14

Question 1

Variation in individuals of a species is caused by

Answer 1

Random assortment
Crossing over
Non disjunction
Random fertilisation 
Mutations
(m exapand?)

Question 2

Random genetic drift (Sewall Wright effect)

Answer 2

A random non direction variation in allele frequency in a small population
ex:

Question 3

founder effect

Answer 3

occurs when a small group moves away from the larger population to a new area and establishes a community which later expands.
the migrant group is usually not genetically representative of the larger group
shows larger frequency of features that are less common in larger group

Question 4

Gene flow

Answer 4

migration of an individual from one population to another (carrying their genes with them)

Question 5

Barriers to gene flow

Answer 5

Geographical barriers (oceans, mountain ranges, large lakes, deserts)
Sociocultural barriers( economic status, educational background)

Question 6

Genetic diseases

Answer 6

cause a change in allele frequency in a gene pool.
fatal diseases would be expected to be slowly eliminated bc person would die before passing it on.
Some still stay eg. Tay Sachs disease (TSD), thalassaemia, sickle cell anaemia)

Question 7

thalassaemia

Answer 7

e

Question 8

Tay Sachs disease

Answer 8

e

Question 9

sickle cell anaemia

Answer 9

e

Question 10

Evolution

Answer 10

the gradual change in the characteristics of a species

theory of evolution through natural selection

Question 11

binomial system of naming

Answer 11

uses the generic (genus) and specific (species) names

Question 12

Darwins theory of Natural selection:

Answer 12

1) variation- all populations of a species will have a range of alleles in the gene pool that can be passed down to the next gen
2) Birth rate- more offsprings produced than the amount. that can live to maturity
3) Natures balance- because of excessive birth rate and limited recourses, there is competition for survival
4) Individuals with characteristics best suited for the environment have a better chance of producing offspring and passing on genes
5) Favoured characteristics passed onto next gen
6) In the gene pool the frequency of alleles that produced favourable characteristics are passed on

Question 13

Survival of the fittest:

Answer 13

more organisms with favourable characteristics survived , while those that had unfavourable would die before they had the chance to pass on their characteristics to the next generation

Question 14

Survival of fittest possible bc of VARIATION

Answer 14

the members of a species vary in characteristics (fitness, body type…)

Question 15

Variation in humans

Answer 15

e

Question 16

Speciation

Answer 16

the process of producing 2 species

Question 17

Parts of speciation

Answer 17

1 -variation exists within a population which share a common gene pool
2- isolation: a barrier forms, dividing the population into 2 (w seperate gene pools) and no interbreeding can occur
3-Selection: different selection pressures act on the populations- changes gene frequencies (produces subspecies)
4-Speciation: over a long time, the changes in gene frequency can be so great that the two populations can no longer interbreed and produce offspring