B4 Flashcards
What do you have to make sure when sampling
Take a big enough sample to make the results a good and reliable estimate -the larger the sample and then the more accurate the results
Sample randomly -the more random the sample the more likely it is to be representative of the population
What are pooters
Suck up insects in a container.there is a mesh to stop insects from getting into your mouth. Its an easy way to gather insects without harm .with this method you get to find out which species are present.although you have to systematic about your sampling in order to get representative results and it is difficult to ideas of number
What are sweep nets
A net to gather insects which is used in long grass or moderately dense woodland where there are lots of shrubs. However difficult to get truly representative samples ,particularly in terms of the relative numbers of organisms
What are pitfall traps
Put into the ground .used to catch insects .they’re able to crawl in through the sides and then they fall in.this method can give an indication of the relative numbers of organisms in a given area if enough are used to give a representative sample
What are Quadrats
Square frames with an area of 0.25 m. They have excellent results if thrown randomly .
Why are animal populations difficult to sample
Most species are highly mobile and are not easily visible because they are usually hiding from predators
Name the capture recapture method
Lincoln index
Explain what happens in the Lincoln index
Animals are caught humanely ,they count them and record their number .they are then marked .they are then released for a suitable amount of time.a second sample is obtained which will contain some marked animals and some unmarked .the numbers of each groups are counted again
Whats the formula that can be used to estimate the total population size in the habitat .
Population size=number in the 1st sample (all marked ) multiplied by number in second sample (marked and unmarked) divided by the number in the second sample which were previously marked in the 1st sample
What is zonation
Zonation is described as a gradual change in the distribution of a species across a habitat.
What is a habitat
Habitat of a plant and an animal is the part of the physical environment where it leaves.
What is a community
The total number of individuals of all the different population of organisms that live together in a habitat at any one time
What is Biodiversity
The variety of different species living in a habitat.
What is an ecosystem
Is a physical environment with a particular set of conditions plus all the organisms that live in it .
Explain what a Natural ecosystems
Theyre not man made .they change over time e.g native woodlands
