4.6.3.2 Speciation

Question 1

Describe the work of Darwin and Wallace in the development of the theory of evolution by natural selection.

Answer 1

• After a variety of zoological discoveries, Wallace proposed a theory of evolution, which matched Darwin’s unpublished ideas that he had kept secret for nearly 20 years. - This encouraged Darwin to collect his scientific ideas and collaborate with Wallace.
• They published their scientific ideas jointly in 1858.

Question 2

Explain the impact of these ideas on biology.

Answer 2

• Resulted in our current understanding

Question 3

What did Alfred Russell Wallace independently propose?

Answer 3

• The theory of evolution by natural selection
• He published joint writings with Darwin in 1858 which promoted Darwin to publish “on the origin of species” (1959) the following year

Question 4

What did Wallace work worldwide gathering evidence for?

Answer 4

• For evolutionary theory
• He is best known for his work on warning colouration in animals and his theory of speciation

Question 5

Wallace did much pioneering work on speciation but more evidence over time led to what?

Answer 5

• Our current understanding of the theory of speciation

Question 6

Describe the steps which give rise to new species.

Answer 6

New species can arise as a result of the following things:
Genetic variation
- each population has a wide range of
alleles that can control their characteristics
Natural selection
- the alleles which help an organism
to survive are selected in each population
Speciation
- the populations become extremely varied and successful interbreeding cannot happen anymore