Vocabulary
A random change to a gene that sometimes results in a new trait is a ____________________.
Mutation
Where do species inherit their body structures?
From ancestor populations
Two animals both have wings and can fly, but one is a bird and the other is an insect. Their wings are very different on the inside.
What is they are not closely related?
Two species both have a rare internal structure that is not found in most other species. A student claims this is just a coincidence.
What is it is unlikely a coincidence; they likely share a common ancestor?
A graph that uses bars to show how characteristics or values are distributed within a group
Why might body structures remain stable in a population?
The species is already well adapted to the environment and there have been no changes in the environment.
Two species have very similar bone structures in their front limbs, even though one swims and the other walks on land.
What is they are closely related?
Two species share a body structure, but one version is used for swimming and the other for walking. A student says they must not be related because they use the structure differently.
What is they are related; the structure was inherited and then changed over time?
The process by which the distribution of traits in a population changes over many generations.
Explain the difference between Natural Selection and Evolution.
Evolution is the big picture. It means the change in a population of organisms over many generations. These changes can include traits, behaviors, or genetic makeup. Evolution explains how species become different over time and can even lead to new species forming.
Natural Selection is one of the main mechanisms that causes evolution to happen. It’s the process where individuals with traits that are better suited to their environment are more likely to survive and reproduce. Over time, those helpful traits become more common in the population.
A simple way to think about it:
Two animals look almost identical and live in similar environments. However, their DNA and internal structures are very different.
What is they are not closely related?
Three species share a basic body structure. Species A and B also share several additional traits that Species C does not have. What does this suggest about their evolutionary history?
What is Species A and B share a more recent common ancestor than with Species C?
A diagram that is a hypothesis of how organisms are related by their shared characteristics.
Cladogram or Phylogenetic Tree
Which process separately occurs in populations after they are separated during speciation?
A whale and a bat have very different lifestyles, but their limb bones have the same basic structure.
What is they share a common ancestor?
Two species share several body structures, but one species also has an additional structure that the other does not. A student claims this means they are not related.
What is they are still related; one species developed a new trait after splitting from a common ancestor?
What is a scientist who studies fossils in order to understand the ancient history of life on earth called?
True or False?
When two species share a structure that is shared with a third species, this can be evidence that the first two species are more closely related to each other than to the third species.
False.
When two species share a structure that is *not* shared with a third species, this can be evidence that the first two species are more closely related to each other than to the third species.
Two species live in similar environments and have similar traits, but scientists discover those traits developed separately over time.
What is they are not closely related because the traits evolved independently?
A scientist compares three species. All share one major structure. Species X and Y share several additional complex structures, while Species Z does not. However, Species Z looks most similar on the outside to Species X.
What is Species X and Y are more closely related, and appearance alone can be misleading?