Unit 2

Question 1

What is 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

What is evolution

Answer 2

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

Question 3

What is selection pressures?

Answer 3

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

Question 4

What are biotic factors? Give 4 examples?

Answer 4

Living factors - eg. Competition, predation, disease and parasitism

Question 5

What are Abiotic factors? Give 4 examples?

Answer 5

Non-living factors - eg. Changes in temperature, light, humidity, pH and salinity

Question 6

What are the two types of evolution?

Answer 6

Random and non-random

Question 7

What is an example of random evolution?

Answer 7

Genetic Drift

Question 8

What is Non-random evolution influenced by?

Answer 8

Selection pressures, and the traits that are selected by these pressures

Question 9

Give 2 examples of non-random evolution?

Answer 9

Natural selection and sexual selection

Question 10

What is variation within a population a result of?

Answer 10

Mutations

Question 11

What are mutations?

Answer 11

The original source of new DNA sequences, which can result in novel alleles

Question 12

Natural selection timeline.

Answer 12

• populations always produce more offspring than the environment can support.
• variation exists within the species (due to different mutations)
• Organisms struggle for survival and are influenced by selection pressures like competition and predation
• those organisms best suited to the environment survive as they have a selective advantage. Those organisms less suited due off. This process is called natural selection (or survival of the fittest)
• The surviving organisms mate, reproduce and pass on useful allelesthat conferred an advantage to the next generation

Question 13

What do selection pressures influence?

Answer 13

The traits in a population based on if they confer a selective advantage or not in that particular environment

Question 14

What is sexual selection?

Answer 14

A form of natural selection, where the increase in allele frequency is determined through the selection of mating partners.

Question 15

What does the selection for mates lead to?

Answer 15

Extreme physical (or behavioural) adaptations to attract mates - this can cause sexual dimorphism in males and females

Question 16

What are the two sub-categories of sexual selection?

Answer 16

Male-male rivalry and Female choice

Question 17

What is male-male rivalry? Give an example?

Answer 17

Large size or weaponry increases access to females through conflict. An example being stags and deer.

Question 18

What is female choice? Give an example?

Answer 18

Female choice involves females assessing the fitness of males. An example being peacocks and peahens

Question 19

What is genetic Drift?

Answer 19

Genetic Drift leads for variation in the relative frequency of different genotypes in a population, when chance events cause unpredictable fluctuations in allele frequencies from one generation to the next.
Certain alleles can be under represented, others over-represented

Question 20

What populations are particularly at risk of losing alleles due to genetic Drift?

Answer 20

Small populations

Question 21

What is a population bottleneck?

Answer 21

An event that drastically reduces the size of a population for at least one generation

Question 22

What is a population bottleneck caused by?

Answer 22

Environmental disaster, overhunting or habitat destruction

Question 23

What is the effect of a population bottleneck?

Answer 23

Reduce the gene pool as many allele types are lost, this leaves a population with a much reduced diversity

Question 24

What is the founder affect?

Answer 24

The founder effect occurs through the isolation of a few members of a population from a larger population.

Question 25

What happens to the gene pool of a new population after the founder effect?

Answer 25

It's not representative of that in the original gene pool

Question 26

What does the Hardy-Wienberg principle state?

Answer 26

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

Question 27

What 5 conditions must be met for the HW principle to apply?

Answer 27

No selection, no mutation, no migration, a large population and random mating

Question 28

Name the 2 Hardy-Wienberg equations?

Answer 28

p + q = 1 p² + 2pq + q² = 1.0

Question 29

What does all the letters in the 2 Hardy-Wienberg equations stand for ? (p + q = 1 and p² + 2pq + q² = 1.0)

Answer 29

p = frequency of dominant allele q = frequency of recessive allele p² = frequency of homozygous dominant genotype 2pq = frequency of heterozygous genotype q² = frequency of homozygous recessive geneotype

Question 30

What is fitness?

Answer 30

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

Question 31

What two terms is fitness defined by?

Answer 31

Absolute or relative terms

Question 32

What happens to alleles with the highest fitness?

Answer 32

They would become more common in a population.

Question 33

What is the overall fitness of an individual affected by?

Answer 33

It's enviroment

Question 34

The fitness of a phenotype and genotype will differ where?

Answer 34

Different environments

Question 35

What is absolute fitness?

Answer 35

The ratio between the frequencies of individuals of a particular genotype after selection, to those before selection (from one generation to the next)

Question 36

What is relative fitness?

Answer 36

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 (from one genotype to the next)

Question 37

What is coevolution?

Answer 37

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

Question 38

A change in the traits of one species acts as what?

Answer 38

A selection pressure on the other species

Question 39

Give 4 examples of co-evolutions?

Answer 39

Herbivores and plants, pollinators and plants, predators and prey and parasites and hosts

Question 40

What is symbiotic interactions?

Answer 40

Co-evolved intimate relationships between members of two different species.

Question 41

What is mutualism?

Answer 41

Both organisms in the interaction are independent on eachother for resources or other services. Both organisms gain something from the relationships - shown as (+/+)

Question 42

What is commensalism?

Answer 42

Only one of the organisms benefits but the interaction doesn't negatively affect the other organism. This interaction can be shown as (+/0)

Question 43

What is parasitism?

Answer 43

The parasite benefits in terms of energy or nutrients and the host is harmed as the result of the loss of these resources. This interaction can be shown as (+/-)

Question 44

What does the red queen hypothesis state?

Answer 44

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

Question 45

What does the red queen hypothesis mean?

Answer 45

Species in these relationships must adapt to avoid extinction. Both organisms must "keep running in order to stay still"