10.8 Changing Population Characteristics

Question 1

selection pressure

Answer 1

factors that affect an organisms chance of survival or reproductive success

Question 2

natural selection

Answer 2

1. differences in genes
2. best adapted to sleelction pressure will survive and reproduced
3. allele for advantageous characteristic passed on to offspring
4. over time proportion of individuals with the advantageous characteristic increases, frequency of allele in the populations gene pool increases
5. New species

Question 3

antibiotic resistant bacteria

Answer 3

MRSA.

bacteria reproduce rapidly and so evolve over a short time

Mutation- process of natural selection

Question 4

peppered moths

Answer 4

changes in environment caused changes in allele frequency for colourings (dark or light)

changed because of changes to tree colour

Question 5

sheep blowflies

Answer 5

lay their eggs in faecal matter around a sheeps tail, the larvae hatch, causing sores

the pesticide diazonin was used to kill them, but they developed resistance very quickly

scientists tested resistance on old and new blowflies.
Diazonin resistance was not found in the old ones but was found in the new ones

however, both old and new had resistant alleles for malathion.

Therefore a pre adaption contributed to the development of diazonin resistance. This is when an organisms existing trait is advantageous for a new situation. The resistance to malathion allowed the blowfiles to rapidly develop resistance to organophosphate chemicals in general.

Question 6

Flavobacterium

Answer 6

organisms evolve to to opportunities that have arisen in the environment

Flavobacterium digest nylon 6, a waste material from factories as it is used to make toothbrushes and violin strings. This is useful as it breaks down waste materials due to the enzymes nylonases but provides the flavobacterium with a source of nutrients

this gene mutation occured to produce nylonases as a result of a gene duplication and a frameshift mutation