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Year 10
Edexcel
Foundation

Common ancestors and transitional species

I can explain the importance of transitional species and common ancestors in the fossil record.

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New
New
Year 10
Edexcel
Foundation

Common ancestors and transitional species

I can explain the importance of transitional species and common ancestors in the fossil record.

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Share activities with pupils
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Lesson details

Key learning points

  1. The fossil record includes species that appear to be the common ancestor of numerous later species.
  2. Evolutionary trees can be used to help visualise the relationships between groups of organisms.
  3. The fossil record includes transitional species with features of both evolutionary ancestors and modern species.
  4. A case study of an example of a transitional species (e.g. Archaeopteryx, which links dinosaurs and modern birds).
  5. There are gaps in the fossil record, e.g. ‘missing links’ between evolutionary ancestors and modern species.

Keywords

  • Fossil record - All the fossils ever found, and their ages, provide a body of evidence called the fossil record.

  • Common ancestor - A species that several other species evolved from. For example, tigers and lions share a common ancestor.

  • Evolutionary tree - A diagram that shows the evolutionary relationships between different groups of organisms.

  • Transitional species - A species that shows intermediate characteristics from evolutionary ancestors and modern species.

Common misconception

Students often struggle to understand the concept of having a common ancestor and confuse it with one species being descended from another.

This lesson uses evolutionary trees to help students visualise the relationships between groups of organisms.

People remember stories far more easily than isolated facts. If time allows, look into the history of the discovery of the first Archaeopteryx fossils (the natural history museum website is a good resource) and tell your class the story of the discovery.
Teacher tip

Equipment

None required.

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Lesson video

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Starter quiz

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6 Questions

Q1.
Match each term to the correct definition.
Correct Answer:ancestors,organisms from which current, living organisms are descended

organisms from which current, living organisms are descended

Correct Answer:evolution,changes in the characteristics of a species over many generations

changes in the characteristics of a species over many generations

Correct Answer:growth and development,changes in an individual organism during its lifetime

changes in an individual organism during its lifetime

Correct Answer:variation,differences between living individuals of the same species

differences between living individuals of the same species

Q2.
What is the fossil record?
Correct answer: All the fossils ever found and their ages.
The habitat where a fossil is discovered.
The mineralised remains of a single dead organism.
The rock in which a fossil is contained.
Q3.
These fossils are part of the fossil record. They are all evolutionary ancestors of the modern whale. Starting with the earliest ancestor, sort them into order. End with the most recent ancestor.
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1 - Indohyus
2 - Pakicetus
3 - Ambulocetus
4 - Dorudon
Q4.
Which statements are true?
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A fossil proves that all members of the species looked exactly the same.
Fossils show us exactly what the living organisms looked like.
Correct answer: From a fossil we get evidence of an organism’s size, shape and body structures.
Most fossils are complete and intact when they are found.
Correct answer: Scientists must use their judgement/ imagination to interpret fossil evidence.
Q5.
Who explains why there are gaps in the fossil record?
Correct answer: Andeep: “There are many fossils out there which we haven’t yet found.”
Jun: “We have only found fossils from the past 10 thousand years.”
Correct answer: Sam: “It’s rare for organisms to become fossils. Conditions aren’t often right.”
Sofia: “Plants, fungi and bacteria can’t be turned into fossils.”
Q6.
How does the fossil record provide evidence for evolution?
It shows how many species there have ever been.
Correct answer: It shows how the features of species have changed over time.
Correct answer: It shows similarities and differences between organisms now and from the past.
It shows that some species are now extinct.
It shows where organisms used to live.

Exit quiz

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6 Questions

Q1.
What does the diagram show?
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a classification key
a family tree
a food web
Correct answer: an evolutionary tree
Q2.
Which species, A, B or C, would be called a common ancestor?
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Correct Answer: A, a
Q3.
Match each species (A, B and C) to the correct description.
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Correct Answer:A,a common ancestor of orangutans and humans

a common ancestor of orangutans and humans

Correct Answer:B,the most recent common ancestor of gorillas and humans

the most recent common ancestor of gorillas and humans

Correct Answer:C,a common ancestor of chimpanzees and humans but not of gorillas

a common ancestor of chimpanzees and humans but not of gorillas

Q4.
Why is Archaeopteryx said to be a transitional species between dinosaurs and modern birds?
An image in a quiz
It does not have any features of dinosaurs or modern birds.
Correct answer: It has features of dinosaurs and modern birds.
It only has features of dinosaurs.
It only has features of modern birds.
Q5.
Who correctly explains why Ambulocetus is considered to be a transitional species between Indohyus and the modern baleen whale?
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Alex: “Ambulocetus has back legs like Indohyus.”
Laura: “Ambulocetus has a broad front foot like the whale’s flipper.”
Correct answer: Lucas: “I think it’s because of both of those things.”
Q6.
True or false? This evolutionary tree diagram suggests that all life on Earth evolved from a common ancestor.
An image in a quiz
Correct answer: true
false
Q6 VectorMine/Shutterstock.com