Biology - Ecology

Ecology

the study of the interactions between living things (organisms) and between organisms and their environment

Biosphere

the part of the planet containing living organisms

Ecosystem

a group of clearly distinguished organisms that interact with their environment as a unit

Habitat

the place where a plant or animal lives

Population

all the members of the same species living in an area

Community

all the different populations in an area

Abiotic Factors

non-living factors

Biotic Factors

living factors

Climatic Factors

refer to weather over a long period of time

Edaphic Factors

relate to soil

Producers

organisms that carry out photosynthesis

Flora

all the plants in an ecosystem

Fauna

all the animals in an ecosystem

Consumers

organisms that take in food from another organism

Primary Consumers

feed on producers

Secondary Consumers

feed on primary consumers

Tertiary Consumers

feed on secondary consumers

Top Consumer

the name given to a consumer that no other organism feeds on

Grazing Food Chain

a sequence of organisms in which each one is eaten by the next member in the chain

Trophic Level

a feeding stage in a food chain

Trophic

relating to feeding and nutrition

Food Web

consists of two or more interlinked food chains

Pyramid of Numbers

represents the number of organisms at each trophic level in a food chain

Ecological Niche

the functional role an organism plays in the community

Nutrient Recycling

the way in which elements are exchanged between the living and non-living components of an ecosystem

Nitrogen Cycle

• nitrogen gas is converted into ammonia (NH3), ammonium (NH4+), or nitrate (NO3-)

• decomposition occurs, organisms release nitrogenous compounds into the soil

• ammonia and ammonium are converted to nitrite, then to nitrate

• denitrifying bacteria in the soil convert nitrate to nitrogen gas

Carbon Cycle

• carbon dioxide is fixed into plant carbohydrate

• living organisms release carbon dioxide

• the decay of organisms releases carbon dioxide

• the combustion of fossil fuels releases carbon dioxide

Nitrogen Fixation

the conversion of nitrogen gas into ammonia (NH3), ammonium (NH4+), or nitrate (NO3-)

Nitrification

the conversion of ammonia and ammonium compounds to nitrite, and then to nitrate

Denitrification

the conversion of nitrates to nitrogen gas

Pollution

any harmful addition to the environment

Pollutants

harmful additions to the environment

Conservation

the wise management of the existing natural resources in an ecosystem, in order to maintain a wide range of habitats and prevent the death and extinction of organisms

Competition

occurs when organisms actively struggle for a resource that is in short supply

Intra Specific Competition

takes place between members of the same species

Inter Specific Competition

occurs between members of different species

Contest Competition

there is an active physical contest between two individual organisms

Scramble Competition

all of the competing individuals get some of the resource

Predation

the catching, killing and eating of another organism

Predator

an organism that catches, kills and eats another organism

Prey

the organism that is eaten by the predator

Parasitism

occurs when two organisms of different species live in close association and one organism (the parasite) obtains its food from, and to the disadvantage of, the second organism (the host)

Exoparasites

live on the outside of the host

Endoparasites

live inside the host

Symbiosis

occurs when two organisms of different species live (and have to live) in close association and at least one of them benefits

Mutualism

a form of symbiosis in which both organisms benefit from the association