Key Terms
What is a trait?
A characteristic of an organism, like eye color or fur length.
Who developed the theory of natural selection?
Charles Darwin
What is a fossil?
The preserved remains or traces of an organism.
What is a species?
A group of similar organisms that can reproduce together.
What do scientists use to estimate the age of fossils?
Layers of rock or radiometric dating
What is variation in a population?
Differences in traits among individuals of the same species.
What do we call it when helpful traits become more common?
Natural selection
How do fossils help us understand evolution?
They show changes in organisms over time.
What is an example of an adaptation in desert animals?
Large ears to release heat, or storing water.
True or False: Evolution happens in one generation.
False – it happens over many generations
What does adaptation mean in evolution?
A trait that helps an organism survive and reproduce in its environment.
How can food shortages lead to natural selection?
Only those best at getting food survive.
What is the fossil record?
A timeline of fossils showing the history of life on Earth.
Why do animals in cold climates have thick fur?
To insulate and protect them from cold temperatures.
What is an example of a rapid environmental change that could cause evolution?
Volcano, flood, drought, or climate change.
What is evolution?
The process by which species change over long periods of time.
Why might a bird with a longer beak survive better than one with a short beak?
It can reach food others can’t, helping it survive and reproduce
Why are older fossils found deeper underground?
Because they were buried by layers of sediment over time.
How can camouflage be an adaptation?
It helps an animal hide from predators.
How can changes in Earth’s environment affect evolution?
It can create new pressures that lead to new adaptations.
What is a common ancestor?
An ancient species that two or more species evolved from.
What would happen if an environment suddenly became colder for a warm-climate species?
Only individuals with traits that help them survive cold might live and pass on those traits.
What kind of information can scientists get from comparing fossil skulls?
How species have changed over time in shape, size, or brain development.
How might a species split into two new species over time?
If groups become isolated and adapt differently to their environments.
How long does it take for evolution to occur?
Many generations (usually thousands or more).