Darwin's Hypothesis and Natural Selection
What is Natural Selection?
Natural Selection is the process by which individuals that are better adapted to their environment are more likely to survive and reproduce.
How do fossils support the theory that certain organisms shared a common ancestor?
They help scientists determine what ancient organisms looked like.
How do members of a species become isolated?
Geographical features such as a river or a fire.
What is an adaptation?
A trait that increases an organism's ability to survive and reproduce.
What was Darwin's Hypothesis?
Darwin hypothesized that species evolve over time and become better adapted to their enviorment
How do similar body structures support the theory that certain organisms shared a common ancestor?
They help scientists determine how closely related ancient species were.
What is Punctuated Equilibrium?
Where a species evolves during short periods of rapid change and then doesn’t change much
Define homologous structures.
Similar structures that related species have inherited from a common ancestor.
How can traits help organisms survive?
Why is Darwin's Hypothesis considered a scientific theory?
Hint: Use your knowledge of the definition of scientific theory
It is a scientific theory because it has multiple pieces of evidence to support it and it is well tested.
What does it take for organisms to be apart of the same species?
They must be able to mate and produce fertile offspring.
Define Gradualism
Small changes that add up to major changes over a long period of time.
Name and describe one factor that affects Natural Selection.
Variation - When organisms experience varying traits such as eye or hair color
Overproduction - When a species produces more organisms then there are resources, causing only the strongest to survive
Competition - When members of a species compete for resources such as food and shelter
How do DNA sequences and protein structures support the theory that certain organisms shared a common ancestor?
They help scientists infer how genetically close ancient species were.
Why do the the Kaibab and Abert squirrels have different colored stomachs?
They have isolated for so long that they have developed different traits.
What is a variation?
Any difference between individuals of the same species.
How is natural selection and evolution connected?
Natural Selection aids better adapted organisms to survive, allowing them to pass on helpful traits to their offspring, causing organisms to change over time.
Which supporting evidence is the most reliable when determining how closely two species are related?
DNA and protein sequences show exactly how closely two species are genetically related.
What does it take for a members of a species to become their own species after being isolated?
When members of a species can no longer reproduce and produce fertile offspring with other members, they are now their own species.
What is overproduction?
When members of a species overproduce and there is not enough resources for every member.