Adaptation, Natural Selection And The Evolution Of Species

Question 1

What may mutations be ?

Answer 1

Neutral, confer an advantage or a disadvantage

Question 2

How often do mutations occur ?

Answer 2

Spontaneous and rarely

Question 3

What are agents which can increase the rate of mutations called ?

Answer 3

Mutagens

Question 4

Give examples of mutagenic agents ?

Answer 4

Chemicals eg mustard gas

Radiation eg gamma rays X-rays and uv light

Question 5

What do mutations alter ?

Answer 5

The amount or structure of the genetic material in an organism

Question 6

What does a change to the amount of genetic material associated with ?

Answer 6

chromosomes

Question 7

What is a change to the structure of genetic material associated with ?

Answer 7

Genes

Question 8

If a mutation cause a change in the phenotype of an organism what is the resulting organism called?

Answer 8

Mutant

Question 9

Why are mutations useful ?

Answer 9

They are the only source of new alleles

Question 10

Why are new alleles essential?

Answer 10

To allow organisms to adapt to a changing environment

Question 11

What do new alleles do ?

Answer 11

Increase variation.

Question 12

What does variation within a population make possible ?

Answer 12

For a population to evolve over time in response to changing environmental conditions

Question 13

What is an adaptation?

Answer 13

An inherited characteristic that makes an organism well suited to survival its environment/niche

Question 14

Describe how a kangaroo rat has adapted itself to survive in its environment ?(5)

Answer 14

Mouth and nasal passage are dry , thereby reducing water loss during breathing.
It’s bloodstream contains a high concentration of anti diuretic hormone.
It’s kidney tubules are very long and promote water reabsorption so effectively that it can produce urine 17 times concentrated as blood.
It’s large intestine is efficient at reabsorbing water from waste material and producing faeces with low water content.
It does not sweat.

Question 15

If a species produces more offspring than the environment can sustain, what will occur?

Answer 15

Natural selection or survival of the fittest

Question 16

What is a mutation ?

Answer 16

Random change to genetic material

Question 17

Describe the 4 stages of natural selection in industrial areas for peppered moths

Answer 17

1. Pollution causes trees to be coated with soot and blacken. The lichens on them die as well.
2. The black are better camouflaged and have less chance of being seen and eaten by a predator.
3. They then have a greater chance of passing the black gene into the next generation through breeding.
4. This results in a greater number of black moths in the next generation.

Question 18

Describe the 4 stages of natural selection in non-industrial areas for peppered moths

Answer 18

1. In non-polluted areas the trees are covered in lichen.
2. The speckled moth is better camouflaged and has less chance of being seen and eaten by a predator.
3. They have a greater chance of passing on the speckled gene onto the next generation through breeding.
4. This results in a greater number of speckled moths in the next generation.

Question 19

What is speciation?

Answer 19

The formation of a new species.

Question 20

When does speciation occur?

Answer 20

After a population has become isolated and natural selection follows a different path due to different conditions/selection pressures.

Question 21

What does speciation involve?

Answer 21

Changes in genotype and phenotype that makes an organism more suited to the environment.

Question 22

What is speciation brought about by?

Answer 22

Evolution

Question 23

Give an example of a barrier which can isolate two populations ?

Answer 23

Mountains / rivers