Nature’s Filter
What is natural selection?
The process where individuals with advantageous traits are more likely to survive and reproduce.
What is an adaptation?
A trait that increases an organism’s ability to survive and reproduce in a specific environment.
What is an environmental pressure?
A factor that affects survival or reproduction, such as predators or climate.
What famous organism is often used to explain natural selection in Galápagos studies?
Finches
Who developed the theory of natural selection?
Charles Darwin.
What type of traits does natural selection act on?
Heritable traits (traits that can be passed to offspring).
What term describes how well an organism survives and reproduces?
Fitness
Name one biotic environmental pressure.
Predation, competition, or disease.
What type of trait changed in peppered moth populations during the Industrial Revolution?
Coloration / Camouflage
Does natural selection occur quickly or over many generations?
Over many generations.
Why must there be variation within a population for natural selection to occur?
Without variation, all individuals would respond the same to environmental pressures.
A thicker fur coat becomes common in a cold environment. Why?
Individuals with thicker fur survive better and reproduce more.
How can limited food act as a selective pressure?
Individuals better at obtaining food are more likely to survive and reproduce.
Why did darker moths become more common in polluted environments?
They were better camouflaged from predators.
Why doesn’t natural selection always lead to “perfect” organisms?
It works with existing variation and current environmental conditions.
How does overproduction of offspring increase competition in a population?
More individuals are produced than can survive, leading to competition for limited resources.
Why is a helpful trait not always an adaptation in every environment?
Environmental conditions determine whether a trait is beneficial.
How does predation influence traits in prey populations?
Prey with traits that help them avoid predators survive more often.
How does antibiotic resistance provide evidence for natural selection?
Bacteria with resistance survive treatment and reproduce.
How is natural selection different from artificial selection?
Natural selection is driven by the environment, while artificial selection is controlled by humans.
Explain why natural selection affects populations rather than individual organisms.
Individuals do not evolve; populations change over generations as beneficial traits become more common.
Predict what would happen to a population if the environment suddenly changed and explain why.
Traits that were once beneficial may become harmful, changing survival and reproduction patterns.
Analyze how two different environmental pressures could act on the same population at once.
Multiple pressures can favor different traits simultaneously, shaping complex adaptations.
Use one real-world example to explain how evidence supports natural selection leading to adaptation.
(Student explains using finches, moths, bacteria, etc., connecting trait → survival → reproduction.)
Construct an explanation showing how natural selection leads to adaptation in a population over time.
Variation exists → environmental pressure favors certain traits → individuals with those traits reproduce more → traits become common.