Communities of Organisms Flashcards
What is meant by the distribution of organisms in an area?
The spread of different organisms over an area.
Name 3 physical factors that affects the distribution of organisms in an area
Any from: temperature, nutrients, amount of light, availability of water, availability of oxygen in water or soil, availability of carbon dioxide
Why do we take multiple measurements when collecting data in an area?
To make the results more reliable
How do we calculate the mean?
Add up all the values and divide the answer by the number of values there are
How do we calculate the median?
Rearrange the values from smallest to largest and find the middle value
How do we calculate the mode?
Find the value that that appears the most
Calculate the mean, median and the mode from the following results:
1, 8, 11, 6, 1, 44, 7, 30, 88
Mean: (1+8+11+6+1+44+7+30+88) ÷ 9 = 21.78
Median: 1, 1, 6, 7, 8, 11, 30, 44, 88 = 8
Mode: 1, 1, 6, 7, 8, 11, 30, 44, 88 = 1
What is meant by biodiversity?
The variety of organisms that live in an area
Give an example of an area with a high amount of biodiversity
The countryside
Give an example of an area with a low amount of biodiversity
Urban areas
To count the number of species in a large area it is easier to carry out…
Sampling
What is the definition of Random Sampling?
A computer picks coordinates at random from a grid on a map. A quadrat is placed at these random location and a sample (count of organisms) is taken.
What is the definition of Systematic Sampling?
Coordinates from a grid on a map are chosen at set intervals. A quadrat is placed at these locations and a sample (count of organisms) is taken.
How can the reliability of sampling be improved?
By taking more samples (place more quadrats)
If the reliability is improved then the estimated population of a species will be more…
Valid
