Lecture 9 - Sexual reproduction Flashcards Preview

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Flashcards in Lecture 9 - Sexual reproduction Deck (26)
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1
Q

Sexual reproduction

A

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

2
Q

1st type of recombination

A

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

3
Q

2nd type of recombination

A

Crossing over

Homologous chromosomes actually intermingle and exchange with each other

4
Q

Gonochoristic

A

Separate male and female

5
Q

Hermaphroditic

A

Both male and female structures in the same individual

Simultaneously or sequentially

6
Q

Genotypic sex-determination (GSD)

A

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

7
Q

Environmental sex-determination (ESD)

A

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

8
Q

Costs of mating

A
Gamete production
Intrasexual selection
Intersexual selection
Locating a mate
Mate choice
Parental care
Sexually transmitted diseases
9
Q

Cost of producing males

A

Males not essential for reproduction

Asexual females produce twice as many daughters as sexual females

10
Q

Why have sexual reproduction?

A
  • Increases diversity of traits in species, helps species survive in changing environment
  • Spreads adaptive mutations through population
  • Intermixes different mutant alleles of different genes
11
Q

Fisher-Muller hypothesis

A

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

12
Q

Muller’s Ratchet

A

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

13
Q

Hill-Robertson interference

A

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

14
Q

How is Hill-Robertson interference stopped?

A

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

15
Q

Red Queen Hypothesis

A

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

16
Q

Mutational deterministic hypothesis

A

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

17
Q

simultaneous hermaphrodites

A

Male and female reproductive organs at the same time

18
Q

Sequential hermaphroditism

A

Temporal switch from one sex to the other

19
Q

Protandrous

A

Switch from male to female

20
Q

Protandrous example

A

Clownfish

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

21
Q

Protogynous

A

Switch from female to male

22
Q

Protogynous example

A

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

23
Q

Synchronizing reproduction

A

Seasonal breeding
Environmental cues
Behavior and pheromones’

24
Q

External fertilisation

A

Fertilisation outside female reproductive tract

Requires moist habitat

25
Q

Internal fertilisation

A

Fertilisation inside female reproductive tract

Generally requires intromittent organ

26
Q

Cyclic Parthenogenesis

A

Switch between parthenogenesis and sexual reproduction