1.5 Predation

Question 1

EXAM QUESTION:

stickleback
freshwater shrimp mayfly lava
single-celled producer

Use the diagram to explain the likely effect of a sudden decrease in the stickleback population on the population of mayfly larvae.

Answer 1

1. (With fewer fish) reduced
predation / not being eaten
results in more freshwater
shrimps;
2. Increased competition for
food/resources / more
producers eaten by shrimps /
more shrimps eating
producers;
3. Less food/resources for mayfly

Question 2

Define predator

Answer 2

An organism that consumes another organism (prey)

Question 3

Define prey

Answer 3

An organism that is consumed by another organism (predator)

Question 4

Define predation

Answer 4

When one organism is consumed by another.

Question 5

In laboratory habitat? (4)

Answer 5

Prey exterminated by predator:
Small range and variety
No refuges/hiding places
Less chance of survival

Question 6

In natural habitat? (4)

Answer 6

Prey population decreased by predator, not exterminated
Great range and variety
Many refuges/hiding places
Greater chance of survival

Question 7

Why are predation investigations unreliable? (2)

Answer 7

Laboratory results - do not reflect what happens in the wild.
Natural results - impossible to count every organism

Question 8

Describe the effect of predator-prey relationships on population size (4)

Answer 8

1. Predators eat prey, prey population decreases
2. Competition increases, predator population decreases
3. Fewer predators, prey population increases
4. More prey, predator population increases

Question 9

Cyclic fluctuations create? most?

Also caused by? (2)

Answer 9

Selection pressure, advantageous alleles remain in population.
Disease, climatic factors.