AP Biology Unit 8 - Ecology

Population

a group of organisms of the same species populating a given area

Community

(ecology) a group of interdependent organisms inhabiting the same region and interacting with each other

ecosystem

a system formed by the interaction of a community of organisms with their physical environment

biosphere

the regions of the surface and atmosphere of the Earth (or other planet) where living organisms exist

habitat

the type of environment in which an organism or group normally lives or occurs

niche

(ecology) the status of an organism within its environment and community (affecting its survival as a species)

size

the property resulting from being one of a series of graduated measurements (as of clothing)

population density

number of individuals per unit area

dispersion

The pattern of distribution of organisms in a population

age structure

proportion of people in different age groups in a population

survivorship curves

They show the likelihood of survival at different ages throughout the lifetime of the organism.

type I

Survivorship curve in which the likelihood of dying is small until late in life, when mortality increases rapidly (such as Humans or elephants).

type II

Survivorship curve in which there is an equal likelihood of dying throughout life (such as birds or small mammals).

type III

Survivorship curve in which organisms are most likely to die when young; the few survivors tend to live until old age (such as oysters, salmon, or insects).

biotic potential

the maximum reproductive rate of an organism, given unlimited resources and ideal environmental conditions

carrying capacity

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

limiting factors

Conditions in the environment that put limits on where an organism can live

density-dependent factors

limiting factors (such as competition, predation, parasitism, and disease) that are affected by the number of individuals in a given area

density-independent factors

limiting factor that affects all populations in similar ways, regardless of population size

reproductive rate

R= (births-deaths)/N [N- population size at beginning of interval]

growth rate

the amount by which a population's size changes in a given time

intrinsic rate

the mean rate of growth of a population calculated by birth minus death rates when the population is free of competition with other species and from other factors that affect growth.

exponential growth

growth pattern in which the individuals in a population reproduce at a constant rate

logistic growth

growth pattern in which a population's growth rate slows or stops following a period of exponential growth

sigmoid curve

a period of exponential growth; population approaches its environmental limits, growth slows and finally stabilizes, fluctuating around the carrying capacity of the environment

population cycles

some populations have boom and bust cycles. Large growth, and then a lot of death, and then growth.

r-selected species

Species that reproduce early in their life span and produce large numbers of usually small and short-lived offspring in a short period.

opportunistic species

individuals that take advantage of what they have. usually like insects. they have short life spans, they die quickly, mature very quickly, they usually only get one chance to reproduce, when they do they have tons of offspring, and consequently don't take care of their kids.

k-selected species

Species that produce a few, often fairly large offspring but invest a great deal of time and energy to ensure that most of those offspring reach reproductive age.

competitive exclusion principle

ecological rule that states that no two species can occupy the same exact niche in the same habitat at the same time

resource partitioning

in a biological community various populations sharing environmental resources through specialization thereby reducing direct competition

niche shift

when competition between two species causes a change in habit to access a wider range of resources; this may include accessing suboptimal resources

realized niche

the range of resources and conditions a species actually uses or can tolerate at optimal efficiency; smaller than fundamental niche

niche overlap

Situation in an ecosystem in which different species are in competition for the same resources. In natural ecosystem is typically zero or minimal.

predation

the act of preying by a predator who kills and eats the prey

true predator

A predator that typically kills its prey and consumes most of what it kills.

parasite

an animal or plant that lives in or on a host (another animal or plant)

parasitoid

insects lay their eggs in hosts (often paralyzed), young hatch, eat host alive

herbivore

any animal that feeds chiefly on grass and other plants

granivore

an animal that feeds primarily on seeds.

grazer

an aquatic intervertebrate such as a snail or water penny that eats aquatic plants, especially algae growing on surfaces

browsers

Animals that may eat only part of a plant but may weaken it in the process

symbiosis

the relation between two different species of organisms that are interdependent

mutualism

the relation between two different species of organisms that are interdependent

commensalism

the relation between two different kinds of organisms when one receives benefits from the other without damaging it

parasitism

the relation between two different kinds of organisms in which one receives benefits from the other by causing damage to it (usually not fatal damage)

secondary compounds

chemical compounds produced by plants strictly for repelling or attracting predators or pollinators.

camouflage

the act of concealing the identity of something by modifying its appearance

aposematic coloration

The bright coloration of animals with effective physical or chemical defenses that acts as a warning to predators

mimicry

the resemblance of an animal species to another species or to natural objects

mullerian mimicry

evolution of two species, both of which are unpalatable and, have poisonous stingers or some other defense mechanism, to resemble each other

batesian mimicry

A type of mimicry in which a harmless species looks like a species that is poisonous or otherwise harmful to predators.

ecological succession

(ecology) the gradual and orderly process of change in an ecosystem brought about by the progressive replacement of one community by another until a stable climax is established

climax community

a relatively stable long-lasting community reached in a successional series; usually determined by climax and soil type

pioneer species

in primary succession on a terrestrial site, the plants, lichens, and microbes that first colonize the site

primary succession

an ecological succession that begins in a an area where no biotic community previously existed

secondary succession

succession on a site where an existing community has been disrupted

trophic levels

The hierarchical levels of the food chain through which energy flows from primary producers to primary consumers, secondary consumers and so on.

primary producers

An autotroph, usually a photosynthetic organism. Collectively, autotrophs make up the trophic level of an ecosystem that ultimately supports all other levels.

primary consumers

animals that feed on producers; ex. herbivores

secondary consumers

carnivores that eat herbivores

tertiary consumers

Animals that feed on animal-eating animals. They feed at high trophic levels in food chains and webs. Examples are hawks, lions, bass, and sharks. Compare detritivore, primary consumer, secondary consumer.

detritivores

organisms that feed on the detritus and decomposing organic material of living organisms

decomposers

organisms that break down wastes and dead organisms and return raw materials to the environment

ecological pyramids

show the relative amount of energy or matter contained within each trophic level in a given food chain or food web

ecological efficiency

Percentage of energy transferred from one trophic level to another in a food chain or web

food chain

(ecology) a community of organisms where each member is eaten in turn by another member

food web

a diagram that shows the feeding relationships between organisms in an ecosystem

hydrologic cycle

The cycle through which water in the hydrosphere moves; includes such processes as evaporation, precipitation, and surface and groundwater runoff

carbon cycle

the circulation and reutilization of carbon atoms especially via the process of photosynthesis and respiration.

nitrogen cycle

the transfer of nitrogen from the atmosphere to the soil, to living organisms, and back to the atmosphere

nitrogen fixation

the assimilation of atmospheric nitrogen by soil bacteria and its release for plant use on the death of the bacteria

nitrification

the oxidation of ammonium compounds in dead organic material into nitrates and nitrites by soil bacteria (making nitrogen available to plants)

denitrification

process in which fixed nitrogen compounds are converted back into nitrogen gas and returned to the atmosphere

ammonification

the formation of ammonia compounds in the soil by the action of bacteria on decaying matter

phosphorus cycle

The movement of phosphorus atoms from rocks through the biosphere and hydrosphere and back to rocks.

biomes

a broad, regional type of ecosystem characterized by distinctive climate and soil conditions and a distinctive kind of biological community adapted to those conditions.

tropical rain forests

a woodland of tall trees growing in a region of year-round warmth and abundant rainfall

epiphytes

plants such as mosses, lichens, and orchids, that grow on other plants but do not take nutrients from them

savannas

a region of grassland with scattered trees lying between the equatorial forest and the hot deserts in either hemisphere.

temperate grasslands

dominated by grasses, trees and large shrubs are absent. Temperatures vary more from summer to winter, and the amount of rainfall is less than in savannas. Temperate grasslands have hot summers and cold winters. Occur in South Africa, Hungary, Argentina, the steppes of the former Soviet Union, and the plains and prairies of central North America.

temperate deciduous forests

biome, occupy regions that have warm summers, cold winters, and moderate precipitation, shed leaves in winter,

deserts

a barren region with little or no rainfall, usually sandy and without trees..

taigas

Biome that is characterized by coniferous (pines, firs, and other trees with needles for leaves).Winters are cold and snowy

tundras

biome, subject to very cooold winters, during summer, the upper soil thaws, but the deeper soil, the permafrost, remains permanently frozen, grasses, and plants tolerant of soggy soils

permafrost

ground that is permanently frozen

fresh water biomes

biomes, ponds, lakes, streams, and rivers

marine biomes

biome, include estuaries (where ocean meets river), intertidal zone (where oceans meet land), continental shelves (the relatively shallow oceans that border continents), coral reefs, and the pelagic ocean (the deep oceans)

ozone holes

the thinning of the ozone layer over Antarctica (and to some extent, over the Arctic).

acid rain

rain containing acids that form in the atmosphere when industrial gas emissions (especially sulfur dioxide and nitrogen oxides) combine with water

desertification

Degradation of land, especially in semiarid areas, primarily because of human actions like excessive crop planting, animal grazing, and tree cutting.

deforestation

the removal of trees

pollution

undesirable state of the natural environment being contaminated with harmful substances as a consequence of human activities

biological magnification

increasing concentration of a harmful substance in organisms at higher trophic levels in a food chain or food web

algal blooms

a vast increase in the concentration of diatoms and other photosynthetic protists.

eutrophication

process by which a body of water becomes too rich in dissolved nutrients, leading to plant growth that depletes oxygen