All AP Biology

stimulus

internal or external signal(s) that elicit a response from an organism

signalling behavior

communication between organisms that can change behavior; can result in differential reproductive success

innate behaviors

genetically controlled and can occur without prior experience or training

learned behaviors

behaviors developed through experience

cooperative behaviors

involve teamwork between organisms of the same species

parasitoid

organisms that lay their eggs on a host

endotherms

use thermal energy from metabolism to maintain homeostatic body temperature

ectotherms

lack efficient internal mechanisms to maintain homeostatic body temperature

metabolic rate

amount of energy expended by an animal over a specific amount of time

population

a group of the same species in an area

community

the different populations that live in an area and interact with each other

ecosystem

community of organisms in an area and the abiotic factors that they interact with

biome

a large geographic area with similar climate and vegetation

hydrologic cycle

the movement of water on, above, between, and below Earth’s surface

carbon cycle

the movement of carbon through Earth’s atmosphere, oceans, land, and organisms

nitrogen cycle

describes the transformation and movement of nitrogen through various forms and reservoirs

phosphorus cycle

describes the movement of phosphorus through the Earth’s crust, oceans, and organisms

autotrophs

capture energy from processes like photosynthesis or chemosynthesis by converting inorganic substances into organic compounds

heterotrophs

obtain energy by consuming organic matter and breaking it down to release energy and power their cellular processes

population density

how close individuals in a population live to each other

density-dependent factors

biotic or abiotic factor whose effect on population size relies on a population’s density

density-independent factors

biotic or abiotic factors that affect population size regardless of population density

carrying capacity

maximum number of individuals an environment can sustain

species diversity

the variety of species and quantity of individuals in each species in a community

species composition

the identity of each species in the community

Simpson’s diversity index

mathematical measurement of the biodiversity of a habitat

mutualism

relationship wherein both species benefit

commensalism

relationship wherein one species benefits at no cost or benefit to the other

predator-prey

relationship wherein one species eats the other

parasitism

relationship wherein one species benefits at the expense of another

trophic cascade

the negative effect the removal of or decrease in a key species has on other trophic levels

niche partitioning

a decrease in competition over limited resources between two similar species because each species is accessing the resource in different ways

keystone species

species that the community structure depends on

invasive species

a species that is non-native to a specific area and harms the community it is introduced to

habituation

loss of responsiveness to stimuli

imprinting

formation of a long-lasting behavior response during a sensitive period

spatial learning

memory of structure of an environment; landmarks, cognitive maps

associative learning

classical conditioning and operant learning

classical conditioning

learning process where a neutral stimulus becomes associated with an automatic response through repeated pairing with a meaningful stimulus

operant learning

trial and error learning; modifies voluntary behaviors through +/- reinforcement

cognition/problem-solving

awareness, reasoning, recollection, and judgement

nitrogen fixation

conversion of gaseous nitrogen into ammonia by soil bacteria

nitrifying bacteria

organisms that convert ammonium into nitrite, then nitrate, which is usable by plants

denitrifying bacteria

organisms that balance the amount of nitrate by converting some of it back to gaseous nitrogen

eutrophication

results from excess phosphorus and nitrogen runoff; creates algal blooms, followed by dead zones

primary consumers

second trophic level in the food chain; herbivores that eat producers

secondary/tertiary consumers

upper levels on the trophic pyramid; usually omnivores and carnivores that are some top predators

scavengers

animals that consume dead and decaying matter rather than live prey

decomposers

organisms that break down dead plants/animals into essential nutrients

taxis

oriented movement

Mullerian mimicry

when two or more harmful, toxic, or otherwise dangerous species evolve to share similar warning signals (color, patterns, behavior) to mutually benefit from predator avoidance

Batesian mimicry

survival strategy where a harmless species evolves to resemble a harmful or otherwise dangerous species to deceive predators and avoid predation

aposematism

defense mechanism wherein animals use conspicuous signals (bright colors, bold patterns, sounds) to indicate danger to predators

evolution

the change in the genetic makeup of a population over time

natural selection

process by which organisms with adaptations better suited to an environment have a greater chance of survival and reproduction, thereby passing the adaptations to subsequent generations

competition

organisms struggle with other organisms for limited resources

variation

genetic differences among organisms within a population

adaptations

traits that provide an advantage in a particular environment

fitness

the ability of an organism to survive and produce fertile offspring

reproductive success

component of evolutionary fitness; refers to the production of offspring

heritability

the ability to pass on adaptations

genetic variation

the genotypic and phenotypic differences between individuals in a population; increases the probability that a population will survive when environmental conditions change

selective pressure

biotic or abiotic factors that influence survivability; ex. disease, predation, climate change, food availability

artificial selection

process by which humans select desirable traits in other species and selectively breed individuals with the desired traits

fossils

preserved remains, traces, or impressions of once living organisms

morphological homologies

modified traits shared among different species

homologous structures

variation in a structure derived from a common ancestor

vestigial structures

reduced/obsolete features that serve little to no purpose for the organism

analogous structures

structures that evolved independently in different species due to environmental conditions or selective pressures

genetic drift

random change in the frequency of a particular allele within a population

bottleneck events

when a large, diverse population is suddenly reduced to a small population

founder effect

random process that reduces genetic variation within a small population due to separation from a larger population

gene flow/migration

movement of individuals between populations causing an exchange of alleles between populations

Hardy-Weinberg

a model for describing and predicting allele frequencies in a nonevolving population

pathogen

infectious agent that can produce a disease; evolve and cause emergent diseases; chemically compatible with the host and coevolves

phylogenetic tree

branched diagram showing the evolutionary relationships amongst species

cladogram

simplified diagram used to show evolutionary relationships amongst species

out-group

lineage on a evolutionary diagram that is least closely related to the other organisms on it

derived character

trait in a recent species that has evolved from an ancestral trait

species

a group capable of interbreeding and exchanging genetic information to produce viable and fertile offspring

speciation

the creation of new species; needs reproductive isolation

prezygotic barriers

prevent production of a fertilized egg

temporal isolation

species breed during different times of day, seasons, or times of year

behavioral isolation

species have different courtship behaviors or mate preferences

mechanical isolation

species have differences in their reproductive structures

gamete isolation

sperm of one species is unable to fertilize another species’ eggs

postzygotic barriers

prevent a zygote from developing into a viable, fertile offspring

hybrid inviability

a zygote is produced but is not compatible, so doesn’t develop

hybrid sterility

offspring is produced that survives but is sterile

hybrid breakdown

first-generation hybrids are viable and fertile, but subsequent generations are feeble or sterile

allopatric speciation

evolution of new species due to a population being geographically separated for a long period of time

sympatric speciation

evolution of a new species due to individuals being reproductively isolated from a surviving ancestral population

punctuated equilibrium

evolution occurs rapidly after a long stasis period; caused by changing ecological conditions

gradualism

evolution occurs slowly over hundreds of thousands or millions of years; slow change in ecological conditions

adaptive radiation

evolution of new species that allows empty ecological roles to be filled; can make speciation rates particularly rapid

convergent evolution

process by which similar environmental conditions select for similar traits in different populations/species over time

analogous structures

similar traits in distantly-related or unrelated species

deletrious traits

traits that reduce the chance of survival

adaptive traits

traits that increase the chance of survival

extinction

the disappearance of a species such that no future generations will naturally populate the earth