B4a-Ecology in the Local Environment
large but brief summary of B4a for GCSE OCR Biology B
- Created by: bridgiieexo
- Created on: 10-12-16 21:28
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- B4a-Ecology in the Local Environment
- Sampling methods
- Population is the total number of individuals living in a certain area.
- Can be determined by sampling methods
- Sampling must be done randomly
- larger sample=more reliable results
- Can be determined by sampling methods
- Pooters
- Insects can be gathered up easily and without harm
- Insects are sucked into a beaker trough a straw
- Fine mesh is over the other straw so they do not get sucked into your mouth
- easy to find out exactly what species are present in a certain area
- Difficult to get representative samples of organisms.
- Sweepnets
- Used in long grass or in woodlands where there are lots of shrubs
- Sweepnets
- Sweepnets
- Used in long grass or in woodlands where there are lots of shrubs
- Pitfall Traps
- Set into the grounds to catch insects
- Can give an indication of the relative numbers of organisms in a given area
- Occasionally can be filled with ethanol or detergent and water in order to kill the samples and stop them from escaping
- Can give an indication of the relative numbers of organisms in a given area
- Set into the grounds to catch insects
- Quadrats
- square frames, typically with a side length of 0.5m
- if placed randomly, can provide excellent results
- Easy to estimate the population of a certain species
- Population is the total number of individuals living in a certain area.
- Estimating animal Populations.
- More difficult than sampling because most species are highly mobile
- Not always visible either because they are usually hiding from predators
- Use the capture recapture method
- Captured humanely-counted, marked and then released.
- Same animals are captured and counted again
- Captured humanely-counted, marked and then released.
- More difficult than sampling because most species are highly mobile
- Zonation is the gradual change in the distribution of species across a habitat
- Important ecological terms
- Habitat-part of the physical environment where an animal or plant lives
- Population-the number of individuals of a species in a defined area
- Community-total number of all the different populations of organisms that live in a habitat
- Biodiversity-variety of different species living in a habitat
- Ecosystem-physical environment with a particular set of conditions
- and all the organisms that live in it
- Natural ecosystems are not man made
- They can still change over time
- Rivers and lakes
- Artificial ecosystems are man made
- carefully controlled to maintain a constant environment
- Sampling methods
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