Genetic diversity and adaptation

Question 1

Mutation is…

Answer 1

a change in the base sequence of the DNA

Question 2

Reasons for mutation

Answer 2

1. high energy radiation
2. ionising radiation
3. chemicals

Question 3

2 types of gene mutation + how they work

Answer 3

1. Base deletion

• A base is removed from the sequence which leads to a frameshift

Base substitution

• A base is substituted with another base

Question 4

What is chromosome non - disjunction?

Answer 4

When the chromosomes or chromatids do not split equally during anaphase

Question 5

How can chromosome non - disjunction occur?

Answer 5

1. Changes in whole sets of chromosomes (polyploidy)
2. Changes in the number of individual chromosomes (anueploidy)

Question 6

What does meiosis produce

Answer 6

4 haploid daughter cells that are genetically different from each other

Question 7

Independent segregation is…

Answer 7

when homoglous pairs of chromosomes line up opposite each other at the equator of the cell and are separated it is random.

Question 8

How to caculate the possible combinations of chromosomes in the daughter cells produced

Answer 8

2^n

Question 9

Crossing over is…

Answer 9

when chromatids become twisted and form a chiazma, this creates tension on the chromatids , causing chromatids to break . Broken parts recombine with the other chromatid.

Question 10

how to identify meiosis in a life cycle

Answer 10

diploid (2n) becomes haploid (n)

Question 11

genetic diversity is…

Answer 11

the number of different alleles of genes in a population

Question 12

Evolution is the…

Answer 12

change in allele frequency over man generations in a population

Question 13

Process of natural selection

Answer 13

1. New alleles for a gene are created by random mutations.
2. If the new alleles increases the chances of the individual to survive in that environment, then they’re more likely to survive and reproduce.
3. This reproduction passes on the advantageous allele to the next generation
4. As a result, over many generations , the new allele increase in frequency in the population

Question 14

Types of selection and what it is and is it effected by environment

Answer 14

1. Directional selection

• One the extremes hase the selective advantage
  -Occurs when there is a change in the environment

2. Stabilising selection

• The modal trait has the selective advantages
• Occurs when there is no change in environment