Year 6 Science: Living things change over time
Part of the Year 6 Science fossils and living things over time chapter. Chapter overview · whole chapter on one page
Living things change over time
Over millions of years, living things have changed. Some groups have died out, which means that no living members of the group are left. This is called extinction. A group that is extinct is only known from fossils and from records.
Some groups have survived for millions of years. Ferns and dragonflies, for example, have living members today, although they are not the same as the ones that lived long ago.
The table shows four living things, and whether each one is still alive today.
| Living thing | Still alive today? |
|---|---|
| Trilobite | no, extinct |
| Woolly mammoth | no, extinct |
| Fern | yes |
| Dragonfly | yes |
Key ideas
- Extinct means that no living members of a group are left.
- Fossils tell us about groups that are now extinct.
- Some groups have survived, and living things have changed over time.
- Ferns and dragonflies are still alive today.
Method. Find the row that says no.
- Read the table. The trilobite and the woolly mammoth are both extinct.no, extinct
- Write the name. Trilobite is one extinct living thing.Trilobite
- Write the answer. Trilobite
Check. The woolly mammoth is also extinct. ✓
Method. Count the rows that say extinct.
- Count the rows. The trilobite and the woolly mammoth are extinct.two rows
- Write the number. So two of the four living things are extinct.2
- Write the answer. 2
Check. The fern and the dragonfly are still alive. ✓
Method. Read the dragonfly row.
- Read the row. The table says yes for the dragonfly.yes
- Decide. So the dragonfly is alive today.yes
- Write the answer. yes
Check. Dragonflies have living members today. ✓
Watch out
Watch out: an extinct group is not the same as a group that has changed. A fern alive today is not the same as a fern from millions of years ago, but ferns have not died out.
Exam tip
Exam tip. Say that a group is extinct when none of its members are alive, and use the fossil record as evidence.
Try it (with your teacher, or a grown-up at home). Look at a picture of a fern and a picture of a fossil fern, if you can find one in a book or safe website, with a grown-up. Compare the leaves. Talk about what has stayed the same, and what might have changed.
Exercise 5D Living things change over time
Method. Read the definition.
- Read the definition. Extinction means that no living members of a group are left.extinction
- Write the answer. extinction
Check. Extinct groups are known from fossils. ✓
Method. Read the rows.
- Read the rows. The table says the trilobite is extinct, and the fern is alive.trilobite extinct
- Write the name. So the extinct one is the trilobite.Trilobite
- Write the answer. Trilobite
Check. The fern is still alive today. ✓
Method. Read the table.
- Read the row. The table says no, extinct, for the woolly mammoth.no
- Decide. So the answer is no.no
- Write the answer. no
Check. Mammoths are known from fossils and remains. ✓
Method. Count the rows that say yes.
- Read the rows. The fern and the dragonfly say yes.fern and dragonfly
- Write the number. So two are still alive.2
- Write the answer. 2
Check. Two are extinct, and two are alive. ✓
Method. Read the table.
- Read the row. The fern row says yes.yes
- Decide. So ferns are still alive.yes
- Write the answer. yes
Check. Ferns have living members today. ✓
Method. Think about change over time.
- Think about change. Living things change over millions of years, and this change is called evolution.change over time
- Write one word. So the word is evolution.evolution
- Write the answer. evolution
Check. Evolution is covered in more detail in Chapter 6. ✓
Method. Use the table.
- Read the table. The trilobite and the woolly mammoth are extinct.extinct
- Decide. So Ali is not right.no
- Write the answer. no
Check. Some groups have died out. ✓
Method. Count both kinds of row.
- Count the extinct rows. Two rows say extinct.2
- Count the living rows. Two rows say yes.2 and 2
- Write the answer. 2 and 2
Check. The table has four rows. ✓
Method. Think about survival.
- Think about the groups. Some groups have survived for millions of years.survived
- Think about change. They have changed over time, so their living members are still here.changed
- Write the answer. Accept any sentence that says these groups have survived and changed over time, so living members are still alive.
Check. Survival and change are both part of the story. ✓
Method. Think about fossils.
- Think about the living. Extinct groups have no living members to study.no living members
- Think about the fossils. Fossils show what they looked like, so we know about them.looked like
- Write the answer. Accept any sentence that says fossils are the only evidence of groups that are no longer alive, so they show what they looked like.
Check. Fossils are the record of the past. ✓
Method. Think about the layers.
- Think about different layers. Different fossils are found in layers of different ages.different layers
- Think about change. So the living things in the layers have changed over time.changed
- Write the answer. Accept any sentence that says different fossils are found in different layers, so the living things changed over time.
Check. Layers in time order show change. ✓