Bio test 4 definitions

natural selection

The process by which organisms better adapted to their environment tend to survive and produce more offspring.

artificial selection

The process by which humans select traits they find desirable and breed organisms to enhance those traits.

evolutionary adaptation

A trait that increases an organism's ability to survive and reproduce in its environment.

Homology

Similarity in characteristics resulting from shared ancestry.

vestigial structures

Anatomical features that are present in an organism but have lost their original function through evolution.

Population

A group of individuals of the same species that live in the same area and interbreed.

gene pool

The total collection of genes and alleles in a population.

genetic drift

A change in the gene pool of a small population due to chance.

gene flow

The transfer of alleles or genes from one population to another.

sexual selection

A form of natural selection where individuals with certain traits are more likely to obtain mates and reproduce.

relative fitness

The contribution an individual makes to the gene pool of the next generation relative to others.

directional selection

A mode of natural selection that favors one extreme phenotype over others.

disruptive selection

A type of natural selection that favors extreme phenotypes over intermediate ones.

stabilizing selection

A type of natural selection that favors intermediate variants and acts against extreme phenotypes.

Ecology

The study of the interactions living things have with each other and with their environment.

Community

A community consists of all the different species that live together in a particular area.

Ecosystem

A community of living organisms in conjunction with nonliving components of their environment.

Biosphere

The global sum of all ecosystems.

biotic factors

The living components of an ecosystem.

abiotic factors

The non-living chemical and physical parts of the environment.

Phytoplankton

Microscopic marine algae that form the base of the aquatic food web.

Zooplankton

Small, often microscopic animals that drift in water and feed on phytoplankton.

primary production

The process by which organisms produce organic compounds through photosynthesis.

carbon footprint

The total amount of greenhouse gases generated by our actions.

Estuary

A coastal area where freshwater and saltwater meet and mix.

intertidal zone

The area between high tide and low tide along coastlines.

Wetlands

Areas where water covers the soil or is present near the surface for significant periods.

tropical forests

Dense forests located near the equator characterized by high rainfall and warm temperatures.

Savannas

Grass-dominated ecosystems with scattered trees and warm temperatures year-round.

Deserts

Areas with low and unpredictable rainfall.

Chaparrals

Ecosystems with mild, rainy winters and hot, dry summers.

age structure of a population

Refers to the number of individuals in different age groups within a population.

survivorship curve

Describes how soon members of a species tend to die within their lifespan.

life history

Refers to the traits that affect an organism's schedule of reproduction and survival.

opportunistic life history (r-Selected Species)

Species characterized by high reproductive rate and little parental care.

equilibrial life history (K-Selected Species)

Species that invest significant parental care in fewer offspring.

exponential population growth

Occurs when the number of new individuals is proportional to the number present.

carrying capacity (K)

The maximum population density that can be sustained within a defined geographical area.

limiting factors

Environmental conditions that restrict growth, abundance, or distribution of a population.

logistic population growth

Occurs when growth rate decreases as population size approaches carrying capacity.

density-dependent factors

Factors that affect population growth in relation to population density.

density-independent factors

Factors that affect population growth regardless of density.

invasive species

Non-native organisms that can cause harm to local ecosystems.

population momentum

Continued growth of a population after fertility rates have declined.

ecological footprint

A measure of the land and resources required to sustain consumption patterns.

Biodiversity

The variety of life in a particular habitat or ecosystem.

Competition

The interaction between organisms that vie for the same resources.

Predation

An ecological interaction where one organism hunts and consumes another.

Parasitism

An interaction where one organism benefits at the expense of another.

Commensalism

An interaction where one organism benefits and the other is neither helped nor harmed.

Mutualism

An interaction where both organisms involved benefit from the relationship.

ecological niche

Refers to the role and position a species has in its environment.

Herbivory

A form of predation where an herbivore feeds on plants.

trophic level

The position an organism occupies in a food chain.

Autotroph

Organisms that produce their own food using light or chemicals.

Heterotroph

Organisms that rely on other organisms for nutrition.

Producers

Organisms that create their own food through photosynthesis.

primary consumers (or herbivores)

Organisms that eat producers.

secondary consumers (carnivores)

Organisms that eat primary consumers.

tertiary consumers

Predators that eat secondary consumers.

quaternary consumers

Top-level predators that eat tertiary consumers.

Decomposers

Organisms that break down dead or decaying organisms.

food chain

A linear sequence of organisms through which nutrients and energy pass.

food web

A complex network of interconnected food chains.

biological magnification

The increasing concentration of toxic substances in organisms at each food chain level.

Biogeochemical cycle

The movement of chemical elements between living organisms and the physical environment.

abiotic reservoir

A non-living storage area for elements in biogeochemical cycles.

Producer

Organisms that produce their own food through photosynthesis.

Consumer

Organisms that rely on other organisms for food.

Decomposers

Organisms that break down dead or decaying organic material.

Greenhouse effect

A natural process that warms the Earth's atmosphere by trapping heat.

Greenhouse gases

Gases that absorb and emit infrared radiation, leading to the greenhouse effect.