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75 Cards in this Set
- Front
- Back
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What is Ecology?
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Study of the relationship between organisms and their environment
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What is a relationship?
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Interactions with physical and biological components
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What is an environment?
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Everything that affects a living organism
includes non-living and living factors. |
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What is a population?
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Population: group of individuals of a single species inhabiting a specific area
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What is an ecological community?
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Ecological community: association of interacting species living in a particular area
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What is an ecosystem?
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Ecosystem: a biological community plus all of the abiotic factors influencing
that community |
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What is a landscape?
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Landscape: an area of land containing a patchwork of ecosystems
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What is a biosphere?
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Biosphere: the portions of earth that support life
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What is evolution?
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Evolution: Change in allele frequencies within a population (or species) over time
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What is a gene?
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Gene:
material structure (i.e. DNA) or information that is carried by the particular DNA sequence and is used to produce a protein |
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What is a locus?
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Position that an allele occupies on a chromosome
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What is an allele?
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Unit of heredity that controls the expression of a trait
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What is allele frequency?
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Specification of the alleles present at every locus and the number or proportions of different alleles at each locus
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What is evolution by natural selection?
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Evolution by Natural Selection:
change of allele frequencies caused by differential success (survival and reproduction) of individuals within the population resulting from their interaction with the environment |
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What is evolution by sexual selection?
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Evolution by Sexual Selection:
change of allele frequencies caused by differential mating success of individuals within the population resulting from their interaction with other individuals |
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What are the three variables necessary for evolution by selection?
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Variation in the phenotype
Variation in phenotype is correlated to fitness differences Variation in genotype is underlying variation in phenotype |
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What is a phenotype?
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Phenotype: external, observable expression of a trait of an organism
e.g. body size, eye color |
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What is a genotype?
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Genotype: Sum of hereditary information (genes) carried by an individual
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What is phenotypic plasticity?
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Phenotypic plasticity: Change in the average phenotype expressed by a genotype in different environments
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What is the pehnotypic reaction norm?
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Phenotypic reaction norm: Systematic change of a phenotypic trait that occurs in response to a systematic change in an environmental variable
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What is an ecotype?
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locally adapted and
genetically distinctive populations within a species |
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What is fitness?
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Fitness: Contribution of an individual animal to the gene pool in the next generation.
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What is strength of selection? (s)
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difference between selected parents and the population as a whole (within a generation)
measured as selection differential |
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What is directional selection?
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One extreme phenotype is favored
Mean of trait changes over time Common during periods of environmental change or when population migrate to new areas with different environmental |
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What is stabilizing selection?
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Average phenotypes are favored
Variance of trait decreases over time Common under stable environmental conditions or when counteracting selection pressures (e.g. tails in peacock) |
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What is disruption selection?
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Both extreme phenotypes are favored
Variance of trait increases over time Rare |
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What is heritability? (h^2)
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Heritability (h2): Ratio of variation in genotype to variation in phenotype
h2 = VG / VP [0,1] Heritability is a measure for potential for evolution. |
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What is the response to selection? (R)
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Response to Selection (R):
difference between selected offspring and the unselected population (across generations Response to selection (R) depends on Genetic variation (measured as heritability, h2) Strength of selection (measured as selection differential, S) R = h2 S |
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What are factors influencing maintenance of genetic variation?
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Mutations: point mutations (change in nucleotide in DNA) chromosomal mutations (structure or number)
Variation in environment (time and space); i.e. changing direction of selection Sexual Reproduction |
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What is genetic drift?
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Evolution through genetic drift:
Change of allele frequencies by chance |
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What are features of genetic drift?
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Genetic drift:
effects can be positive (increase fitness), neutral (no effect on fitness), or negative (decrease fitness) reduces genetic variation over time (i.e. frequency of some alleles increases; frequency of other alleles decreases) more likely in small populations than in large populations |
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Question: How can we determine that allele frequencies have changed due to evolution?
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Hardy-weinberg equalibrium
Prediction of allele frequencies in the absence of evolution Comparison of allele frequencies between expectations derived from Hardy Weinberg equilibrium with allele frequencies of real populations |
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What is a biome?
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Biome:
terrestrial regions inhabited by certain types of life, especially vegetation are largely defined by the dominant forms of plants which provide structure |
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What is the coriolis effect?
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Coriolis effect causes apparent deflection of winds clockwise in the N hemisphere and counterclockwise in the S hemisphere.
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What are the 3 climate zones?
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Polar zone 60*+ north/south
Temperate zone 30-60* north/south Tropical zone equator to 30* north/south |
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What is soil?
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Soil: a complex mixture of living and non-living material
Classification of soils based on vertical layering (soil horizons) Profile provides a snapshot of soil structure in a constant state of flux. |
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What is the Organic horizon in soil?
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Organic Horizon
plant leaf litter and highly fragmented |
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What is the A horizon made out of?
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A Horizon
mineral soil mixed with organic matter minerals and organic matter gradually leached from A horizon |
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What is the B horizon made out of?
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B Horizon / Depositional Horizon
Leached material deposited in B horizon |
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What is the C horizon made out of?
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C Horizon
weathered parent material may include rock fragments often lies on bedrock |
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What does the amount of water available to plants depend on?
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Amount of water available to plants depends on
Precipitation Evaporation |
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What does the amount of water available to an ecosystem depend on?
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Amount of water available to ecosystem
Precipitation Evapotranspiration (evaporation of plants and soil) |
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What is potential evapotranspiration? (PET)
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Evapotranspiration depends on temperature.
Potential evapotranspiration (PET): Potential amount of water loss from an ecosystem at a given temperature Plants have sufficient water available, if available amount of water to is equal or larger than PET. |
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What is a climate diagram?
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Climate diagram: summarizes climatic information using a standardized structure
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What two factors influence whether of not an individual can live somewhere?
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Properties of environment determining
where organism can live: Conditions Resources |
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What are conditions?
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Properties of environment determining where organism can live:
Conditions: physicochemical factors (e.g. temperature, pH, humidity, salinity) not consumed or used by organism organism can alter conditions |
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What are resources?
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Properties of environment determining where organism can live:
Resources: consumed by organisms for maintenance, growth and reproduction plants: solar radiation, carbon dioxide, water, mineral nutrients animals: bodies of other organisms as food, water, mineral nutrients |
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Condition can have effects on what?
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appearance,behavior and physiology
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True/false: Effects of conditions can be both temporary and permanent.
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True
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True/false: Most species perform best in a fairly narrow range of temperatures.
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True
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Why do animals differ in their optimal temperature ranges?
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adaptation and acclimation
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How do organisms respond to temperature changes?
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Adaptation
Acclimation Migration |
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What is acclimation?
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Acclimation: change in physiology of an organism in response to change in the environment whereas no genetic changes occur.
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What are the limits to acclimation and adaptation?
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Limits to acclimation and adaptation.
A species can usually adapt to a larger range of environments that it can acclimate to. Differences between population living at different temperatures may be due to acclimation or adaptation. Experiments such as common garden experiment needed to distinguish between acclimation and adapatation. |
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What is homeostasis?
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When environmental conditions change, individual organisms can either:
acclimate (i.e. change internal physiology) maintain homeostasis by counteracting environmental changes Example: Change in salt concentration in water Freshwater vs. Salt water |
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What is important in homeostatis and surface to volume ratio?
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Surface to volume ratio important to homeostasis
The smaller the surface area in relation to volume, the slower the exchange of substances and energy between organism and environment |
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What is a homeotherm?
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Homeotherms
maintain a relatively constant internal environment only birds and mammals |
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What is a poikilotherm?
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Poikilotherms
Body temperature varies directly with environmental temperature all organisms besides birds and mammals |
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What is an endotherm?
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Endotherms
Relies mainly on internal sources of energy for regulation of body temperature |
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What is an ectotherm?
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Ectotherms
Relies mainly on external sources of energy for regulation of body temperature e.g. fish, reptilies |
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How is temperature regulation calculated?
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Regulation of body temperature requires balancing heat gain against heat loss
HS = Hm + Hcd + Hcv + Hr - He HS = Total heat stored in an organism Hm = Gained via metabolism Hcd = Gained / lost via conduction Hcv = Gained / lost via convection Hr = Gained / lost via electromag. radiation He = Lost via evaporation |
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Poikilothermic endotherms
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Rely on metabolic energy.
Examples: swimming muscles of large marine animals: fish (e.g. tuna) and sharks insects control temperature of flight muscle |
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What are some poikilothermic endotherms?
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some heat flowers
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What are some homeothermic endotherms?
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Rely on metabolic energy and keep internal environment relatively constant only birds and mammals
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What is the thermoneutral zone?
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range of environmental temperatures over which the metabolic rate of a homeothermic animal does not change.
zone:Width varies among endothermic species |
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How do animals survive extreme temperatures?
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Inactivity
Seek shelter during extreme periods. Reducing Metabolic Rate Hummingbirds enter a state of torpor when food is scarce and night temps are extreme. Hibernation – Winter Estivation - Summer |
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What is diffusion?
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Diffusion: if 2 environments differ in water or salt concentrations,
substances move down their concentration gradients |
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What is osmosis?
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Osmosis: diffusion through a semipermeable membrane
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How do organisms maintain water balance?
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Through:
Eating and drinking Metabolic water: water released during cellular respiration example: oxidation of glucose C6H12O6 + 6O2 6CO2 + 6H2O Wia= Wd + Wf + Wa - We – Ws Wia= Animal’s internal water Wd = Drinking Wf = Food Wa = Absorbed by air We = Evaporation Ws = Secretion / Excretion |
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What is water vapor density?
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water vapor per unit volume of air
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What is relative humidity?
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Water Vapor Density /
Saturation Water Vapor Density x 100 |
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What is saturation water vapor density?
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quantity of water vapor air can
potentially hold pressure of water vapor in water saturated air |
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What is water vapor pressure?
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pressure exerted by water vapor
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What is Water vapor pressure deficit?
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water vapor pressure – saturation water pressure [Pa]
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How can you conserve water?
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Many terrestrial organisms equipped with waterproof outer covering.
Concentrated urine / feces. Condensing water vapor in breath. Behavioral modifications to avoid stress times. Drop leaves in response to drought. Thick leaves Few stomata Periodic dormancy |
