biodiversity & distribution of organisms ( key areas 1&2)

The range (variety/number) of species within an ecosystem.

A group of organisms which can interbreed and produce fertile offspring.

The total number of living organisms of one type (species) living in a habitat.

BIOTIC factors are living things that affect the distribution of organisms e.g., competition for resources, grazing, predation, food availability, and disease.

Competition is the struggle between individuals when resources are in short supply / limited e.g. food, light, water etc. The effects of competition include the more successful species increasing in number and less successful species decreasing in number.

The place where an organism lives e.g. in water, in soil, trees etc.

All the organisms (e.g. plants, animals and micro-organisms) that live in a particular area.

All the organisms (the community) living in a particular habitat and the non-living components with which the organisms interact. Sometimes written as: Community + habitat

interspecific intraspecific

a producer makes their own food by photosynthesis

a consumer is an animal which eats other organisms

A predator is an animal that hunts and eats other animals

prey is an animal that is hunted and eaten by other animals

a herbivore is an animal which eats only plants

an omnivore is an animal which eats plants and animals

a carnivore is an animal which eats only animals

A decomposer is an organism which feeds on dead organisms.

they represent the direction of energy flow

hunting, fishing, using chemicals that cause pollution

interspecific - competition which occurs amongst different species for one or a few of the resources they require

intraspecific - competition which occurs amongst individuals of the same species for all resources required, intraspecific competition is more intense than interspecific

ABIOTIC factors are non - living things that affect the distribution of organisms e.g. temperature, pH, light intensity and humidity

at low levels of grazing slow growing species will die as they are out competed for resources by faster growing species

at intermediate levels of grazing some of the faster growing species are eaten so as a result the slower growing species are able to survive therefore increasing biodiversity