Unit 2 - Topic 3 - Variation and Sexual Reproduction - Section A - Costs and Benefits of sexual and asexual reproduction Flashcards
What are the costs of sexual reproduction
Males unable to produce offspring; only half of each parent’s genome passed onto offspring, disrupting successful parental genomes
Why do the benefits outweigh the costs of sexual reproduction
An increase in genetic variation in the population
What does genetic variation provide
The raw material required for adaptation, giving sexually reproducing organisms a better chance of survival under changing selection pressures
What can explain the persistence of sexual reproduction
The Red Queen hypothesis
Co-evolutionary interactions between
parasites and hosts may select for what
Sexually reproducing hosts
What hosts and parasites have greater fitness
Hosts better able to resist and tolerate parasitism have greater fitness. Parasites better able to feed, reproduce and find new hosts have greater fitness
What happens if hosts reproduce sexually
The genetic variability in their offspring reduces the chances that all will be susceptible to infection by parasites
Why can asexual reproduction be successful reproductive strategy
As whole genomes are passed on from parent to offspring
What happens in asexual reproduction
Just one parent can produce daughter cells and establish a colony of virtually unlimited size over time.
When is maintaining the genome of the parent an advantage
In very narrow, stable niches or when re-colonising disturbed habitats
What are examples of asexual reproduction in eukaryotes
Vegetative cloning in plants and parthenogenesis in lower plants and animals that lack fertilisation
What is parthenogenisis
Reproduction from a female gamete without fertilisation
In asexual reproduction offspring can be reproduced what
More often and in larger numbers
Where is parthenogenesis more common
Cooler climates, which are disadvantageous to parasites, or regions of low parasite density or diversity
What can allow some natural selection in asexual populations
Asexually 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
