10.8 Changing population characteristics

Question 1

what is a selection pressure?

Answer 1

factors which affect an organism’s chances of survival

Question 2

outline natural selection

Answer 2

random mutation occurs to create genetic variation in a population

selection pressure occurs on a population

organisms with advantageous characteristics are selected for (survive) while those without are selected against (die)

the surviving organisms reproduce over many generations and pass down their advantageous characteristics to their offspring

the allele frequency of the advantageous characteristic increases

Question 3

outline antibiotic resistance in bacteria

Answer 3

mutation to a bacteria population occurs which gives it resistance to an anti-biotic

resistant bacteria survived
non-resistant died

resistant bacteria reproduce over many generations rapidly and pass on the advantageous allele to their offspring

allele frequency for resistance increases

Question 4

outline pesticide resistance

Answer 4

there is variation in a population of insects

random mutation causes an insect to be resistant to pesticides

resistant insects survive
non-resistant die

resistant lives to reproduce over many generations and pass down the allele for resistance to their offspring

allele frequency for resistance increases

Question 5

implications of pesticide resistance for humans

Answer 5

crop infestations are harder to control

farmers resort to using broader pesticides which also kill beneficial insects

the creation of new pesticides takes time and money

Question 6

implications of anti-biotic resistance for humans

Answer 6

hard to treat infections caused by anti-biotic resistance

the creation of new drugs is expensive and takes time