Topic 4---B: Diversity and Selection- 4. Natural selection

Question 1

What does natural selection increase?

Answer 1

The proportion of the advantageous alleles within a population

Question 2

What does randomly-occuring mutations sometimes result in?

Answer 2

New alleles being formed

Question 3

How does natural selection work?

Answer 3

• There is a variation of individuals in a population
• Individuals that have an allele that increases their chance of survival are more likely to survive, reproduce and pass on their genes including the beneficial allele rather than individuals with less advantageous alleles
• This means that a greater proportion of the next generation inherits the beneficial allele
• They in turn are more likely to survive, reproduce and pass on their genes
• So the frequency of the beneficial allele in the population increases from generation to generation.
• This leads to evolution as the advantageous alleles become more common in the population

Question 4

What are adaptations?

Answer 4

Features that help organisms to survive in their environment

Question 5

What are the 3 types of adaptations

Answer 5

Behavioural
Physiological
Anatomical

Question 6

Behavioral adaptations

Answer 6

These are ways an organism acts that increase its chance of survival

Question 7

Behavioral adaptations examples

Answer 7

Possums sometimes play dead- if theyre being threatened by a predator they do this to escape attack so it increases their chance of survival

Question 8

Physiological adaptations

Answer 8

These are processes inside an organisms body that increase its chance of survival

Question 9

Physiological adaptations examples

Answer 9

Brown bears hibernate- they lower there rate of metabolism over winter- this conserves energy so they dont need to look for food in the month when its scarce which increases their chance of survival

Question 10

Anatomical adaptations

Answer 10

These are structural features of an organisms body that increase its chance of survival

Question 11

Anatomical adaptations examples

Answer 11

Otters have a streamlined shape making it easier to glide through the water- this makes it easier for them to catch prey and escape predators increasing their chance of survival