Genetic diversity Flashcards
the greater number of different alleles that all members of a species possess…..
the greater the genetic diversity of that species.
what does a greater genetic diversity mean?
the more likely that a species will be able to adapt to some environmental changes. this is because it has a wider range of alleles and therefore a wider range of characteristics
when is genetic diversity reduced?
when a species has fewer different alleles
what is selective breeding also known as?
artificial selection
what does selective breeding involve?
selecting individuals with desired characteristics and using them to parent the next generation
what happens to the number of alleles during selective breeding?
the number of alleles is deliberately restricted to a small number of desired alleles.
why is selective breeding carried out?
to produce high yielding breeds of domesticated animals and strains of plants.
what is an example of selective breeding?
plants e.g. wheat with large grains, high gluten content and resistance to disease
What is the founder effect?
when just a few individuals from a population colonise a new region
why will the new population show less genetic diversity than the population from which they came from?
the few individuals only carry a small fraction of the alleles of the whole population
when is the founder effect often seen?
when new volcanic islands rise out of the sea
what may the population over time develop into?
a separate species, with fewer alleles that are less able to adapt to changing conditions
what is genetic bottlenecks?
populations from time to time may suffer a dramatic drop in numbers. the few survivors will possess a much smaller variety of alleles than the original population- their genetic diversity will be less.
what are some ethical issues with selective breeding?
- Leads to varieties of animals with narrower ranges of alleles, hence less genetic diversity
- Is selective breeding interfering with nature?
- What features should be selected for and who decides?
what two main purposes are cattle selectively bred for?
meat and milk
