Evolution through Natural Selection

Question 1

Define natural selection

Answer 1

The process fo life forms with traits that enable them to adapt to specific environmental pressures will tend to survive and reproduce in greater numbers of their kind.

Question 2

What are the three observations of natural selection

Answer 2

1. Variation
2. Birth rate
3. Natures balance

Question 3

Describe observation one - variation

Answer 3

All members of a species show variation.

Question 4

Describe observation two - birth rate

Answer 4

Is always far greater than the availability of resources would allow.

Question 5

Describe observation three - natures balance

Answer 5

Despite a high birth rate population numbers stay fairly constant.

Question 6

What are the two interpretations Charles Darwin demonstrated

Answer 6

1. struggle for survival
2. survival of the fittest

Question 7

Describe interpretation one - struggle for survival

Answer 7

Due to excessive birth rate and limited resources.

Question 8

Describe interpretation two - survival of the fittest

Answer 8

Because there is variation within the species, those with the characteristics best suited for survival are the ones that survive, reproduce and pass on those characteristics.

Question 9

What is microevolution

Answer 9

Changes of allele frequencies within a species or population over a short period of time

Question 10

What is macroevolution

Answer 10

Major evolutionary change, especially with regard to the evolution of whole taxonomic groups over long periods of time through the accumulation of microevolutionary change.

Question 11

What is an example of microevolution

Answer 11

Bacteria

Question 12

What is an example of macroevolution

Answer 12

Evolution of Horses

Question 13

Define evolution

Answer 13

Evolution is a change in the allele frequencies of biological populations over successive generations.

Question 14

How is a variation created/occurs

Answer 14

Mutations

Question 15

How is variation increased

Answer 15

Sexual reproduction

Question 16

How does natural selection lead to evolution?

Answer 16

1. Variation in population
2. More individuals produced can be supported by the environment
3. Struggle for survival (competition for resources)
4. Individuals with favourable genetic characteristics outcompete individuals lacking favourable characteristics
5. Favours individuals survive
6. Survivors have offspring
7. Desirable alleles passed onto offspring
8. Increase in favoured allele in the gene pool

Question 17

What are 3 adaptations that occur over time

Answer 17

1. Environments change over time
2. Favourable characteristics therefore also change
3. This causes the gene pool to change and the population to evolve.

Question 18

Define what selection pressures are

Answer 18

Selection pressures are any feature of the environment that reduces or increases the fitness of a particular phenotype in a population of organisms.

Question 19

What are three forms of selection pressures

Answer 19

1. Resource availability
2. Environmental conditions
3. Biological factors

Question 20

Describe resource availability as a selection pressure

Answer 20

Refer to the presence of sufficient food, habitat and mates

Question 21

Describe environmental conditions as a selection pressure

Answer 21

Refer to temperature, weather conditions or geographical access

Question 22

Describe biological factors

Answer 22

Refer to predators and pathogens

Question 23

What are the three different types of natural selection

Answer 23

1. Stabilising selection
2. Directional selection
3. Distributive selection

Question 24

What is stabilising selection

Answer 24

When selection pressures are not changing and the optimal trait becomes more common.

Question 25

What is directional selection

Answer 25

When changing selection pressures leads to changing traits overtime.

Question 26

What is disruptive selection

Answer 26

A selection that favours extremes of phenotype range.

Question 27

Draw a graph/diagram demonstrating a stabilising selection

Answer 27

Check book

Question 28

Draw a graph/diagram demonstrating a directional selection

Answer 28

Check book

Question 29

Draw a graph/diagram demonstrating a disruptive selection

Answer 29

Check book