Sexual Reproduction Flashcards
Define asexual reproduction
Copying and proliferation
Define sex
Fusion of gametes by 2 different parents
Benefits of asexual reproduction:
Cheap, easy and error free
Transmits successful parental genome intact
No meiosis or fertilisation
Evolved first
Why did testes and ovaries evolve?
As mechanisms to transfer gametes - machinery for meiosis
Recombination and segregation result from
Meiosis
The paradox of sex: name the 4 factors
Time consuming
Costly
Dangerous
Complicated
Twofold cost of sex=
Females transmit genes at half the rate of asexual females
What determines the variation in reproductive cycles?
Environmental conditions
For sex to evolve, 1 of 2 assumptions must have been violated. What are the assumptions?
Every female produces equal number of offspring
No differential survival - both have equal chance of offspring survival
Asexual reproduction is not advantageous if…
Paternal care is required for survival of offspring. Most males contribute genes only
Differential survival leads to natural selection which…
Creates phenotypic variation, resulting in genetic variation leading to recombination and possible mutations … Sex
Which populations have higher genetic variation?
Sexual
Which populations have higher mutation rates?
Asexual
What does recombination do?
Reveals hidden variation but can also reform bad genotypes
2 population genetics models:
Millers ratchet
Red queen
Mutation problems are 100% inherited in asexual populations .. Sex solves this. What model is this?
Mullers Ratchet
Red queen model does what?
Brings together novel genotypes with potentially higher fitness and increases the effectiveness of natural selection
Mullers Ratchet and the Red Queen models both rely on what?
Recombination
Advantage of the rare is an example of
Red Queen
Mullers Ratchet cleanses mutational load by …
Sex!
