Changes in The Genetic Makeup Of A Population

Question 1

Gene pool

Answer 1

The gene pool is the set of all genes, or genetic information, in any population, usually of a particular species

Question 2

Mutation

Answer 2

permanent, heritable change in the nucleotide sequence in a gene or a chromosome.

Question 3

Genome

Answer 3

Aggregation of all genes in a single organism.

Question 4

Point mutation

Answer 4

Changes to a single base pair.

Question 5

Block mutation

Answer 5

Entire segments of DNA.

Question 6

Types of point mutations

Answer 6

• silent mutations
• missense mutations
• nonsense mutations
• frameshift (base addition and deletion)

Question 7

Duplication

Answer 7

Where segment of DNA is repeated again and again.

Question 8

Inversion

Answer 8

Where a segment of dna is ‘chopped up’ and reinserted in the same place, but backwards.

Question 9

Insertion

Answer 9

Where a segment of dna from another molecules is copied and inserted into the middle or another segment of dna.

Question 10

Block deletion

Answer 10

Segment of dna is removed

Question 11

Translocation

Answer 11

Where a segment of dna fro one molecule reaches and reinsert itself in another molecule.

Question 12

Aneuploidy

Answer 12

Aneuploidy is the presence of an abnormal number of chromosomes in a cell.

Question 13

Polyploidy

Answer 13

Cell contains two or more sets of chromosomes.

Question 14

Selection pressures

Answer 14

an agent of differential mortality or fertility that tends to make a population change genetically. Selection pressures are the driving mechanism of natural selection.

Question 15

Artificial selection

Answer 15

Breeder acts as a selection pressure.

Question 16

Species

Answer 16

Complete set of all organism that are able to mate and produce viable and fertile offspring.

Question 17

Gene flow

Answer 17

Movement of alleles from one population to another.

Question 18

Genetic drift

Answer 18

variation in the frequency of different genotypes in a population, due to the chance disappearance of particular genes and alleles.

Question 19

Bottleneck effect

Answer 19

A population bottleneck is the rapid reduction in the size of a population due to environmental events (such as earthquakes, floods, fires, disease, or droughts) or human activities (such as genocide).

Question 20

Founder effect

Answer 20

When a population of reduced genetic diversity colonises a land and the colonising population is unrepresentative of the amount of alleles from the larger population in which they left.

Question 21

Allopatric speciation

Answer 21

Occurs when a population becomes divided by a geographical barrier. This prevents gene flow by stopping sub-populations from interbreeding.

Question 22

Forms of speciation

Answer 22

• parapatric (populations are separated and gene flow is possible but instead in individuals chose to breed with individuals iduals that are closer).
• sympatric speciation
• peripatric speciation
• allopatric speciation

Question 23

Isolating mechanisms

Answer 23

Prezygotic:
- geographical
- morphological
- behavioural
- gamete mortality
Postzygotic:
- hybrid sterility

Question 24

Evolution

Answer 24

Change in the genetic composition of populations over time.

Question 25

Speciation

Answer 25

Evolution of a new species from an ancestral species.

Question 26

Allopatric speciation steps

Answer 26

1. Populations become separated by a geographical barrier that prevents gene flow.
2. Two populations experience different selection pressures due to different environments and/ or mutations arising.
3. Over time the two populations become so different that if brought back together they would be unable to produce viable and fertile offspring (and thus different species).

Question 27

Disadvantages of selective breeding

Answer 27

Selectively bred populations low lower genetic variation which results in them being more susceptible to environment change and more genetic abnormalities can occur.

Question 28

Selective breeding steps

Answer 28

1. Choose the trait that is desired.
2. Interbreed parents who most closely have the desired trait.
3. Select the offspring with the best form of the trait and interbred these offspring.
4. Continue this process until the population reproduces the desired trait.