evolution

Question 1

define evolution

Answer 1

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

Question 2

during evolution how do the changes in allele frequency occur

Answer 2

During evolution, changes in allele frequency occur through the non-random processes of natural selection and sexual selection, and the random process of genetic drift

Question 3

what does natural selection act on

Answer 3

Natural selection acts on genetic variation in populations

Question 4

how does variation arise

Answer 4

Variation in traits arises as a result of mutation.

Question 5

what is the result of selection

Answer 5

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

Question 6

what does population produce

Answer 6

Populations produce more offspring than the environment can support

Question 7

what are individuals with variations that are better for the environment tend to do

Answer 7

Individuals with variations that are 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 8

what is sexual selection

Answer 8

Sexual selection is the non-random process involving the selection of alleles that increase the individual’s chances of mating and
producing offspring

Question 9

what may sexual selection lead to

Answer 9

Sexual selection may lead to sexual dimorphism

Question 10

what may sexual selection be due to

Answer 10

Sexual selection can be due to male-male rivalry and female choice

Question 11

what is male-male rivalry

Answer 11

Male-male rivalry: large size or weaponry increases access to females through conflict.

Question 12

when does genetic drift occur

Answer 12

Genetic drift occurs when chance events cause unpredictable fluctuations in allele frequencies from one generation to the next

Question 13

in what type of population is genetic drift more important in

Answer 13

Genetic drift is more important in small populations, as alleles are more likely to be lost from the gene pool

Question 14

when do population bottlenecks occur

Answer 14

Population bottlenecks occur when a population size is reduced for at least one generation.

Question 15

how do founder effects occur

Answer 15

Founder effects occur through the isolation of a few 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 16

what is a gene pool altered by

Answer 16

A gene pool is altered by genetic drift because certain alleles may be underrepresented or over-represented and allele frequencies change

Question 17

what happens when rapid selection pressures are strong

Answer 17

Where selection pressures are strong, the rate of evolution can be rapid

Question 18

what are selection pressures

Answer 18

Selection pressures are the environmental factors that influence which individuals in a population pass on their alleles.

Question 19

what can selection pressures be

Answer 19

They can be biotic: competition, predation, disease, parasitism; or abiotic: changes in temperature, light, humidity, pH, salinity.

Question 20

what does the hw principle state

Answer 20

The Hardy-Weinberg (HW) principle states that, in the absence of evolutionary influences, allele and genotype frequencies in a population will remain constant over the generations

Question 21

what can the Hardy- Weinberg principle be used to determine

Answer 21

The HW principle can be used to determine whether a change in allele frequency is occurring in a population over time

Question 22

what do changes suggest

Answer 22

Changes suggest evolution is occurring

Question 23

Define fitness

Answer 23

Fitness is an indication of an individual’s ability to be successful at surviving and reproducing

Question 24

what is fitness

Answer 24

Fitness is a measure of the tendency of some organisms to produce more surviving offspring than competing members of the same species

Question 25

how can fitness be defined

Answer 25

Fitness can be defined in absolute or relative terms

Question 26

what is absolute fitness

Answer 26

Absolute fitness is the ratio between the frequency of individuals of a particular genotype after selection, to those before selection

Question 27

what is relative fitness

Answer 27

Relative fitness is 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 28

what do each of the letters represent in the Hardy-Weinberg theory

Answer 28

p squared+ 2pq +q squared = 2 1
p = frequency of dominant allele
q = frequency of recessive allele
p squared = frequency of homozygous dominant
genotype
2pq = frequency of heterozygous genotype
q squared = frequency of homozygous recessive
genotype

Question 29

what is the hw principle used to calculate

Answer 29

Use the HW principle to calculate allele, genotype and phenotype frequencies in populations.

Question 30

what happens if the absolute fitness is 1

Answer 30

If the absolute fitness is 1, then the frequency of that genotype is stable. A value greater than 1 conveys an increase in the genotype and a value less than 1 conveys a decrease.

Question 31

What is co-evolution

Answer 31

Co-evolution is the process by which two or more species evolve in response to selection pressures imposed by each other

Question 32

what does a change in the traits of one species acts as

Answer 32

A change in the traits of one species acts as a selection pressure on the other species

Question 33

what is the red queen hypothesis

Answer 33

The Red Queen hypothesis states that, in a co-evolutionary relationship, change in the traits of one species can act as a selection pressure on the other species

This means that species in these relationships must adapt to avoid extinction

Question 34

what is co - evolution frequently seen in

Answer 34

Co-evolution is frequently seen in pairs of species that have symbiotic interactions

The impacts of these relationships can be positive (+), negative (-) or neutral (0) for the individuals involved Mutualism, commensalism, and

Question 35

define symbiosis

Answer 35

Symbiosis: co-evolved intimate relationships between members of two different species.

Question 36

define commensalism

Answer 36

Commensalism: only one of the organisms benefits (+/0).

Question 37

define mutualism

Answer 37

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

Question 38

define parasitism

Answer 38

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

Question 39

What are most mutations

Answer 39

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

Question 40

What are mutations the original source of

Answer 40

Mutation is the original source of new sequences of DNA. These new sequences can be novel alleles.

Question 41

What does female choice involve

Answer 41

Female choice involves females assessing the fitness of males.