NEW AP Biology Unit 8 Ecology

ethology

how evolutionary processes shape inherited behavior and how animals respond to stimuli

nature vs nurture

genetic vs environmental factors; innate vs learned behavior

proximate cause

how a behavior occurs or how it is modified; stimulus and "nurture" component

ultimate cause

why the behavior occurs in context of natural selection

stimulus

external/internal/mixed signal that causes a response from an organism

signaling behavior

exchanging information with one another in response to internal changes and external cues; can change behavior

communication mechanisms

visual, audible, tactiel, electrical, chemical

signal purposes

dominance, find food, establishing territory, ensure reproductive success

cooperative behavior

between organisms; tends to increase the individual fitness and population survival

biotic factors

living (or once living) components of an environment

abiotic factors

nonliving (physical and chemical) factors of an environment

energy net gain

results in energy storage or growth of an organism

energy net loss

results in loss of mass and eventual death of an organism

fecundity

organism's reproductive capacity; the higher the fecundity, the less energy it invests to EACH offspring

metabolic rate

the total amount of energy an animal loses in a unit of time; measured in calories, heat loss, O2 consumed, CO2 produced; high rate for small organisms

endotherms

use thermal energy from metabolism (and a developed hypothalamus, the central control of thermoregulation)

ectotherms

use external soures, such as sunlight, to regulate their body temperatures

trophic levels

shows the dynamics of a community depending on the feeding relationships (energy transfer) between organisms

trophic cascade

a disruption in the normal food chain that disrupts other trophic levels

ecological levels of organization

population -> community -> ecosystem -> biome

autotrophs

organisms that do not require consuming other organisms for nutrients and energy

primary producers

capture physical or chemical energy (photosynthesis and chemosynthesis)

primary production

the amount of light energy converted into chemical energy

net primary production

NPP=GPP-R

secondary production

the amount of chemical energy in a consumer's food that is converted into biomass

heterotrophs

rely on autotrophs because they cannot make their own food

detritivores

break down large organic molecules (detritus) into smaller ones

decomposers

break down the small organic molecules even further

seasonal reproduction

a reproductive strategy that is in response to resource availability

food chain

the transfer of food energy up the trophic levels

food web

linked food chains

biogeochemical cycles

nutrient cycles that contain both biotic and abiotic factors; hydrologic cycle, C cycle, N cycle, P cycle

changes in energy availability

can result in changes in population size and disruptions to an ecosystem through trophic cascades

population

a group of individuals of the same species living in an are

population density

the number of indiviulas per unit area; ρ=N/A

population distribution

clumped, uniform, random

population size

birth and death rate, migration, demography

survivorship curves

age-specific survival patterns; Type I, II, and III

change in population size

dN/dt = B - D

exponential growth

growth model for populations under ideal conditions, abundant resources, free to reproduce; mostly r-selected species

exponential growth formula

dN/dt = r max * N

r max

maximum per capita growth

logistic growth

growth model for population where the per capita rate of increase approaches zero as the population size nears its carrying capacity

logistic growth phases

phase I (exponential growth), phase II (slowed growth), phase III (stabilization)

logistic growth formula

dN/dt = r max * N * (K-N)/K

carrying capacity

K; the sustainable abundance of a species supported by the ecosystem's resources

density-dependent regulation

e.g., competition, predation, territoriality, disease, reproduction rates

density-independent regulation

e.g., weather, natural disasters, etc.

community

populations of different species living closely and capable of interacting

habitat

place/part occupied by an organism

niche

the role and position a species has in its environment

fundamental niche

the niche potentially occupied

realized niche

the portion of the fundamental niche the species actually occupies

species richess

the total number of different species

relative abundance

the proportion of each species represent of all the individuals in the community

species diversity

accounts for both the number and relative abundance of different species

species composition

the identity of each species within a community

competition

negative-negative relationship

competition exclusion principle

two species cannot coexist permanently when competing for the same resource

niche partitioning

natural selection drives competing species into different niches

predation

positive-negative relationship between consumers

types of defense

physical, chemical, aposematic coloration, cryptic coloration (camoflage), mimicry

aposematic coloration

coloration or marking to warn predators; poison dart frogs and canyon frogs

herbivory

positive-negative relationship between a consumer and a producer

mimicry

when a harmless species mimics a harmful one; larva mimicking a snake

symbiosis

when 2 or more species live in direct contact with each other

parasitism

positive-negative symbiosis; parasite requires a host to pass at least one part of its life cycle

mutualism

positive-positive symbiosis; acacia trees provide Beltan bodies and ants protect the trees from other predators

commensalism

positve-neutral symbiosis; birds and trees; generally the species have different niches

Simpson's diversity index

1-∑(n/N)2; a higher index indicates higher biodiversity

keystone species

species that others in ecosystem are heavily reliant on due to important ecological niche (e.g., coral reefs and honey bees)

ecological succesion

the gradual process by which the species composition of a community changes and develops after a disturbance

primary succesion

starts with an entirely new habitat that has not been colonized; moss and lichen

secondary succseion

a series of changes that clears an existing community but leaves soil intact

heterozygote advantage

when the heterzygous genotype has a higher relative fitness than either the homozygous dominant or recessive genotype

invasive species

species that outcompete native species; usually free of predators and reproduce fast; high diversity communities are more resistant

anthropogenic disturbances

habitat loss; transporting invasive species; overharvesting; global change (pollution)

endangered species

organisms at high risk of extinction; mostly due to human activity

biogeographical factors

large scale factors that contribute to a range of diversity observed; latitude, area, pathogens