Unit 2: Ecology AP Bio

ecology

the study of how organisms interact with each other and their environment

population density

number of individuals per unit of area

biodiversity

variety of life in a place on Earth

carrying capacity

the maximum population size that can be supported by the available resources, symbolized as K

climate

the long-term prevailing weather conditions at a given place

microclimate

climate patterns on a very fine scale, such as the specific climate conditions underneath a log

abiotic

nonliving, referring to the physical and chemical properties of an environment

biotic

pertaining to the living factors - the organisms - in an environment

canopy

the uppermost layer of vegetation in a terrestrial biome

disturbance

a natural or human-caused event that changes a biological community and usually removes organisms from it

detritus

dead organic matter

dispersal

the movement of individuals away from their parentpo location

population

a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring

density

the number of individuals per unit area or volume

dispersion

the pattern of spacing among individuals within the boundaries of a population

mark-recapture method

a sampling technique used to estimate the size of animal populations

territoriality

A behavior in which an animal defends a bounded physical space against encroachment by other individuals, usually of its own species

cohort

a group of individuals of the same age in a population

survivorship curve

A plot of the number of members of a cohort that are still alive at each age; one way to represent age-specific mortality

intrinsic rate of increase

(r) In population models, the per capita rate at which an exponentially growing population increases in size at each instant in time

logistic population growth

Population growth that levels off as population size approaches carrying capacity

semelparity

Reproduction in which an organism produces all of its offspring in a single event; also called big-bang reproduction

iteroparity

Reproduction in which adults produce offspring over many years; also called repeated reproduction

K-selection

Selection for life history traits that are sensitive to population density

r-selection

Selection for life history traits that maximize reproductive success in uncrowded environments

density independent

Referring to any characteristic that is not affected by population density

density dependent

Referring to any characteristic that varies with population density

innate behavior

animal behavior that is developmentally fixed and under strong genetic control. Innate behavior is exhibited in virtually the same form by all individuals in a population despite internal and external environmental differences during development and throughout their lifetimes

learned behavior

The modification of behavior as a result of specific experiences

competition

A negative-negative interaction that occurs when individuals of different species both use a resource that limits the survival and reproduction of each species

competitive exclusion

The concept that when populations of two similar species compete for the same limited resources, one population will use the resources more efficiently and have a reproductive advantage that will eventually lead to the elimination of the other population

ecological niche

The sum of a species’ use of the biotic and abiotic resources in its environment

realized niche

the niche occupied by a species in the prescence of competition

fundamental niche

the niche occupied by a species in the absence of competition

resource partitioning

the dividing of resources to enable similar species to coexist in a community

niche partitioning

the process by which competing species utilize different resources or occupy different ecological niches to reduce competition and coexist in the same environment

character displacement

when differences in a trait evolve as a resulrt of resource partioning

exploitation

a positive-negative ecological interaction in which individuals of one species benefit by feeding on (and thereby harming) individuals of the other species

predation

an interaction in which an individual of one species, the predator, kills and eats an individual of the other species, the prey

herbivory

a positive-negative ecological interaction in which an organism eats part of a plant or alga

parasitism

a positive-negative ecological interaction in which one organism, the parasite, benefits by feeding upon another organism, the hose, which is harmed

mutualism

a positive-positive ecological interaction that benefits individuals of both interactingspecies

commensalism

a positive-neutral ecological interaction that benefits the individuals of one species but neither harms nor helps the individuals of the other species

symbiosis

an ecological relationship between organisms of two different species that live together in direct and intimate contact

species richness

the number of different species present

species diversity

variety of species in a specific area

relative abundance

the percentage that each species represent of the whole community

trophic structure

the different feeding relationships in an ecosystem, which determine the route of energy flow and the pattern of chemical cycling

food chain

The pathway along which food energy is transferred from trophic level to trophic level, beginning with producers

invasive species

non-native organism that disrupts ecosystems and poses a threat to biodiversity

keystone species

a species that is not necessarily abundant in a community yet exerts strong control on community structure by the nature of its ecological role or niche

ecological succession

primary succession

secondary succession

evapotranspiration

ecosystem

all the organisms in a given area as well as the abiotic factors with which they interact; one or more communities and the physical environment around them

law of conservation of mass

A physical law stating that matter can change form but cannot be created or destroyed. In a closed system, the mass of the system is constant

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 production

The amount of light energy converted to chemical energy (organic compounds) by the autotrophs in an ecosystem during a given time period

primary consumers

an herbivore; an organism that eats plants or other autotrophs

secondary consumers

a carnivore that eats herbivores

tertiary consumers

a carnivore that eats other carnivores

gross primary production

the total primary production of an ecosystem

net primary production

the gross primary production of an ecosystem minus the energy used by the producers for respiration

net ecosystem production

the gross primary production of an ecosystem minus the energy used by all autotrophs and heterotrophs for respiration

limiting nutrient

an element that must be added for production to increase in a particular area

eutrophication

A process by which nutrients, particularly phosphorus and nitrogen, become highly concentrated in a body of water, leading to increased growth of organisms such as algae or cyanobacteria

secondary production

The amount of chemical energy in consumers’ food that is converted to their own new biomass during a given time period

production efficiency

The percentage of energy stored in assimilated food that is not used for respiration or eliminated as waste

trophic efficiency

The percentage of production transferred from one trophic level to the next higher trophic level

biogeochemical cycles

any of the various chemical cycles, which involve both biotic and abiotic components of ecosystems

10% rule

when energy is transferred from one trpohic level to the next, around 10% of the energy is passed on while 90% is lost, usually as heat

trophic pyramid

graphical representation of the energy flow and relationships among different organisms in an ecosystem

trophic cascade

ecological phenomenon triggered by the addition or removal of top predators

bioaccumulation

complex ecological process that disrupts ecosystems, threatens wildlife, and poses risks to human health