2.4 Sex and Behaviour

Question 1

Define parental investment

Answer 1

The use of resources by a parent to benefit future or existing offspring

Question 2

Result of parental investment

Answer 2

increased number of offspring and their improves chances of survival, therefore increasing the evolutionary fitness of the parent

Question 3

What type of eggs do selection pressures favour and why?

Answer 3

large eggs as they can store more energy for new offspring

Question 4

Which parent makes a larger investment in terms of energy for their offspring? and how?

Answer 4

Female. Due to the production of larger gametes and the gestational period in mammals

Question 5

Describe the characteristics of R-selected populations and K-selected populations.

Answer 5

on physical flashcard

Question 6

Explain the difference between internal and external fertilisation

Answer 6

internal occurs within the female while external does not

Question 7

Costs of external fertilisation

Answer 7

• Many gametes are not fertilised
• No/limited parental care
• Few offsprings survive

Question 8

Costs of internal fertilisation

Answer 8

• A mate must be located (requires energy)
• Requires the direct transfer of gametes

Question 9

Benefits of internal fertilisation

Answer 9

• Increased chance of sucessful fertilisation
• Fewer eggs needed
• Offspring can be retained internally for protection and development
• Higher offspring survival rate

Question 10

What are mating systems based on

Answer 10

How many mates an individual has during one mating season

Question 11

Define polyandry

Answer 11

One female mates with a number of males in one breeding season

Question 12

Define Polygyny

Answer 12

One Male mates with a number of Females in one breeding season

Question 13

Successful courtship behaviour in birds and
fish can be a result of

Answer 13

Species-specific sign stimuli and fixed action pattern responses

Question 14

Sexual selection selects for

Answer 14

Characteristics that have little survival benefit for the
individual, but increase their chances of
mating

Question 15

What is a product of sexual selection

Answer 15

Sexual dimorphism

Question 16

Describe Sexual dimorphism in terms of males and females

Answer 16

Females are generally inconspicuous

Males usually have more conspicuous markings,
structures and behaviours.

Question 17

Describe Reverse Sexual dimorphism

Answer 17

In this case the females may be bigger and brighter than the males

Question 18

Define Sexual dimorphism

Answer 18

Differences between the two sexes of one species, except reproductive organs

Question 19

What is female choice

Answer 19

Females assessing honest signals of the fitness of males

Question 20

What do honest signals indicate?

Answer 20

Honest signals can indicate favourable
alleles that increase the chances of survival
of offspring (fitness) or a low parasite burden
suggesting a healthy individual.

Question 21

What happens in lekking species regarding female choice

Answer 21

In lekking species, males gather to display at
a lek, where female choice occurs

Question 22

Describe different male behaviours in lek’s

Answer 22

Dominant males occupy the centre of the lek

Subordinates and juveniles are at the fringes
as ‘satellite’ males. They try to intercept females in the crowd

Question 23

Success in male-male rivalry through conflict increases

Answer 23

Access to females for mating

Question 24

What do males typically fight for and with what?

Answer 24

Males will fight for dominance and access to
females, often using elaborate ‘weapons’
such as antlers, tusks, horns.