ch. 19 and 20 vocab (speciation and ecology)

species

individuals capable of interbreeding freely with each other but not with members of other species

speciation

the process of forming new species

sympatric speciation

origin of a new species in populations that overlap geographically

allopatric speciation

origin of a new species in populations that are separated geographically

reproductive isolating mechanisms

different reasons why individuals may no longer be able to reproduce

spatial

prezygotic reproductive isolating mechanism in which organisms select different places to live and reproduce

behavioral

prezygotic reproductive isolating mechanism in which organisms differ in mating behaviors

temporal

prezygotic reproductive isolating mechanism in which organisms reproduce during different times so their mating periods do not overlap

mechanical

prezygotic reproductive isolating mechanism in which the reproductive organs of organisms are incompatible due to size and shape

gametic

prezygotic reproductive isolating mechanism in which the sperm and egg of organisms are incompatible

post zygotic

the zygote forms but the embryo does not survive or grows up to be sterile

extinction

death of all members of a species

mass extinction

episode during which a large number of species become extinct

ecology

study of the interactions among organisms and their physical environment

biotic

pertaining to living organisms

abiotic

pertaining to nonliving factors

pre-zygotic

a reproductive isolating mechanism that prevents the formation of a zygote

producers

organisms that change energy into food

consumers

organisms that eat producers and other consumers

decomposers

organisms that absorb nutrients from nonliving organic material such as corpses, fallen plant material, and the wastes of living organisms, and convert them into organic molecules

autotrophs

organisms that have the ability to make their own food

heterotrophs

organisms that cannot make their own food and must depend on an outside source for nutrients

symbiotic relationships

ecological interactions that involve two different species that live together in direct contact

commensalism

a symbiotic relationship in which one organism benefits but the other is neither helped nor harmed

mutualism

a symbiotic relationship in which both participants benefit

parasitism

a symbiotic relationship in which the symbiont benefits at the expense of the host

food chains

pathways along which food is transmitted from trophic level to trophic level beginning with producers

food webs

elaborate and interconnected food chains

detritus

dead organic material

trophic level

any of the several levels of a food chain, whose species are based on their main nutritional source

energy pyramid

ecological pyramid that represents the amount of available energy and the loss of usable energy in each trophic level

global biogeochemical cycles

pathways that involve both biotic and abiotic components

reservoir

a source unavailable to producers

exchange pool

source from which organisms take chemicals

gaseous cycle

cycle in which a chemical element is drawn from and returns to the atmosphere

sedimentary cycle

cycle in which a chemical element is drawn from the soil by plant roots, eaten by consumers, and is returned to the soil by decomposers

the water cycle

the gaseous cycle in which freshwater evaporates from bodies of water, falls to the ground as precipitation, and eventually returns to oceans over time

condensation

the process of a gas changing to a liquid

transpiration

the process of evaporation of water from plants

the carbon cycle

the gaseous cycle in which photosynthesis takes up carbon dioxide from the atmosphere and cellular respiration returns it to the atmosphere

the nitrogen cycle

the gaseous cycle in which nitrogen is converted into many forms while passing from the atmosphere to the soil and organisms and then returning to the atmosphere

nitrification

production of nitrates which plants can also use

denitrification

conversion of nitrate back to nitrogen gas by denitrifying bacteria

eutrophication

over enrichment of water caused by humans that leads to excessive algal and bacterial growth and oxygen depletion

the phosphorus cycle

the sedimentary cycle in which phosphorus moves through soil, rock, and organic material

growth rate

per capita rate of increase

biotic potential

the highest per capita rate of increase for a population

lag phase

growth is small because the population is small

exponential growth phase

growth is accelerating and the population is exhibiting its biotic potential

deceleration phase

the rate of population growth slows down

stable equilibrium phase

little if any growth takes place because birth and death rates are about equal

carrying capacity

the number of individuals of a species that a particular environment can support

limiting factors

factors that limit population growth

cohort

group of individuals born at the same time

type 1 survivorship curve

a survivorship curve in which most individuals survive until old age

type 2 survivorship curve

a survivorship curve in which the number of survivors decreases consistently over time

type 3 survivorship curve

a survivorship curve in which most individuals die early

doubling time

length of time it takes for population size to double

density independent factors

abiotic factors

r-selection

selection for life history traits that are sensitive to density independent factors.

r-selected species

species in which population is controlled by abiotic factors.

k-selection

selection for life history traits that are sensitive to density dependent factors

density dependent factors

biotic factors

k-selected species

species which population is controlled by biotic factors

competition

interaction between two organisms in which both require the same limited resource

interspecific

competition between two different species

intraspecific

competition between organisms of the same species

competitive exclusion principle

no two species can occupy the same ecological niche at the same time

ecological niche

role organisms plays in the community, includes habitat, resources used, and interactions

resource partitioning

slight differences in the way a resource is used

populations

all individual organisms of one species living in a particular area

communities

all populations living in a particular area

ecosystems

all of the living and non-living factors that interact in an area

biosphere

anywhere on earth where life exists

biome

one of the world's major ecosystems