Genetic Diversity

Question 1

what causes variation between species, and between individuals within a species?

Answer 1

DNA; it determines proteins that make up an organism, and different alleles within a species produces intraspecific variation

Question 2

What is an advantage of genetic variation?

Answer 2

More likely that a species will be able to adapt to an environmental change. The wider range of alleles and therefore characteristics increases chance of an individual having a suited characteristic.

Question 3

Describe selective breeding (artificial selection)

Answer 3

• individuals with desired characteristics are identified and chosen to parent the next generation
• offspring without characteristics are prevented from breeding, therefore alleles for unwanted characteristics are bred out
• produces high-yielding breeds of domesticated animals and strains of plants

Question 4

Describe the founder effect

Answer 4

• when a few individuals from a population colonise a new region
• only a fraction of alleles are present, is not representative of whole pop
• smaller gene pool (less alleles), so low genetic diversity
• may develop into a new species

Question 5

Describe genetic bottlenecks

Answer 5

• occurs when an event causes a drop in numbers of a population
• few survivors will have fewer alleles therefore diversity is reduced
• as pop is reestablished diversity remains restricted

Question 6

Outline some issues surrounding the ethics of selective breeding

Answer 6

• whoever funds scientific research may have influence on outcome
• how are the ‘desired characteristics’ decided
• how are the advantages of increased yield and animal welfare balanced
• maybe interfering with nature