Ecology Unit - AP Biology Notes.pdf

Ethology *Ethology: study of animal behavior *Behavior: what an animal does and how it does it; genetic and environmental factors cause; needed for survival and reproduction - Changes due to natural selection *Behavioral Ecology: study of the ecological and evolutionary basis for animal behavior...

Ethology *Ethology: study of animal behavior *Behavior: what an animal does and how it does it; genetic and environmental factors cause; needed for survival and reproduction - Changes due to natural selection *Behavioral Ecology: study of the ecological and evolutionary basis for animal behavior *Proximate Cause: describes a behavior and “how” it occurs *Ultimate Cause: “why” behavior happens in the context of natural selection/reproduction Innate Behavior *Innate Behavior: developmentally fixed; not learned; expressed in most of population *Fixed Action Patterns: not learned actions (innate); connected to a sign stimulus; unchangeable - Triggered by a sign stimulus → makes sure that necessary actions are done without practice *Kinesis: random movement; how fast random movement is to increase chances of moving in an environment they like *Taxis: oriented/automatic movement; towards or away from stimulus *Migration: innate behavior; regular and long distance movement; WHOLE community moves *Circadian Rhythm: internal biological clock - Long Cycle: maintains 24 hr cycle; find position relative to the Sun or magnetic field - Short Cycle: activity and rest synchronized with light and dark environment *Circannual Rhythm: behavioral rhythms associated with the yearly cycle of seasons; influenced by periods of darkness and light in an environment *Signal: creates a change in behavior; animal communication - Pheromones: chemicals that affect species - Visual: bee wiggle and warning flash - Tactile: touch; Male fruit flies tap female flies to mate - Auditory: screech of blue jay - INNATE BEHAVIOR Learned Behavior *Learned Behavior: behaviors modified based on specific experiences *Young-Fostering Study: young of one species is placed into the care of adults from another species in the same or similar environment - Amount the offspring’s behavior changes → how much social and physical environment affect their behavior - Characteristics can change behavior of generations (mice leaving their children) *Twin Study: the influence of genetics and environment on behavior; identical twins grown up in different households and compare *Habituation: loss of responsiveness to stimuli; birds not being afraid of humans in NY - Simple learning *Imprinting: learning and innate; limited to a sensitive period and irreversible; allows for bonding to occur (pair bond) - Ultimate Cause: higher success of offspring surviving (reproduction success) *Spatial Learning: Cognitive Maps → remember certain locations/resources based on landmarks *Associative Learning: associate one environmental feature to another (bright color = bad taste) - Classical Conditioning: random stimulus doesn’t have to match response (ring bell = dog salivating) - 100% learned behavior *Operant Conditioning: type of associative learning; trial and error → associate OWN behavior to a reward or punishment *Cognition: process of knowing; involving awareness, reasoning, recollection, and judgment - Problem Solving Behavior needs cognition *Social Learning: learning by observing others - Forms culture: sharing information through social learning and teachings; influence the behavior of individuals in a population - Alter behavioral phenotypes and influence fitness of individuals Food and Reproduction *Foraging: getting food behavior; recognize, capture, and consume food; minimize cost of energy and max benefits of food - Lowest amount of attempts to get food etc. *Sexual Selection: seeking, attracting, choosing, and competing for mates - Ornaments: health and vitality *Agonistic Behavior: settle disputes over resources (mates) *Sexual Dimorphism: extent to which females differ from males in appearance - Monogamous species look very similar - Polygamous species have shower sex that those of the other sex *Intersexual Selection: members of one sex chose their mate based on their characteristics *Intrasexual Selection: competition between members of one sex for mates *Lower Certainty of Paternity: less investment the males can give to offspring *Promiscuous Mating: no strong pair bonds between animals; greater reproductive success; lower certainty of paternity *Monogamous Mating: relationship M/F; higher certainty of paternity *Polyamous Mating: one sex is mating with many of another sex; greater reproductive success; lower certainty of paternity - Polygny = single male and many females - Polyandry = single female many males Kin Selection *Antidiuretic Hormone (ADH): known as vasopressin; a peptide that binds to a specific receptor in the CNS - Helps form pair-bonds after mating *Altruism: selfless behavior; reduces individual fitness; increases fitness of population *Inclusive Fitness: total effect of an animal in spreading its genes + helping close relatives *Kin Selection: type of natural selection; altruistic behavior; increasing reproductive success of relatives - Ex. sacrifice their own lives so that closely related organisms can live *Coefficient of Relatedness: r; fraction of genes that are shared on average - Hamilton’s Rule: natural selection will favor altruism if the saved have a high coefficient of relatedness to the organism and how many offsprings the saved can make → rB > C - B= how many offsprings can be made if saved - C= cost of altruistic act on organism Ecological Hierarchy *Ecology: scientific study of interaction between organisms and the environment - Biotic Influences: living organisms, their behaviors and interactions with others - Abiotic Influences: nonliving; temp, water, salinity, sunlight, and soil *Hierarchy (Highest at the top) - Biosphere: global ecosystem - Landscape: connected ecosystems - Ecosystem: community of organisms and physical factors - Community: populations of different species in an area - Population: population of a species living in an specific area - Organisms Climate *Climate: long-term weather conditions in an area - Temperature + Precipitation + Sunlight + Wind *Microclimate: small scale environment variation *Macroclimate: seasonal, regional, or local level *Climate Change: some species may not survive shifting ranges *Global Climate Patterns Depend on: - Sunlight Intensity: latitudinal variation - Air Circulation and Precipitation Patterns - Ocean Currents - Mountains that affect rainfall Types of Biomes *Biomes: major types of ecosystems that occupy very broad geographic regions - Climate, elevation determine what type *Climograph: plot of temperature and precipitation in a particular region - Desert: low precipitation and high temperature - Temperate Grassland: medium precipitation and low to high temperature - Tropical Forest: high precipitation and medium temperature *Disturbance: event that changes a community and removes organisms from it; alters resource availability - Storms or human made disturbance *Types of Biomes: Tropical Rainforest, Desert, Savanna (Kenya), Chaparral (mountains with greens), Temperate Grasslands, Northern Coniferous Forest (green evergreens), Temperate Broadleaf Forest (NY), Tundra (no trees), Lakes, Wetlands, Streams, Rivers, Estuaries (fresh mix with salt), Intertidal Zones, Oceanic Pelagic Zone (Open Water), Coral Reefs, Marine Benthic Zone (deep sea and hydrothermal vents) *Thermocline: an abrupt change in temperature; oceans and lakes; separates upper, warmer layer from colder, deeper layer Biogeography *Biogeography: geographic distribution of a species - Factors: - Dispersal: movement away from origin - Behavior: habitat type - Biotic Factors: other species, food resources, competition, predators, pollinators - Abiotic Factors: temp, water, oxygen, salinity, sunlight, rocks and soil *Territoriality: the defense of a bounded physical space against encroachment by other individuals Dispersion of Population *Population: group of individuals of a SINGLE SPECIES living in the same general area - Density= # of organisms/area - Dispersion: pattern of spacing between individuals *Patterns of Dispersal: - Clumped: most common; near resource - Uniform: competitive interactions - Random: unpredictable spacing; not common in nature Survivorship Curve *Survivorship Curve: represents # of individuals alive at each age  - Type 1: low death rate initially (flat line and curve down) - Type II: constant death rate over lifespan (negative linear) - Type III: high death rate early in life (down curve and flat out at x-axis) Types of Populations and their Growth *Exponential Population Growth: ideal conditions, population grows rapidly - r= intrinsic rate of increase *Logistic Model: incorporates carrying capacity and stagnates - K=max stale population *Life Table: summarizes the survival and reproduction rates of individuals in a specific age group of a population - Cohort: group of individuals of the same age that are followed from birth to death *K-Selection: population is close to carrying capacity *R-Selection: maximum reproductive success; exponential growth, no care, high birth numbers, poor survival of young, density independent - Ex. cockroaches Factors Limiting Population Growth *Life History: traits that affect an organism’s time of reproduction and survival *Density-Dependent Factors: population matters *Density-Independent Factors: population is NOT a factor *Population Dynamics: populations fluctuations from years and places; influenced by many factors and affect other species *Metapopulation: local populations are linked; heavily affected by immigration and emigration Interspecific interactions *Interspecific Interactions: positive, negative, or neutral to organisms *Competition: -/-; two or more species compete for the same short supply resource *Exploitation: - Predation: +/-; one species kills and eats another → mimicry adaptation - Herbivory: +/-; herbivore eats part of a plant/alga → plants have chemical defenses and herbivores developed specialized adaptations *Symbiosis: individuals live in close contact with one another - Parasitism (+/-); parasite gets its nutrients from a second organism (the host) which is harmed - Mutualism (+/+); both species benefit - Commensalism (+/0); one species benefits and the other is unaffected *Facilitation: +/+ or +/0; species have positive effects on the survival/reproduction of the other species without intimate contact of symbiosis *Interspecific Competition: resources are in short supply - -/- *Competition Exclusion Principle: two species cannot coexist in a community if their niches are identical - One with a slight reproductive advantage will eliminate the other *Resource Partitioning: differences in niches that allow similar species to coexist *Ecological Niche: sum of the total amount of abiotic/biotic resources an organism uses - Fundamental Niche: niche potentially occupied by the species - Realized Niche: portion of fundamental niche the species actually uses - Ex. Chthamalus would use all of the shore (fundamental niche), but Balanus takes up part of the shore in reality → Chthamalus realized niche is smaller than fundamental niche Predation *Defense Adaptations - Cryptic Coloration: color camouflage - Aposematic/Warning Coloration: bright color of poisonous animals - Batesian Mimicry: harmless species mimic color of harmful species - Mullerian Mimicry: 2 bad-tasting species resemble each other; both will be avoided - Herbivory: plants avoid this by chemical toxins, spines, and thorns Community Structure *Species Diversity = Species Richness (# of different species) + relative abundance of each species *Simpson Diversity Index: calculate Species diversity based on species richness and relative abundance *Highly diverse communities are more resistant to invasive species - Invasive Species *Invasive Species: organisms that become established outside of native range *Kudzu: vine plant from Japan, noxious weed taht kills trees and shrubs *Dutch Elm Disease: fungus carried by beetles - Arrived to U.S. on logs from Netherlands - Death of many elm trees across U.S., Europe, and Canada - Try to cultivate resistant strains of elm trees *Potato Blight: fungus disease caused Irish Potato Famine in 1840s - Arrived in Ireland from ships coming from the U.S. - Only 1 species of potato planted in Ireland → all where susceptible to disease  - 1 million people died - Problem with monoculture and lack of genetic diversity Trophic Structures *Trophic Structure: determined by the feeding relationships between organisms *Trophic Levels: links in the trophic structure *Food Chain: transfer of food energy from plants → herbivores → carnivores → decomposers *Limiting Factors to Length of Food Chain: - Inefficiency of energy transfer along chain - Long food chains less stable *Food Webs: two or more food chains linked together - Species may weave into the web at more than one trophic level → secondary consumers eating primary and producers *Dominant Species: has the highest biomass or is the most abundant in the community *Keystone Species: exert control on community structure by their important ecological niches - Loss of sea otter → more sea urchins, less kelp forests - Less Grizzly Bear → less nutrient transfer - Prairie Dogs → keeps environment trim Ecological Transitions *Disturbance: removes organisms or changing resource availability *Ecological Succession: transitions in species composition in a certain area over ecological time *Primary Succession: plants and animals invade where social has not formed yet - Colonization of volcanic island or glacier *Secondary Succession: existing community is cleared by a disturbance that leaves soil intact - Abandoned farm, forest fire Biogeographic Factors *Biogeographic Factors: 1. Latitude: species more diverse in tropics 2. Area: larger areas are more diverse *Biogeographic Islands: natural labs for studying species diversity - Influenced by size and distance from mainland - Larger islands → more immigration, lower extinction - Far from mainland → immigration falls, increase extinction *Ecosystem: sum of all organisms living within its boundaries (biotic community) AND abiotic factors that are interacted with - Energy Flow - Chemical Cycling Energy Flow in an Ecosystem *Energy CANNOT be recycled → must be constantly supplied by Sun *Autotrophs: primary producers; photosynthetic (plants and algae) - Use light energy to create sugars and organic compounds → inorganic to organic *Heterotrophs: can’t make their own food - Trophic levels above primary producers → depend on producers photosynthetic output *Primary Consumers: herbivores eat primary producers *Secondary Consumers: carnivores that eat herbivores *Tertiary Consumers: carnivores that eat secondary consumers *Detritivores or Decomposers: important group of heterotrophs; get energy from detritus (nonliving organic material) → important to material cycling - Fungi and prokaryotes Primary Production *Primary Production = amount of light energy converted to chemical energy - Affected by light availability and nutrient availability - Temperature and moisture control it *Gross Primary Production (GPP): total primary production in an ecosystem *Net Primary Production (NPP): gross primary production (minus) energy used by primary producers for respiration ® - NPP = GPP - R *NPP: storage of chemical energy available to consumers in an ecosystem *Eutrophic: nutrient rich lake supporting algae growth Trophic Level Energy Transfer *Energy transfer between trophic levels is only 10% efficient *Production Efficiency: only fraction of E stored in food - Energy used in respiration lost as heat **ENERGY FLOWS within an ecosystem** *Ecological Pyramids: gives insight to food chains; loss of energy limits number of top level carnivores - Most food webs only have 4-5 trophic levels *humans would get more energy through plants rather than eating animals Biogeochemical Cycles *Biogeochemical Cycles: nutrient cycles that contain biotic and abiotic components - Organic → inorganic parts of an ecosystem *Carbon Cycle: CO2 removed by photosynthesis and added by burning fossil fuels *Nitrogen Cycle:  1. Nitrogen Fixation - N2 → ground → nitrogen fixing bacteria 2. Nitrification: - (by nitrifying bacteria) Ammonium → nitrite → nitrate - Absorbed by plants 3. Denitrification - Remaining Nitrate → N2 (by denitrifying bacteria) - Release N2 into atmosphere *Phosphorus Cycle: - Largest Source: marine sediments - Made Available: weathering and erosion; absorbed by plants from soil - Inorganic Phosphate: PO4 Restoration Ecology *Bioremediation: use of organisms to detoxify polluted ecosystems *Bioaugmentation: introduce desirable species to add essential nutrients *Biggest Threats to Biodiversity: habitat alteration, fragmentation, and destruction *Extinction Vortex → introduce new individuals from other populations of the same species to increase genetic diversity *Biological Magnification: toxic chemicals in the environment pose a greater risk to top-level predators than to primary consumers