Biology - Ecological Techniques

Definitions:

Population: All the individuals of a species present in an ecosystem

Community: All the organisms present in an ecosystem

Ecological Niche: An organisms role within an ecosystem. Encompasses a species physiology, food source and habitat.

Habitat: Where an organism lives in an ecosystem

Abiotic: Non-living factors

Biotic: Living factors

Ecology: Is the scientific study of the factors which determine the abundance and distribution of organisms

Abundance: Number of individuals of a species found in a given space.

Distribution: Geographical area within which that species can be found

How can you collect a random sample?

Mark out a grid and use a random number generator to calculate co-ordinates this in turn avoids sampling bias. Count the abundance of species at each quadrat and take a relatively large sample allowing it to be representative of the population.

How can you be sure a sample is sufficient?

You can calculate a running mean, at first it will fluctuate however once this narrows your sample size is great enough to be representative of the population.

Percentage Cover:

This is a measure of the proportion of ground occupied by the species, it estimates area covered by that species

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