Biology- Unit 8

Question 1

What is a phenotype?

Answer 1

Observable characteristics of an organism

Question 2

What is a genotype?

Answer 2

The alleles present within cells of an organism

Question 3

What is co-dominance?

Answer 3

Both alleles contribute to the phenotype without mixing

Question 4

What can a chi-squared test be used for?

Answer 4

Discontinuous variation data
If the sample size is large
The value obtained is compared to a critical value
If X2 is smaller than critical then accept null hypothesis

Question 5

What is ‘stabilising’ natural selection?

Answer 5

Reduced variation in population
Conserves phenotypes already present
Selects against extreme phenotypes
Very little change

Question 6

What is ‘disrupted’ natural selection?

Answer 6

Increases diversity of population
Small subpopulations evolve different niches
Selects for extreme phenotypes

Question 7

What is ‘directional’ natural selection?

Answer 7

Shows a change from one phenotype to another

More advantageous to environment

Question 8

What is a population bottleneck?

Answer 8

The effect of events that reduce the size of the population by at least half
Decrease in gene pool
Reduction in genetic diversity

Question 9

What is the flounder effect?

Answer 9

Small number of individuals become isolated

Form a new population with allele frequencies not representative of the original population

Question 10

What is a genetic drift?

Answer 10

Random changes in the gene pool of a population that occur by chance
Not advantageous or disadvantageous

Question 11

What are the limitations of the Hardy-Weinberg equation?

Answer 11

No mutations
Random mating
Large population
Isolated population
No selection pressure(s)