Unit 4 - Populations

Question 1

What does GPP stand for and what does it mean?

Answer 1

Gross Primary Productivity - the rate at which plants in a particular area can use light energy to incorporate it into food matter. (the rate at which photosynthesis occurs.)

Question 2

What does NPP stand for and what does it mean?

Answer 2

Net Primary Productivity - It is the Gross Primary Productivity - energy lost from respiration. (The amount of energy the primary consumer receives - from the producer.)

Question 3

What does Net Primary Production mean?

Answer 3

It is the amount of chemical energy, in biomass, which is created by primary producers in a certain length of time.

Question 4

Why might light energy hitting a leaf not be absorbed?

Answer 4

Some light energy:

• Is reflected
• Penetrates straight through the leaf
• Is at the incorrect wavelength to be absorbed.
• Is absorbed as heat energy

Question 5

How is energy lost within a trophic level, by consumers?

Answer 5

• Movement
• Heat
• Egestion
• Respiration

Question 6

What is a habitat?

Answer 6

The place where an organism normally lives

Question 7

What is a population?

Answer 7

Individuals of the same species in a given area.

Question 8

What is a community?

Answer 8

Multiple populations - of different species - in the same area.

Question 9

What is an ecosystem?

Answer 9

The interaction between a community and the surrounding abiotic factors.

Question 10

What is a niche?

Answer 10

An organism’s role in it’s ecosystem.

Question 11

What is interspecific competition?

Answer 11

Competition for food, habitats/land and mates between organisms of different species.

Question 12

What is intraspecific competition?

Answer 12

Competition for food, habitats/land and mates between organisms of the same species.

Question 13

What are biotic factors?

Answer 13

Living components that affect organisms.

Question 14

What are abiotic factors?

Answer 14

Non-living components that affect organisms.

Question 15

What is random sampling (of a population)?

Answer 15

Sampling a population in a way that eliminates bias.

Question 16

What is systematic sampling?

Answer 16

Regular sampling across an area, e.g transect line.

Question 17

Describe the capture, mark, release, recapture method of sampling.

Answer 17

A sample of organisms from the target population is safely caught and marked in a way that will not harm the organisms. They are then released back into their habitat and then a certain amount of time later, e.g 2 weeks, the same number of organisms are caught again from the same habitat.

Question 18

What is the formula for population size based on the capture, mark, release, recapture method?

Answer 18

number in 1st sample x number in 2nd sample
____________________________________
number of organisms marked in 2nd sample

Question 19

What is a transect line?

Answer 19

A line of rope or string that is placed across a habitat. (Any organism that passes over the line is recorded.)

Question 20

What is a belt transect?

Answer 20

Two lines parallel to each other placed across a habitat. (any organisms within the ‘belt’/between the two lines are recorded.)

Question 21

What is the capture, mark, release, recapture method aimed to do?

Answer 21

Estimate the size of the population.

Question 22

What 6 assumptions are made when using the capture mark release recapture method?

Answer 22

• the proportion of marked : unmarked individuals marked in the 2nd sample is the same proportion for the whole population.
• Individuals in the 1st sample distribute themselves evenly.
• The population has a definite boundary - no/very little emigration or immigration occurs.
• There are no/very few births and deaths between the 1st and 2nd samples.
• the marking method does not harm or kill organisms.
• the marking is not lost/stays on organisms between 1st and 2nd sample.