Natural Selection
Natural selection always leads to stronger animals.
false -It leads to animals better adapted to their environment, not necessarily stronger.
True or False: All members of a species are genetically identical
False — Variation exists within a species.
True or false: Selection pressure can make a trait advantageous or disadvantageous
true
True or False: Evolution happens to individuals, not populations.
False - Evolution occurs in populations over generations, not individuals.
Who proposed the theory of natural selection?
Charles Darwin
What is variation?
Differences between individuals of the same species.
True or False: A drought (very dry weather) could be a selection pressure for animals living in a rainforest.
True — A drought could change which animals survive based on who can cope with less water.
True or False: Evolution happens in just one lifetime.
False — It happens slowly over many generations.
What happens to traits that help an animal survive?
They get passed on more often to the next generation.
True or False:
Behavioral adaptation is a type of adaptation.
true
Give 1 example of a selection pressures in nature.
predators, weather, food resources, disease
What is the main idea behind the theory of evolution?
A: Species change over time through natural selection and adaptation.
Name the four key steps in natural selection.
Mutation, variation, reproduction and survival, inheritance
Explain how natural selection acts on variation within a population.
Individuals with advantageous traits are more likely to survive and reproduce, passing those traits on.
How can a change in environment cause one trait to become more common in a population?
The environment favors organisms with that trait, so they survive and have more babies, passing it on.
Name two types of mutations.
A: Point mutations (change in one base) and frameshift mutations (adding or deleting bases).
Explain how natural selection can lead to a new species over time.
Through long-term accumulation of differences in isolated populations, eventually leading to reproductive isolation.
Why is genetic variation important for a population’s survival in changing environments?
Because it gives some individuals traits that help them survive new challenges, so the population can adapt over time.
Explain how a change in the environment can act as a selection pressure and lead to a population changing over time.
A change (like colder weather) may help individuals with thicker fur survive and reproduce more. Over generations, more animals will have thick fur — the population changes.
How do scientists use DNA to show that species are related?
They compare DNA sequences—more similar DNA means species share a recent common ancestor.