Evolution and natural selection · Grade 10
In Grade 10 you learn: fossils and evolution; extinction.
Living things today are not the same as those that lived millions of years ago. Over many generations, species change: this is evolution. Charles Darwin and Alfred Russel Wallace explained how it happens. Individuals vary, and those best suited to their environment survive and pass on their genes. This is natural selection.
Key facts
- Evolution is a change in the inherited features of a population over time. All species evolved from simple life forms that first appeared more than three billion years ago.
- Evidence for evolution: fossils (the remains or traces of organisms preserved in rock), and evolution we can watch happening, such as bacteria becoming resistant to antibiotics.
- A species becomes extinct when no individuals are left: because of new predators, new diseases, more successful competitors, changes to the environment or a disaster.
Worked examples
Example 1
How do fossils give evidence for evolution?
Answer: older rock layers hold simpler organisms; fossils show how species changed and which have become extinct