Organisms and Evolution - Sex and Behaviour

Question 1

Which gender has the greatest parental investment?

Answer 1

Females

Question 2

Why is parental investment so great in some animals even although it is costly?

Answer 2

It increases the probability of production and survival of

young

Question 3

How are r-selected and k-selected organisms classified?

Answer 3

Based on level of parental investment in offspring and number of offspring produced

Question 4

What are the characteristics of r-selected species?

Answer 4

Smaller;
Have a shorter generation time; 
Mature more rapidly; 
Reproduce earlier in their lifetime, often only once; Produce a larger number of smaller offspring, each of which receives only a smaller energy input; 
Limited parental care;
Most offspring will not reach adulthood

Question 5

What are the characteristics of k-selected species?

Answer 5

Larger and live longer;
Mature more slowly;
Can reproduce many times in their lifetime;
Produce relatively few, larger offspring;
High level of parental care;
Many offspring have a high probability of surviving to adulthood

Question 6

Where does r-selection tend to occur?

Answer 6

In unstable environments where the species has not reached its reproductive capacity

Question 7

Where does k-selection tend to occur?

Answer 7

In stable environments

Question 8

What are the benefits of external fertilisation?

Answer 8

Very large numbers of offspring can be produced

Question 9

What are the costs of external fertilisation?

Answer 9

Many gametes predated or not fertilised;
No or limited parental care;
Few offspring survive

Question 10

What are the benefits of internal fertilisation?

Answer 10

Increased chance of successful fertilisation;
Fewer eggs needed;
Offspring can be retained internally for protection
and/or development;
Higher offspring survival rate

Question 11

What are the costs of internal fertilisation?

Answer 11

A mate must be located, which requires energy expenditure;

Requires direct transfer of gametes from one partner to another

Question 12

What are mating systems based on?

Answer 12

How many mates an individual has during one breeding

season

Question 13

What are the mating systems?

Answer 13

Polygamy - Polygyny
- Polyandry
Monogamy

Question 14

Define polygamy?

Answer 14

Individuals of one sex have more than one mate

Question 15

Define polygyny?

Answer 15

One male mates exclusively with a group of females

Question 16

Define polyandry?

Answer 16

One female mates with a number of males in the same breeding season

Question 17

Define monogamy?

Answer 17

The mating of a pair of animals to the exclusion of all others

Question 18

What can successful courtship behaviour in birds and

fish be a result of?

Answer 18

Species-specific sign stimuli and fixed action pattern responses

Question 19

Describe sexual selection

Answer 19

Sexual selection selects for characteristics that have little survival benefit for the individual, but increase their chances of mating

Question 20

What do many species exhibit as a product of sexual selection?

Answer 20

Sexual dimorphism

Question 21

Describe males and females involving sexual dimorphism?

Answer 21

Females are generally inconspicuous; males usually have more conspicuous markings, structures and behaviours

Question 22

What type of sexual dimorphism occurs in some species?

Answer 22

Reversed sexual dimorphism

Question 23

What does female choice involve?

Answer 23

Females assessing honest signals of the fitness of males

Question 24

What do honest signals indicate?

Answer 24

Favourable alleles that increase the chances of survival
of offspring (fitness) or a low parasite burden suggesting a healthy individual

Question 25

What happens in lekking species?

Answer 25

Males gather to display at a lek, where female choice occurs

Question 26

What are the details of lekking?

Answer 26

Some bird species exhibit lekking behaviour.
Dominant males occupy the centre of the lek, with subordinates and juveniles at the fringes as ‘satellite’ males. During the display,
Female choice occurs

Question 27

Success in male-male rivalry through conflict (real or ritualised), increases access to what?

Answer 27

Females for mating

Question 28

What happens with male-male rivalry?

Answer 28

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