2.3a - Costs and Benefits of Sexual and Asexual Reproduction Flashcards
Costs of sexual reproduction:
- males unable to produce offspring
- only half of each parent’s genome passed onto offspring
- disrupting successful parental genomes
Benefits outweigh costs due to…
an increase in genetic variation in the population
Genetic variation provides…
the raw material required for adaption, giving sexually reproducing organisms a better chance of survival under changing selection pressures
The Redd Queen hypothesis can explain…
the persistence of sexual reproduction
Co-evolutionary interactions between parasites and hosts may…
select for sexually reproducing hosts
What gives hosts better fitness?
able to resist and tolerate parasitism
What gives parasites better fitness?
ability to feed, reproduce and find new hosts
If hosts reproduce sexually, the genetic variability in their offspring…
the genetic variability in their offspring reduces the chances that all will be susceptible to infection by parasites
Asexual reproduction can be a successful reproductive strategy as…
whole genomes are passed on from parent to offspring
In asexual reproduction, only one parent…
can produce daughter cells and establish a colon of virtually unlimited size over time
Maintaining the genome of the parent is an advantage particularly in…
very narrow, stable niches or when re-colonising disturbed habitats
Examples of asexual reproduction in eukaryotes
vegetative cloning in plants and parthenogenesis in lower plants and animals that lack fertilisation
Parthenogenesis is…
reproduction from a female gamete without fertilisation
In asexual reproduction, offspring can be reproduced…
more often and in larger numbers
Parthenogenesis is more common in…
cooler climates, which are disadvantageous to parasites, or regions of low parasite density or diversity
Asexual reproducing populations are not able to…
adapt easily to changes in their environment, but mutations can occur that provide some degree of variation and enable some natural selection and evolution to occur
Organisms that reproduce principally by asexual reproduction also often have…
mechanisms for horizontal gene transfer between individuals to increase variation
Examples of have mechanisms for horizontal gene transfer
the plasmids of bacteria and yeasts
Prokaryotes can exchange genetic material…
horizontally, resulting in faster evolutionary change than in organisms that only use vertical transfer
