Sexual Selection

Question 1

Natural is the primary mechanism of what?

Answer 1

Sexual selection.

Question 2

Why do some birds have ornaments and colors that do not improve their survival ability?

Answer 2

This is due to sexual selection. These traits evolve from sexual selection.

Question 3

Sexual selection increase the reproductive sucess of the individuals even in the expense of their survival.

(True or false?)

Answer 3

True

Question 4

How does sexual selection come about?

(According to darwin’s theory?)

Answer 4

The challenge for males to access females lead to sexual selection

Question 5

What are the two mechanisms of sexual selection?

Answer 5

Intersexual selection and
Intrasexual selection

Question 6

What is intersexual selection?

Answer 6

Members of one sex choose the opposite sex.

Question 7

What is intrasexual selection?

(Also known as competition)

Answer 7

Members of the same sex evoke selection on each other.

Question 8

Describe the gametes of females and males?

Answer 8

Male: Abundant and motile
Females: Fewer, Highly nutritious, Larger and non-motile gametes.

Question 9

What are limitations to reproduction in Females and Males?

Answer 9

• Males are limited by access to females.
• Females are limited to access of resoures to produce their large gametes.

Question 10

What is anisogamy?

Answer 10

The fusion or union of two gametes which different in size and form.
It is a form of sexual reproduction.

Question 11

Bateman’s Principle

(2 things)

Answer 11

1. Females should be choosier than males due to their eggs being expensive. Females reproductive success is limited compared to females.
2. Because females are choosier than males it will lead to greater variation in the reprodutive success of males.

Question 12

What influences stronger effects of sexual selection?

Answer 12

Higher reproductive variance.

Question 13

With stronger variance there will be sexually dimorphic traits that are exaggerated in the sex with the highest reproductive variance.

(true or false)

Answer 13

True

Question 14

What is the characteristics of successful females?

Answer 14

• Will not take away reproduction opportunities from females.
• Results in smaller variance in reproductive success.

Question 15

What is characteristics of a successful males?

Answer 15

• If receives a disproportionate share of reproduction they will take away reproduction opportunities from other males.
• Can potentially sire many offsprings.
• Leads to higher reproductive variation among males.

Question 16

Parental care

(female biased)

Answer 16

• Female biased postzygotic investment.

Question 17

Anisogamy

(female biased pre)

Answer 17

Female-biased prezygotic investment.

Question 18

Sexual Dimorphism

Answer 18

Elaborated trait expression in males

Question 19

Which sex have strong selection in aNISOGAMY?

Answer 19

Stronger selection on males.

Question 20

Which sex have higher reproductive fitness and why?

Answer 20

Males due to them being under the most sexual selection due to mate selection of females.

Question 21

Sexually dimorphic species. Give examples

Answer 21

Mandrills (brightly colored nose area and larger than females)
Triplewart seadevils ( males are much larger than female)
Elephant seals (Males have elephant nose)
Orange tip butterflies (have an orange tip)
Lions (males have busy head area)
Mandarin duck (same plumage but brightly colored males).
Peafowl ( Peacock male have large colored peak).

Question 22

The degree and direct of sexual dimorphism can be explained by relative selection gradient of each sex.

(True or false)

Answer 22

True

Question 23

When females provide parental care what happens?

(reproductive success varience?)

Answer 23

• Females become limited resoucre for males due to them being occupied with offsprings post-mating.
• Therefore the reproductive success varience in males will be higher.

Question 24

In biparental care what happens?

(reproductive success varience)

Answer 24

• Male have a lower reproductive success varience as he does not put energy into making additional mating opportunities.
• This is where both sexes take care of the offspring.

Question 25

What happens when males are the sole parental care giver? | (Reproductive success variance)

Answer 25

* Reproductive success will be larger in females * Males are now the limiyed resource to females.

Question 26

Male deers are able to retain females for a longer period in combat. What type of selection?

Answer 26

Pre-copulatory: To monopolize harem and single female. | (Intrasepecific selection or competition)

Question 27

What kind of selection is mate choice?

Answer 27

Mate selection between opposite sexes to gain either indirect or direct benefit.

Question 28

WHat is the pre-copulation in intersexual selection?

Answer 28

Males display at leks

Question 29

What is the post-copulation of intersexual selection?

Answer 29

Female reproductive morphology does not allow for sperm directly contacting the egg.

Question 30

Why do females choose their mates than to choose at random or the first male they get in contact with?

Answer 30

* Direct benefit they get from male such as : protection, food and care for offspring. * Indirect benefit: where they reap the benefit through their offspring.

Question 31

Male choice originally evolved to facilitate adaptive choice for traits conferring a survival advantage. | (true of false?)

Answer 31

True

Question 32

Genetically superior mates produce fittner offspring. | (What kind of infirect benefit is that?)

Answer 32

Good Gene

Question 33

Females that mate with preferred fathers produce sons that will have high mating success. | (What kind of infirect benefit is that?)

Answer 33

Sexy son

Question 34

Differences among males provide females with information on their genetic qualities of different males that can be inheritied by the offspring. | (Good gene or Sexy sonn?)

Answer 34

Good gene

Question 35

Characteristics of good genes. | (3 characteristics).

Answer 35

1. Genes that allow males to carry handicap traits but are still surviving. 2. Genes that signal resistance to diseases. 3. Genes that are more compatible with those of females.

Question 36

Females choose an arbitary trait that provides no information on the male quality and do not reinforce the effects of natural selection.

Answer 36

Sexy son. They choose the sexually attractive male in order to help males reproduce sucessfuly in the future.

Question 37

Sexual selection is stronger than natural selection. But can lead to great extravagance that lead to death of the male. | (true or false?)

Answer 37

True

Question 38

The ability of females to affect the likelihood of sperm fertilizing their eggs is called ?

Answer 38

Female choice.

Question 39

When females mate with multiple males their sperm compete inside the female to access the egg. What is this called?

Answer 39

Sperm competition or male-male competition.

Question 40

What causes sexual conflic?

Answer 40

When genetic interest do not aligned.

Question 41

Sexual conflict results in an evolutionary arms race. | (True of false)

Answer 41

True