Fossils and the diversity of life
Answers are for parents and teachers.
1
If about 75 % of 40 species of a group disappeared, about how many remained?
40 × 75 ÷ 100 = 30 disappeared, so 10 remained.
2
Describe how to make a mould and a cast with clay and salt dough.
Press an object in clay and remove it (mould); fill the hollow with salt dough and dry it (cast).
3
Explain the difference between homologous and analogous structures with an example of each.
Homologous: same plan, like an arm and a whale flipper. Analogous: same job, different plan, like a bird wing and an insect wing.
4
How much earlier than the extinction 66 million years ago did Archaeopteryx live (about 150 million years ago)?
150 − 66 = 84 million years.
5
Name two things that the fossil record can tell us about the past.
For example the order in which life appeared, mass extinctions, relatives of living animals and old environments (any two).