Organisms

Question 1

Evolution

Answer 1

The change over time in the proportion of individuals in a population differing in one or more inherited traits

Question 2

Changes in allele frequency occur during evolution through

Answer 2

• The non random processes of natural selection and sexual selection
• Random processes of genetic drift

Question 3

Variation in traits arises from

Answer 3

Mutations

Question 4

Mutation

Answer 4

Original source of** new sequences of DNA**(raw materials of evolution)
Can be rare (novel) alleles

Question 5

Most mutations are

Answer 5

Harmful or neutral, rare cases they are beneficial to fitness of individual

Question 6

Natural selection definition

Answer 6

Non random increase in frequency of DNA sequences that increase survival

Question 7

Natural Selection process

Answer 7

• Population produces more offspring than environment can support
• **Variation **amongst offspring cuz of mutations
• Selection pressures
  -Individuals with a selective advantage survive to reproduce and pass on their favourable alleles to offspring
• Favourable alleles provide advantage to next gen and become more frequent

Question 8

Selection results in?

Answer 8

• Non random increase of advantageous alleles.
• Non random decrease of non advantageous alleles.

Question 9

Selection Pressures

Answer 9

Environmental factors that influence which individuals in a population can pass on their alleles.

Question 10

Selection Pressures can be

Answer 10

Biotic: Comp
predation
disease,
parasitism

Abiotic: changes in temp
               light
            	humidity
                pH
          Salinity

Question 11

Why would rate of evolution be rapid

Answer 11

Selection pressures are STRONG

Question 12

Sexual Selection

Answer 12

Involves Selection of alleles that increase the individuals chances of mating and producing offspring, its non random.

Question 13

What does sexual selection select for

Answer 13

Characteristics that have little survival benefit for the individual but increase chances of mating

Question 14

What happens if sexual selection occurs

Answer 14

The increase in allele frequency is determined through selection of mating partners

Question 15

Sexual selection may lead to

Answer 15

Sexual dimorphism, and be due to male male rivalry and female choice.

Question 16

Sexual dimorphism

Answer 16

physical difference between male and females of same species other than sex organs.

Question 17

Male male rivarly

Answer 17

Large size or weaponry increases
access to females through conflict

Question 18

Female choice

Answer 18

Involves females assessing fitness of males

Question 19

Gentic drift

Answer 19

Occurs when chance events cause unpredictable fluctuations in allele frequencies from one gen to the next

Question 20

genetic drift is more important in

Answer 20

Small populations, as alleles are more likely to be lost from the gene pool.

Question 21

Population bottlenecks

Answer 21

Occur when a population size is reduced for at least one gen

Question 22

Founder effects

Answer 22

Occur through isolation of a few members of a population from a larger one. Gene pool of new population is not representative of that in the original gene pool

Question 23

Why is a gene pool altered

Answer 23

genetic drift causes certain alleles to be under or over represented and allele frequencies change

Question 24

Hardy Weinberg principle

Answer 24

States that in the absence of evolutionary influences allele and genotype frequencies in a population will remian constant over the gens

Question 25

Conditions for maintaining HW equilibrium

Answer 25

• No natural selection
• Random mating
• No mutation
• Large population
• No gene flow