Chapter 9 - Genetic Diversity and Adaptation

Question 1

What is gene mutation?

Answer 1

It is a change to the sequence of bases in the genetic code - 2 examples of which are base deletion or base substitution

Question 2

Do all gene mutations result in non functional proteins?

Answer 2

No, thanks to the degeneracy of the genetic code

Question 3

What can happen to the number of chromosomes during which process?

Answer 3

During meiosis, the number of chromosomes can change spontaneously due to non-disjunction events

Question 4

What is the product of meiosis?

Answer 4

4 Daughter cell which are genetically different from each other

Question 5

Give the process of the first stage of meiosis

Answer 5

2 Homologous pairs of chromosomes line up in the equator of the cell next to each other according to random assortment (mother chromosomes randomly mixed with father), and begin to cross over (swap some genes) before being pulled into different cells (still as two chromatids) resulting in two genetically different haploid daughter cells

Question 6

What happens in the second stage of meiosis?

Answer 6

The two hapolid daughter cells essentially carry out mitosis like normal with half the regular chromsomes, resulting in another two haploid daughter cells

Question 7

Define genetic diversity:

Answer 7

The number of different alleles of genes in a population

Question 8

Give the stages and principles of natural selection:

Answer 8

Random mutation occurs, changing an allele and therefore the phenotype of an organism
The new phenotype gives the organism a biological advantage, resulting in them being selected against less often, so they survive more than the organisms without their mutation
Due to the fact they survived and those without the mutation have not so easily, the mutated organism is more able to breed and pass on the gene to their offspring
Over many generations the new allele increases in frequency in the population

Question 9

Give an example of directional selection

Answer 9

Bacteria with more antiobiotic resistance

Question 10

Give an example of stabilising selection

Answer 10

Baby birth weights - too heavy don’t survive childbirth, too light may not survive infancy as easily

Question 11

What sorts of adaptations may lead to natural selection?

Answer 11

Behavioural, anatomical or physiological