Topic 2

Taxonomy

the naming, describing, and classifying of organisms both living and extinct

Species

a group of organisms that share common characteristics and are able to interbreed and produce fertile offspring

Population

a group of organisms of the same species living in the same area at the same time, and which are capable of interbreeding

Community

a group of two or more populations of species living in the same area at the same time

Habitat

the environment in which a species normally lives

Ecosystems

made up of organisms and their physical environment, and the interactions between the living and non-living components within them

Niche

the particular set of abiotic and biotic conditions and resources upon which an organism or a population depends

Biotic factors

living components of an ecosystem and their interactions

Abiotic factors

non-living, physical factors that influence organisms and ecosystems

Ecological niche

the role of a species in an ecosystem

Intraspecific competition

competition between members of the same species

Interspecific competition

between members of different speciees

Predation

when one animal, the predator, kills and eats their prey

carnivores

consumers that eat other animals

herbivory

an animal eating a primary producer

parasatism

the relationship between two species in which one (the parasite) lives in or on anther (the host) and gains its food from it

saprotroph

an organism that feeds on dead organic material

Scavenger

an animal that deeds on carrion, decaying flesh

detrivores

eat (ingest) their food and then use enzymes to break it down

decomposers

secrete enzymes to break down their food but do not eat it

pathogen

an organism that causes harm to its animal or plant host

limiting factors

factors which slow down growth of a population as it reaches its carrying capacity

carrying capacity

the maximum number of a species that can be sustainably supported by a given area

density-dependant limiting factors

cause a population’s growth rate to change with increasing population density, are biotic

density-independent limiting factors

change the size of a population regardless of its density, are abiotic

keystone species

one that plays a critical role in maintaining the structure of the ecosystem in which it lives

biosphere

an ecological system composed of the parts of the Earth where life exists

first law of thermodynamics

the principle of conservation of energy

cellular respiration

the process by which glucose is broken down to release energy for living processes

entropy

the unavailability of a system’s thermal energy for conversion

photosynthesis

the processes by which organisms make their own food from water and carbon dioxide using energy from sunlight

compensation point

rates of respiration and photosynthesis are equal, when the plant is neither adding biomass nor using it up

second law of thermodynamics

as energy is transferred or transformed in a system, it is degraded to a less useful form of energy such as heat, and entropy increases

Maximum Sustainable Yield

net productivity of a species/trophic level that can be harvested without reducing future supply

Gross productivity (GP)

the total gain in biomass by an organism

Net productivity (NP)

the amount remaining after losses due to respiration (GP-R)

biocides

substances or microorganisms that destroy, deter, or render harmless living things

bioaccumulation

increasing concentration of non-biodegradable pollutants in organisms or trophic levels ver time

biomagnification

the increasing concentration of non-biodegradable pollutants along a food chain

stores

remain in equilibrium with the environment, with equal amounts absorbed and released

sinks

where there is net accumulation of the elements

sources

where there is net release of the element

carbon fixation

when living organisms sequester carbon naturally by absorbing carbon dioxide and converting it into biomass in photosynthesis

residence time

the average period that an atom remains in store

biome

a group of comparable ecosystems that have developed in similar climatic conditions wherever those conditions occur

climate

atmospheric conditions over relatively long periods of time

weather

conditions in the atmosphere over a short period of time

hotspots

areas predicted to have a high turnover of species due to climate change

climax vegetation

the dominant and stable community of plant species at the end of a succession

succession

the process of change over time in an ecosystem involving pioneer, intermediate, and climax communities

zonation

the change in community along an environmental gradient due to factors such as changes in altitude, latitude, tidal level or distance from shore, coverage by water

pioneer community

the first community that grows on bare ground

climax community

has reached a stable stage of a limited number of species

primary succession

the colonisation of bare ground or rock with no existing living things

secondary succession

a succession started by an event such as forest fire or flood when sees that are dormant may be in the soil