Biology - Genetic Variation

Question 1

Punnett Square

Answer 1

A prediction in the phenotypes of an organism from known/possible genotypes

Question 2

Homologous Chromosomes

Answer 2

Pairs of chromosomes containing the same genes at the same loci

Question 3

Genome

Answer 3

All of an organism’s genes

Question 4

Bottleneck effect

Answer 4

Reduction of genetic diversity
A population is suddenly reduced to few individuals

Question 5

Speciation

Answer 5

A species diverging into 2 or more species over time

Question 6

Independent assortment

Answer 6

Homologous chromosomes line up at a random order at the equator cell in meiosis

Question 7

How does independent assortment lead to genetic variation?

Answer 7

Increased number of unique gametes/sex cells, maternal & paternal chromosomes are seperated

Question 8

How does the bottleneck effect affect genetic diversity?

Answer 8

Gene pool decreases, less individuals to breed with, decreasing genetic variation

Question 9

Segregation

Answer 9

One allele goes into each gamete. Seperation of homologous chromosomes

Question 10

How does segregation affect genetic variation?

Answer 10

The dominant and recessive traits are split up, ensuring that the recessive is able to be shown. Each gamete has a different combo of alleles.

Question 10

Gene flow

Answer 10

Exchanging of alleles between different populations of a species

Question 11

Founder effect

Answer 11

Few individuals within a larger population move away, starting a smaller population

Question 11

How does the founder effect affect genetic diversity?

Answer 11

Smaller gene pool, fewer allele frequencies

Question 11

Genetic drift

Answer 11

Random changes in allele frequencies within a gene pool

Question 12

How do linked genes decrease genetic variation?
(Independent assortment, crossing over, segregation)

Answer 12

1. Can’t independently assort and will be inherited together
2. Crossing over can seperate linked genes due to large distance between loci
3. Segregation doesn’t seperate linked genes, so will both end up in the same gamete

Question 13

How does a gametic mutation lead to a new allele?

Answer 13

A mutation has to occur in the gametes to be passed down, not the somatic cells, as those mutations don’t get passed down to offspring.

Question 14

When a population is facing hardships & humans intervine (translocation)

Answer 14

The species will continue facing hardship, with inbreeding, etc.

Question 15

Genetic variation

Answer 15

Variety of alleles present in a gene pool

Question 16

What does natural selection lead to?

Answer 16

Increased frequencies of favourable alleles, decreased frequencies of unfavourable alleles.

Question 17

Variation in gametes

Answer 17

New alleles aren’t being produced from parent cells (no new genetic info) but the combinations are different.

Question 18

Why are mutations the ultimate source of gen variation?

Answer 18

They introduce entirely new alleles into a population

Question 19

Different phenotypes in different environments

Answer 19

One is favourable in one climate, where the other one is favourable in the other

Question 20

Impacts that death, migration, have on small/big populations

Answer 20

Death has a bigger impact on small populations, but has little effect of large pops. This leads to alleles being lost, decreased gen var. Same for immigration