1 A habitat is a place where an organism lives. The niche of an organism is the role that it plays in the community.2 A population is a group of organisms of the same species, living in the same place at the same time, that can interbreed with one another. A community is all the organisms, of all the diff erent species,...

Living organisms need nitrogen because nitrogen atoms are an essential part of proteins, nucleic acids and ATP. The air contains about 78% nitrogen gas. However, this is in the form of nitrogen molecules, in which two nitrogen atoms are held together by a very strong triple covalent bond. This is very unreactive.Nitrogen...

Ecology is the study of the ways in which organisms interact with their environment.Levels of ecological organisationA habitat is a type of environment in which an organism lives. For example, the habitat of a giraffe is grassland (savannah) with groups of trees such as Acacia. The habitat of a woodlouse (Oniscus) is a...

• Levels of ecological organisation• Energy flow through ecosystems• Recycling of nitrogenLearning OutcomesCandidates should be able to:(a) define the terms habitat, niche, population, community and ecosystem and be able to recogniseexamples of each ;(b) explain the terms autotroph, heterotroph, producer, consumer and...