Unit 2.4b

Question 1

What is monogamy?

Answer 1

It’s when a pair of animals mate to the exclusion of all others i.e. they mate for life

Question 2

Why do animals often choose monogamy?

Answer 2

It means both parents are involved in parental care so offspring that require high levels of parental care receive this

Question 3

How does monogamy benefit parents?

Answer 3

More viable offspring are produced as their parental care is provided for

Question 4

Is this Schistosoma parasite monogamous?

Answer 4

Yes very, the female of the pair lives within a canal like structure of the body of the male

Question 5

What is polygamy?

Answer 5

Is your umbrella term for individuals of one sex having more than one mate

Question 6

What two categories can polygamy be divided into?

Answer 6

Polygyny and Polyandry

Question 7

What is polygyny?

Answer 7

It is when one male mates exclusively with a group of females

Question 8

In polygyny what are the roles of the male and females?

Answer 8

In mammals, the female is often the food source for young i.e. milk
The males often have a role of protecting, but not feeding

Question 9

What is polyandry?

Answer 9

This is when one female mates with a number of males during the same breeding season

Question 10

What is courtship?

Answer 10

It’s a specialised behaviour that attracts a member of the opposite sex and leads to mating

Question 11

How do you courtship rituals increase the chance of sexual reproduction?

Answer 11

Animals use signals that only other members of the same species can understand. This could be giving of chemicals or making sounds or certain displays to initiate mating. This means that individuals can mate when they are most fertile.

Question 12

What is a fix action pattern?

Answer 12

It is an instinctive behaviour sequence is relatively consistent within the species and will run to completion

Question 13

What are fixed action patterns a series of?

Answer 13

They are a series of sign stimuli followed by responses

Question 14

What is a sign stimulus?

Answer 14

This stimulus triggers fixed action pattern response in another individual of the species.

Question 15

Are conspicuous physical traits in animals, beneficial or not?

Answer 15

It is both beneficial and negative for organisms, but in light of natural selection the benefits outweigh the negatives.
The negatives are that organisms are more visible to predators decreasing survival chances
The benefits are greater success in obtaining mates, i.e. higher fitness

Question 16

What does sexual dimorphism usually refer to?

Answer 16

Physical difference between male and females of the same species. However, the males are usually larger have secondary sex structures (ie. Antlers) and are much more colourful than the females.

Question 17

How did sexual dimorphism come to be?

Answer 17

Sexual selection

Question 18

Why are females not usually coloured?

Answer 18

To increase the survival of her offspring as it reduces predation

Question 19

What is reverse sexual dimorphism?

Answer 19

When the normally inconspicuous female is larger and more ornate than the male

Question 20

Why are males often smaller in reverse sexual dimorphism?

Answer 20

Because they often have to travel long distances in search of females so smaller size means more speed and stealth

Question 21

Why is it sometimes beneficial for mothers to be larger than the male?

Answer 21

If gestation and lactation, last for a few months, lodging mothers are able to provide for this better

Question 22

What is an example of reverse sexual dimorphism?

Answer 22

Myotis bats have larger females as producing eggs has a much higher energy cost than producing male sperm. Female bats would also not be able to fly and catch prey if they were smaller as they need to support the mass of their offspring.

Question 23

What are the two types of sexual selection that determine reproductive success?

Answer 23

Male-male rivalry
Female choice

Question 24

What is male-male rivalry?

Answer 24

It is when males fight for dominance when acquiring and defending territories and mates, giving them access to females. They often use weapons like antlers, tusks and horns

Question 25

What is an alternative that males take to mate instead of male-male rivalry?

Answer 25

Adopting the role of a ‘sneaker’ or ‘satellite’ male as this avoids engagement in direct conflict

Question 26

Do males or females have primary control over reproduction?

Answer 26

Females

Question 27

What are the three main male roles that play a part in female choice?

Answer 27

Male resources
Male appearance
Courtship displays

Question 28

What does female choice allow the female to assess?

Answer 28

It allows them to assess how much parental care the male may offer

Question 29

What does male courtship an appearance provide for the females?

Answer 29

Honest signals of male fitness. It indicates if it’s a healthy male with low parasite, burden, and the presence of any advantageous genes

Question 30

Why do females like to choose the healthier/better males?

Answer 30

To increase their own fitness and reproductive success as they have to put a greater investment in reproduction so healthier offspring means less parental care

Question 31

What is lekking?

Answer 31

It’s when males cluster in a communal display area (known as a leak) during breeding season where they can display themselves and fight each other to attract females. The females observe, and then select the fittest male to mate with.

Question 32

How do you males arrange themselves in a lek?

Answer 32

Dominant males occupy the centre
Subordinates and juveniles at the fringes as ‘satellite’ males