Sampling techniques 11.3

Question 1

What are some techniques and tools used to sample animals

Answer 1

• Sweep nets: used to catch insects in areas of long grass
• Tree beating: take samples of invertebrates living in tree/bushs.
  ^large white cloth stretched under tree.
  ^tree shaken/beaten to dislodge invertebrates.
• kick sampling: used to study organisms in river.
  ^river bank/bed kicked to disturb substrate.
  ^net is held downstream to capture any organisms released

Question 2

How are plants usually sampled

Answer 2

• quadratic sampling

Question 3

what are the 2 main types of quadrets

Answer 3

• Point quadrat
• Frame quadrat

Question 4

what is a point gradrat

Answer 4

it consists of a frame containing a horizontal bar. At set interval along the bar, long pins can be pushed through the bar to reach the ground. Each species of plant the pin touches is recorded

Question 5

what is a frame quadrat

Answer 5

It consists of a square frame divided into a grid of equal sections. The type and number of species within each section of the quadrat is recorded

Question 6

what are the 3 main ways of using a frame quadrat to sample populations of plants in living habitats

Answer 6

• To calculate density, number of certain plant in quadrent gives density per square metre
• to calculate frequency, count number of certain species in boxes within quadrent (used when species r hard to count)
• % cover, % cover of certain species is estimated in quadrent

Question 7

what technique can be used to estimate animal population size

Answer 7

capture-mark-release-recapture is often used to estimate a population size.
This involves capturing as many individuals of a species in an area as possible. The organisms are marked and then released back into the community.
Time is allowed for the organisms to redistribute themselves throughout the habitat before another sample of animals is collected.
By comparing the number of marked individuals with the number of unmarked individuals in the second sample.
The greater the number of marked individuals recaptured, the smaller the population

Question 8

what is meant by abiotic factors

Answer 8

Abiotic factors are the non-living conditions in a habitat.
examples are the amount of light and water availability

Question 9

Name some examples of abiotic factors and the sensor used to detect it

Answer 9

Question 10

what are the advantages of being able to detect abiotic factors with sensors in sampling

Answer 10

• rapid changes can be detected
• human error in taking a reading is reduced
• more accurate
• data can be stored and tracked on a computer