Evolution vocabulary
Use technical vocabulary for evolution and natural selection — adaptation, evolution, natural selection, extinct, extinction, fossil record, species, common ancestor, mutation, variation — and explain the mechanism of natural selection using these terms in the correct sequence
What a learner can do afterwards
- Use 'adaptation' correctly to describe a feature that helps an organism survive in its environment
- Explain natural selection using 'variation', 'selection pressure', and 'reproduction' correctly in sequence
- Use 'extinct' and 'extinction' correctly and distinguish them from 'endangered'
The lesson
Every living thing belongs to a species: a group that can breed together, like all giraffes or all housecats. Within a species, individuals are not identical. This is called variation. A giraffe with a slightly longer neck than its herd-mates is an example of variation. Variation often starts with a mutation, a random change in an organism's genes that can be passed on to its offspring.
When a feature helps an organism survive and reproduce in its environment, we call it an adaptation. A polar bear's thick white fur is an adaptation: it keeps the bear warm and hides it in the snow. Adaptations build up over many generations.
Giraffe ancestors had necks of different lengths, and that was variation. When food near the ground grew scarce, that shortage acted as a selection pressure. Giraffes with longer necks could reach higher leaves, so they were more likely to survive and reproduce. Their calves inherited the longer-neck trait. Repeated over many generations, this process is natural selection, and it is one way evolution happens.
If every member of a species dies out, the species is extinct, and that event is called extinction. Don't confuse this with endangered: an endangered species has very few members left, but it has not disappeared yet.
Scientists study the fossil record, the traces and remains of past life preserved in rock, to trace species back to a common ancestor: an earlier species that two or more living species evolved from. Evolution is simply the word for how species change across generations.
Variation creates differences, selection pressure decides who survives and reproduces, and repeated over generations that is evolution, while species that cannot keep up may become extinct.
Watch it
Where it sits
Learn first
Nothing; this is a starting point.
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.