What are the two causes of variation?

Important Questions on Variation and Inheritance

MEDIUM

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Student's Book>Chapter 4 - Variation and Inheritance>End of Chapter Review>Q 8

A normal human body cell contains $46$ chromosomes in the nucleus. However, a sperm cell contains only $23$. Explain why this is the case.

MEDIUM

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Student's Book>Chapter 4 - Variation and Inheritance>End of Chapter Review>Q 8

Explain how a person could inherit a characteristic, such as 'earlobe attachment', from her mother.

MEDIUM

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Student's Book>Chapter 4 - Variation and Inheritance>End of Chapter Review>Q 9

Write a sentence that includes and explain the terms 'DNA', 'chromosome' and 'gene'.

MEDIUM

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Student's Book>Chapter 4 - Variation and Inheritance>End of Chapter Review>Q 11

What does inheritance mean?

MEDIUM

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Student's Book>Chapter 4 - Variation and Inheritance>End of Chapter Review>Q 11

Explain how a child could be born with attached earlobes like his father.

HARD

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Student's Book>Chapter 4 - Variation and Inheritance>End of Chapter Review>Q 13

Why was Darwin's trip on HMS beagle very important in helping him develop his theory of natural selection?

HARD

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Student's Book>Chapter 4 - Variation and Inheritance>End of Chapter Review>Q 13

Suggest why Darwin's theory of natural selection was opposed when he announced it?

HARD

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Student's Book>Chapter 4 - Variation and Inheritance>End of Chapter Review>Q 14

Look at the figure given above. Use your knowledge of natural selection to explain the following situation. The number of red frogs (like the one in the middle of the picture) decreases in subsequent generations, to the point that there are none remaining in $50$ years’ time.