GROUPS- PROTECTION AGAINST PREDATORS

Question 1

Social groups respond to_____ while animals aggregrate as a result of ______

Answer 1

Each others presence; specific environmental features e.g. food

Question 2

3 advantages of grouping?

Answer 2

1.Protection against predators
2.Improves foraging
3.Protection from physical factors

Question 3

What ecological pressures favour group living?

Answer 3

Predators and food

Question 4

How does being in a group provide protection from predators?

Answer 4

Increased vigilance
Dilution
Predator confusion

Question 5

1.Increased vigilance

Answer 5

Each individual spends less time in watching out and so has more time feeding. The more scanners the quicker the response

Question 6

Why do individuals not cheat -profit from vigilance of others but don’t look out themselves?

Answer 6

Theory that the first animal to spot predator has best chance of escape (e.g. Thompsons gazelles)

Question 7

2.Dilution

Answer 7

The larger the group, the smaller the chance that any individual will be taken by a predator
Slight negative of larger group being more obvious

Question 8

Shielding “Selfish herd” (Hamilton)

Answer 8

Members of a group use other members as protection- a living shield-against predators.

Question 9

3. Predator confusion

Answer 9

Many prey moving about make it hard for predator to fix on and follow any one of them

Question 10

Example of predator confusion -pike

Answer 10

Predatory fish pike catches more prey when given one fish at a time rather than a shoal

Question 11

Why animals give alarm calls?

Answer 11

Whole group moves to protect animal who saw predator (as they know location)

Question 12

Group defensive behaviour includes?

Answer 12

Mobbing predators

Question 13

Value of mobbing behaviour?

Answer 13

Distracts predators from mobbers offspring