biology-ecosystem ecology

Organism

One individual living thing.

Population

All organisms of the same species living in the same area.

Community

All populations of different species living in the same area.

Ecosystem

A community of organisms and the nonliving environment they interact with.

Population density

The number of individuals living in a certain area.

Population distribution

How individuals are spread throughout an area.

Clumped distribution

Organisms live in groups, often near resources.

Uniform distribution

Organisms are evenly spaced apart.

Random distribution

Organisms are spread unpredictably.

Birth rate

The number of births in a population.

Death rate

The number of deaths in a population.

Immigration

Individuals move into a population.

Emigration

Individuals leave a population.

Density-dependent factor

A factor that has a greater effect as population density increases, such as disease or competition.

Density-independent factor

A factor that affects populations regardless of density, such as floods or fires.

Limiting factor

Anything that restricts population growth.

Carrying capacity

The largest population an environment can sustainably support.

Biotic factor

A living influence on an ecosystem, such as predators or food.

Abiotic factor

A nonliving influence, such as sunlight, water, or temperature.

Exponential growth

Rapid population growth when resources are abundant; forms a J-shaped curve.

Logistic growth

Population growth that slows as it approaches carrying capacity; forms an S-shaped curve.

Competition (-/-)

Two organisms compete for resources, harming both.

Predation (+/-)

One organism kills and eats another organism.

Herbivory (+/-)

An animal eats parts of a plant.

Mutualism (+/+)

Both species benefit from the interaction.

Commensalism (+/0)

One species benefits while the other is unaffected.

Parasitism (+/-)

A parasite benefits while harming its host.

Amensalism (-/0)

One species is harmed while the other is unaffected.

Intraspecific competition

Competition between members of the same species.

Interspecific competition

Competition between members of different species.

Sepals

Protect the developing flower bud.

Petals

Attract pollinators with color and scent.

Stamen

The male reproductive structure of a flower.

Anther

Produces pollen.

Filament

Supports the anther.

Carpel/Pistil

The female reproductive structure of a flower.

Stigma

Receives pollen.

Style

Connects the stigma to the ovary.

Ovary

Contains ovules and develops into the fruit after fertilization.

Ovule

Contains the egg cell and develops into a seed after fertilization.

Pollen

Contains the male reproductive cells.

Angiosperms

Flowering plants that produce seeds enclosed in fruits.

Pollination

The transfer of pollen from the anther to the stigma.

Fertilization

The fusion of a sperm cell and an egg cell.

Zygote

The fertilized egg that develops into an embryo.

Double fertilization

One sperm fertilizes the egg to form a zygote, while another forms the endosperm that nourishes the embryo.

Seed

Contains the plant embryo and a food supply.

Fruit

Develops from the ovary and helps protect and disperse seeds.

Energy flow

The movement of energy through an ecosystem, usually from the Sun to producers and consumers.

Nutrient cycling

The movement and reuse of nutrients between organisms and the environment.

Producer

An organism that makes its own food.

Consumer

An organism that obtains energy by eating other organisms.

Decomposer

An organism, such as a fungus or bacterium, that breaks down dead matter and waste.

Food chain

A single pathway showing how energy moves between organisms.

Food web

Multiple connected food chains in an ecosystem.

Trophic level

An organism's feeding position in a food chain or food web.

10% rule

Approximately 10% of energy transfers from one trophic level to the next.

Bi