Lesson 13: Speciation

Question 1

What 3 different ideas did the scientist Alfred Russel Wallace work on?

Answer 1

• Proposed the Theory of Evolution by natural selection (along with Charles Darwin.)
• How animals evolved to have warning colouration.
• His theory of speciation.

Question 2

How did Darwin and Alfred Russel Wallace work together?

Answer 2

• Wallace published joint writings with Darwin in 1858
• This promoted Darwin to publich On the Origin of Species in 1859.

Question 3

True or False

Wallace stayed in his home- town, exploring samples in his laboratory to help him to develop his evolutionary theory.

Answer 3

• FALSE!
• Wallace travelled WORLDWIDE gathering evidence for evolutionary theory.

Question 4

Why is Alfred Russel Wallace’s work on speciation so important?

Answer 4

• He was a pioneer for the idea of speciation (came up with the idea FRESH.)
• But more evidence over time has led to the current understanding of the theory of speciation.

Question 5

What are 5 the steps that lead to the rise of a new species?

Answer 5

1.) Organisms within a species are separated into two groups by a geographical barrier ie. a river.
2.) Over time, natural selection will favour different alleles on both sides of the barrier (because conditions on both sides are different.)
3.) No interbreeding between populations so no mutations can spread between the two populations.
4.) Over many generations, the two populations will change.
5.) If the two populations mix again, they will be so different that they will no longer be able to reproduce to produce fertile offsrping. They have become two different species!!

Question 6

In order to prove that two organisms are within the same species, what do the two organisms need to be able to do?

Answer 6

• They need to be able to reproduce AND produce fertile offspring.