Populations and Ecosystems
Population = All the organisms of one species in a habitat at one time
Community = All the organisms of all species in a habitat at one time
Ecosystem = A self supporting unit where all organisms interact with biotic and abiotic factors
Niche = The role of a species in its environment
The study of the inter-relationships between organisms and their environment is called ecology. The layer of land, air and water that surrounds the Earth is called the biosphere. An ecosystem is more or less a self contained functional unit made up of all the living (biotic) features and non living (abiotic) features in a specific area. Within each ecosystem are groups of different organisms called a community, which live and interact in a particular place at the same time. A group of interbreeding organisms occupying the same place at the same time is called a population, and the place where they live is known as a habitat.
- Eliminates bias - more representative sample
- When a species occurs in groups - large number of smaller quadrats
- More species = more quadrats
- Larger species = large quadrats
- Shows transition of species distribution along transect
- Line transect - any organism over which line passes is recorded
- Belt transect - shows density of species
- Abundance = number of individuals of a species within a given space.
- Frequency = likelihood of a particular species occurring in a quadrat (gives idea on general distribution but not on density). Number of samples a species is recorded in.
- Percentage Cover = estimate of the area of which a plant species covers…