Evolution

Question 1

What is evolution?

Answer 1

The change over time in the proportion of individuals in a population differing in 1 or more inherited traits.

Question 2

What happens during evolution?

Answer 2

Changes in allele frequency occur through the non-random process of genetic drift.

Question 3

What does natural selection act on?

Answer 3

Genetic variation in populations

Question 4

What does variation in traits in a population arise from?

Answer 4

Mutation.

Question 5

What is mutation?

Answer 5

The original source of new sequences of DNA

Question 6

What can the new sequences that come from mutations be?

Answer 6

Novel alleles

Question 7

Most mutations are …

Answer 7

Harmful or neutral

Question 8

In rare cases mutations may be?

Answer 8

Beneficial to the fitness of an individual.

Question 10

Populations produce more offspring than the environment can support. Which individuals survive longer to produce more offspring, breeding to pass on those alleles that conferred an advantage to the next generations?

Answer 10

Individuals with variations that are better suited to their environment.

Question 11

Selection results in…

Answer 11

The non-random increase in the frequency of advantageous alleles and the non-random decrease in the frequency of deleterious alleles.

Question 12

What is sexual selection?

Answer 12

The non-random process involving the selection of alleles that increase the individuals chances of mating and producing offspring.

Question 13

What may sexual selection lead to?

Answer 13

Sexual dimorphism.

Question 14

What can sexual selection be due to?

Answer 14

Male-male rivalry and female choice.

Question 15

What is male to male rivalry?

Answer 15

Large size or weaponry increases access to females through conflict.

Question 16

What is female choice?

Answer 16

Involves females assessing the fitness of males.

Question 17

When does genetic drift occur?

Answer 17

When chance events cause unpredictable fluctuations in allele frequencies from one generation to the next.

Question 18

When is genetic drift more important?

Answer 18

In small populations, as alleles more likely to be lost from gene pool.

Question 19

When do population bottle necks occur?

Answer 19

When population size is reduced for at least 1 generation.

Question 20

When does founder effect occur?

Answer 20

Through the isolation of afew members of a population from a larger population. The gene pool of the new population is not representative of that in the original gene pool.

Question 21

Why is gene pool altered by genetic drift?

Answer 21

Because certain alleles may be underrepresented or overrepresented and allele frequencies change.

Question 22

When selection pressures are strong…

Answer 22

Rate of evolution can be rapid.

Question 23

What are selection pressures?

Answer 23

The environmental factors that influence which individuals in a population pass on their alleles.

Question 24

Examples of biotic selection pressures?

Answer 24

Competition, predation, disease, parasitism

Question 25

Examples of abiotic selection pressures?

Answer 25

Changes in temperature, light, humidity, pH and salinity

Question 26

What does the HW principle state?

Answer 26

In the absence of evolutionary influences, allele and genotype frequencies in a population will remain constant over generations.

Question 27

What are the conditions for maintaining the HW equillibrium?

Answer 27

- No natural selection - Random mating, no mutation - Large population size - No gene flow (through migration, in or out)

Question 28

What can the HW principle be used to determine?

Answer 28

Whether a change in allele frequency’s is occurring in a population over time. change suggests evolution is occurring.

Question 29

Formula for HW principle?

Answer 29

p2 + 2pq + q2 = 1

Question 30

p= q=

Answer 30

p= frequency of dominant allele q= frequency of recessive allele

Question 31

p2 = q2 =

Answer 31

p2 = frequency of homozygous dominant genotype q2 = frequency of homozygous recessive genotype

Question 32

2pq=

Answer 32

Frequency of heterozygous genotype

Question 33

What is fitness an indication of?

Answer 33

an individuals ability to be successful at surviving and reproducing.

Question 34

What is fitness a measure of?

Answer 34

The tendency of some organisms to produce more surviving offspring than competing members of the same species.

Question 35

What does fitness refer to?

Answer 35

The contribution made to the gene pool of the next generation by individual genotypes.

Question 36

What is absolute fitness?

Answer 36

The ratio between the frequency of individuals of a particular genotype after. selection to those before selection.

Question 37

Formula for absolute fitness

Answer 37

Frequency of particular genotype before selection / Frequency of particular genotype after selection

Question 38

What is relative fitness?

Answer 38

The ratio of the number of surviving offspring per individual of a particular genotype to the number of surviving offspring per individual of the most successful genotype.

Question 39

Formula for relative fitness?

Answer 39

Number of surviving offspring per individual of a particular genotype / Number of surviving offspring per individual of the most successful genotype.

Question 40

What is Co-evolution?

Answer 40

The process by which 2 or more species evolve in response to selection pressures imposed by each other

Question 41

What does a change in traits of 1 species act as?

Answer 41

A selection pressure on the other species.

Question 42

When is co evolution frequently seen?

Answer 42

In pair of species that have symbiotic interactions.

Question 43

What is symbiosis?

Answer 43

Co-evolved intimate relationship between members of 2 different species

Question 44

What can the impacts of these symbiotic relationships be for the individuals involved?

Answer 44

Positive, negative or neutral.

Question 45

What is mutualism?

Answer 45

Both organisms in the interaction are interdependent on eachother for resources or other services. As both organisms gain from the relationship, the interaction is (+/+)

Question 46

What is commensalism?

Answer 46

Only one of the organisms benefit (+/0)

Question 47

What is parasitism?

Answer 47

The parasite benefits in terms of energy or nutrients and the host is harmed as a result of the loss of these resources (+/-)

Question 48

What does the red queen hypothesis state?

Answer 48

In a co-evolutionary relationship, change in the traits of 1 species can act as a selection pressure on the other species.

Question 49

What does the red queen hypothesis mean?

Answer 49

Species in these relationships must adapt to avoid extinction.