B14: Genetics and Evolution

Question 1

What were three organisms that caused extinction? How did they cause extinction?

Answer 1

• New predators can wipe out unsuspecting prey animals very quickly if the prey animals do not have adaptations to avoid them.
• New diseases can bring about extinction, especially if the whole population of an animal or plant are close together.
• One species can cause another to become extinct by successful competition. New mutations can give one type of organism a real advantage over another.

Question 2

Define extinction.

Answer 2

The permanent loss of all the members of a species.

Question 3

What are fossils?

Answer 3

The remains of organisms from millions of years ago that can be found in rocks, ice and other places.

Question 4

Why are fossils useful for scientists?

Answer 4

Fossils give us information about organisms that lived millions of years ago. This allows scientists to understand how different species have evolved over time.

Question 5

What is believed to be the thing that destroyed the dinosaurs?

Answer 5

A giant asteroid which caused huge fires, earthquakes, landslides, and tsunamis. This caused lots of dust in the atmosphere which made everywhere almost dark and killed off many species which relied on sunlight.

Question 6

Why are resistant bacteria a challenge?

Answer 6

• reproduce rapidly.
• mutations produce new strains.
• resistant strains survive and reproduce.
• resistant strains spread.

Question 7

What are the three ways we can prevent resistant bacteria appearing?

Answer 7

• doctors shouldn’t prescribe antibiotics inappropriately.
• patients should complete the full course of antibiotics prescribed.
• agricultural use of antibiotics should be restricted.

Question 8

What is MRSA?

Answer 8

MRSA (Methicillin-Resistant Staphylococcus Aureus) is a bacteria that is resistant to methicillin.

Question 9

What do evolutionary trees show us?

Answer 9

Evolutionary trees show how different organisms are related.

Question 10

Why do we study the similarities and differences between organisms?

Answer 10

So we can classify them into Archaebacteria, eubacteria, or eukaryota.

Question 11

What new system did Woese propose?

Answer 11

Woese proposed three domains, divided into six kingdoms. The first was named Eukaryotes which consisted of four kingdoms: the protista, fungi, plants and animals. The second was named Archaebacteria. The third was named Eubacteria.

Question 12

What were the two main changed Woese made with his new system?

Answer 12

He created three domains.

He split the kingdom of Monera into Archaebacteria and Eubacteria.