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Lecture 2,3,4,5
Ecology 2,3,4,5
| Question | Answer |
|---|---|
| Ecology | Interactions between organisms and their biological (biotic) and physical (abiotic) environments. |
| Homeostasis | Keep conditions within a safe or normal range. |
| Stochasticity | Randomness |
| Microcosms | Simplified systems used to study ecology |
| Proximate Factors | What caused it and how? |
| Ultimate Factors | Why is it evolutionary beneficial? |
| Species | Group of potentially interbreeding individuals that's reproductively isolated from other groups. |
| Population | Group of interbreeding individuals of the same species that inhabit the same geographic area. |
| Uniformitarianism (by Lyell) | Earth was shaped by slow-moving forces still in operation |
| Gene Pool | Entire set of alleles in a population |
| Evolution | Change in allele frequencies over time |
| Mutation | A change in the nucleotide sequence of DNA. The ultimate source of genetic variation. Most are harmful. |
| Adaptive Evolution | Results in the contributions of other individuals. |
| Directional Selection | Favors one extreme, curve shifts one side. ONE direction |
| Stabilizing Selection | Extreme phenotypes are removed, favors intermediate/average traits. STABLE-stay in the middle |
| Disruptive Selection | Favors both extremes, middle is removed. DISRUPT=split apart into two peaks |
| Genetic Drift | A change in the gene pool/allele frequencies due to chance. Especially in small populations |
| Bottleneck Effect | A natural disaster unselectively kills most individuals in a population. The surviving population has less genetic variation. |
| Inbreeding Depression | Mating between closely related individuals that increases homozygosity, decreases heterozygosity, and raises the risk of recessive genetic diseases and extinction, especially in small populations. |
| Founder Effect | Genetic drift is likely when individuals colonize an isolated habitat. |
| Gene Flow | Migration between populations can change allele frequencies. |
| Large populations are more susceptible to... | genetic stability against random change |
| Smaller populations are more susceptible to... | genetic drift . |
| Hardy-Weinberg Equilibrium | Genotype frequencies in a population in which allele frequencies are not changing through time. p=dominant allele q=recessive allele p+q=1 |
| Genotype frequencies | P^2=AA 2pq=Aa Q^2=aa P^2+2pq+q^2=1 |
| Natural Selection | Individuals with traits that improve survival/reproduction leave more offspring, causing those traits to become more common. |
| Fitness (W) | Relative reproductive success of a genotype |
| Adaptive Landscape | shows relationships between allele frequencies and mean population fitness. |
| Heritability (h^2) | Within a population, traits are varying due to genetic differences. |
| Breeder's Equation | R=h^2S r- response to selection h^2- narrow-sense heritability S-selection differential |
| Intraspecific Variation | Differences among individuals or populations of the same species. |
| Sources of variation | Genetic and environmental |
| Local adaptation | When a population EVOLVES traits that increase survival/reproduction in its local environment |
| Phenotype | Genetics+Environment+ GxE (interaction between genetics and environment) |
| Phenotypic plasticity | Ability of an organism to change its traits, behavior, or physiology in response to environmental conditions without changing its DNA |
| Acquired Traits | Result from an individual's experiences/environment (not genetically inherited) Physical- damaged tail Behavioral- learned behaviors |
| Tolerance range | Range of environmental conditions an organism can survive. (lower limit, optimal range, upper limit) |
| Temporal Environmental Variation | Environmental conditions can change over time. the more constant, the easier to adapt to. |
| Avoidance (stay away from it) | Avoid exposure to harsh conditions. Migration, resting, reproduction timing |
| Tolerance | Remain exposed but survive within environmental limits. Salt, water, temperature/water tolerance. |
| Evolutionary Trade-Off | An adaptation provides a benefit but also has a cost Migration- benefits: access to food costs: exposure to predators |
| Principle of Allocation | Resources are limited, so investing in one function leaves fewer resources for others. ex: adaption to extreme heat reduce ability to tolerate extreme cold |
| Physical constraints | Organisms must obey the laws of physics |
| Historical constraints | Evolution works with structures and traits that already exist |
| Temperature | Measure of average kinetic energy of molecules |
| Temperature affects | Enzyme activity, biological reaction rates, water loss/availability |
| Macroclimate | Large-scale, long-term patterns of weather/climate |
| Microclimate | Small-scale differences in environmental conditions within a local area. Under vegetation, rocks, in shaded areas |
| Factors affecting microclimates | Altitude, aspect (direction a slope faces), Albedo (how much radiation a surface reflects) |
| Burrows | Can create unique microclimates and are often cooler because of soil moisture. |
| Water temperature changes more slowly than air temperature. Why? | Water has a high specific heat (high thermal inertia). |
| Organismal Temperature | Determined by the balance between heat gained and heat lost. |
| Organisms respond to heat by | Changing heat exchange (physiological, morphological, behavioral) and tolerating changes in internal temperature. |
| Conduction | Heat transfer through direct, two bodies in contact |
| Emissivity | Heat transfer through electromagnetic radiation (bodies not in contact) |
| Convection | Heat transfer between an object and moving air/water |
| Evaporation | Heat loss when water evaporates |
| Animal body temp regulation: Poikilotherm | Body temp varies substantially with environmental temperature. (most ectotherms) |
| Animal body temp regulation: Homeotherm | Body temperature stays relatively stable/within narrow limits. most birds and mammals. |
| Animal source of heat: Ectotherm | Obtains heat from external environment (reptiles, fish, invertebrates' behavior and their environmental choices maximizes performance) |
| Animal source of heat: Endotherm | Generates heat through internal metabolism. Greater temp difference -> faster heat loss |
| Newton's Law of Cooling | Rate of heat loss is proportional to difference between body temp and environ. temp |
| Surface Area | Controls heat exchange, volume relationship varies with body size |
| Volume/Mass | Stores and generates heat |
| Small endotherms have a ___ time maintaining body temperature | harder |
| Bergmann's rule | Endotherms have large body sizes in colder climates and smaller body sizes in warmer climates |
| Insulation | Reduces heat loss by trapping air and reducing heat transfer. skin, feathers, fur, blubber |
| Circulatory adaptations: Vasodilation | Blood vessels in skin increases/widen, facilitating heat loss |
| Circulatory adaptations: Vasoconstriction | Blood vessels decreases/narrow, lowering heat loss |
| Contercurrent circulation | Arteries and veins run close together so heat can transfer between them. |
| Evaporative cooling | Water evaporation removes heat from the body |
| Metabolic heat | Animals can increase heat production through shivering and increased metabolic activity. especially in cold environments to minimize heat loss |
| Antifreeze Molecules/Proteins | Slows formation of bonds between water molecules, prevent/slow ice crystal formation |
| Heat-shock proteins | Proteins produced during heat stress that help protect and stabilize cellular proteins |
| Torpor | A reversible reduction in metabolic activity and body temp that conserves energy. Animals must use stored energy to exit torpor. |
| Hibernation | Long-term torpor, usually during winter. Facultative (when conditions require it) and Obligate (part of normal life cycle) |
| Estivation | Summer torpor used to survive high temp, dry conditions, limited water. |
| Daily torpor | Short term lasting part of a day. |
| Temp adaptations in plants | Morph, physio, behavioral adaptations/responses |
| Cold adaptations in plants (arctic/alpine plants) | Increase radiative heating (absorb more solar radiation) Decrease convective cooling (reduce heat loss to moving air) |
| Heat adaptations in desert plants | Limited soil water -> less transpiration -> less evaporative cooling |
| Plants can avoid unfavorable seasons through | dormancy buds/seeds |
| Thermoneutral zone | Endotherm maintaining body temperature without extra metabolic adjustment. |
| Organismal Ecology | Individual organisms interact with their environment. |
| Community Ecology | Interactions among populations of different species living together |
| Ecosystem Ecology | Biotic communities and their abiotic environment. |
| Measures of Central Tendency | Mean, median, mode |
| Mark Recapture Method | Estimating population size by marking individuals, releasing them, and later recapturing a sample to see how many are marked. |
| Lincoln-Peterson Index | Estimates population size using 2 samples |
| Smaller number of recaptures-> | larger estimated population |
| Bailey's Correction | A modification designed to improve the estimate when the basic lincoln-peterson assumptions make the original estimate less reliable. |
| Evolutionary adaptation | The population becomes better suited to its environment over generations. Describes WHAT results from natural selection |
| Darwin's Argument | 1. Variation 2. Overproduction 3. Limited resources 4. Differential survival/reproduction 5. Heredity + change |
| Relative fitness | Contribution an individual makes to the gene pool of the next generation relative to the contributions of other indiviudals. |
| Natural selection CANNOT fashion perfect organisms (evolution of organisms is constrained) | 1. Existing variations 2. Historical constraints 3. Compromises 4. Chance+environment 5. No long term goal |
| Hardy-Weinberg Equilibrium Assumptions | No natural selection Very large population → no genetic drift Random mating No gene flow No mutation |
| Quiz question: what are adaptations used by animals to TOLERATE hot or cold temperatures in their environment? | Adjusting metabolic heat, heat shock proteins, insulating fur or fat, countercurrent exchange in circulatory system... NOT MIGRATION (since migration is avoidance) |
| Quiz question: As body size increases, there is an... | increase in metabolic rate, a decrease in metabolic rate per kilogram of body mass, and decrease in surface area-to-volume ratio. |
| Quiz question: An ectothermic poikilotherm might need to bask in the sunlight for a few hours every morning before its body temp is high enough to forage for food. TRUE OR FALSE | True |
| Quiz question: Acclimation | An individual organism ADJUSTS to a new environmental condition during its lifetime. No genetic change is require |
| Quiz question: If a plant cell increases the concentration of solutes in its cytoplasm, the cell's water potential decreases. TRUE OR FALSE | True |
| Thermogenic plant | Metabolic heat production (mitochondrial activity) |
| Water Vapor Density | Amount of water vapor per unit volume of air |
| Saturation Water Vapor Density | Maximum amount of water vapor air can hold. Increases as temperature increases. |
| High Relative Humidity | Air contains more water -> less evaporation |
| Low Relative Humidity | Air is drier -> more evaporation |
| When RH is less than 98%, | atmospheric water potential is very low |
| Two major challenges for terrestrial organisms | 1. Evaporative water loss 2. Limited access to replacement water |
| Evaporation cools organisms, but it also causes | water loss |
| Freshwater | Low osmolarity, hypotonic organisms |
| Seawater | High osmolarity, hypertonic organisms |
| Terrestrial challenges | Prevent water loss |
| Freshwater challenges | Prevent excess water from entering |
| Marine challenges | Prevent water loss to salty environment |
| Lichens | Poikilohydric (water content changes with environmental conditions). Can tolerate periods of drying. |
| Factors affecting microclimates: Altitude | Higher altitude-> lower temperature |
| Factors affecting microclimates: Aspect | Direction a SLOPE faces. changes the amount of sunlight received. |
| Factors affecting microclimates: Albedo | Dark SURFACES-> absorb more energy. Proportion of incoming light that is reflected. Snow->high albedo->reflects more energy |
| Water potential | Water moves from high water potential to low water potential |
| Pure water: ψ = | 0 MPa |
| Solute potential (ψsolute) | Dissolved substances lower water potential. more solute->more negative |
| Matric potential (ψmatric) | Water attracted to surfaces through adhesion/cohesion. |
| Pressure potential (ψpressure) | In plants, negative pressure can result from transpiration. |
| Root development | Root systems often reflect water availability. Deep roots are advantageous when water is deeper in the soil. |
| Morphological adaptations: Reduced leaf area → | less surface for water loss |
| Morphological adaptations: Deep roots→ | access deeper water |
| Morphological adaptations: Water storage → | stores water for dry periods |
| Morphological adaptations: Thick leaves → | reduce water loss |
| Morphological adaptations: Suberization → | Suberin creates a waterproof barrier |
| Morphological adaptations: Few stomata → | reduces water loss |
| Succulence | Increased osmolarity helps retain water in tissues. |
| C3 Plants (least specialized for hot/dry conditions) | Hot conditions -> increased evaporation -> stomata close. Closing stomata causes: decrease of co2 and photosynthesis. increase of o2 and photorespiration. |
| C4 Plants (Spatial separation) | Adaptation to hot, dry conditions. Can partially close stomata to conserve water. CO2 is initially captured in mesophyll cells. Calvin cycle occurs in bundle-sheath cells. |
| CAM Plants at night (temporal separation) | Stomata open, CO2 enters, CO2 is stored as organic acids. |
| CAM Plants during the day (temporal separation) | Stomata close, CO2 is released from organic acids, CO2 enters the calvin cycle. |
| Plants can avoid drought stress by: | Synchronizing growth with wet periods *Drought deciduousness (dropping leaves during drought) *Desert annuals (complete life cycle during wet periods) *Dormancy (temporarily stop growth/activity) |
| Metabolic water | produced during cellular respiration |
| More water vapor in air-> and why? | Less evaporation. Smaller water vapor gradient between organism and environment |
| High Vapor Pressure Deficit | Dry air-> more evaporation |
| Low Vapor Pressure Deficit | Humid air-> less evaporation |
| Water conservation | Behavior, anatomy, kidney adaptations |
| Nephron | Main functional structure of the kidney. |
| Loop of Henle: Descending limb | Permeable to water, water leaves the tubule, urine becomes more concentrated. |
| Loop of Henle: Ascending limb | Not permeable to water, NaCl (salt) leaves the tubule->helps create the kidney's osmotic gradient. |
| Collecting duct | Water is reabsorbed as fluid moves toward the inner kidney. Produces highly concentrated urine. |
| Kangaroo Rat | Maximizes kidney's osmotic gradient. Produces extremely concentrated urine and minimizes water loss. |
| Waste: Ammonia | Most toxic, most water needed |
| Waste: Urea | Intermediate toxicity, moderate water needed |
| Waste: Uric acid | Least toxic, least water needed |
| General Water-Conservation Strategies in Terrestrial Animals | Waterproof outer coverings Concentrated urine Dry/concentrated feces Behavioral adaptations → nocturnal activity, sheltering, etc. |
| Isosmotic | Internal and external solute concentrations are equal. |
| Osmoconformer | Internal water/solute concentration changes with the environment. |
| Osmoregulators | Maintains internal water and solute concentrations/balance within narrow limits. -Actively controls despite outside salinity |
| Hyperosmotic | Environment has higher solute concentration than body fluids. |
| Hypoosmotic | Environment has lower solute concentration than body fluids. |
| Marine Fish | Hyperosmotic relative to their body fluids. Marine = drink + dump salt |
| Freshwater Fish | Hypoosmotic relative to their body fluids. Dump water + grab salt |
Created by:
Brookelol