1. What is "variation" ?
Answer
Differences in the characteristics of individuals in a population.
2. What is another term for "artificial selection" ?
a) Selective breeding b) Natural selection c) Genetic engineering d) Cross-breeding
Answer
a) Selective breeding
3. Name two methods of cloning animals.
Answer
Embryo transplants and adult cell cloning.
4. Explain how mutations can lead to rapid change in a species.
Answer
Very rarely a mutation will lead to a new phenotype. If the new phenotype is suited to a change in the environment, it can lead to a relatively rapid change in the species through natural selection.
5. The finch is a type of bird. Different species of finch live on different islands, but they evolved from a common ancestor. Explain how two different species of finch could develop from a common ancestor.
Answer
The ancestral population is separated, by a geographical barrier for example, so they cannot interbreed. There is genetic variation in the two populations, or mutations can occur. Each population will experience different environmental conditions and natural selection will occur as some phenotypes are favoured. The alleles for the favourable phenotype are passed on to the offspring and eventually the two populations become so different in phenotype that they can no longer interbreed to produce fertile offspring and two new species have formed.
6. Give one reason why inbreeding is a disadvantage.
Answer
Some breeds are particularly prone to disease and inherited defects.
7. Suggest one possible benefit of genetic modification in humans.
a) Increased resistance to antibiotics
b) Improved ability to produce insulin
c) Overcome inherited disorders
d) Enhanced natural selection
Answer
c) Overcome inherited disorders
8. Describe how plants are cloned using tissue culture.
Answer
Small groups of cells are taken from part of a plant and used to grow identical new plants.
9. Describe how animals are cloned using embryo transplants.
Answer
The cells from a developing animal embryo are split apart before they become specialised, then the identical embryos are transplanted into host mothers.