Sex and mating

Question 1

What is reproduction?

Answer 1

The production of offspring

Question 2

What is sex?

Answer 2

Fusion of genetic material from two different parents

Question 3

What is different about asexual reproduction?

Answer 3

Doesn’t require sex, as all genes come from one parent, to make genetically identical offspring

Question 4

What are the benefits of asexual reproduction?

Answer 4

Quick, easy, cheap and relatively effort free and straightforward

Question 5

What are the types of asexual reproduction?

Answer 5

fragmentation, binary fission, budding, parthenogenesis

Question 6

What is fragmentation?

Answer 6

The breaking of the body into pieces followed by the regeneration of body parts missing - net effect is reproduction

Question 7

What is binary fission?

Answer 7

Single cells divide into the independent, identical daughter cells

Question 8

What is budding?

Answer 8

Offspring grows out of the body of the parent, specialised masses of cells are released form the parent that develop onto a new individual e.g. in hydra

Question 9

What is parthenogenesis?

Answer 9

virgin birth, occurs in several fish/insects, unfertilised eggs develop into offspring but are not haploid - not in mammals due to haploid printing

Question 10

When in a cycle of asexual/sexual reproduction would you expect each type to occur?

Answer 10

Low stress = asexual
high stress = sexual
depends on environmental factors

Question 11

When did sexual reproduction evolve?

Answer 11

1.5 - 2 billion years ago

Question 12

What are the three fundamental processes involved in sexual reproduction?

Answer 12

Gametogenesis (formation of gametes), mating (transferring of gametes), fertilisation (fusion of gametes)

Question 13

What are the requirements of external fertilisation?

Answer 13

Requires water, gametes are shed into the water

Question 14

What are the problems encountered with external fertilisation?

Answer 14

Can’t control delivery, requires a huge number of gametes and there is heavy predation of eggs

Question 15

What is indirect internal fertilisation?

Answer 15

Male deposits sperm ‘packet’ (spermatophore) and the female picks it up

Question 16

What is direct fertilisation?

Answer 16

Copulation, sperm is transferred directly into the female, often by intermittent organs

Question 17

What is a hectocotylus?

Answer 17

a modified arm used by male octopuses and some other cephalopods to transfer sperm to the female in direct fertilisation

Question 18

What is a hermaphrodite?

Answer 18

Individual has both male and female parts, generally not self fertilising. Partners exchange sperm and use it to fertilise their own eggs

Question 19

What happens during the copulation of bean weevils?

Answer 19

Female is wounded internally as penis has spines, leading to early death in the female. Female kicks to dislodge the male

Question 20

What is traumatic insemination?

Answer 20

Female lacks genital opening, males pierce membranes and place sperm into the females haemocoel e.g. in bed bugs

Question 21

What is sexual cannibalism and why might it be advantageous?

Answer 21

Female kills mate during or after copulation, may be partly for nutrition, could be beneficial for males to maximise paternity, or for females to prevent paternal monopoly

Question 22

How does the Wolbachia hijack sexual reproduction?

Answer 22

Is a type of Bactria, transferred in eggs of wasps and antes etc, but not in sperm, can kill males in some species