Comparisons Flashcards
Costs of sexual reproduction
Males are unable to produce offspring
Only 1/2 of each parents genome is passed onto offspring
Disruption of successful parental genomes
Benefits of sexual reproduction
Increase in genetic variation which gives organisms a better chance of survival under changing selection pressures.
Costs of asexual reproduction
Asexually reproducing populations are not able to adapt easily to changes in their environment.
Benefits of asexual reproduction
Whole genomes can be passed on from parent to offspring ( this is an advantage particularly in very narrow stable niches / when recolonising disturbed habitats )
Benefit of hermaphroditism
The benefit to the individual organism is that if the chance of encountering a partner is an uncommon event, then there is no requirement for that partner to be of the opposite sex.
R selected species
R selected species are small species that have a short lifespan. They mature rapidly and have a limited level of parental care. Each offspring receives a small energy input by parents and so the offspring have a low survival probability. E.g. rats
R selection tends to occur in unstable environments.
K selected species
K selected species are large species that have a longer lifespan. They mature slowly and have a high level of parental care. Each offspring receives a large energy input by parents and so the offspring have a high survival probability. E.g. elephants
K selection tends to occur in STABLE environments.
Benefits of internal fertilisation
Increased chance of successful fertilisation
Fewer eggs are needed
High offspring survival rate
Offspring can be retained internally
Costs of internal fertilisation
A mate must be located, which requires energy expenditure.
Requires direct transfer of gametes.
Benefits of external fertilisation
Large numbers of offspring can be produced
Costs of external fertilisation
Many gametes are not fertilised
Few offspring survive
No or limited parental care
Advantages of in vivo
Provides data for effects in whole organisms
Allows study of complex interactions
Disadvantages of in vivo
Expensive and time consuming
Ethical and legislative concerns
Difficult to control confounding variables
Difficult to prove causation
Advantages of in vitro
Simpler and less expensive
Easier to control confounding variables
Easier to interpret results
Can demonstrate correlation and causation
Disadvantages of in vitro
Difficult to extend results to a whole organism or different species
Difficult to model complex interactions
