SB3a - sexual and asexual reproduction

what is sexual reproduction?

fertilisation of a female sex cell by a male sex cell

what is asexual reproduction?

reproduction without fertililisation, involving only one parent organism.

what does asexual reproduction produce?

clones - offspring that are genetically identical to the parent

what does sexual reproduction do?

combines characteristics from both parents, producing offspring that are different from each other

what is the advantage of sexual reproduction?

can survive if offspring moves to an area with different environmental conditions/if environment changes

what are examples of changes in the environment?

changes in temperature, new pest/disease come to the area

what is the main benefit of sexual reproduction?

loads of genetic variation within the population

why is genetic variation a benefit in the short term?

population is less likely to get wiped out by a single event (e.g. new disease)

why is genetic variation a benefit in the long term?

population can adapt to changing conditions

what does genetic variation allow to happen?

evolution - species adapt over time and more favourable/desirable traits are most likely to be passed on

what does variation mean?

there is a greater chance that some offspring will be better suited to new conditions and will be more likely to survive and reproduce (evolution)

what is a disadvantage of sexual reproduction?

takes a lot more time and energy

why does sexual reproduction take more time/energy?

animals have to find a potential mate (time consuming) and then impress them

state an example of a feature useful for impressing but not for survival.

feathers of birds like peacock

what is an advantage of asexual reproduction?

faster

why is asexual reproduction faster?

only one parent is needed so there is no need to find a mate

when is asexual reproduction an advantage?

when there are a lor of resources (e.g. food)

what does asexual reproduction being quick allow?

a single organism to quickly colonise a new area

what are examples of a single organism colonising a new area?

bacteria on food, plants on a piece of ground

what is a disadvantage of asexual reproduction?

all offspring are clones so there is no genetic variation

what does no genetic variation mean?

offspring are more susceptible to disease - a new disease could wipe out the whole population, less chance of adapting to new conditions such as change in climate or new competitor