Evolution - Lecture One

Question 1

What are 3 conditions needed for natural selection to occur?

Answer 1

• Heritable characters
• Characters varying between individuals
• Differential fitness between individuals

Question 2

What is the definition of evolution?

Answer 2

Genetic change over time in a population

Question 3

How do fossils show evidence of evolution?

Answer 3

• We can view changes in species over time
• We can view species that no longer exist

Question 4

How does imperfection and the left recurrent laryngeal nerve evidence evolution?

Answer 4

• The larynx evolved from the branchial arch
• During evolution, the function of the brachial arch changed but the laryngeal nerve stayed in the same position
• This shows how the function has changed and been adapted due to natural selection

Question 5

How does imperfection and human vestigial traits evidence evolution?

Answer 5

• Human vestigial traits are traits we have that have lost their function over time, like muscles in our ears
• They show evolution because some functions and features have changed, leaving behind parts as evidence

Question 6

How does biogeography (eg oceanic islands) evidence evolution?

Answer 6

• Species living in different areas have specific adaptations to their environment
• EG species native to ocean islands have specific adaptations to their environment, with similar traits to species living on land nearby

Question 7

How does biogeography and convergent evolution evidence evolution?

Answer 7

• Distantly related species can evolve to have similar adaptations due to similar selection pressures, without having the same genetics
• This shows evolution because the species have adapted through natural selection in response to a common selection pressure

Question 8

How does seeing natural selection in action evidence evolution?

Answer 8

• We can actively see natural selection occur, showing evolution because we can watch it occur, eg through industrial melanism

Question 9

How does molecular genetics evidence evolution?

Answer 9

Using molecular genetics we can track evolution by comparing genetic sequences or looking at proteins

Question 10

What is the molecular clock and how is it important?

Answer 10

• The molecular clock is used to state whether the rate of substitutions of genetics is constant
• We can use it to identify when different species diverged