Spontaneous generation has been offered as an explanation for

What did Pasteur do in his experiments on spontaneous generation that other scientists before him had not done?

The apparatus shown below was used by scientists in the 1950s to re-create the conditions of early Earth.

Refer to the illustration above. Miller and Urey’s apparatus was designed to demonstrate that life on Earth might have originated from

Presently, scientists think that DNA

Scientists think that the first cells resembled modern

Scientists have inferred that the first cells were

Which of the following is a true difference between photosynthetic organisms and chemosynthetic organisms?

The surface of Earth is protected from damaging ultraviolet light by

Which of the following is thought to have been an important early function of aerobic respiration?

Many scientists think that early aerobic prokaryotes invaded larger cells and eventually gave rise to

Which of the following are examples of fossils?

Darwin drew ideas for his theory from observations of organisms on

Darwin thought that the animals of the Galápagos Islands were similar to those of the nearby coast of South America because

The process by which a population becomes better suited to its environment is known as

According to Darwin, evolution occurs

The major idea that Darwin presented in his book The Origin of Species was that

Natural selection is the process by which

Natural selection could not occur without

Populations of the same species living in different places

Scarcity of resources and a growing population are most likely to result in

Since natural resources are limited, all organisms

Refer to the illustration above. The similarity of these structures is one form of evidence that the organisms

Which of the following is most likely a vestigial structure?

Homologous structures in organisms provide evidence that the organisms

Anatomical structures that appear to be derived from a functional structure in an ancestor, but that currently do not serve an important function, are called

The beak of a bird and the beak of a giant squid evolved independently and serve the same function. The beaks are

Evidence that evolution occurs includes all of the following except

Over millions of years, plants and their pollinators have

Refer to the illustration above. While the shark and dolphin are similar in appearance, dolphins evolved from ancestors that were very different from sharks. The current similarity between sharks and dolphins is an example of

If the half-life of a radioactive isotope is 5,000 years, how much of the radioactive isotope in a specimen will be left after 10,000 years?

The age of fossils, such as those of bones, can sometimes be determined by

Isotopes are forms of the same element that differ in

The period of time it takes for one-half of a radioactive isotope to decay is called its ____________________.

The diagram above illustrates the radioactive decay of potassium-40. The half-life of potassium-40 is about ____________________ billion years.

Any preserved trace of an ancient life form is a(n) ____________________.

A species that has disappeared permanently is said to be ____________________.

A heritable change in a species over time is called ____________________.

The process by which organisms with traits well suited to an environment survive and reproduce more successfully than organisms less suited for that environment is called ____________________.

According to Darwin, the ____________________ limits the rate at which organisms survive and reproduce.

____________________ structures are similar because they originated in a common ancestor.