Burns AP Biology 8.1-8.7

stimulus

A change in an organism's surroundings that causes the organism to react

endotherms

Animals (such as birds or mammals) that can regulate their body temperature.

Ex:Muscular contractions require energy

ectotherms

An animals that warms itself mainly by absorbing heat from its surroundings

Ex:Snakes require less energy

metabolic rate

the rate at which the body uses energy

-gain results in energy storage OR growth

-loss results in loss of mass and death

trophic levels

levels of nourishment in a food chain

-based on what they eat AND relationship to other organisms

food chain

A series of steps in which organisms transfer energy by eating and being eaten

-10% rule

autotrophs

Organisms that make their own food by capturing energy from physical or chemical sources

-photosynthetic or chemosynthetic

Ex:Consuming hydrogen (w/without 02)

heterotrophs

An organism that obtains organic food molecules by eating other organisms or their by-products.

-metabolizes major MACROMOLECULES

Ex: Chemical energy such as coffee

10% law

only 10% of the energy from one trophic level is transferred to the next

-reason for various reproductive strategies

population

A group of individuals that belong to the same species and live in the same area

density dependent

limiting factor that DEPENDS on population SIZE (abiotic/biotic)

Ex: competition, territoriality, disease, predation

density independent

limiting factor that affects ALL populations in similar ways, REGARDLESS of population SIZE (abiotic/biotic)

Ex: natural disasters, floods, forest fires, volcanic eruptions, and pollution

logistic growth model

a growth model that describes a population whose growth is initially exponential, but slows as the population approaches the carrying capacity of the environment

carrying capacity

Largest number of individuals of a population that a environment can support

-both limiting factors can cause a pop to reach this

community

assemblage of different populations that live together in a defined area

species diversity

The number AND relative abundance of species in a biological community.

Ex: 15 sharks and 62 sea turtles

species composition

refers to the IDENTITY of EACH species in the community

Ex: An ocean community having 2 species of angelfish

mutualism

A relationship between two species in which both species benefit

commensalism

A relationship between two organisms in which one organism benefits and the other is unaffected

predator prey

When one organism feeds on another organism (negative)

parasitism

A relationship between two organisms of different species where one benefits and the other is harmed (negative)

trophic cascade

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

niche partitioning

natural division of resources based on competitive advantages

keystone species

A species that influences the survival of many other species in an ecosystem

-usually smaller because overpop depletes resources

invasive species

plants and animals that have migrated to places where they are not native

interspecific competition

competition between members of different species

intraspecific competition

competition between members of the same species