Digging Up the Past
What are preserved remains or traces of organisms that help scientists understand life from long ago?
Fossils
If the weather becomes much warmer, which animals are most likely to survive?
Animals that have traits to help them survive in the heat.
What is an inherited trait?
A characteristic passed from parents to offspring.
Birds with longer beaks can reach food that shorter-beaked birds cannot. Which birds are likely to leave more offspring?
Birds with longer beaks.
What scientist is best known for developing the theory of natural selection?
Charles Darwin.
Name one thing that fossils tell scientists about organisms that lived millions of years ago?
What the organisms looked like, where they lived, how they have changed over time, etc.
Why do some organisms survive environmental changes while others do not?
Some organisms have inherited traits that give them an advantage.
Which process creates offspring that are genetically different from their parents?
Sexual reproduction.
A disease kills most trees in a forest. Which squirrels are most likely to survive?
Squirrels with traits that help them find food in the new environment.
What is natural selection?
The process in which organisms with helpful inherited traits survive and reproduce more successfully.
Why do scientists study fossils found in different rock layers?
To compare organisms from different time periods and see how life has changed.
A forest becomes darker after a wildfire. Which moth color would most likely survive better: light-colored or dark-colored?
Dark-colored moths.
Do mutations help, harm, or have no effect on an organism?
Mutations can do any of those three things
Over many generations, what happens to traits that improve survival?
They become more common in the population.
Why is reproduction an important part of natural selection?
Helpful traits can only become more common if they are passed to offspring.
A fossil of a fish is found on top of a mountain. What does this suggest about that location long ago?
The area was once underwater.
A lake dries up, leaving only muddy areas. Over many generations, what is likely to happen to fish that can survive in muddy water?
They will become more common because they survive and reproduce.
Why are differences between individuals important in a population?
Some differences help organisms survive and reproduce.
Why doesn't an individual organism evolve during its lifetime?
Evolution happens across many generations as populations change.
Which happens first: organisms reproduce, helpful traits become common, or variation exists?
Variation exists
Scientists discover a fossil with traits of both reptiles and birds. Why is this fossil important?
t provides evidence that one group of organisms evolved from another and share a common ancestor.
Why doesn't every organism survive when its environment changes?
Not every organism has inherited traits that help it survive the new conditions.
If every rabbit in a population had exactly the same traits, why might that be a problem?
A single environmental change could affect all of them because none have different traits that might help them survive.
A student says, "The fastest cheetahs practiced running, so their babies were born faster." What is wrong with this explanation?
Learned traits are not inherited. Only inherited traits can be passed to offspring.
Explain why natural selection causes populations to change over time instead of changing individual organisms.
Individuals are born with their traits and usually do not change them. Over generations, individuals with helpful inherited traits survive and reproduce more, making those traits more common in the population.