BISC208 Exam 3

Biotic Factors

All of the living organisms in an area that affect an organism's interaction with the environment.

Abiotic Factors

The nonliving components of the environment, including physical and chemical factors.

Habitat

The biotic and abiotic factors present in an organism's surroundings.

Population

A group of individuals of the same species living in a particular geographic area.

Community

All the populations of organisms living close enough together for potential interaction.

Ecosystem

Both the abiotic and biotic components of the environment in an area.

Biosphere

All of Earth that is inhabited by life, extending from the atmosphere to the depths of the oceans.

Primary Succession

Begins in a virtually lifeless area with no soil, such as after a volcanic eruption.

Secondary Succession

Occurs when a disturbance destroys an existing community but leaves the soil intact.

Mutualism

A form of symbiosis where both partners benefit from the relationship, such as corals and dinoflagellates.

Interspecific Competition

Competition that occurs when the niches of two populations overlap and both need a resource that is in short supply.

Altruism

Behavior that benefits others at a cost to oneself, often explained by kin selection.

Population Density

The number of individuals of a species per unit area or volume.

Trophic Structure

The feeding relationships between organisms in a community, defining how energy and nutrients flow.

Carbon Cycle

The cycle of carbon between biotic and abiotic components of the environment, involving processes like photosynthesis and respiration.

Phosphorus Cycle

The cycle of phosphorus through the ecosystem, primarily sourced from the weathering of rocks.

Nitrogen Cycle

The cycle of nitrogen in the ecosystem, which depends on bacterial processes to convert atmospheric nitrogen into usable forms for organisms.

Biomagnification

The process where the concentration of toxins increases in organisms at each successive trophic level.

Greenhouse Gases

Gases that trap heat in the atmosphere, contributing to climate change.

Ecological Niche

The sum of an organism’s use of the biotic and abiotic resources in its environment.

Examples of Abiotic Factors:

Water, sunlight, soil, temperature

Examples of Biotic Factors:

Animals, plants, bacteria

Organism

Individual

Population

Group of individuals living in a particular area

Community

Multiple populations living close enough to interact

Ecosystem

Both abiotic and biotic components of the environment in an area

Landscape

An array of ecosystems usually visible from the air as patches

Biosphere

All of Earth from deep ocean to atmosphere

DDT

Pesticide employed against mosquitoes

DDT Debate

Argues against widespread use of chemicals lingering in food, soil and water and affecting birds of prey

Biomagnification

Small levels of toxin get concentrated as it rises in trophic levels. Since birds of prey are at the top DDT affects them most.

Equatorial regions

Receive sunlight more directly

Higher latitudes

Receive sunlight at more of a slant

Seasons

Caused by Earth’s permanent tilt. Summer tipped toward the sun, winter tipped away.

Gulf Stream

brings warm water from the carribean up the coast of north america then over to north europe

Downstream rivers

wide, slow moving, high nutrients, murky

near river source

narrow, fast, cold, low nutrients, clear

wetlands

reduce flooding, filtration of pollutants

Innate behaviors

do not need to be learned

Clumped dispersion

individuals are grouped in patches due to resources or predators

uniform dispersion

individuals are equally spaced due to territorial interactions

random dispersion

spaced in unpredictable ways like random dispersal of windblown seeds

survivorship curves

plot survivorship as the proportion of individuals from an initial population that are alive at each age

type 1 survivor

humans, most live to old age and drop slowly

type 2 survivor

squirrels, uniform death

type 3 survivor

marine organisms, lot of death in younger organisms, some survive to old age

boom and bust cycles

predator cycles closely follow prey cycles, moose go up followed by wolf go up