sampling techniques

• state all the possible non-random sampling techniques used to collect living organisms

  • pooter- sucking in small insects using mouthpiece, inlet tube, and filter to prevent entrance to mouth
  • sweep nets- insects in long grass
  • pitfall traps- deep hole dug in ground, covered with roof, propped above so doesn't fill with rain. Done overnight to capture nocturnal species
  • tree beating- white cloth under tree, tree shaken/beaten, insects fall onto cloth
  • kick sampling- kicking the river banks to disturb substrate, net held downstream to catch organisms released into water
• how are plants sampled?

  • using quadrats
  • quadrats can be placed systematically along a belt/line transect
• what are the two different types of quadrats?

  • point quadrat
  • frame quadrat
• what are the two different types of quadrat and what do the look like?

  • point quadrat
  • frame quadrat

  
• what sampling technique is used to place quadrats? random or non-random?

  random
• how do you calculate species evenness within a frame quadrat?

  • place multiple quadrats at different points

  three ways of estimating size within quadrat:

  • density- counting organisms in each 1 by 1 square
  • frequency- for individual species hard to count eg grass/moss, count squares number of species present in eg- moss present in 65/100 squares
  • percentage cover- when species is abundant, estimate by eye of the area in a quadrat which a species covers

  
  

  • mean- by adding up individual quadrat results, then dividing this by number of quadrats placed
  • multiply the mean per m2 of the total area
• how do you calculate the number of organisms per m2 of an area

  • place multiple quadrats at different points
  • calculate mean by adding up individual quadrat results, then dividing this by number of samples taken/quadrats placed
  • multiply the mean value per m2 of the total area
• what technique is often used to calculate species evenness for the number of MOVING animals in a population?

  • capture recapture
  • the greater the number of marked individuals recaptured, the smaller the population
• how can species richness be calculated?

  By using a combination of random and non random sampling techniques:

  NON RANDOM-

  • Pooter
  • sweep nets
  • pitfalls
  • tree beating
  • kick sampling
  • line/belt transects

  RANDOM

  • quadrats (frame or line)

  list of species compiled and number of species identified. Scientists can use keys to identify species
• what are the two techniques to calculating species evenness?

  • using frame quadrat- for plants
  • capture-recapture- for moving animals
• what are the different ways of measuring abiotic factors?

  ways:

  A) anemometre

  B) humidity sensor

  C) ph probe

  D) temperature probe/thermometre

  E) oxygen

  F) light

  
• why is the usage of precise sensors to measure abiotic factors useful?

  • eliminates human error
  • high degree of precision
  • rapid changes can be detected