorocarbons (HFCs) GWP (100-year): ~100–14,800 (varies by type), Aminotransferase: Plays a role in amino acid metabolism by transferring amino groups, supporting nitrogen flow w/in Lifetime: ~15–270 years, Potency: Synthetic gases in refrigeration, air conditioning, solvents. Nitrous plant tissues. Processes Fixation: Atmospheric nitrogen (N₂) converted into ammonia (NH₃) or related compounds Oxide (N₂O) GWP (100-year): 298, Atmospheric Lifetime: ~114 years, Potency: A potent greenhouse gas that plants can readily use. This process is catalyzed by nitrogenase, a highly oxygen-sensitive enzyme complex. w/ a longer atmospheric lifetime than many gases. Major sources include agricultural and industrial Biological Nitrogen Fixation (BNF): Performed by symbiotic bacteria, including species from genera such as activities. Methane (CH₄) GWP (100-year): 25–28, Atmospheric Lifetime: ~12 years, Potency: more Rhizobium, Azospirillum, Azoarcus, Herbaspirillum, Klebsiella, and Cyanobacteria. These bacteria convert N₂ to effective at trapping heat than CO₂- livestock, agriculture, landfills, fossil fuel extraction. Carbon Dioxide Lotka-Volterra: prey rise 1st, ammonia (NH₃) under anaerobic conditions. Symbiotic Nitrogen Fixation: Many legumes, such as beans, peas, lentils, (CO₂) GWP (100-year): 1 (baseline), Lifetime: Variable (up to thousands of years when considering ocean predator response. Prey’s and clover, establish symbiotic relationships w/ nitrogen-fixing bacteria (rhizobia) w/in root nodules. These bacteria and land carbon cycles), Potency: less potent per molecule, most abundant anthropogenic greenhouse gas- parameters = max growth per convert atmospheric nitrogen (N₂) into ammonia (NH₃), enriching soil nitrogen levels. The plant provides carbon to the fossil fuel combustion, deforestation, and industrial processes. Other: H2O Vapor (H₂O): most abundant capita. Assume: prey always has bacteria, which in return supply ammonia, converted into forms the plant can use (like amino acids and nucleic acids). greenhouse gas, very short atmospheric lifetime (a few days) and is controlled by temperature (not directly food food supply of predator Cyanobacteria Nitrogen Fixation: Certain Cyanobacteria (such as Anabaena and Nostoc) fix nitrogen in aquatic emitted by human activities) Ozone (O₃): Tropospheric ozone: short atmospheric lifetime, but GWP is depends entirely on size of prey environments or symbiotically w/ plants like rice or ferns, enriching nitrogen content in H2O and soil. Ammonification difficult to quantify over 100 years b/c reactivity and variability. Uses of H2O: Agri: largest global H2O pop., environment does not (Decay or Mineralization): Decomposition of organic nitrogen (from dead organisms, excretory waste) into ammonium usage, irrigation to grow crops, can consume over 70% of freshH2O resources in regions. Industry: change, predators have limitless (NH₄⁺) by ammonifying bacteria and fungi. This step is crucial for returning nitrogen stored in biological tissues to the manufacturing processes, cooling in power plants, and product creation- mining, chemical manufacturing, appetite, both can be described soil, where it can be reused by plants. Ammonium (NH₄⁺) produced during ammonification can either be taken up by food processing. Domestic Use: household- smallest percentage of H2O use. Energy Production: by single variable. plants directly or further converted in the nitrification process. Nitrification: Step 1: Ammonium (NH₄⁺) is oxidized to hydropower generation, cooling in thermoelectric plants, biofuel production. Environmental Maintenance. nitrite (NO₂⁻) by ammonia-oxidizing bacteria (AOB) such as Nitrosomonas and Nitrosospira. Step 2: Nitrite (NO₂⁻) is Haber-Bosch: produces ammonia (NH₃) from N₂ and hydrogen (H₂) at 400–500°C and 150–300 atm, then converted to nitrate (NO₃⁻) by nitrite-oxidizing bacteria (NOB), such as Nitrobacter. Nitrate is the most readily using an iron catalyst, enabling large-scale fertilizer production that revolutionized agriculture. Nitrogen absorbed form of nitrogen for most plants and is vital for synthesizing amino acids and other nitrogenous compounds. comes from air, hydrogen from natural gas, and unreacted gases are recycled. While critical for feeding the Assimilation: Plants absorb nitrates (NO₃⁻) from the soil and convert them into organic molecules, such as amino pop, it causes environmental issues like eutrophication, nitrous oxide emissions, and CO₂ from fossil fuels. acids, proteins, and nucleic acids- process aided by enzymes, including nitrate and nitrite reductases- facilitate the Alternatives include green hydrogen from renewable energy and sustainable nitrogen fixation methods. reduction of nitrate to ammonia w/in the plant’s tissues. Assimilation produces large quantities of amino acids and other nitrogenous compounds, which are critical for plant growth and development. Denitrification: Under anaerobic GENETICS: homozygous for gene when they have 2 identical alleles, homozygous dominant or homozyg recessive. Heterozygous indiv: 2 diff alleles. Genotype: combination of alleles an indiv has, while the conditions, specific bacteria convert nitrate (NO₃⁻) back to atmospheric nitrogen (N₂), completing the nitrogen cycle. phenotype is observable expression of that genotype- dominant allele expresses its trait even when only Denitrifying bacteria, including Pseudomonas, Paracoccus, and Clostridium, reduce nitrates and nitrites to N₂ or nitrogen oxides (N₂O). Denitrification helps regulate soil nitrogen levels, although excessive denitrification can lead to one copy is present, while recessive allele only expresses its trait when 2 copies are present. Hemizygous nitrogen loss in agricultural settings. N Fixing Bacteria/ Plant Interactions Relationships: Nitrogen-fixing bacteria, refers to having only one allele for a gene, ex. males w/ X-linked traits. In codominance, both alleles equally contribute to the phenotype, incomplete dominance results in blended phenotype in heterozygous such as Rhizobium and Bradyrhizobium, form root nodules on leguminous plants (e.g., alfalfa, soybeans). In these nodules, bacteria fix atmospheric nitrogen, supplying the plant w/ ammonia. Free-Living Nitrogen-Fixers: PLANTS: Photosynthetic Break Point: light intensity- photosynthesis rate begins to level off because the Azospirillum and Azotobacter fix nitrogen independently in soil. Although less efficient than symbiotic bacteria, they process is no longer limited by light availability;transition from light-limited to light-saturated. Saturation contribute to nitrogen availability, especially in grasslands and wetland soils. Significance of Legumes: Legumes host Point: light intensity beyond an increase in light does not lead to an increase in photosynthesis- nitrogen-fixing bacteria in their root nodules, facilitating nitrogen fixation and producing compounds like amino acids photosynthetic machinery at maximum efficiency. Compensation Point: light intensity at which the rate of and nucleotides- improves soil fertility, reduces dependence on synthetic fertilizers, and supports sustainable photosynthesis = rate of respiration, just enough energy through photosynthesis to meet respiratory needs agriculture by replenishing nitrogen in crop rotations. Ecological and Agricultural Importance of the Nitrogen w/o growth.Total Plant Production: total biomass or energy produced by a plant through photosynthesis Cycle Soil Fertility: Through nitrogen fixation and ammonification, the nitrogen cycle enriches soil, supporting plant over a given time. It includes both the energy used for growth and the energy used for respiration. growth and increasing crop yields. Sustainable Farming: Crop rotation w/ leguminous plants reduces the need for Evapotranspiration: In areas w/ dense vegetation, transpiration contributes to precipitation. Loss of chemical fertilizers by naturally replenishing soil nitrogen. Environmental Impact: Excessive nitrogen, often from vegetation can reduce rainfall, creating drier conditions that inhibit plant regrowth—a feedback loop. fertilizers, can lead to eutrophication in aquatic systems. Maintaining balance in nitrogen cycling processes is essential Phytoaccumulation: absorb pollutants in soil C3 Photosynthesis: The most common form; CO₂ is fixed for ecosystem health and to mitigate effects such as algal blooms and hypoxia in H2O bodies. Nitrogen= 78% of directly by Rubisco in the Calvin cycle. Works best in cool, moist environments. C4 Photosynthesis: CO₂ is atmosphere. ANAMMOX is anaerobic ammonium oxidation, DNRA is dissimilatory nitrate reduction to initially fixed by PEP carboxylase into a four-carbon compound before entering the Calvin cycle. Efficient in ammonium, and COMMAMOX is complete ammonium oxidation.Red Nitrogen: N cycling in terrestrial ecosystems hot, sunny environments, minimizes photorespiration. CAM (Crassulacean Acid Metabolism) (arid/semi-arid environments)- high N fixation, where N compounds are transformed into forms for plants and Photosynthesis: CO₂ is fixed at night to avoid H2O loss, stored as organic acids, and processed during the micros, deserts/nutrient-limited ecosystems- also agri. N mineralization: inorganic nitrogen is obtained by day. Adapted for arid conditions, common in succulents. Rings: rainforest would grow wider rings. tissue decomposition of dead organisms and degradation of organic nitrogenous compounds. As this process releases origin for prickles, spines, and thorns: prickles=derived from epidermis (corky projections), ammonium, it is also known as ammonification, although this term is also used for other dissimilatory processes. spines=modified leaves and derived from leaf tissue, thorns=modified stems (derived from stem tissue). Bioavailable Nitrogen: fixation is spontaneous process, but N isn’t bioavail b/c activation energy of reaction is too high Types of seed germination: hypogeal, epigeal, vivipary w/o specialized enzymes; triple bond prevents it from easily entering an unstable state. TEK: Key Components: Knowledge:(local plant/animal species like ID & behaviors & cycles/habitats in Enzymes Involved: Rubisco (Ribulose-1,5-bisphosphate carboxylase-oxygenase): Rubisco is the most abundant ecos),Management (management of natural resources, hunting/ag(roforestry)/maintain balance & enzyme on Earth and plays a pivotal role in the Calvin cycle, a part of photosynthesis in plants, algae, and sustainability), Sustainability and Resilience (emphasizes the sustainable use of resources, ensuring cyanobacteria. It catalyzes the reaction between CO₂ and ribulose-1,5-bisphosphate (RuBP), fixing atmospheric CO₂ that they are available; Indigenous as stewards of the land, responsibility to maintain health, adaptive into organic molecules. PEP Carboxylase (Phosphoenolpyruvate Carboxylase): essential in C₄ and CAM (Crassulacean management practices, knowledge is constantly updated). Cultural and Spiritual Dimensions: nature is Acid Metabolism) plants, particularly in arid or high-temperature environments. PEP carboxylase binds CO₂ to sacred, rituals/ceremonies, Intergenerational Transmission: passed down orally thru storytelling- done phosphoenolpyruvate (PEP), creating oxaloacetate, which is later transformed into malate or aspartate- initial carbon through lived experience, Holistic Perspective (considers interconnectedness of all living & contrasts w/ fixation occurs in specialized cells and enables efficient carbon capture by concentrating CO₂ in specific compartments, reductionist), example TEK is fire management, fishing/hunting/ag(roforestry)/H2O management. minimizing photorespiration and optimizing carbon fixation in challenging conditions. Carbonic Anhydrase: Found in Importance: Climate Change Adaptation, Biodiversity Conservation, Integration w/ Western Science, both photosynthetic and non-photosynthetic cells, carbonic anhydrase accelerates the conversion of CO₂ and H2O into Recognition/Rights, Challenges: Loss of Knowledge/Displacement & Land Loss. carbonic acid (H₂CO₃), which can dissociate into bicarbonate (HCO₃⁻) and protons (H⁺). This reaction helps regulate 𝐻 =− Σ[(𝑝𝑖) · 𝑙𝑛(𝑝𝑖)] : measures abundance and evennes Simpson- diversity, intracellular pH and maintain CO₂ balance. Carbonic anhydrase is essential in aquatic photosynthetic organisms, where it aids in CO₂ uptake by rapidly converting dissolved bicarbonate ions back to CO₂, which is readily used by Rubisco. Species: Cryptic: look same, genetically diff, Sibling: same as cryptic; cannot be interbred, form through speciation. Morphospecies: defined by physical characteristics (can be inaccurate if cryptic arise). Key Processes: Photosynthesis, Cellular Respiration, Decomposition, Carbon Sequestration: long-term storage of carbon in various reservoirs, including vegetation, soil, oceans, and geological formations. Carbon can be sequestered Sympatrics: same area/remain separate, reproductive barriers. Allopatric: different regions, isolated, no gene flow, can cause cryptics. Polymorphic: species w/ different variations/morphs- genetically same. naturally by plants through photosynthesis and stored in plant biomass or soil. Human-driven approaches, like Isospecies: similar (can be ecotypes, polymorphic, of subspecies)- may be genetically diff. Ecotypes: pops reforestation, wetland restoration, and soil management practices, are often implemented to enhance sequestration of a species that adapt to a specific region. Synanthropic: species used to being around humans- could capacity. Carbon-Fixing Organisms: Terrestrial Plants, Algae and Phytoplankton: Algae and phytoplankton are outcompete native species Relict Species: (living fossil) refers to a species or group of species that have responsible for a significant portion of global carbon fixation, especially in marine environments. Through survived from an earlier period in Earth's history but have become much rarer or restricted in their current photosynthesis, they capture atmospheric CO₂ and form the foundation of aquatic food webs. Cyanobacteria: earliest distribution- ancient lineage, limited distribution, survive past climates, used rare niches. Paleoendemics: photosynthetic organisms, are key players in carbon fixation in aquatic ecosystems. They not only fix CO₂ but also once widely distributed but are now restricted to smaller/isolated regions. Lazarus taxa: thought to have produce oxygen as a byproduct. Some cyanobacteria have specialized cells called heterocysts for nitrogen fixation, been extinct, rediscovered alive. ELVIS TAXON: organisms mistakenly IDed as previously extinct taxon; which enables them to thrive in nitrogen-poor environments and support other organisms by enriching the ecosystem acc. a separate lineage evolved to resemble the extinct group thru convergent evolution. w/ bioavailable nitrogen. Effective Plants for Carbon Sequestration: Algae, Trees (Oak, Pine, Mangroves), Grasses (Prairie and Savanna Species). Sequestration Hotspots: areas especially good at capturing carbon. Carbon Removal: Successional Trajectories: pattern of species change Inbreeding Depression: natural selection weeds out Direct Air Capture (DACCS): captures CO₂ directly from the ambient air using chemical processes. Captured CO₂ can harmful alleles, reduce survival of affected organisms. Biotic Homogenization: 2 or more evenly distributed then be stored in geological formations (CCS) or used in various products (CCU). DAC is energy-intensive but offers a communities become more and more similar over time. Anthropogenic: anything to do w/ humans Habitat way to reduce atmospheric CO₂ concentrations beyond what natural processes can achieve. Mineral Carbonation Perforation: Habitat fragmentation- small gaps disrupt lager habitats. Anthropogenic Allee Effect: human (Enhanced Rock Weathering - ERW): accelerates the natural weathering process by spreading finely ground silicate activity increase demand for a rare species. Refugium Debris: Pockets of habitat that provide temporary rocks (e.g., basalt) on land, which reacts w/ CO₂ to form stable carbonate minerals. This approach has potential for shelter. Plastic Biofilm: layer of microbial communities that colonize plastic debris. Ecological Redlining: long-term carbon storage, especially in agricultural soils. Biochar Production: stable form of carbon produced by historical neglect of urban areas for green spaces Islandization: fragmentation of ecosystems into pyrolyzing organic material (e.g., crop residues) in low-oxygen conditions. When applied to soils, biochar enhances “islands” by humans. Habitat Compression: reduction of suitable habitat b/c humans. Genetic Pollution: soil fertility and locks carbon away for centuries. Soil Carbon Sequestration (Regenerative Agriculture): no-till spread of gene from GMO organisms to the wild- reduce local adaptation. Xenobiotic Compounds: foreign farming, crop rotation, and cover cropping increase soil organic carbon by enhancing microbial activity and minimizing chem. substances- pesticides, etc. Anthrome: Anthropogenic biome. Eco-functional decoupling: soil disturbance- improves soil health and carbon storage.TYPES OF CARBON Black Carbon: Fine particulate matter interconnected functions w/in are disrupted Nutrient Loading: Excess intro of nutrients Species Filtering: produced from the incomplete combustion of fossil fuels, biofuels, and biomass. A significant contributor to global selective survival of species b/c environmental changes (similar to selective mortality) Behavioral warming as it absorbs sunlight and heats the atmosphere; also impacts air quality and human health. Blue Carbon: Plasticity: change of behavior in response to environment Pseudoreplication: samples are treated as Carbon captured and stored in coastal and marine ecosystems, such as mangroves, salt marshes, and seagrasses. independent when they aren’t (unintentional human intervention) Niche Compression: restriction of niche Helps mitigate climate change by sequestering large amounts of CO₂. Green Carbon: Carbon stored in terrestrial due to comp, habitat loss, stressors Plasticity-Limited Mortality: Occurs when behavioral/physio plasticity ecosystems, particularly forests, grasslands, and soils. Includes carbon sequestered through photosynthesis in plants, is insufficient to adapt to rapid changes NRW (Natural Resource Wealth): economic value of natural playing a key role in carbon cycling. Brown Carbon: Organic carbon emitted as a byproduct of biomass burning, resources VRE: Variable Renewable Energy Minimum Viable pop: smallest pop for extinction Intermittent including smoldering fires and biofuel combustion. Contributes to atmospheric heating but has weaker warming Voluntary Lethargy: behavioral adapt to reduce activity during stress HFOs (Hydrofluoroolefins): synthetic effects compared to black carbon. White Carbon: Refers to diamonds or crystalline carbon in geological contexts. Not refrigerants to replace HFCs SWS: Soil H2O Storage directly relevant to climate but important in materials science and geochemistry. Gray Carbon: Carbon emissions OCEANS/AQUATIC: Atlantic Multidecadal Oscillation: change- sea surface temps in North Atlantic change associated w/ industrial processes and manufacturing, particularly concrete and steel production. A major contributor warm/cool- 60/80 years. Pacific Decadal Oscillation: climate pattern of sea surface temps- 20/30 years. to anthropogenic greenhouse gas emissions. Red Carbon: Represents carbon linked to degradation and loss of forests OTEC (Ocean Thermal Energy Conversion): temp difference between deep/surface ocean to generate renew due to activities like deforestation or wildfires. Highlights the carbon emissions released during forest destruction. energy Marine and Hydrokinetic: generate renew energy- ocean/river currents OHI- Ocean Health Index. Yellow Carbon: occasionally used to describe atmospheric organic aerosols that scatter light. Less commonly Coriolis Effect: deflects direction of wind in the north hemisphere to the right/left in south. Intertidal discussed but influences atmospheric chemistry and light scattering. Soil Organic Carbon (SOC): Carbon stored in Zone: Closest to land; varies between high/low tide (beach)- sandy/rocky/muddy shores. Neritic Zone: soil as a result of decomposed organic matter. A critical component of soil health and global carbon storage. Extends from intertidal zone to 200m (continental shelf edge)- Light penetration supports photosynthesis, Enzymes: Phosphatase: Breaks down organic phosphorus compounds, releasing phosphate for plant uptake. well-oxygenated, low pressure, stable temp. Benthic Realm: consisting of sand, silt, dead organisms- high Adenosine Triphosphatase (ATPase): Involved in energy transfer and phosphorus utilization w/in cells, helping plants nutrient content. Abyssal Zone: 4000m, very cold, high pressure, low/no oxygen, high nutrient content and organisms use phosphorus effectively. Phytase: Breaks down phytate (a stored form of phosphorus in plants) and NICHE CURVES Species Curves: shows how efficiently it uses different parts of the resource spectrum- helps release phosphorus in a form that can be absorbed by other organisms, especially in agricultural and soil peaks indicate the optimal resource usage level (each species is most effective); width represents niche systems. Processes: Weathering: Phosphorus naturally enters ecosystems through the weathering of rocks, releasing breadth, showing how specialized or generalized each species is in its resource use. Narrower curves phosphate ions (PO₄³⁻) into soil and H2O, where they become available to plants and microorganisms. Absorption by indicate more specialization, while wider curves show broader utilization. Niche Overlap: overlapping Plants: Plants absorb phosphate from the soil and incorporate it into organic compounds, such as DNA, ATP, and shared resources where species compete. distances- degree of separation in their resource use. Smaller phospholipids, supporting growth and cellular functions. Decomposition: When plants and animals die, decomposers distances imply greater overlap and thus more competition. Altering Elements: Increasing peak: exert break down organic matter, releasing phosphorus back into the soil in an inorganic form for reabsorption by plants. greater competitive pressure on species i and k in the overlapping resource areas. Wider breadth= more Sedimentation: In aquatic environments, excess phosphorus may settle at the bottom and eventually become part of generalized, narrower curve= specialization, distance change= change in overlap. Environmental Tolerance sedimentary rocks, effectively removing it from the active cycle for long periods. Phosphorus-Fixing Organisms: Curve: Optimal Range: The range of conditions where the organism performs best, achieving maximum Mycorrhizal Fungi: These fungi form symbiotic relationships w/ plant roots, helping them absorb more phosphorus growth, reproduction, or survival. This is often represented as the peak of the curve. Zone of Stress: The and enhancing phosphorus availability in ecosystems Phosphate-Solubilizing Bacteria (e.g., Pseudomonas, Bacillus): areas on either side of the optimal range where the organism experiences stress but can still survive. release organic acids that dissolve phosphorus from mineral sources, making it more available to plants. Performance is reduced in this zone. Tolerance Limits: The extreme ends of the curve beyond which the Phytoplankton: In marine ecosystems, phytoplankton incorporate phosphorus, passing it up the food chain and organism cannot survive. These are the upper and lower tolerance limits for the environmental factor. forming an essential base for marine nutrient cycles. Human Impacts: Fertilizer Use: Synthetic phosphorus fertilizers Zone of Intolerance: The conditions outside the tolerance limits where the organism cannot survive. used in agriculture significantly increase phosphorus levels in soils. Excess phosphorus from these fertilizers often Functional Divergence: variation in traits among species that allows them to occupy different niches or runs off into nearby H2Oways, leading to nutrient pollution and eutrophication in rivers, lakes, oceans. Eutrophication perform distinct roles w/in an ecosystem- key aspect of biodiversity that influences ecosystem stability results in harmful algal blooms that deplete oxygen in H2O bodies, creating "dead zones" where aquatic life cannot and functioning. Bell Curves in Species Distribution: Shape Representation: The bell-shaped curves likely survive, disrupting aquatic food webs. Livestock Farming: Animal manure is rich in phosphorus, and intensive represent how species traits (body size, diet) are livestock farming produces large quantities of waste; improperly managed, manure runoff from farms introduces excessive phosphorus into nearby H2O systems, exacerbating eutrophication and impacting H2O quality. Importance: Essential for Growth: Phosphorus: key nutrient for DNA, RNA, ATP, and cell membranes, vital for plant and animal growth. Sustains: Phosphorus cycling supports plant productivity, which in turn sustains herbivores & higher levels of the food chain- cycle maintains soil fertility, ensuring long-term agricultural productivity and ecosystem stability. Enzymes: Adenosine 5’-phosphosulfate (APS) Reductase: An enzyme in both sulfate-reducing and sulfur-oxidizing bacteria that catalyzes the reduction of APS to sulfite, a critical step in both anaerobic and aerobic sulfur metabolism. Sulfite Reductase: Converts sulfite to hydrogen sulfide (H₂S) in sulfate-reducing bacteria, an essential step in anaerobic environments. Sulfate Adenylyltransferase: Converts sulfate (SO₄²⁻) into adenosine 5’-phosphosulfate (APS) in sulfur-assimilating organisms as part of the assimilation process. Sulfur Oxygenase Reductase (SOR): Used by some sulfur-oxidizing bacteria to convert elemental sulfur into sulfite and thiosulfate, intermediates in sulfur oxidation pathways. Thiosulfate Reductase: Catalyzes the reduction of thiosulfate (S₂O₃²⁻) into sulfur or sulfide, depending on environmental conditions. Processes: Sulfur Mineralization/Decomposition: Organic sulfur in dead organisms or waste products is broken down into hydrogen sulfide (H₂S) or sulfate (SO₄²⁻) by decomposers, such as bacteria and fungi. This process recycles sulfur back into the soil, where it can be used by plants or further processed by microorganisms. Sulfate Reduction: Assimilatory Sulfate Reduction: Plants and some microorganisms absorb sulfate (SO₄²⁻) from the soil and convert it into organic forms, such as amino acids (e.g., cysteine and methionine). The process begins w/ the conversion of sulfate to adenosine 5’-phosphosulfate (APS) and then to sulfite (SO₃²⁻) by APS reductase. Sulfite is subsequently reduced to hydrogen sulfide (H₂S) by sulfite reductase, allowing incorporation into organic sulfur compounds. Dissimilatory Sulfate Reduction: Performed by anaerobic bacteria (e.g., Desulfovibrio, Desulfotomaculum) in oxygen-deprived environments, where sulfate acts as a terminal electron acceptor, producing H₂S. Sulfate-reducing bacteria (SRB) are commonly found in sediments and marshes and are significant contributors to sulfur cycling in anaerobic ecosystems. Sulfur Oxidation: Chemolithotrophic Sulfur Oxidation: Bacteria, such as Thiobacillus and Beggiatoa, oxidize hydrogen sulfide (H₂S) to sulfur (S⁰) and then to sulfate (SO₄²⁻). These bacteria are found in environments rich in sulfur compounds, such as hot springs, hydrothermal vents, and sulfur-rich soils. Sulfur oxidizers play a crucial role in environments w/ high sulfur content, preventing the accumulation of toxic H₂S by converting it to less toxic sulfate. Phototrophic Sulfur Oxidation: Certain photosynthetic bacteria (e.g., Chlorobium and Chromatium) can oxidize H₂S to elemental sulfur using light as an energy source. These bacteria are important in anoxic, light-exposed aquatic environments, where they form dense sulfur-rich communities. Sulfur Assimilation: Plants, algae, and certain bacteria assimilate sulfate from the soil or H2O, incorporating it into organic sulfur compounds, such as amino acids, coenzymes, and vitamins. Pathway: Sulfate (SO₄²⁻) is converted to APS by sulfate adenylyltransferase and then reduced to sulfide (S²⁻), which is incorporated into amino acids like cysteine. This form of sulfur is essential for protein synthesis and cellular function in plants, which pass it along the food web. Volatilization (Sulfur Gas Emissions): Some sulfur compounds are volatilized, releasing gasses like hydrogen sulfide (H₂S), dimethyl sulfide (DMS), and carbonyl sulfide (COS) into the atmosphere. Volatile sulfur compounds are primarily produced by microbial activity in soil, H2O, and decaying organic matter. In the atmosphere, DMS plays a role in cloud formation and climate regulation by forming sulfate aerosols. Sulfur Deposition: Atmospheric sulfur compounds, including sulfur dioxide (SO₂) from both natural sources (e.g., volcanoes) and human activities (e.g., burning fossil fuels), are deposited back into the earth’s surface through precipitation. When sulfur dioxide (SO₂) dissolves in H2O, it forms sulfuric acid (H₂SO₄), leading to acid rain that can alter soil chemistry and impact ecosystems. Microbial Interactions/Environmental: Sulfate-Reducing Bacteria (SRB): Anaerobic bacteria (Desulfovibrio) are crucial in reducing sulfate to H₂S in sediments, influencing sedimentary and aquatic sulfur pools. Sulfur-Oxidizing Bacteria (SOB): Aerobic sulfur oxidizers such as Thiobacillus oxidize sulfide to sulfate, important in soil health and detoxifying environments w/ high sulfur content. Photosynthetic Sulfur Bacteria: Green and purple sulfur bacteria oxidize sulfide in anoxic, light-exposed environments, playing a unique role in sulfur recycling w/in certain ecosystems. Plant-Bacteria Symbiosis Certain plants, especially those in sulfur-deficient soils, can interact w/ sulfur-oxidizing bacteria to facilitate sulfur uptake. Mycorrhizal fungi also enhance sulfur assimilation in plant roots, especially in ecosystems where sulfur is less available. Ecological and Agricultural Importance of the Sulfur Cycle Soil Fertility and Crop Yields: Sulfur is an essential macronutrient for plants, playing a role in protein and enzyme function. Crops deficient in sulfur exhibit reduced growth and yield, and sulfur fertilization can significantly improve agricultural productivity. Environmental Pollution: Human activities release large amounts of sulfur dioxide (SO₂) into the atmosphere, which can result in acid rain. Acid rain affects soil pH, harms aquatic life, and alters ecosystem dynamics. Climate Regulation: Dimethyl sulfide (DMS) produced by marine organisms can influence cloud formation & global climate patterns. DMS oxidation in the atmosphere forms sulfate aerosols, which have cooling effects on the climate. Exchangeable potassium replenishes the soil solution when potassium ions are released into the soil solution and exchange places w/ other cations, such as calcium (Ca²⁺), magnesium (Mg²⁺), and hydrogen (H⁺) ions. This process is known as cation exchange, where potassium ions move from the Cation Exchange Complex (CEC) into the soil solution to replace other cations that have been absorbed by plants or leached away. When the concentration of potassium in the soil solution decreases due to plant uptake or leaching, potassium ions held in the CEC become available to replenish the solution, ensuring a continuous supply of potassium to plants. Raising the pH improves the CEC by making the soil more alkaline, which reduces the concentration of hydrogen ions (H⁺) in the soil. As the H⁺ concentration decreases, the CEC, which is the ability of soil to hold and exchange cations, increases because fewer H⁺ ions occupy the exchange sites. This creates more space for other essential cations, including potassium (K⁺), to occupy these sites. The higher CEC enhances the soil's ability to retain and supply nutrients like potassium to plants. Exchangeable potassium can become fixed potassium under conditions of fluctuating wet and dry seasons. In soils w/ certain clay minerals, particularly those w/ high cation exchange capacity, potassium ions can become "fixed" w/in the clay layers. This occurs when the soil goes through cycles of wetting and drying, causing clay particles to expand and contract. When the soil swells during wet periods, potassium ions are temporarily displaced into the interlayer spaces of the clay structure. During dry periods, as the clay shrinks, potassium ions become trapped w/in the clay particles, making them unavailable to plants for a period of time. This process of fixation can reduce the amount of potassium available for plant uptake, especially in soils w/ high clay content. Potassium's role in the potassium cycle: Potassium is an essential nutrient for plant growth, playing a critical role in processes such as photosynthesis, enzyme activation, and osmoregulation. Plants absorb potassium from the soil solution, where it is primarily found in exchangeable form. Once taken up by plants, potassium is incorporated into plant tissues and eventually returned to the soil through organic matter decomposition, plant residues, and root exudates. Potassium in plant residues and decaying organic matter is mineralized back into the soil as part of the natural cycle. The cycle is influenced by factors like soil pH, texture, organic matter content, and the presence of other nutrients, ensuring a continuous supply of available potassium for plant growth. Leaching and loss of potassium: Potassium is a highly soluble nutrient and can be lost from the soil through leaching, particularly in areas w/ heavy rainfall or excessive irrigation. Unlike other nutrients such as nitrogen and phosphorus, potassium does not form insoluble compounds that bind it to soil particles. Instead, it is easily washed away by H2O, which can lead to potassium depletion in the soil. This highlights the importance of managing potassium levels through fertilization and soil conservation practices to prevent nutrient loss and maintain healthy plant growth. Carbon Cycle: Respiration: C6H12O6+6O2 → 6CO2+6H2O+energyC6​H12​O6​+6O2​→6CO2​+6H2​O+energy Combustion: Fuel (e.g., CH4)+2O2→CO2+2H2O. Ocean Uptake: CO2+H2O↔H2CO3↔H+HCO3−↔2H+CO^2_3− (above/below)​. Nitrogen Cycle: Nitrogen Fixation: N2+3H2→2NH3. Nitrification: NH3+O2→NO2−+3H++2e−; NO2−+O2→NO3−. Assimilation: Plants absorb nitrates and convert them into organic compounds (e.g., amino acids). Ammonification: Organic nitrogen is converted back to