Distribution and Abundance B6 Flashcards
What is a transect?
A line through a habitat along which organisms are sampled.
What is abundance?
Abundance is the number of organisms.
What is distribution?
Distribution is where the organisms are.
What is sampling and why is it commonly used?
Sampling is where only a certain amount of organisms are measured and the measurements are used to make predictions for the total population. It is used because measuring a whole area would be very time consuming or impossible.
What does a transect measure?
Transects are used to observe and record changes in distribution across an area.
What are quadrats?
Quadrats are square frames that have been subdivided into lots of smaller squares.
What is an example of the use of a quadrat?
1) Place tape measures along the length and width of an area, forming a large grid.
2) Use a random number generator to generate 10 pairs of random coordinates.
3) Place quadrats at these coordinates and count how many dandelions are in each quadrats.
4) Calculate the mean number of dandelions per m^2.
5) Estimate the total population size using the mean number per m^2 answer the total area of the field.
What is an example of the use of a transect?
1) A transect line usually tape measure is laid out in a straight line between the lake and woodland.
2) Quadrats are placed at regular intervals along the transect line.
3) The abundance of dandelions is measured by counting the number of dandelions in each quadrats along the transect line.
4) Step 1-3 are separated using new transect lines (these must be parallel to the first). By using multiple transect lines, the data gathered is more representative of the area.
What is a pooter?
A pooter is used for catching small insects on the ground, it is a small suction device with mesh to stop people from sucking bugs into their mouth.
What is a pitfall trap?
Pitfall traps are used for catching small crawling insects. They consist of a hole in the ground and something covering the top so that no water comes into the hole and kills the insects.
What is a pond net?
A pond net is used for catching water invertebrates/small fish. It is a net with small mesh so that fish etc. can be caught.
What is a sweep net?
A sweep net is used for catching flying insects. A sweep net is almost like a pond net but it has no mesh.
What is the capture-mark-recapture method?
1) Capture a sample of the population and count the number of animals caught in the trap. 2) Mark them in a harmless way and release them back into the environment. 3) Recapture another sample of the population and count how many are marked. 4) Then estimate a population size with the equation: number in 1st sample x number in 2nd sample ➗ number in 2nd sample that are marked.
What is the equation for the estimate of a population size when using the capture-mark-recapture method?
Population size = no. in 1st sample x no. in 2nd sample ➗ number in 2nd sample that are marked.
