Life on Earth - Speciation

Question 1

What is speciation?

Answer 1

Formation of a new species

Question 2

When does speciation occur?

Answer 2

After a population is divided by an isolation barrier

Question 3

Define the term ‘isolation barrier’

Answer 3

Causes the population to be separated and they can no longer interbreed freely

Question 4

List and give examples of the 3 types of isolation barrier

Answer 4

• Behavioural barrier - mating preferences
• Ecological barrier - different tolerance of pH or salinity
• Geological barrier - River, ocean, mountain range, etc.

Question 5

Explain the process of speciation

Answer 5

1. Populations are divided by an isolation barrier, different mutations happen in each sub-population.
2. Natural selection selects these different mutations due to different selection pressures for each group.
3. Each sub-population evolves till both groups are entirely new species.
4. The two species can no longer interbreed to produce fertile offspring, even if the isolation barrier is removed.

THE ORDER IS ISOLATION - MUTATION - NATURAL SELECTION - EVOLUTION