1800 - 1900

Question 1

Who were the trailblazers of evolution between 1800 and 1900?

Answer 1

• Charles Darwin
• Alfred Russel Wallace

Question 2

What did the data that Charles Darwin collected make him aware of?

Answer 2

• immense diversity among organisms, both living and extinct
• variation of individuals of the same species, suggesting species were not unchangeable
• often puzzling distribution of different species

Question 3

What did Darwin realise from his interest in geology?

Answer 3

• the earth is extremely old which allowed time for species to evolve (he could see these changes in fossils from the different sedimentary rock layers)
• there has been great geological change over time with different areas and land masses becoming isolated
• isolation leads to species changing

Question 4

What were the 2 hypotheses explained by Darwin?

Answer 4

1. Modification with descent (or evolutionary change)
2. Natural selection

Question 5

How did Darwin explain descent with modification?

Answer 5

• all related organisms descended from a common ancestor
• the ancestral species spread into a variety of new habitats
• because they adapted to the new local conditions, they became modified and thus diversified into new species
• the diversification was by branching (i.e. the ancestral species gave rise to 2 or more new related species)
• some species died out

Question 6

What is the significance of Alfred Russel Wallace?

Answer 6

• he and Charles Darwin share the reputation for having discovered natural selection