Organisms Evolution

Question 1

Evolution is

Answer 1

the change over time in the proportion of individuals in a population differing in one or more inherited characteristics.

Question 2

During evolution, changes in allele frequency occur through

Answer 2

the non-random processes of natural selection and sexual selection and the random process of genetic drift.

Question 3

Natural selection acts on

Answer 3

the genetic variation in a population. Population produces more offspring than the environment can support. Individuals with variations better suited to their environment tend to survive longer and produce more offspring, breeding to pass on those alleles that conferred an advantage to the next generation.

Question 4

Sexual selection is

Answer 4

the non-random process involving the selection of alleles that increase the individual’s chances of mating and producing offspring. Sexual selection may lead to sexual dimorphism. Sexual selection can be due to male-male rivalry and female choice.

Question 5

When selection pressures are strong, the rate of evolution can be

Answer 5

rapid.

Question 6

The Harvey-Weinberg (HW) principal states that

Answer 6

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

Question 7

The HW principle is used to determine whether

Answer 7

a change in allele frequency is occurring in a population over time. Changes suggest evolution is occurring.

Question 8

Variation in traits arises as a result of

Answer 8

mutation.

Question 9

Mutation is the original source of

Answer 9

new sequences of DNA.

Question 10

These new sequences can be

Answer 10

novel alleles.

Question 11

Most mutations are

Answer 11

harmful or neutral, but in rare cases they may be beneficial to the fitness of an individual.

Question 12

Selection results in the non-random increase in the

Answer 12

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

Question 13

Male-male rivalry:

Answer 13

large size and weaponry increase access to females through conflict.

Question 14

Female choice involves

Answer 14

assessing the fitness of males.

Question 15

Population bottlenecks occur when

Answer 15

the population size is reduced over at least one generation.

Question 16

Founder effects occur through

Answer 16

the isolation of some members of a population from a larger population.

Question 17

The gene pool of the new population is not representative of that

Answer 17

in the original gene pool.

Question 18

Selection pressures are environmental factors that influence

Answer 18

which individuals in a population will pass on their alleles.

Question 19

Selection pressures can be biotic:

Answer 19

competition, predation, disease and parasitism

Question 20

Selection pressures can be abiotic:

Answer 20

changes in temperature, light, humidity, pH, salinity.

Question 21

The conditions for maintaining the HW equilibrium are:

Answer 21

no natural selection, random mating, no mutation, large population size and no gene flow (through migration, in or out).

Question 22

Use the HW principle to calculate the

Answer 22

allele, genotype and phenotype frequencies in populations. the formula is (2p^2 + 2pq + q^2 = 1),
Where p = frequency of dominant allele; q = frequency of recessive allele.
P2 = frequency of homozygous dominant genotype, 2pq = frequency of heterozygous genotype and q2 = frequency of homozygous recessive genotype.

Question 23

Fitness is

Answer 23

an indication of an individual’s ability to be successful at surviving and reproducing. It refers to the contribution made to the gene pool of the next generation by individual genotypes.

Question 24

Absolute fitness is

Answer 24

the ratio between the number of individuals of a particular genotype before selection, to those after selection.

Question 25

Relative fitness is

Answer 25

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 26

Fitness is a measure of

Answer 26

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

Question 27

If absolute fitness is 1, then the

Answer 27

frequency of that genotype is stable.

Question 28

If the value for absolute fitness is > 1,

Answer 28

it conveys an increase in the genotype.

Question 29

If the value for absolute fitness is < 1,

Answer 29

it conveys a decrease in the genotype.

Question 30

Co- evolution is

Answer 30

the process by which two or more species evolve in response to selection pressure imposed by each other. A change in the traits of one species can act as a selection pressure on the other species.

Question 31

Co-evolution is frequently seen in

Answer 31

pairs of species with a symbiotic relationship. The impacts of these relationships can be positive(+), negative(-) or neutral(0) for the individuals involved.

Question 32

Types of symbiotic interactions

Answer 32

Mutualism, commensalism and parasitism

Question 33

The Red Queen Hypothesis states that,

Answer 33

changes seen in the traits of one species acts as a selection pressure on the other species. This means species in these relationships must adapt to avoid extinction.

Question 34

Symbiosis is

Answer 34

the co-evolved intimate relationship between members of two different species.

Question 35

In mutualism:

Answer 35

both organisms in the interaction are interdependent on each other for resources or other services.

Question 36

In mutualism: both organisms gain from the relationship,

Answer 36

the interaction is (+/+)

Question 37

In commensalism only one of the organisms benefit,

Answer 37

the interaction is (+/-)

Question 38

In parasitism:

Answer 38

the parasite benefits in terms of energy or nutrients and the host is harmed.

Question 39

In parasitism as the result of the loss of these resources,

Answer 39

the interaction is (+/-)