Topic 4 Human Evolution

Question 1

Who was Ardi?

Answer 1

A 4.4 million‑year‑old hominin showing both tree‑climbing and walking features.

Question 2

Who was Lucy?

Answer 2

A 3.2 million‑year‑old hominin with a more human‑like pelvis and ability to walk upright.

Question 3

What did Leakey discover?

Answer 3

1.6 million‑year‑old Homo erectus fossils with larger brains and advanced walking ability.

Question 4

How do fossils show human evolution?

Answer 4

They reveal gradual changes in brain size, posture and tool use.

Question 5

How do stone tools provide evidence for evolution?

Answer 5

Tools become more complex over time, showing increased intelligence.

Question 6

How are stone tools dated?

Answer 6

By dating surrounding rock layers or carbon‑dating organic remains nearby.

Question 7

What is the pentadactyl limb?

Answer 7

A limb with five digits found in many vertebrates.

Question 8

Why does the pentadactyl limb support evolution?

Answer 8

Similar structure suggests a common ancestor.

Question 9

What is the five‑kingdom system?

Answer 9

Classification into: Animals, Plants, Fungi, Protists, Prokaryotes.

Question 10

Why was the five‑kingdom system replaced?

Answer 10

It didn’t reflect deep genetic differences between organisms.

Question 11

What is the three‑domain system?

Answer 11

Classification into: Archaea, Bacteria, Eukarya.

Question 12

What evidence led to the three‑domain system?

Answer 12

Genetic analysis (rRNA sequencing) showing major differences.

Question 13

What are Archaea?

Answer 13

Single‑celled organisms with unique biochemistry, often extremophiles.

Question 14

What are Bacteria?

Answer 14

True bacteria with different cell wall structures from Archaea.

Question 15

What are Eukarya?

Answer 15

Organisms with complex cells containing a nucleus.

Question 16

Why is the three‑domain system more accurate?

Answer 16

It reflects evolutionary relationships based on DNA.