Turtles, alligators, and crocodiles are thought to be related to dinosaurs. What is the main source of evidence that scientists use to show this relationship and how these organisms may have changed over time?

• Photographs of dinosaurs
• Hair and skin samples
• Direct observation
• Fossil record

In all animals with backbones, gills are present at some point during their development. What does this indicate about these organism's evolutionary histories?

• They all evolved separately from each other over hundreds of years.
• They all share a common ancestor from millions of years ago.
• They all start out their lives living in the water.
• They all lose their gills as they age and develop into adults.

A scientist wants to develop a timeline of the prehistoric wooly mammoth to today's elephant. How could the fossil record assist in their investigation?

• It cannot help with their investigation.
• It can demonstrate how the organisms changed over time.
• It can demonstrate the structure of a modern-day eleephant.
• It can demonstrate similarities in muscle structure in both organisms.

A student wanted to provide evidence that evolution had occurred in a snake species. Which pieces of evidence would support the investigation? Select all that apply.

• Comparing the fossil record to today's organisms
• Modeling each organisms habitat for differences
• Comparing the diet of each organism
• Comparing similar structures between organisms.

Based on the fossil record, the ancestor of the whale was a land animal. This image shows the evolution of its body shape and limbs over time. The organism at the top of the image is the most ancient, and the organism at the bottom is the most modern. Which explanation best describes the change of the organism throughout time?

• Based on the fossil record, the whale quickly adapted to its changing environment.
• Based on the fossil record, the whale's ancestor was forced to change its diet, because the climate became colder.
• Based on the fossil record, the whale's ancestor crossbred with an alligator, because alligators have superior hunting instincts and moved into the water.
• Based on the fossil record, the whale's ancestor gradually changed from limbs to flippers because of the changing environment including the increase in the volume of water.

Homologous structures represent shared developmental patterns that suggest species are related. The two species have changed over time from a ___________ ancestor. The more alike the structures are, the more closely related the two species are.

• developmental
• common
• less

In all animals with backbones, gills are present at some point during their development. What does this indicate about these organisms' evolutionary histories?

• a. They all start out their lives living in water.

• b. They all lose their gills as they age and develop into adults.

• c. They all share a common ancestor from millions of years ago.

• d. They all evolved separately from each other over hundreds of years.

According to the diagram, which of the following statements is true?

• a. Fossil A is the oldest.

• b. Fossil B is the youngest.

• c. Fossil C is younger than Fossil D.

• d. Fossil C and D are the same age.

Fossils can tell us about Earth's past. Which of the following statements are true? Select all that apply.

• a. Fossils can only represent bones and shells of extinct animals.

• b. Fossils can give clues about environmental changes where the organism lived.

• c. Fossils can give clues of changes in the organism's body structure over time.

• d. Fossils can be used to date the time period of rocks and rock layers when the organism lived.

A student was investigating the differences in the organism's patterns of growth at different stages of development. Which pattern is supported by the diagram?

• a. The organisms look most similar just before birth.

• b. All of the organisms have tails in stage 2 and stage 3.

• c. All of the organisms have large heads at stage 2 and stage 3.

• d. Differences among the organisms increase from stage 1 to stage 3.