Year 11 Biology: Fossils and Extinction, Variation and Evolution

Introduction to Fossils and Extinction

What are Fossils?

Fossils are the remains or traces of plants and animals that lived a long time ago. They can be bones, shells, or even footprints! Fossils help us understand what life was like on Earth millions of years ago.

Example: Think of a dinosaur bone that was buried in the ground and turned into a fossil over millions of years. When scientists find it, they can learn about how dinosaurs lived.

How Do Fossils Form?

Fossils form in several steps:

1. Death: An animal or plant dies and falls into water or mud.
2. Burial: It gets covered by sediment (like mud or sand).
3. Pressure: Over time, more layers of sediment build up, causing pressure.
4. Mineralisation: The remains slowly turn into rock as minerals fill in the spaces.

What is Extinction?

Extinction happens when a species (a type of plant or animal) has no living members left. This can happen for various reasons, like changes in the environment, loss of habitat, or competition for food.

Example: The woolly mammoth is an extinct species. They lived during the Ice Age but disappeared due to climate change and hunting by humans.

Introduction to Variation and Evolution

What is Variation?

Variation means that individuals in a species are different from one another. These differences can be in size, colour, shape, or behaviour. Variation is important because it helps species adapt to their environment.

Example: In a litter of puppies, some may be black, and others may be brown. This is variation!

What is Evolution?

Evolution is the process by which species change over time. It usually happens through a process called natural selection.

1. Natural Selection: It is the idea that the individuals with traits that help them survive are more likely to reproduce. Over time, these traits become more common in the population.

Example: If a group of rabbits has both white and brown fur, the brown rabbits may survive better in a forest with brown dirt. Over generations, more rabbits will be brown.

Key Rules and Tips

• Fossils: Remember the steps of fossil formation. It can help you understand how old fossils are.
• Extinction: Think about how changes in the environment can affect the survival of species.
• Variation and Evolution: Keep in mind that variation is crucial for evolution. Without differences, there would be no natural selection.

Questions

Easy Level Questions

1. What is a fossil?
2. How do fossils form?
3. What is extinction?
4. Give an example of an extinct animal.
5. What is variation in species?
6. Why is variation important?
7. What is evolution?
8. What is natural selection?
9. Can you name a type of fossil?
10. What happens to a species when it goes extinct?
11. How can fossils help us learn about the past?
12. What do we call an animal that no longer exists?
13. Why do animals have different colours and shapes?
14. What are some ways fossils can form?
15. Why might a species become extinct?
16. What evidence do fossils provide?
17. What is a species?
18. Can plants also be fossils?
19. Why do some species survive better than others?
20. How can humans impact extinction?

Medium Level Questions

1. Explain the process of fossil formation in detail.
2. What factors can lead to extinction?
3. Describe how natural selection works.
4. How do fossils help scientists understand evolution?
5. What is the difference between a fossil and a living organism?
6. Can extinction be prevented? How?
7. What role does variation play in survival?
8. Give an example of a species that has evolved over time.
9. What is the significance of the fossil record?
10. How does climate change affect extinction rates?
11. What adaptations might help an animal survive?
12. How do scientists date fossils?
13. What is selective pressure?
14. How can human activity lead to extinction?
15. Why is it important to protect endangered species?
16. What can we learn from studying extinct species?
17. Describe a major extinction event in Earth’s history.
18. How do mutations contribute to variation?
19. What is the relationship between variation and evolution?
20. How can fossils show changes in the environment?

Hard Level Questions

1. Discuss the process of fossilisation in detail, including the types of fossils.
2. Explain how the theory of evolution links with natural selection.
3. What evidence supports the theory of evolution?
4. How has the understanding of extinction changed over time?
5. Discuss the impact of invasive species on native populations.
6. What are “living fossils”? Give an example.
7. How do scientists use DNA to study evolution?
8. Explain the significance of transitional fossils.
9. What are the ethical considerations in conservation biology?
10. How do geological time scales relate to the study of fossils?
11. Discuss the role of genetic variation in a population’s ability to adapt.
12. How do environmental changes drive evolution?
13. What is the impact of overfishing on species extinction?
14. Explain the concept of co-evolution with an example.
15. How do fossils provide insight into ancient ecosystems?
16. Discuss the role of climate in the extinction of species.
17. What are the limitations of the fossil record?
18. How can the study of fossils influence modern medicine?
19. Explain how plate tectonics can affect evolution and extinction.
20. Discuss two major theories of species extinction.

Answers and Explanations

Easy Level Answers

1. A fossil is a preserved remain or trace of a plant or animal from the past.
2. Fossils form when organisms die, get buried, and their remains change into rock over time.
3. Extinction is when a species no longer has any living members.
4. The woolly mammoth is an example of an extinct animal.
5. Variation is the differences among individuals in a species.
6. Variation is important because it allows species to adapt and survive.
7. Evolution is the change in species over time.
8. Natural selection is the process where individuals with beneficial traits survive and reproduce.
9. A dinosaur bone is a type of fossil.
10. A species goes extinct when there are no more members alive.
11. Fossils help us learn about past environments and how species lived.
12. An animal that no longer exists is called extinct.
13. Animals have different colours and shapes to adapt to their environments.
14. Fossils can form from sedimentation, freezing, or being trapped in amber.
15. A species might become extinct due to habitat loss, climate change, or competition.
16. Fossils provide evidence of past life, environments, and how species changed.
17. A species is a group of similar organisms that can breed and produce fertile offspring.
18. Yes, plants can also be fossils.
19. Some species survive better due to traits that help them find food or avoid predators.
20. Humans can impact extinction through pollution, habitat destruction, and climate change.

Medium Level Answers

1. Fossil formation involves death, burial, pressure, and mineralisation over time.
2. Factors leading to extinction can include environmental changes, loss of habitat, and overhunting.
3. Natural selection works by favouring individuals with beneficial traits that help them survive.
4. Fossils show how species have changed and adapted over time, indicating evolutionary links.
5. Fossils are the remains of past organisms, while living organisms are currently alive.
6. Extinction can be prevented through conservation efforts and habitat protection.
7. Variation allows for different traits in a population, which can aid survival during changes.
8. An example of an evolving species is the peppered moth, which changed colour in response to pollution.
9. The fossil record is significant as it provides a timeline of life and changes on Earth.
10. Climate change can lead to habitat loss and altered food sources, increasing extinction rates.
11. Adaptations like camouflaging help animals blend in and avoid predators.
12. Scientists date fossils using methods like carbon dating or stratigraphy.
13. Selective pressure is any factor that affects an organism’s ability to survive and reproduce.
14. Human activity such as deforestation and pollution can lead to extinction.
15. Protecting endangered species helps maintain biodiversity and ecosystem balance.
16. Studying extinct species can reveal how past lifeforms adapted and survived.
17. The Permian-Triassic extinction event is an example of a major extinction event.
18. Mutations create new traits, leading to variation within a population.
19. Variation is essential for evolution because it provides the raw material for natural selection.
20. Fossils can show environmental changes, like shifts in climate or landforms.

Hard Level Answers

1. Fossilisation involves processes like moulds, casts, and permineralisation, creating different fossil types.
2. The theory of evolution links with natural selection as it explains how species adapt and evolve over time.
3. Evidence supporting evolution includes fossil records, genetic similarities, and observed natural selection.
4. Understanding of extinction has evolved, now including concepts like gradual decline and human impact.
5. Invasive species can outcompete native species for resources, leading to extinction.
6. “Living fossils” are species that have remained relatively unchanged for millions of years, like the coelacanth.
7. Scientists use DNA comparisons to understand relationships and evolution between species.
8. Transitional fossils show intermediate traits between ancestral and descendant species.
9. Ethical considerations in conservation include the rights of species, habitat protection, and human impact.
10. Geological time scales help us understand the timing and sequence of fossil events.
11. Genetic variation enhances a population’s ability to adapt to environmental changes.
12. Environmental changes can create new challenges, driving evolution as species adapt.
13. Overfishing can remove key species from ecosystems, disrupting balance and leading to extinction.
14. Co-evolution is the process where two species influence each other’s evolution, like bees and flowers.
15. Fossils provide insights into the structure and relationships of ancient ecosystems.
16. Climate changes can alter habitats and food sources, leading to species extinction.
17. Limitations of the fossil record include gaps in data, incomplete specimens, and bias in preservation.
18. Fossil studies can lead to medical breakthroughs by understanding ancient diseases and organisms.
19. Plate tectonics can cause habitat changes, influencing evolution and extinction of species.
20. Two major theories of extinction are the “impact hypothesis” (asteroid impacts) and “volcanic activity” causing climate shifts.