Lecture 9 - Sexual reproduction

Question 1

Sexual reproduction

Answer 1

A method of reproduction involving the fusion of haploid gametes to form a diploid zygote

Question 2

1st type of recombination

Answer 2

Independent assortment of homologues chromosomes
Some get maternal cope of chromosome some get paternal
Gamete could have majority from father, majority from mother, or a mix between the two

Question 3

2nd type of recombination

Answer 3

Crossing over

Homologous chromosomes actually intermingle and exchange with each other

Question 4

Gonochoristic

Answer 4

Separate male and female

Question 5

Hermaphroditic

Answer 5

Both male and female structures in the same individual

Simultaneously or sequentially

Question 6

Genotypic sex-determination (GSD)

Answer 6

sex is determined genetically, by the chromosome or gene composition of a cell or organism

Question 7

Environmental sex-determination (ESD)

Answer 7

sex is determined by environmental conditions encountered during an organism’s development (temperature, day length, proximity of conspecifics, etc)

Question 8

Costs of mating

Answer 8

Gamete production
Intrasexual selection
Intersexual selection
Locating a mate
Mate choice
Parental care
Sexually transmitted diseases

Question 9

Cost of producing males

Answer 9

Males not essential for reproduction

Asexual females produce twice as many daughters as sexual females

Question 10

Why have sexual reproduction?

Answer 10

• Increases diversity of traits in species, helps species survive in changing environment
• Spreads adaptive mutations through population
• Intermixes different mutant alleles of different genes

Question 11

Fisher-Muller hypothesis

Answer 11

sexual reproduction can combine the beneficial mutations from different individuals, accelerating adaptive evolution

Question 12

Muller’s Ratchet

Answer 12

describes the process by which the genomes of an asexual population accumulate deleterious mutations in an irreversible manner

Question 13

Hill-Robertson interference

Answer 13

Selection on a given locus is interfered with by selection on linked loci

Question 14

How is Hill-Robertson interference stopped?

Answer 14

Recombination can get rid of some of the Hill-Robertson interference

Question 15

Red Queen Hypothesis

Answer 15

Constant rate of evolutionary change in response to a continually changing environment

Question 16

Mutational deterministic hypothesis

Answer 16

Several deleterious mutation together have a negative effect greater than the sum of each on its own

Question 17

simultaneous hermaphrodites

Answer 17

Male and female reproductive organs at the same time

Question 18

Sequential hermaphroditism

Answer 18

Temporal switch from one sex to the other

Question 19

Protandrous

Answer 19

Switch from male to female

Question 20

Protandrous example

Answer 20

Clownfish

Largest male replaces female (largest male transitions into a female)

Question 21

Protogynous

Answer 21

Switch from female to male

Question 22

Protogynous example

Answer 22

Wrasse
Very territorial (large male advantage)
If small it’s better to be female

Question 23

Synchronizing reproduction

Answer 23

Seasonal breeding
Environmental cues
Behavior and pheromones’

Question 24

External fertilisation

Answer 24

Fertilisation outside female reproductive tract

Requires moist habitat

Question 25

Internal fertilisation

Answer 25

Fertilisation inside female reproductive tract

Generally requires intromittent organ

Question 26

Cyclic Parthenogenesis

Answer 26

Switch between parthenogenesis and sexual reproduction