Sampling Organisms

• What do abiotic factors not include?

  Living organisms
• What should you be able to describe by the end of this video according to the speaker?

  How to use quadrats and transects
• How do abiotic factors affect the number of organisms in a location?

  Abiotic factor levels vary from place to place
• What technique do scientists use to determine the number of organisms in an area?

  Sampling
• What are the two main methods of sampling discussed in the video?

  Random sampling and sampling along a transect
• What is random sampling primarily used for?

  To compare organism numbers in different areas
• What is a quadrat?

  A wooden or plastic square
• How is a quadrat used?

  It is placed on the ground
• What types of organisms can be effectively sampled using a quadrat?

  Plants and slow-moving animals
• A scientist wants to test if fewer ferns grow in sunny areas versus shady areas; which sampling method is most suitable?

  Random sampling
• In random sampling, how are quadrat locations determined?

  Using random numbers
• Why is it important to place the quadrat a large number of times during random sampling?

  To get valid results
• Why might a single quadrat placement not accurately represent an entire area?

  It may not reflect the whole area
• What does random sampling allow scientists to do regarding plant species?

  Compare numbers in different conditions
• If a study finds significantly more ferns in dark conditions than in light conditions, what can researchers conclude?

  The hypothesis is correct
• What equation is used to estimate the total population size of a species?

  Total area divided by area sampled, multiplied by number counted
• When is sampling along a transect most useful?

  When investigating species changes across a habitat
• What is a transect?

  A line such as a tape measure
• How is a transect line placed in a habitat?

  So it runs across the habitat
• What is used to count organisms at intervals along a transect?

  A quadrat
• What does sampling along a transect help to determine?

  How organism numbers change across a habitat
• On a rocky shore, scientists use a transect to study species distribution; what are they likely investigating?

  How species change across the shore
• Where would sampling along a transect be useful to investigate plant distribution?

  On a sand dune
• Why is it important to repeat a transect a number of times?

  To get valid results
• What can repeating transects provide valid data on?

  How species numbers change across the dune
• What ecological characteristics can be determined using quadrats and transects?

  Abundance and distribution of species
• What does the abundance of a species refer to?

  The number of organisms present
• What is meant by the term "distribution" of a species?

  Where the organisms are located
• What is an ecosystem?

  A community of living organisms and their physical environment
• What is placed at regular intervals along the transect line?

  A quadrat