Measuring Populations

The measure of the average length of time an individual will live.

• Demography

• Life Expectancy

• Baby Boom

• Growth Rate

What is the life expectancy of males in Canada in the year 2000 ?

• 77

• 74

• 82

• 80

If 50 crabs were captured and marked and then released and then a few days later 25 were caught and of those 5 were marked. What would the estimate of the population be?

• 500

• 250

• 75

• 200

Conservationists want to find the population of a species of mountain goat. On one day they capture 12 goats, tag them and release. A week later they capture 8 goats, 5 of which are tagged. What would the estimate of the population be?

• 19

• 40

• 72

• 30

Why do scientists use sampling techniques to gather population data?

• their lazy

• it is not possible to count an entire population

• it is too easy to count an entire population

• they like to make estimations

If I wanted to know approximately how many blades of grass are inside the track, which sampling method could I use?

• Count every blade of grass

• Mark and Recapture Technique

• Random Sampling Technique

Which of the following accurately describes the difference between mark recapture and random (quadrant) sampling?

• Quadrant sampling is used for mobile populations and mark recapture is used for stationary populations

• Quadrant sampling is used for stationary populations and mark recapture is used for mobile populations

• Quadrant sampling can only be used for small populations

• Mark & recapture sampling can only be used for small populations

Say you are doing mark & recapture with a population of fish, but most of your marked fish die before your recapture is conducted. Will your population estimate be overestimated or underestimated?

• it will be an overestimate

• it will be an underestimate

• it will not effect your estimate

• it will still be accurate

Tags

NGSS.HS-LS2-2

When a population needs to be estimated, scientists:

• count every individual they can find

• randomly guess the population

• sample the population and use a formula to estimate

When scientists wish to sample plant populations, which technique should they use?

• Random (Quadrant) Sampling

• Mark and Recapture