Genes in EcoSystems

Question 1

Name the 2 Hardy Weinberg equations

Answer 1

p+q= 1

P2+q2+2pq=1

Question 2

Define Gene pool

Answer 2

all the alleles of all the genes of all the individuals in a population a a given time

Question 3

Define allelic frequency

Answer 3

Number of times an allele occurs in a gene pool

Question 4

What 5 conditions must be met for the HW equation?

Answer 4

No mutations arise 
Population is isolated
No selection/ each allele = chance of being passed on
Large population
Mating is random

Question 5

Name 3 causes of genetic variation

Answer 5

Mutations
Meiosis
Random fertilization of gametes

Question 6

Define selection pressures

Answer 6

Environmental factors that limit the population of a species

Question 7

Process of evolution by natural selection depends on three things:

Answer 7

Production of more offspring that can be supported
Genetic variation within a population
Variety of phenotype that selection operates against

Question 8

Name 3 examples of selection pressures

Answer 8

Predation
Disease
Competition

Question 9

Describe what occurs to those with the advantageous phenotype

Answer 9

Advantageous phenotype
means more likely to produce more offspring and pass on the favourable alleles to the next gen
which increases the allelic frequencies

Question 10

The larger the population……..

Answer 10

more genetically variable
greater chance of advantageous alleles
so higher chance of survival

Question 11

Name the 3 types of selection

Answer 11

Stabilising
Directional
Disruptive

Question 12

Define Stabilising Selection

When does this occur?

Answer 12

Preserves the average phenotype and selection against extreme phenotypes.

Occurs when environment is stable for a long period

Question 13

Define Directional Selection

Answer 13

When the environment changes so does the favorable phenotypes- to an extreme

Question 14

Define Disruptive Selection

Answer 14

Favours individuals with the extreme phenotypes rather that those with mean phenotype

Question 15

Define Speciation

Answer 15

Evolution of a new specifies from existing ones

Question 16

Define Adaptive radiation

Answer 16

Adaption from the different environments experienced by diff. population due to different selection pressures leading to different phenotypes

Question 17

Define Genetic Drift

Answer 17

Change in allele frequency due to change effects

Question 18

Define Genetic Bottleneck

Answer 18

Sharp reduction in the size of the population

Question 19

Define Founder effect

Answer 19

When a population is descended from a small number of colonising ancestors causing low genetic variation

Question 20

Explain the standard ans to a speciation q.

Answer 20

Population becomes geographically isolated
Each experience different environments hence different selection pressure
So there is genetic variation between the populations as they are in sperate gene pools.
Those with advantageous mutated alleles survive+ reproduce for increase allelic frequency
Populations become so varied they cannot reproduce to have fertile offspring hence are different species

Question 21

Define Allopatric speciation

Answer 21

When species are geographically isolated

Question 22

Define Sympatric Speciation

Answer 22

Same country but still became diplomatically isolated

Question 23

The flowering times of the two
species are different.
Using this information, suggest how these two species of palm tree arose by
sympatric speciation

Answer 23

Occurs in the same
habitat/environment/population;
Mutation/s cause different flowering times; Reproductive separation/isolation
OR
No gene flow
OR
Gene pools remain separate;
Different allele/s passed on/selected
OR
Change in frequency of allele/s; Disruptive (natural) selection;
 Eventually different species cannot (inter)breed
to produce fertile offspring