17: Animal Migration

Question 1

FULL Definition of Animal Migration

Answer 1

Movement of individuals/populations between two well-defined habitats on a temporally predictable basis (usually with a return journey)

Question 2

Define Anadromy

Answer 2

Some fish (e.g. salmon) migrate from freshwater to salty oceans to forage and grow, before returning to freshwater to breed (some do this once, some multiple times)

Question 3

Define Catadromy

Answer 3

The reverse of anadromy (migration from salty oceans to freshwater, and back again)

Question 4

Define Diel Vertical Migration (DVM)

Answer 4

The synchronised movement of zooplankton and fish up and down in the water column over a daily cycle

Question 5

Explain the probable reason for Diel Vertical Migration

Answer 5

Predators of these zooplankton are visually oriented, so staying near the surface during the day would make them more vulnerable to being eaten

Question 6

Name 4 potential costs of migration

Answer 6

Energetic cost of moving
Increased predation risk en route
More pathogens and parasites
Uncertainty of conditions on arrival

Question 7

What is the reason for migration of Norwegian Red Deer?

Answer 7

Foraging migration - they change their grazing locations in response to waves of vegetation greening

Question 8

What is the reason for migration in Arctic Shorebirds?

Answer 8

To reduce the risk of nest predation (varies significantly with latitude)