Lecture 1: Introduction to Ecology, Levels of Organisation

Transcription

1 DEFINITION OF TERMS Lecture 1: Introduction to Ecology, Levels of Organisation Ecology Habitat Niche Population Community Ecosystem ECOLOGY this is the study of relationships of living organisms with each other and their non living or physical surroundings (abiotic) Biotic and Abiotic Factors Biotic factors that are or were alive/living in an ecosystem. Examples: animals, plants, insects, bacteria, fungi, and dead organisms. Abiotic Factors Factors in an environment that are not or never were alive. Examples: rock island, gases, water, sun, minerals and temperature. HABITAT This is the typical environment in which an organism lives. This is determined by physical ( abiotic) and biotic factors. Physical or abiotic factors are the soils, moisture, heat and light. The biotic factors are the living organisms. An organism may not thrive if this is also a perfect location for its main competitors and predators or lacks its preferred food or nesting materials. For example the habitat of a Jew s ear fungus is a woodland, the biotic factors are live/ dead wood from which it obtains its nutrition. The abiotic factors are it is autumnal, needs cooler temperatures, high moisture levels in the soil and high humidity. There maybe a particular location within the same overall habitat that may have their own special conditions and these are called microhabitats such as a bark of a rotting tree. 1

2 Habitat A place where an organism lives or can be found. NICHE This the role taken by a type of organism within its community. This is classified into: the potential niche, and the realised niche. Ecological niche The ecological niche is the functional position of an organism in its environment, comprising its habitat and the resources offered by the habitat and the periods of time during which it is active. This describes both the location and the job of an organism, for example, pollinator, decomposer, predator, producer, within a particular community or ecosystem POTENTIAL NICHE The abiotic and biotic conditions under which an organism could occur REALISED NICHE A role an organism is forced to occupy as a result of pressure from and interactions with other organisms eg superior competitors. This niche is usually narrower. POPULATION A group of organisms of one species occupying a defined or specific area. 2

3 COMMUNITY This is a group of organisms belonging to a number of different species that coexist in the same habitat or area and interact through trophic and spatial relationships. Eg algae, fish, mosquito larvae etc in a pond ECOSYSTEM This is a community of organisms and their physical environment interacting as an ecological unit. Biomes A biome is a large geographical area with a similar climate. The Biosphere The biosphere is the region on Earth where all life exists. Collectively, all the biomes of the planet earth make up the biosphere. Levels of ecological organisation The most basic level of ecological organization is the individual/species. A group of individuals of the same species make up a population. A community is all the populations of living organisms in an area. An ecosystem is an interacting system that consists of groups of organisms and their nonliving environment. Levels of ecological organisation cont.. No individual organism lives completely on its own. It may live with other individuals of the same species to form a population. Several populations living together make up a community. Several communities in a given area make up an ecosystem. Several ecosystems in a given area make up a biome. Several biomes in a given area make up the biosphere. 3

4 Levels of Organization Summarised. Levels of organization Ecology is... The Biosphere the thin layer of the earth that supports life. If the earth was the size of an apple, the biosphere would be the thickness of its skin. Yuh know me; I keep it homeostatic. An organism has all the characteristics of life. Hey Marty, tell those two to keep their interaction PG. A population is group of interacting and interbreeding organisms. Members of a population must be all the same species. 4

5 A community is a group of interacting populations. A community includes all the living things (biotic factors) in one place. It contains no abiotic factors. Is he trying to tell me something? An ecosystem is a community plus its non-living (abiotic) environment. Abiotic Factor Biotic Factor The end..!!!!! QuesTions.???? 5