Week 1: Introduction to evolution

Question 1

Describe the theory of evolution by natural selection.

Answer 1

• Living things may vary within populations
• Offspring resemble their parents (heritable traits)
• Success in reproduction depends on individual traits

Question 2

Describe the inevitability of evolution.

Answer 2

Once you have a system with variation, reproduction, inheritance of traits and differential survival according to those traits, evolution is inevitable

Question 3

Describe survival of the stable.

Answer 3

• Stability= simplest form of natural selection
• Replicators that are more stable last longer and have more chance to replicate
• Higher copying fidelity

Question 4

Describe the variation in replicators.

Answer 4

• Errors in copying
• New variant produces copies of itself
• Population descended from a single molecule

Question 5

Describe the beginning of the cosmos.

Answer 5

• The Big Bang happened 15 billion years ago and photons are still arriving from it
• Stars began to form 12 billion years ago
• Earth formed 4.5 billion years ago

Question 6

What is the life from space theory?

Answer 6

• A meteorite called the Munchinson Meteorite could have contained ribose
• But this is scientifically unlikely

Question 7

What is the significance of RNA?

Answer 7

• It has catalytic abilities
• Some viruses use RNA as an information or as an enzyme
• DNA monomers are synthesized from RNA
• Essential for cell processes

Question 8

Describe the first prokaryotes.

Answer 8

• 4000 years ago (only life forms for 2000 yrs)
• Fossil stromatolites

Question 9

What did Jean-Baptiste Lamarck discover?

Answer 9

• Recognised species were changing over time
• He though that this might follow the changing environment
• And acquired characteristics were inherited

Question 10

What did Cuvier discover?

Answer 10

• Recognised that species could go extinct
• And that species had separate origins but constant in form

Question 11

When was the voyage of the Beagle?

Answer 11

1832 to 1836

Question 12

What were Darwin’s postulates?

Answer 12

• Variations within populations
• Some of this variation is heritable
• Individuals vary in their ability to survive and reproduce
• Survival and reproduction are non-random