BIOC63 Lecture Notes PDF

Lecture 1 September 4, 2024 9:34 AM Conservation biology: integrated multidisciplinary field with goals of preserving species and ecosystems...

Lecture 1 September 4, 2024 9:34 AM Conservation biology: integrated multidisciplinary field with goals of preserving species and ecosystems VS. Environmentalism: Movement thar involves political change and education activism. The goal is to protect the overall environment. Sustainability: something that can continue indefinity Environmental sustainability: rate of renewable resources harvest Biological diversity: the variety of life that exists Genetic diversity ○ Important because it avoids creating inbred effects ○ Inbreeding depression Ecosystem diversity ○ Variation of species across ecosystems ○ Variation of ecosystems in an area Species diversity ○ All life on earth Traditional Speciation: act of one lineage diverging into two lineages EX: Whales and Hippos Phyletic speciation: act of one lineage changing overtime EX: Whales, homo sapiens Hybrid speciation: formation of a novel species through hybridization between two parents This doesn’t occur often because 1. they need to prefer other hybrids 2. Hybrids need to survive to reproductive age 3. Hybrids need to not be sterile 4. Hybrids need to be fit, even better adapted Adaptive radiation: BIOC63 Page 1 4. Hybrids need to be fit, even better adapted Adaptive radiation: Can result in very species rich areas (happened in the Galapagos, Darwin's finches) Can be very difficult to figure out the path taken to achieve the species that occurred Ring species: Occurs when each neighbouring population is slightly different but can still interbreed When the "ring" closes, and population A and H meet up again, they are no longer able to interbreed BIOC63 Page 2  longer able to interbreed How do we determine biodiversity: 1. Species richness: number of species in a given area a. Alpha diversity (local diversity) b. Gamma diversity (regional diversity) BIOC63 Page 3  c. Beta diversity (rate of species turnover) Species concepts: 1. Biological species concept (BSC): if they can interbreed and produce viable offspring, they are the same species Pros: populations that look and behave similarly might be similar. Includes reproductive isolation BIOC63 Page 4  Cons: even if species can interbreed, doesn’t mean that they are the same species (Ex: dogs, wolves and coyotes). What about asexual species? Difficult to tell if fossils can interbreed 2. Morphological species concept (MSC): do they look the same or do they look different? Morphospecies: organisms on a waiting list to get categorized Pros: Simple, easy to measure. Emphasizes characteristics that are simple to measure Works for fossils, asexual species and allopatric species Cons: sexual dimorphism can be misleading to group BIOC63 Page 5  cryptic species (look identical but the genome is different) would be lumped together using this method because they look extremely similar, if not identical to another species The method is arbitrary because how much variation is enough variation? BIOC63 Page 6 3. Evolutionary species concept (ESC): a species is a group of individuals that share unique similarities of their DNA, share an evolutionary history Pros: DNA is the basic building blocks of life so this concept can be very widely applied Includes an evolutionary history component Cons: Generally vague (what % of DNA has to be different for an organism to be considered a different species?). Genes can also introgress due to backcrossing Evolutionarily significant Units (ESUs): Populations that contain unique genetic variation & evolutionary history. Generally based on unique variation in neutral genetic markers Background extinction rate: Normal rate of extinction Mass extinction: Statistically significant rate of extinction far beyond background extinction BIOC63 Page 7  Major threats to biodiversity: - Habitat loss - Globalization (releasing invasive species to native areas, spread of pathogens, etc) BIOC63 Page 8  Ecosystem services: Provisioning services Regulating Services Cultural services Definition Products obtained directly from Benefits obtained from the regulation of Non-material benefits obtained from ecosystems ecosystem processes ecosystems Example - Food - Climate - Spiritua regulati l and on religiou s services - Fresh - Inspirat water ion - Fuel wood - Fiber - Educati on - Disease BIOC63 Page 9  - Disease regulati on - Water regulati on - Water purifica tion - pollinat ion Supporting services Definition Services necessary for the production of ALL other ecosystem services (provisioning, regulating and cultural) Example - Soil fermen tation - Nutrien t cycling - Primary product BIOC63 Page 10  product ion BIOC63 Page 11 Lecture 2 September 11, 2024 9:10 AM Species accumulation curve: Results when counting the number of species in a given area until reaching a plateau (until only the rare species are left) However, different environments, there are different rates of species accumulation. If you're counting microorganisms, there might be no plateau, since they're very under represented. If this is the case, its more likely to be relative measures used, not the actual physical species. How are new species found?: 20 000 new species are described each year But estimates may actually vary from 4 million -> 1 trillion Living fossil is a weird term because all you're saying is that the body plan was successful. Implies they're primitive when if you look at the fossil version, its not going to be the same species as the current version. Living fossil implies that they are frozen in time, but they are likely still evolving today EX: coelacanth EX: Duck billed platypus has a primitive trait(lays eggs) but has a lot of derived traits(can sense electrical impulses in fish) Global biodiversity patterns: Latitudinal and longitudinal gradient: Species diversity increases as one moves from the poles to the tropics (Latitudinal). In birds, mammals and amphibians, they all have the highest diversity in the tropics Why is most diversity in the tropics?: 1. There's no particular reason (Null model) ○ Its just the pattern in which nature falls, there is no underlying reason ○ The tropics are larger and simply able to hold higher In marine species, there's going to be more biodiversity on continental shelves due to higher primary amounts of biodiversity productivity than the deep ocean (Longitudinal) ○ EX: Mid-domain hypothesis Pattern may be due to placing species in a bounded domain. Island Biogeography theory: If you put a bunch of pencils in a pencil case and shake it The number of species an island can support is determined by around, then by chance, there will be more overlapping 1. The size of the island pencils in the middle 2. The distance to the nearest source of colonists Excluding rescue effect means that only size of the island matters 2. The tropics have much higher diversification rates (Evolutionary Including rescue effects means that both size and distance matters hypothesis) ○ There is a much higher rate of diversification. Every niche that could be filled has been filled which means that when a species dies, there will immediately a species that takes it place. ○ Species area relationship: More land=more species EX: the mangrove experiment ○ Climactically stable and larger surface area which means Some researchers removed all the insects from mangrove islands and watched what happened less species are likely to go extinct and increases support for higher population sizes Some mainland habitats act like islands EX: mountain peaks 3. The tropics are older (Historical hypothesis) Key word: TIME Altitudinal gradient: ○ The tropical climate has existed for longer and more an Species diversity decreases with increasing altitude uninterrupted period of time ○ 100mya , the entire world was tropical (megathermal Local topography: forests - rainforest and warm seasonal forests). Tundra is likely 2mya. Historical factors: 4. The tropics simply support more life (Ecological hypothesis) The most species diverse places on earth: Key word: RATE - Tropical forests ○ Higher carrying capasity ○ Covers about 7% of global land surface ○ There is higher primary productivity which increases sugar ○ The most diverse terrestrial biome where over 50% of earths species are found production -> higher energy (Species-energy hypothesis) ▪ 40% of angiosperms, gymnosperms and ferns ▪ Between 5 and 30 million insects The tropics are both a cradle (most species originated in the tropics and ▪ 40% of birds (excluding island endemics and migratory species then spread) and a museum (the rate of extinction is lower in the tropics ○ Includes rainforest and dry deciduous forests. so you find linages that are very old evolutionarily) - Coral reefs ○ Covers about 0.1% of global land surface ○ The most diverse aquatic biome ▪ Contains 1/3 of all marine fish species ▪ Highly productive due to the zooxanthellae that live inside them ○ Coral reefs as well as deep sea Coldwater corals are rapidly declining ▪ Deep sea corals don’t use zooxanthellae due to lack of sunlight, they use plankton ▪ Species rich ○ 20% have been destroyed by humans through pollution, etc. - All ocean habitats (again, most near continental shelves) ○ Covers much of earth’s surface ○ Diversity covers a broader range of phyla/classes than terrestrial systems ▪ 28 modern animal phyla (out of 35) found in oceans ▪ 1/3 of these animal phyla are ONLY found in the oceans (only 1 modern animal phylum is exclusively terrestrial, in contrast) ○ Potential explanations include: oceans are older / larger (great volume) / more physically complex (e.g. sediment types, water depth, light penetration depth, etc.), oceans have been isolated from one another by landmasses, many places within oceans have stable climates - Soil (very deep in the soil where life was previously thought couldn't exist) - Inside of the human body, or other living organisms BIOC63 Page 12 Lecture 3 September 18, 2024 9:07 AM Population dynamics: Population dynamics are influenced by- 1. Deterministic factors: predictable changes In a deterministic model, the input and output are always predicted EX: seasonal changes 2. Stochastic processes: unpredictable processes In a stochastic model, the same input can result in entirely different outputs. EX: disease, drift Demographic uncertainty: random variation in individual reproductive success and mortality which impact population size. EX: individuals within a population will not have the same number of offspring. EX: Sex ratio - sewage dumping sometimes changes sex ratio in fish, if all fish are female, reproduction will be impacted. Environmental uncertainty: unusual environmental occurrences that affect a population's size EX: Invasive species, interaction of a specialized predator, hurricanes, competitive interactions Genetic uncertainty: EX: Genetic drift Stochastic extinction: The inability to predict which species will be extinct, almost impossible. ALL populations change over time, none are static. Ways to increase a species risk of extinction: 1. Decreasing suitable habitats and lowering population sizes 2. Increasing stochasticity, increasing population fluctuations Small population paradigm: - Population viability: long term persistence of a population, tied to population size. ○ Population viability as population size ○ Population viability as population size - Extinction vortex: the tendency of small populations to decline towards extinction overtime Why does this occur?- 1. Environmental and demographic uncertainty factors 2. Genetic factors (inbreeding and drift) 3. Positive population regulation Negative population regulation: As population size , individual fitness EX: Covid, the reason it spread so fast was because there are so many people. Positive regulation: As population size , individual fitness EX: Allee effect - Individual fitness is reduced when population density is reduced, often occurs in very small populations - Inability to find a mate - Predator avoidance ○ safety in numbers, more eyes to look around ○ The more individuals, the more hesitant a predator will be to attack - Mating/ courtships is threatened ○ Inbreeding depression can occur ○ Loss of genetic diversity - Thermoregulation, individuals can stay together to preserve warmth - Information network The Allee threshold: once the population size reduces past a certain point, the population reduces significantly Natural selection: - There is variation Small populations: - some variation is heritable - Only alleles with very high S values evolve through natural - The variation impacts fitness selection If the variation is good, it remains - Most regions of the genome act like they are neutral, with If the variation is negative, it leave genetic drift as the main force which determines the fate If variation is neutral, it stays often of alleles Large Populations: Selection coefficient: - Even alleles with very low S values evolve through selection The degree to which a gene at one locus is expected to reduce or increase the fitness of an individual - Natural selection becomes the main force determining the possessing that gene at that locus relative to the rest of the population. fate of alleles S=0 -> The fitness is average S=1-> the variant dies young, before reproducing offspring If individual live a long life but they're infertile, S still=1 S=0.1-0.9 -> variant lives to the percentage of the decimal S=0.3 = variant lives 30% less time or produces 30% less offspring relative to the rest of the population Genetic drift: Random change in allele frequency in a population due to random chance events - Always occurring - Most pronounced in small populations Drift in small populations can result in a decrease of heterozygosity BIOC63 Page 13 Random change in allele frequency in a population due to random chance events - Always occurring - Most pronounced in small populations Drift in small populations can result in a decrease of heterozygosity And A loss of alleles Inbreeding depression: Breeding with close relatives in small populations will reveal deleterious mutations. - Reduces heterozygosity. ○ In very large populations, deleterious alleles hide in heterozygotes but because inbreeding decreases heterozygosity, the expression of deleterious recessive phenotypes increase ▪ However, genetic purging can occur wherein through the reduction of heterozygotes, the deleterious alleles get revealed and purged. ▪ This the fitness of the overall population but the population low lacks genetic variation. ○ As populations shrink, relatedness between its members increases, thus inbreeding depression impacts smaller populations more Extinction: Extinct: species has completely disappeared Extinct in the wild: species exist ex-situ only, often in the pet trade but can exist in locations other than the native range Extirpation: local extinction Regional extinction: species is removed from a region of interest Ecological extinction: Species once played a large part of their ecosystem but as their population reduced, the habitat is heavily impacted. Endemic: a species that is restricted to one geographic location. May be in refrence to only the breeding ground of a species. Not necessarily endangered. Artificially rare: A species that was once widespread and now has a narrow range due to human activity Neoendemic: A species that has a narrow range because it recently speciated from a widespread, closely related species Paleoendemic: Endemic species that are the only living descendent of their lineage. Biodiversity hotspot: Places with high degrees of biodiversity High-irreplaceability areas: Places that have at least one at risk endemic species. What makes a species vulnerable to extinction: - Being rare increases chance of extinction ▪ Species that exist in very small populations ▪ Species that have one or few populations - Having a rare niche, or specialized habitats - Being present in areas that are filled with people (in the case of canada) and/or are overhunted by people - Having a very large home range, require a lot of space to survive. If fragmentation occurs, which it often does, they are at risk. - Species that have large body size/have low reproductive rate (k-selected species) - Species that have low dispersal rate - Species that have little genetic diversity Mass extinctions: All mass extinction events are directly or indirectly caused by climate change. BIOC63 Page 14 Lecture 4 September 25, 2024 9:21 AM Mass extinctions: Time periods are determined based on the mass extinctions that occurred. Fossil lays beneath each extinction event contains organisms very different from the ones after the extinction. Climate change is linked to all major mass extinction events Biosphere impacts climate, climate impacts biosphere However, now we are in the 6th major mass extinction - Often mass extinctions have been caused by multiple species, this one is caused by only one species ( Homo sapiens) ○ Caused by co-opting resources (Water, etc.), spread of invasive species , habitat fragmentation, spread of pathogens (from animals to humans, from humans to animals), exploitation of other species, impacts of climate change In the last 350 years, the highest extinction rates have been on islands Anthropocene: Interval of time where human activity dominates the key processes on earth - Some argue it started during the neolithic revolution but most agree that it started during the industrial revolution (textile manufacturing, gas lighting, steam engines) -> 1750 ○ The industrial revolution started globalization - Then the technological revolution occurred (electricity, factories, automobiles and roads which fragment habitats)->1850 ○ The technological revolution furthered globalization - Humans are growing faster than exponential growth ○ The age structure is now primarily post-reproductive ○ More people are living in cities compared to the country meaning that now, farmers are becoming more scarce and are responsible for feeding more people. So, now commercial farms are becoming more common which are terrible for the environment. Population momentum- Population increases when its predicted to be decreasing and population decreases when it should be predicted to increase. Sustainability- Something that can continue indefinitely Seven major threats to biodiversity: These threats can be a) Fully additive - the total effect is the sum of individual effects b) Partially additive- the total effect is less than the sum of individual effects c) Synergistic- the total effect is more than the sum of individual effects Habitat loss: habitat fragmentation, habitat degradation and habitat destruction 1. Habitat fragmentation Something that was once continuous being fragmented into smaller sections Edge habitat - Habitat that differs on the edge of a habitat vs the interior. - Types of species found on edge habitats are different than those on the interior EX: In forests, the edge has more sun while in the interior, the canopy is so dense that sun can not get through. Thus, they support different species Edge Effect - More of what's there becomes edge. Edge is proportional and becomes more of what the habitat consists of. The edge itself does not get larger, it just takes up more of the habitat Population effects - Fragmentation creates barriers between populations, restricting panmixia - This restriction can diminish populations sizes due to inbreeding and diminishing gene flow Metapopulation modelling - Set of local subpopulations that persist and balance between random local extinctions and establishment of new populations. - A patch could be a source - high reproductive success - A patch could be a sink - low reproductive success - Habitat fragmentation could create a metapopulation structure ▪ Patches that are further apart are more isolated, individuals are less likely to travel that distance 2. Habitat destruction EX: rainforests habitats- Rainforests are the most diverse terrestrial biome wherein 50% of earths species are found. They play a role in watershed management and regional climate. They are also an extremely important carbon sink. 1% is lost per year due to deforestation and land use changes such as shifting cultivation EX: corral reefs- corral bleaching can occur through ocean acidification and increase in global temperatures. Intense loss of oceanic biodiversity because of this. Shifting cultivation (Slash and burn agriculture) ▪ Cleared fields are farmed and then abandoned due to decreased soil fertility Commercial interests ▪ Large scale farming or logging Desertification ▪ Conversion of ecosystems in seasonally dry climates (grassland, scrubland, deciduous forests, temperate shrubland) into man made deserts by human activity. BIOC63 Page 15  temperate shrubland) into man made deserts by human activity. ▪ Caused by repeated agriculture use, overgrazing, soil erosion. 3. Habitat degradation (Lecture 5) Physical degradation The physical degradation of an environment due to soil loss, sedimentation deposits, desertification due to agricultural practices, etc. Chemical degradation The chemical degradation of a habitat due to pesticide usage, N inputs due to fertilizer or untreated sewage causing, for example, eutrophication. EX: DDT use which were linked to the decline of fish, dolphin, raptors, etc. Found in polar bear tissue as the pesticide travelled far beyond the area it was originally used in. In raptors, DDT use was found to cause fragile eggs -> the eggs broke as the females would try to incubate them. Thus, the population declined. So, captive breeding programs were attempted where hand puppets were used to mimic grown raptors because baby raptors would identify who they were supposed to mate with based on who was feeling them. 4. Spread of invasive species (on purpose or on accident; Lecture 5) 5. Spread of pathogens 6. Impacts of global climate change 7. Overexploitation of species BIOC63 Page 16 Lecture 5 October 2, 2024 9:23 AM Biomagnification: a substance increases in concentration as it moves up the food chain. Concentration increases are due to: 1. Inability of an organism to break toxin down and so they store it as fat instead. 2. Food chain energetics 3. Water soluble chemicals having low rates of degradation Water pollution: Nutrient pollution causes eutrophication - An excess of nutrients in the system causes growth of algae (algal bloom)->lack of light, decomposers decompose algae that die from not being eaten-> decomposers use a lot of oxygen ->anoxic environment-> fish die -> dead zone - Managing this = biomanipulation: deliberately altering an ecosystem by adding or removing species to control a phenomenon 1. Bottom up manipulation (nutrient availability) Control nutrient concentration, nutrient input Wetland construction/ restoration (natures kidney) 2. Top down manipulation (food web) Control predation, EX: addition of fish to eat zooplankton-eating fish. In oceans its very difficult to do top down because controlling fish in large environment is hard, they just leave for better environments Air pollution: - Acid rain. N-oxide reacts with water vapour ○ Acidic water which kills trees and aquatic organisms, decreases reproductive success of fish, inhibits soil decomposition which decreases the nitrogen cycle which decreases primary productivity ○ Caused by lowering the pH of rainwater - Photochemical smog, N-oxide reacts with sunlight ○ Results in ozone at ground level which damages plant tissue which reduces primary productivity ○ Harmful when inhaled Legislations were put in place to "solve" these issues - USA clean air act ○ Was starting to work but Trump repealed a lot of environmental regulations Fire suppression and habitat degradation: - Occurs in more Mediterranean climates - Deliberate controlled fires were set by indigenous people - Fire tolerant plants require on fires to persist in these areas. EX: grasses grow from the roots so where fires are set, they survive while trees are wiped out. - When fires aren't set, the non-fire tolerant understory grow, outcompete grasses and grasslands shift towards forest habitats. ○ This leads to larger, less frequent wildfires. Invasive species and release: Introduced(exotic) species: a species that occur out side of their native range due to human activity - Could be physical introduction - Could be that humans manipulated the environment to allow for the introduction of a species outside of its range - Most introduced species do not become invasive Invasive species: introduced species that are experiencing rapid increases in abundance. - Results when the species is released from its natural enemies (ecological release) - On islands, predation relaxes so natural selection also relaxes (birds that once flew, can now not fly) so when a predator is introduced to an island, they take advantage of the lack of escape measures Causes of introduction: 1. European colonization Settlers that have no knowledge of the local ecosystem (and don’t care) releasing species that they 'missed from the homeland' EX: Common European starling - 60 pairs were released, now there's 2 million 2. Agriculture, horticulture, aquaculture Species that were introduced as decoration, agricultural crops, etc. The risks of aquaculture include a) Pollution due to fish food b) Risk of pathogens spreading due to bad environmental conditions c) Predators of these fish can get tangled in the nets d) Escaped fish, with farm genetics can interbreed with local, wild fish. This increases amount of bad genes in the wild population 3. Accidental transport Transport in the ballast water of ships BIOC63 Page 17 Transport in the ballast water of ships 4. Biological control (on purpose) Some enemies of invasive species have been introduced to control that species -> as biomanipulation Genetic swamping: The loss of unique haplotypes within a native species due to hybridization with a related, introduced species BIOC63 Page 18 Lecture 6 October 9, 2024 9:12 AM Global carbon cycle: Most of the carbon moving in and out of the environment is from plants (cellular respiration) The issue with human production is that more is moving out then in. There is a noticible, natural fluctuation in CO2 concentartions throughout the year April and May is when it peaks However, after the industrial revolution, CO2 levels increased Climate forcing: natural condituons that impact global climate Orbital forcing: how the tilt of the earth impacts global temperatures Range shifts are changing EX: tundra is becoming tyga because there is now enough topsoil for them to grow as permafrost melts EX: Insect ranges are moving northwards due to increase in temperatures in the north EX: Range contractions in polar bears These range changes are due to climate change because 279 species move with moving climate. When temperatures increased, they moved northwards, when temperatures decreased, they moved southwards so climate change is a strong signal. Spring is arriving earlier Determined by growth of tree, and bud bursts (EX: cherry blossom blooms are the longest dated record, back to 600+ years) Determined by moving of butterflies, first flight of insects Determined by bird migration Climate blowback: Secondary habitat loss Climate change makes crop growth unsuitable in the US but more suitabe in canada Agriculture moves into canada and canada has to make room for it Protected areas get used for agriculture Further habitat loss in canada Digazettement: due to increased populations, governments will role back protections put in place Overexploitation: unstainable harvest of recourses. Often done to open access resources due to cheating. If you know one person will cheat, then more people are likely to cheat Commercial exploitation: exploitation based on monetary gain. Governments can protect the interests of industries rather than the environment. For profit. Subsistence exploitation: many rural people directly exploit wildlife to meet personal needs. For survival Recreational exploitation: recreational hunting, fishing, etc. Ecotourism for fun. Incidental damage: damage to a species from another species Indirect exploitation: damage to landscapes causing loss of wildlife through human action. EX: overgrazing. Water over drafting: Water stress: Deforestation: removal of trees and conversion from one habitat to another Overlogging: often due to an attempt to sustainable harvest but still results in an overexploitation Tragedy of the commons: Maximum sustainable yield (MSY): greatest amount of resources that can be harvested without damaging the population Biggest problem: people assume that the number can not change. Can lead to overexploitation Effective population size: All past events affect current populations, EX: population bottlenecks can BIOC63 Page 19 Effective population size: All past events affect current populations, EX: population bottlenecks can impact the genetic variability within a population which means that the viable population is actually smaller then the actual population. EX: there are 10 males in the population and 90 females, those 10 will father the entirety of the next population. Populations that are all inbred, even if there are a lot of individuals act the same as a population that is tiny. Minimum viable population (MVP): Population viabilty analysis: BIOC63 Page 20 Midterm practice October 10, 2024 9:53 PM Definitions: Application questions: Conservation biology: Conservation Biology vs. Environmentalism Environmentalism: 1. Question: What is the main difference between conservation biology and environmentalism? Sustainability: the use of a resource without overexploiting it. ○ Application: Provide an example where conservation biology takes a scientific approach, while environmentalism focuses on political activism. Biological diversity: Traditional speciation: the divergence of one linage into two Biological Diversity Phyletic speciation: the evolution of one species into a ○ Application: How might inbreeding depression impact small, isolated populations in terms of genetic diversity? difference species over time Inbreeding depression impacts small isolated communities because It lowers rates of heterozygosity which uncovers deleteriousalleles. These deleterious alleles, can lower the overall fitness of a population, reducing survival, reproduction and cause an overall decline in individuals. Hybrid speciation: the combination of two linages into one As there are less individuals in the population, extinction vortex can cause the further lowering of population. Adaptive radiation: the rapid diversification of one linage into 1. Question: How does ecosystem diversity differ from species diversity? Provide examples. serval which occupy different niches. Ecosystem diversity describes the diversity of ecosystems themselves while species diversity describes the diversity of species within an ecosystem. Ring species: interbreeding of populations in a circular Speciation fashion but then, towards the end of the ring, the first 1. Question: Differentiate between traditional and phyletic speciation. population and the last population are so different that they Traditional speciation occurs when one linage splits into two while phyletic speciation occurs when one linage evolves into a different species overtime; there is however no splitting, its just the change within one species to another through time can no longer interbreed. 1. Question: Under what conditions might hybrid speciation occur, and why is it rare? Biological species concept: the categorization of species Hybrid speciation might occur when two species that can reproduce create a hybrid, third species. This is rare because hybridsurvival is rare. When a hybrid occurs, it is often not fit to survive in either of the parent environments and thus fails to reproduce with either of the parent based on their ability to interbreed and produce fertile species. offspring. Does not apply to fossils as we can not able to observe breeding between them and difficult to apply to Adaptive Radiation and Ring Species species with do not overlap allopatrically 1. Question: Describe adaptive radiation and give an example of an area where it has occurred. Evolutionary species concept: the categorization of species Adaptive radiation is the rapid expansion of one linage into many. This occurred in the Galapagos with Darwin's finches and occurred with beetles. based on genetic material. Vague as what percent of genetic ○ Application: How does adaptive radiation contribute to biodiversity? similarity constitutes a species? Depending on the perspective, adaptive radiation can either increase or decrease biodiversity. It could increase biodiversity because if there are few species in an environment, adaptive radiation could fill those unfilled niches. In the perspective of decreasing biodiversity, this could Morphological species concept: species that look alike and be the case if comparing the previous state of biodiversity compared to the 'current' where previously each niche was filled with multiple linages from different backrounds but each niche is now filled with different species of the same linage. likely the same species. Can be applied to fossils but its more 1. Question: What is a ring species, and how does it challenge the concept of species? difficult when it comes to cryptic species due to the fact that A ring species is one wherein populations reproduce and interchange genetics. However, the first and last population can not reproduce due to far different genetics. they look the same but are not genetically related. ○ Application: Use an example to explain how ring species show gradual speciation. Morphospecies: species on a waiting list that are waiting to A ring species could achieve gradual species because as the first and last populations in the ring fail to reproduce, the genetics will begin to deviate sufficiently to produce a different species all together. be categorized Species Concepts Background extinction rate: the historical rate of extinction 1. Question: Compare the Biological Species Concept (BSC) and the Morphological Species Concept (MSC). What are the pros and cons of each? Evolutionary significant units: The biological species concept states that a species is categorized by its ability to breed and produce viable offspring. The advantage is that the concept is simple and allows for concrete guidelines. A disadvantage is that the concept does not apply to fossils or species that never meet Mass extinction: an increased rate of extinction compared to in the wild. The morphological species concept states that a species is categorized by its appearance. An advantage is that it can be applied to fossils but a disadvantage is that it doesn’t take into account cryptic species. the background rate of extinction ○ Application: Discuss why the BSC might struggle to categorize asexual species, while the MSC could misclassify cryptic species. Provisioning services: services wherein a product is obtained The biologicals species concept might struggle to categorize asexual species and they do not reproduce sexually and thus there is no way to apply the theory to them. If an individual reproduces asexually, producing viable offspring doesn’t really constitute as an achievement. The such as food or water. morphological species concept could misclassify cryptic species because they look the same but genetically, they are dissimilar. So they may be grouped together morphologically but genetically should be groups apparent. Regulating services: benefits obtained from ecosystem 1. Question: What is the Evolutionary Species Concept (ESC) and how does it incorporate genetic variation into species classification? regulation such as climate control The evolutionary species concept is one wherein species are classified based on their genetic relatedness. Cultural services: non-material benefits obtained such as ○ Application: Why might genes involved in backcrossing complicate species classification under the ESC? spiritual Genes involved in backcrossing may affect the evolutionary species concept because the presence of another species genes may cause the lumping of the two species together when in reality, they are different species. Supporting services: services that are required to support provisioning services, regulating services and cultural services Extinction such as nutrient cycling 1. Question: Define the background extinction rate and contrast it with mass extinction. Living fossil: an incorrect term used to indicate that a species Background extinctions is the normal rate of extinction through time. The rate remains consistent whereas mass extinction is extinction that becomes statistically significant, far beyond the background extinction rate. is the only surviving linage from an older species. This term is Application: How does habitat destruction contribute to the current high extinction rates? should not be used due to the implication that the older Habitat destruction contributes to high extinction rates because as viable habitats are reduces, populations will decline leading to the extinction vortex. species and the modern one are genetically identical. From 1. Question: How does globalization contribute to the threats facing biodiversity, particularly through the introduction of invasive speci es? the past to the present, the species has evolved. Through globalization, travel from one location to another more often, the rate of new species introductions, either accidental or purposeful become more common. Through ships ballast water for example, organisms can travel very far from their nativehabitat and be introduced to Null model: the hypothesis that states that the biodiversity another location which may disrupt the native species in that habitat. found in the tropics is due to chance and that there is no Ecosystem Services particular reason for it. 1. Question: Describe the four categories of ecosystem services (Provisioning, Regulating, Cultural, and Supporting). Provide one example from each category. Mid domain hypothesis: a subset of the Null model that Provisioning services are those obtained directly from the environment such as food or fresh water. Regulating services are benefits obtained through the regulation of the ecosystem such as climate regulation. Cultural services are non-material benefits obtained from the states that generally when given a subset of boundaries, the environment such as spiritual. Supporting services are those required to maintain all other types of services such as nutrient cycling. highest amount of individuals will naturally gravitate to the Application: How does habitat loss directly impact both provisioning and regulating services in an ecosystem? middle by chance. First and formost, habitat loss reduces the amount of material resources available. If a forrest is logged, the variety fungi that used to grow on those trees can no longer be harvested. As for regulating servivces, if a wetland habitat is degraded orentirely desroyed, water purification Evolutionary hypothesis: the high amount of biodiversity in (regulating service) will be significantly reduced in that ecosystem. the tropics is explained by the higher rates of diversification. 1. Question: Explain why supporting services are foundational for all other ecosystem services. Due to every niche being occupied, when one niche is Supporting services enable all other services to function as they should. For example, nutrient cycling allows plants to grow, which increases primary productivity which may increase provisioning services. These provisioning services may influence cultural practices, etc. emptied, another species will take its place. Having a larger Application: Use soil formation or nutrient cycling to illustrate how the decline of supporting services can cascade through an ecosystem, affecting other services. land area and being climatically stable also has an impact If nutrient cycling declines, there wouldn’t be as much primary productivity which would reduce every other service. Historical hypothesis: the tropics, as one of the most long standing environments, has had more time to support more Species Accumulation Curve species 1. Question: What does a species accumulation curve represent, and why might it plateau at a certain point? Ecological hypothesis: the tropics can support higher life due A species accumulation curve is a representation of how many species may be in an ecosystem. It will plateau when no/few new organisms are found in that ecosystem. Higher rate of… ○ Application: In an experiment where microbial species are being counted, explain why a species accumulation curve might not reach a plateau. How would researchers approach this issue using relative measures instead of actual species counts? Mega thermal forest: large lush forests that used to cover the We will probably never be able to identify all species of bacteria, the accumulation curve will never plateau for that reason. We are always discovering new microbes. Instead of using a species accumulation curve, relative measures should be used wherein the same number of entirety of the earth individuals are counted in each community Species-energy hypothesis: Tropics conducive to plant life Living Fossils due to its climate and thus more primary productivity means 1. Question: Why is the term "living fossil" considered misleading? Provide an example that highlights this. more sugars means more species. The term living fossil should not be used because it not accurate to evolutionary discussions. The term is often used when one species is the sole surviving linage from a very old linage or when a species retains a lot of ancestral traits. In either case, evolution has occurred, the species Deterministic factors: non-random, predictable factors that are present currently, do not have the same DNA as the species living at an older time. One example for the first case is the coelacanth and an example for the second case the platypus. Stochastic factors: random factors Demographic uncertainty: the uncertainty found within Global Biodiversity Patterns populations wherein not every individual of that population 1. Question: Describe the latitudinal gradient of species diversity. How does this pattern vary in different groups like birds and amphibi ans? will have the same number of offspring so the population The gradient of biodiversity is that there is more organisms towards the equator and they start dissipating as you move towards the north. Mammals and amphibians all have higher diversity in the equator but some birds have higher diversity in the poles fluctuates randomly ○ Application: Explain why biodiversity tends to be higher in the tropics compared to the poles. Environmental uncertainty: random environmental There are 4 theories as to why biodiveristy might be higher in the polls. 1. The null hypothesis states that this is no particular reason for the higher diveristy, there just is. A subset of this is the mid-domain hypothesis wherein it just just so happens that within a bounded space, most occurrences like hurricanes species will overlap in the center. 2. evolutionary hypotesis states that there is higher amounts of diverisification in the tropics. When one species goes extinct another species will immediaty take its place. More land also means more space for larger population sizes. 2. Historical Genetic uncertainty: genetic drift, random changes in hypothesis wherein the tropics are said to have had more time to support the life it sustains. 4.ecological hypothesis wherein the carrying capasity is simply larger due to primary productivity (species-energy hypothesis) genetics overtime 1. Question: What is the longitudinal gradient of marine species diversity, and why are continental shelves more biodiverse than the deep ocean Stochastic extinction: we never know which species or which Continental shelves will likely have higher diversity due to higehr nutrients and more access to light compared to deep sea environments population will really go extinct ○ Application: How does primary productivity influence marine biodiversity? Provide an example involving coral reefs or oceanic continentalshelves. Extinction vortex: the effects that lead smaller populations to With more light, more plants can thrive which provides habitats for biodiversity to thrive. extinction Island Biogeography Theory Population viability 1. Question: What are the two main factors that determine the number of species an island can support according to the Island Biogeography Theory? Negative population regulation: individual fitness decreases Distance from the mainland and size of the island. with increasing population ○ Application: Use mountain peaks as an example of mainland habitats acting as islands. Explain how altitude might impact species diversitysimilarly to how island size and isolation affect species richness. Positive population regulation: individual fitness increases Mountains act as examples of mainland islands because the peaks can sometimes act as their own little ecosystem. with increasing population Inbreeding depression: the loss of genetic diversity obtained Species Diversity in Tropical Forests and Coral Reefs from inbreeding, loss of heterozygosity leading to uncovering ○ Application: Discuss why tropical forests are considered biodiversity hotspots, particularly for insects and plants. What environmental factors contribute to this diversity? of deleterious alleles Tropical forests are considered biodiversity hotspots because species are more likely to originate there and less likely to go extinct. They have larger land areas and more stable climates which produces higher percentages of primary productivity Extinct: completely extinct 1. Question: Why are coral reefs considered the most diverse aquatic biome? How do zooxanthellae contribute to this? Extinct in the wild: Extinct in the wild but not in, for example, Coral reefs are considered the most diverse aquatic biome because they support close to 1/3 of marine species while only covering 0.1 percent of earths surface. Zoozathalae support this by photosynthesizing for the coral which can lead It to increasing its size which can support captive breeding programs more organisms Extirpated: locally extinct ○ Application: Given that coral reefs cover only 0.1% of the Earth's surface but host one-third of all marine fish species, discuss the significance of their biodiversity and how human activities threaten coral reefecosystems. Regional extinction: extinct in one region but not another Human activities threaten corals reefs, first by disrupting the Ph of the water through acidification which causes coral bleaching. Then, through ecotourism, some people will take chunks out of the coral to keep for memories but that can put stress on the coral and if everyone does Ecological extinction: the number of individuals falls below a that, there will be no coral left. certain number in which they can not fulfill their role in the Population Dynamics ecosystem that they once did 1. Question: What is the difference between deterministic factors and stochastic processes in population dynamics? Endemism: they only naturally occur in one area Stochastic factors are random while deterministic factors are predictable Artificially rare: humans have made it so they are rare but ○ Application: Explain how both deterministic factors (like seasonal changes) and stochastic events (such as disease outbreaks) could impactthe population dynamics of a bird species in a temperate region. they were not before human intervention Stochastic events like desease outbeak could inflence bird populations by reducing the population size. Neo endemic 1. Question: What is demographic uncertainty, and how can it affect population size? Paleoendemic Demographic uncertainty is the unpredictability of how random birth numbers will affect a population. Not every individual in a population will have the same number of offspring and thus the population year to year will differ. Biodiversity hotspot ○ Application: Discuss how sewage dumping that alters the sex ratio in a fish population might lead to demographic uncertainty and affect the long-term viability of the population. High-irreplaceability areas: an area where there is so many Dumping sewage can cause some male fish to transition into female fish. This reduces the number of males in a population and causes all offspring sired to be from the few male fish available. This may cause inbreeding depression. endemic species that it is very protected. ○ Application: Analyze how an invasive species might create environmental uncertainty in an island ecosystem and describe the potential impacts on the native species. Population momentum: the population is growing when it Invasive species create environemental uncertainty by attering the ecosystem, cometing for resources with native species and predating on the native specie should be shrinking and shrinking when it should be growing. 1. Question: Define genetic uncertainty and give an example of how it might affect population dynamics. Although birth rate is shrinking, there are a lot of people in Genetic uncertainty is the flow of genetics though time, through genetic drfit their reproductive age. ○ Application: Explain how genetic drift can lead to increased extinction risk in small populations of endangered species, such as cheetahs. Fully additive effects : when adding effects together, they Genetic drift impacts small populations more than it does large ones. Deleterious alleles have more a chance of heading to fixation which can affect the fitness of a population. When the population reaches bellow a certain point, inbreeding depression will start to take effect which equal to their addition will uncover more deleterious alleles. Partially additive effects: when adding effects together, they equal less to their addition Stochastic Extinction Synergistic effects: when adding effects together, they equal 1. Question: Why is it nearly impossible to predict which species will go extinct due to stochastic extinction? more than their addition Because its all random Habitat loss: combination of habitat destruction, habitat ○ Application: Describe how decreasing habitat size and increasing environmental stochasticity might push a small mammal species into the "extinction vortex." degradation and habitat fragmentation By increasing environmental stochasticity, more random environmental effects will occur such as floods or hurricanes which creates a very disturbed environment where not many species let alone individuals can survive. Decreasing habitat size, if a species has a very large range can Edge habitat: the habitat on the edge on an ecosystem which put stress on them. When stochasticity increases and loss of habitat occurs, this isolates population which leads population sizes to decrease which will cause inbreeding depression, which will decrease heterozygosity which reduces overall fitness. contains different environmental factors and different 1. Question: How does increasing stochasticity raise the risk of extinction for a population? organisms inside. As a habitat gets fragmented, the Increasing stochasticity leads to more fragmented populations which causes more inbreeding which reveals more deleterious alleles which reduces survival. PROPORTION of edge habitat increases, not the actual ○ Application: In the context of climate change, discuss how increasing environmental stochasticity (e.g., extreme weather events) could increase population fluctuations and drive species towards extinction. amount. More hurricanes means smaller, more fragmented populations which increases inbreeding which reveals deleterious alleles which reduces fitness. Habitat fragmentation: the splitting of habitats by building Small Population Paradigm and Extinction Vortex roads for example. 1. Question: What is the extinction vortex, and why are small populations more prone to entering it? Habitat degradation: the disruption of a habitat through The extinction vortex is one where smaller populations are more venerable to stochastic effects and habitat loss and this leads them into spiralling into inbreeding. Smaller populations are more vunerable because they have less individuals to recoverfrom the stochastic events. incidences that may not be apparent but slowly disrupt the When large populations are hit, there are enough survivors and thus, enough genetic deiveristy to bounce back. If a population starts with 100 and falls to 50, there wont be enough genetic diversity, inbreeding will occur and the extinction vortex will begin. habitat. ○ Application: Evaluate how inbreeding depression and genetic drift can work together to drive a small population, such as the Florida panther, towards extinction. Habitat destruction: the wholesale clearing of a habitat Inbreeding depression will bring forward deleterious alleles that genetic drift may lead to fixation decreasing the fitness of the entire population. Shifting cultivation: slash and burn agriculture methods 1. Question: How does population size influence population viability? wherein entire fields and used and then abandoned leaving Increasing populations increases population viabilty while decreasing populations decrease population viability the soil unusable. ○ Application: Compare how a large population of elephants and a small population of pandas might differ in terms of population viability and risk of extinction. Desertification: the process of turning an ecosystem dry In terms of population vability, the larger a population is, the more likely it is to survive so, if the elephant population is larger, they have ahigher chance of surviving if only looking at size. If we take into account desease spread (negative population regulation) things might be Physical degradation: the degredation of an environment different. As the panada population is smaller, they are less likely to fall into the extinction vortex. through physical means. EX: building a road through a forrest Chemical degradation: the degradation of an environment Positive and Negative Population Regulation through chemical means. EX: increase in pesticide use 1. Question: What is the difference between negative and positive population regulation? Invasive species: an introduced species which becomes Negative population regulation states that as populations increase, individual fitness decreases whereas positive population regulation states that as population increases, invdividual fitness increases as well deterimental to the local system and outcompetes native ○ Application: Using the example of COVID-19, explain how population density affected the virus’s spread and how this relates to negative population regulation. fauna Diseases spread more when there are more people around so as popualtions increase, the more their individual fitness decreases because they have a higher chance of being infected with the virus. Introduced species: an exotic species which remains at a 1. Question: What is the Allee effect, and how does it relate to positive population regulation? stable population without disrupting local ecosystems Positive population regulation - the more a population increases, the more individual fitness increases as well. This is because of the allee effects, the allee effects list the positive advatages to increases population sizes such as mate availability, increases predator protection and Biomagnification thermoregulation, Eutrophication ○ Application: In an endangered population of penguins, describe how the inability to find mates due to low population density could lead toan Allee effect and further population decline. Biomanipulation If penguins arent able to find mates and the popualtion reduces to the point of falling bellow the threshold, then they will likely start inbreeding due to inabilty to find suitable mates, enter the extinction vortex and go extinct. Bottom up regulation Natural Selection and Genetic Drift Top down regulation 1. Question: What are the three key components of natural selection? Dead zone There is variation Acid rain: Nitrates mixed with water vapour The variation is heritable Photochemical smog: nitrates mixes with sunlight That variation can be positive or negative Genetic swamping ○ Application: Explain how natural selection might lead to the spread of a beneficial trait in a population of Darwin’s finches on the Galapagos Islands. BIOC63 Page 21 Eutrophication ○ Application: In an endangered population of penguins, describe how the inability to find mates due to low population density could lead toan Allee effect and further population decline. Biomanipulation If penguins arent able to find mates and the popualtion reduces to the point of falling bellow the threshold, then they will likely start inbreeding due to inabilty to find suitable mates, enter the extinction vortex and go extinct. Bottom up regulation Natural Selection and Genetic Drift Top down regulation 1. Question: What are the three key components of natural selection? Dead zone There is variation Acid rain: Nitrates mixed with water vapour The variation is heritable Photochemical smog: nitrates mixes with sunlight That variation can be positive or negative Genetic swamping ○ Application: Explain how natural selection might lead to the spread of a beneficial trait in a population of Darwin’s finches on the Galapagos Islands. Climate forcing Darwin's finches occupied many niches and the adaptations that they had each filled those niches. Orbital forcing 1. Question: What is a selection coefficient, and how does it measure the impact of genetic variation on fitness? Climate blowback Selection coefficient is the measure of individual fitness compared to the overall population. Overexploitation: ○ Application: A certain genetic variant in a population of deer increases the likelihood of survival by 20%. Calculate the selection coefficient for this variant and explain what it tells us about the variant's effect on fitness. S=0.2, this could indicate that rhe variant lives 20% less time or has 20% less offspring than the average of the population Inbreeding Depression and Extinction 1. Question: What is inbreeding depression, and how does it impact small populations? ○ Application: Analyze how inbreeding depression might have contributed to the decline of the Isle Royale wolf population and propose a management strategy to mitigate this issue. 2. Question: How can genetic purging occur in small populations, and what are its potential effects? ○ Application: Consider a small population of endangered frogs. Discuss how genetic purging might reduce the presence of deleterious allelesbut still leave the population vulnerable due to lack of genetic diversity. Extinction and Endemic Species 1. Question: What is the difference between extinction, extirpation, and regional extinction? ○ Application: Examine how habitat destruction in the Amazon could lead to the regional extinction of certain species without causing theirglobal extinction. 2. Question: What makes a species endemic, and why are endemic species often vulnerable to extinction? ○ Application: Discuss how neoendemic species like the Galápagos tortoises are at risk due to their limited geographic range and specializedhabitat requirements. 3. Question: What are biodiversity hotspots, and why are species in these areas often at higher risk of extinction? ○ Application: Analyze the conservation challenges of protecting a biodiversity hotspot like the Madagascar rainforests, focusing on the presence of high-irreplaceability areas. 4. Question: What factors make a species more vulnerable to extinction? ○ Application: Explain why large-bodied, K-selected species like the African elephant are particularly vulnerable to extinction compared to smaller, r-selected species like rodents. Mass Extinctions 1. Question: How are time periods in the fossil record linked to mass extinctions? ○ Application: Analyze how the climate changes associated with the Cretaceous–Paleogene extinction (when the dinosaurs went extinct) may have influenced the types of organisms that survived and thrived afterward. 2. Question: What distinguishes the current mass extinction from previous ones? ○ Application: Compare the causes of the sixth mass extinction, driven by human activities, with a previous mass extinction caused by natural events, such as the Permian extinction. 3. Question: Why have islands had the highest extinction rates over the past 350 years? ○ Application: Discuss how island ecosystems, like those in the Hawaiian archipelago, have been particularly vulnerable to species extinctions due to human activities such as habitat fragmentation and the introduction of invasive species. Anthropocene 1. Question: What is the Anthropocene, and when do most scientists believe it began? ○ Application: Evaluate the environmental impacts of both the Industrial Revolution and the Technological Revolution, and discuss how theseperiods of human activity contributed to the global biodiversity crisis we face today. 2. Question: How has human population growth changed over time, and what impacts does it have on biodiversity? ○ Application: Analyze how the shift towards commercial farming has impacted ecosystems, particularly in regions where monocultures and large-scale agricultural practices have replaced biodiversity-rich landscapes. 3. Question: What is population momentum, and why is it significant in the context of human population dynamics? ○ Application: Investigate a country where population momentum is occurring. Discuss why this phenomenon leads to unexpected increases in population despite low birth rates and the potential ecological implications. Seven Major Threats to Biodiversity 1. Question: What are the seven major threats to biodiversity, and how can their effects be additive, partially additive, or synergistic? ○ Application: Explain how habitat destruction, invasive species, and climate change could interact synergistically to accelerate the decline of amphibian populations in tropical regions. Habitat Loss 1. Question: What is habitat fragmentation, and how does it affect biodiversity? ○ Application: Examine the consequences of habitat fragmentation in the Amazon rainforest and discuss how edge effects might impact both theplant and animal species living in fragmented forest patches. 2. Question: What is the edge effect, and how does it influence species composition in fragmented habitats? ○ Application: Discuss how the construction of a highway through a forest could alter the species composition by creating new edge habitatsand leading to changes in local biodiversity. 3. Question: How does habitat fragmentation create barriers between populations, and what are the consequences for genetic diversity? ○ Application: Analyze how habitat fragmentation has affected the genetic diversity of the Florida panther and propose conservation strategies to reconnect isolated populations. 4. Question: What is metapopulation modeling, and how does it relate to habitat fragmentation? ○ Application: Apply metapopulation theory to a population of butterflies living in a fragmented landscape, identifying which habitat patches are likely sources of population growth and which are sinks. Habitat Destruction 1. Question: Why are rainforests and coral reefs particularly vulnerable to habitat destruction? ○ Application: Discuss the role that shifting cultivation and commercial logging have played in deforestation of the Amazon rainforest and the consequences for biodiversity and carbon sequestration. 2. Question: How do human activities such as slash-and-burn agriculture contribute to desertification? ○ Application: Examine how overgrazing and poor agricultural practices have led to desertification in the Sahel region of Africa and proposesolutions to mitigate this ongoing environmental degradation. Habitat Degradation 1. Question: What is habitat degradation, and what are its physical and chemical components? ○ Application: Evaluate how the use of pesticides and fertilizers in industrial agriculture has contributed to habitat degradation, particularly focusing on eutrophication in aquatic systems and its impact on fish populations. 2. Question: How did the use of DDT affect raptor populations, and what conservation measures were implemented to help these species recov er? ○ Application: Investigate how raptor species, like the peregrine falcon, were affected by DDT and discuss the success of captive breeding programs in reversing population declines. Invasive Species and Pathogens 1. Question: How do invasive species contribute to biodiversity loss? ○ Application: Provide an example of an invasive species, such as the Burmese python in the Florida Everglades, and describe how it has altered the local ecosystem and threatened native species. 2. Question: How do pathogens spread between humans and wildlife, and what are the implications for conservation? ○ Application: Analyze how the spread of zoonotic diseases, such as the transmission of pathogens between humans and wildlife, has contributed to species declines and disrupted ecosystems. Climate Change and Overexploitation 1. Question: How does global climate change threaten biodiversity? ○ Application: Assess how rising sea temperatures and ocean acidification have contributed to coral bleaching events and their impact on thebiodiversity of coral reef ecosystems. 2. Question: What is overexploitation, and how does it contribute to species extinction? ○ Application: Discuss how the overexploitation of marine species, such as bluefin tuna, has driven populations to critically low levels andpropose sustainable fishing practices to help recover these species. Biomagnification 1. Question: What is biomagnification, and what are the three main reasons why a substance increases in concentration as it moves up the food chain? ○ Application: Discuss how mercury biomagnifies in aquatic food webs, particularly in top predators like sharks, and the potential risks to both the ecosystem and humans consuming seafood. Water Pollution 1. Question: How does nutrient pollution lead to eutrophication, and what are the consequences for aquatic ecosystems? ○ Application: Analyze how nutrient runoff from agricultural practices has contributed to the formation of a dead zone in the Gulf of Mexico and propose potential solutions, including biomanipulation strategies. 2. Question: What is biomanipulation, and how can it be used to manage eutrophication? ○ Application: Provide an example of a wetland restoration project aimed at reducing nutrient pollution and explain how controlling nutrient inputs helps prevent algal blooms. Air Pollution 1. Question: How does acid rain form, and what are its effects on ecosystems and primary productivity? ○ Application: Investigate how acid rain has affected a particular forest ecosystem, such as the Appalachian Mountains, and what measures ha ve been taken to mitigate its impact on trees and aquatic organisms. 2. Question: What is photochemical smog, and what are its environmental and health effects? ○ Application: Discuss the impact of ground-level ozone on urban plant species and human health in a major city like Los Angeles, and analyze the effectiveness of polici es like the Clean Air Act in reducing smog. Fire Suppression and Habitat Degradation 1. Question: Why is fire suppression a problem in certain ecosystems, and how does it lead to habitat degradation? When fires arent set, large trees grow, leaving no light for grasslands (which can sustain fire because they grow from the root). Then when they are set, the trees are set on fire and snowballs into wildfires. ○ Application: Explore how fire suppression in Mediterranean climates has altered the natural landscape, leading to more severe wildfires, a nd explain how controlled burns are used as a management strategy. 1. Question: How do fire-tolerant plants benefit from periodic fires, and what happens when fires are suppressed? ○ Application: Discuss how fire suppression has affected grassland ecosystems in California and what role indigenous fire management practic es might play in restoring these habitats. Invasive Species 1. Question: What is the difference between introduced species and invasive species? Introduced species do not outcompete native species while invasive species outcompete the native species Question: How does ecological release contribute to the success of invasive species? Ecological release states that invasive species are successful because they experience an ecological release from their native predators. They not longer have predators that are found in their introduced range and thus have more energy to allocate togrowth or reproduction ○ Application: Analyze how the introduction of the brown tree snake to Guam led to the decline of native bird populations and altered the is land's ecosystem due to the absence of natural predators. It is likely that the snake began to overconsume the bird species leading to their decline Causes of Invasive Species Introduction 1. Question: What are some of the main causes of invasive species introduction, and how do they contribute to biodiversity loss? a) Introduction by european colonizers b) Accidental introduction c) from aquaculture or farming d) For biocontrol 1. Question: How does aquaculture contribute to the spread of genetic pollution? Aquafarming creates environments that leads the fish to inbreed and there are so many in the area that disease spreads very e asily. ○ Application: Investigate how escaped farmed salmon have interbred with wild salmon populations in the Pacific Northwest, and discuss the e cological and genetic consequences of this hybridization. Farmed salmon are genetically inferior to wild salmon due to small farming spaces and inbreeding so when they interbreed, the faulty genetics of farmed salmon integrate itself into the genetics of the wild salmon so that the deleterious alleles are no w present in the wild salmon. 1. Question: What is biological control, and how can it be both a solution and a potential problem when managing invasive species? Biological control is that of an environemt using biotic methods. Either the introduction of a predator in an invasive specie s native range to control that native species, etc. ○ Application: Provide an example of a biological control attempt, such as the introduction of the cane toad in Australia, and analyze why i t failed to control pests and became an invasive species itself. The introduction of cane toads to Australia is an example of top down control wherein the introduction of the toads was used to control the population of another native species. This aproach failed because the cane toads just became an invasive speci es themselves, eating all the native species Genetic Swamping 1. Question: What is genetic swamping, and how does it affect native species? Genetic swamping occurs when a closely related species of a native species interbreed togther and the native species geneticsbecome muddled ○ Application: Discuss how hybridization between native red wolves and introduced coyotes in the southeastern United States has led to conce rns about the loss of the red wolf's unique genetic identity. The genetics of the coyetees probably started to overtake those of the wolf. BIOC63 Page 22