Year 8 Biology: Genes and Natural Selection Questions

Introduction to Genes and Natural Selection

Hello, Year 8! Today, we are going to explore two important ideas in biology: genes and natural selection. Let’s break them down together!

What are Genes?

Genes are like tiny instructions inside our bodies. They tell our bodies how to grow and develop. Genes are made of a substance called DNA. Here are some key points about genes:

1. Inherited Traits: Genes are passed from parents to children. For example, if your parents have brown eyes, you might have brown eyes too.
2. Different Forms: A gene can have different versions, called alleles. For instance, a gene for flower colour might have a red allele and a white allele.
3. Physical Characteristics: Genes control traits like height, hair colour, and even how our bodies work.

What is Natural Selection?

Natural selection is a process that explains how species change over time. Here’s how it works:

1. Variation: In any group of living things, there are differences. For example, some rabbits might be faster than others.
2. Survival: The faster rabbits are more likely to escape predators and survive. This is called “survival of the fittest.”
3. Reproduction: The rabbits that survive are more likely to have babies. If they pass on their fast genes, the next generation may also be fast.
4. Change Over Time: Over many generations, these small changes can lead to a new species!

Examples of Genes and Natural Selection

• Peppered Moths: In England, before the Industrial Revolution, most peppered moths were light-coloured. However, when pollution darkened the trees, the darker moths were better camouflaged from predators. They survived and reproduced more, leading to a higher number of dark moths over time.
• Darwin’s Finches: On the Galápagos Islands, different finches have different beak shapes. Some have long beaks for getting insects, while others have short beaks for cracking seeds. The beak shape that helps a bird find food means it is more likely to survive and have babies with the same beak shape.

Key Rules, Tips, and Tricks

• Remember the Steps of Natural Selection: Think of the acronym VSRR (Variation, Survival, Reproduction, and Change).
• Use Examples: Relate what you learn to real-life situations or animals you know.
• Visual Aids: Diagrams showing how traits are passed on can really help.
• Ask Questions: If you don’t understand something, don’t hesitate to ask!

Questions on Genes and Natural Selection

Easy Level Questions

1. What are genes?
2. What substance are genes made of?
3. What do genes control in our bodies?
4. What is an allele?
5. Who do you inherit your genes from?
6. What does “survival of the fittest” mean?
7. Give an example of a trait you might inherit.
8. What happens to animals that cannot survive?
9. Why are differences important in natural selection?
10. What might happen to a species if all individuals are the same?
11. How do faster rabbits survive better?
12. What do you call it when animals change over time?
13. Name a creature that has different forms (e.g., colour).
14. What is natural selection?
15. What is the main idea behind natural selection?
16. How can a gene for a trait be passed on?
17. Give an example of a trait controlled by a gene.
18. What does it mean to reproduce?
19. What do you think happens to the traits of animals that survive?
20. What role does the environment play in natural selection?

Medium Level Questions

1. Explain how peppered moths are an example of natural selection.
2. What role do predators play in natural selection?
3. How do scientists study genes?
4. Describe what variation means in a species.
5. How does natural selection lead to evolution?
6. What is the connection between genes and traits?
7. Why might a species go extinct?
8. Give an example of a change in a species due to natural selection.
9. How can two animals with the same genes look different?
10. How do changes in the environment affect natural selection?
11. What is a mutation, and how can it affect a gene?
12. Can natural selection happen quickly? Why or why not?
13. How does reproduction support natural selection?
14. What is the significance of Darwin’s finches?
15. How can natural selection affect a population?
16. Explain how a specific trait can be an advantage.
17. What is genetic diversity, and why is it important?
18. How does climate change impact natural selection?
19. Can humans influence natural selection? How?
20. Discuss why some traits are more successful than others.

Hard Level Questions

1. Explain the process of natural selection in detail.
2. Discuss the role of genetic variation in natural selection.
3. How do environmental changes drive natural selection?
4. Describe a real-world example of natural selection in action.
5. How do scientists use fossils to understand natural selection?
6. What is the significance of Charles Darwin’s theories?
7. How do recessive and dominant alleles affect traits?
8. Discuss the concept of fitness in the context of natural selection.
9. Explain how speciation occurs through natural selection.
10. What are some ethical implications of genetic research?
11. How do human activities impact natural selection?
12. Discuss the difference between artificial and natural selection.
13. What are some challenges in studying natural selection?
14. How do scientists track changes in species over time?
15. Explain the importance of reproductive success in evolution.
16. How do interspecies relationships affect natural selection?
17. Discuss the role of genetics in adaptation.
18. What evidence exists to support the theory of natural selection?
19. Explain how natural selection can lead to antibiotic resistance in bacteria.
20. What future changes do you predict for species due to natural selection?

Answers to the Questions

Easy Level Answers

1. Genes are instructions for our bodies.
2. Genes are made of DNA.
3. Genes control traits like height and eye colour.
4. An allele is a different version of a gene.
5. You inherit your genes from your parents.
6. It means the best-suited animals survive and reproduce.
7. An example is eye colour.
8. They cannot reproduce and pass on their genes.
9. Differences allow some to survive better.
10. They might not adapt well to their environment.
11. Faster rabbits escape predators better.
12. It means species change over time.
13. A chameleon can change colours.
14. Natural selection explains how species evolve.
15. The best traits help survival and reproduction.
16. They can be passed on through reproduction.
17. An example is fur colour in animals.
18. It means to have babies.
19. They will likely pass on their traits.
20. The environment can favour certain traits.

Medium Level Answers

1. Darker moths survived better in polluted areas.
2. Predators reduce the number of weaker animals.
3. They study genes using DNA analysis.
4. Variation means differences in a species.
5. Natural selection causes species to adapt over time.
6. Genes determine traits like eye colour.
7. A species might go extinct if it cannot adapt.
8. An example is the increase in dark moths due to pollution.
9. Different environment conditions can lead to different traits.
10. Changes can favour certain traits that help survival.
11. A mutation is a change in a gene and can create new traits.
12. It can happen quickly if environmental changes are drastic.
13. More successful animals pass on their traits.
14. They show how species adapt to different food sources.
15. It affects which traits are passed on to the next generation.
16. A specific trait can help an animal find food more efficiently.
17. Genetic diversity helps species adapt to changes.
18. It can create new selection pressures on species.
19. Yes, through breeding and habitat changes.
20. They can lead to the evolution of new traits.

Hard Level Answers

1. It involves variation, survival, reproduction, and change over time.
2. Variation provides different traits for selection.
3. Changes can favour some traits over others.
4. The peppered moths adapting to industrial pollution is an example.
5. Fossils show how species have changed over time.
6. Darwin proposed that species evolve through natural selection.
7. Dominant alleles mask recessive ones in traits.
8. Fitness refers to how well an organism survives and reproduces.
9. Speciation can occur when populations adapt to different environments.
10. It raises questions about genetic manipulation.
11. Deforestation can change habitats and affect species.
12. Artificial selection is human-driven, while natural is environmental.
13. Environmental changes can be slow and complex.
14. They use genetic studies and observational data.
15. Reproductive success ensures genes are passed on.
16. Relationships can create competition or cooperation.
17. Genetics help organisms adapt to their environments.
18. Fossils, genetic evidence, and observed changes support it.
19. Bacteria that survive antibiotics can reproduce and pass on resistance.
20. Climate change and habitat loss are major factors.

Feel free to review these concepts and questions as you continue learning about genes and natural selection!