8th Grade Q3 Review 2021-2022

Why do scientists use the fossil record as evidence for the scientific theory of evolution?

• The fossil record provides evidence of all species that have ever existed.

• The fossil record provides evidence that extinct species share similarities with current species.

• The fossil record provides evidence that all extinct species became fossilized at the same time.

• The fossil record provides evidence that extinct species are genetically identical to current species.

How does the use of radioactive dating help scientists develop the evolutionary tree of fossilized organisms?

• it tells when a fossilized organism was born

• it tells where a fossilized organism was found

• it tells the approximate age of a fossilized organism

• it tells how quickly new species evolved from fossilized organisms

Many states in the United States have fishing regulations that allow fishermen to keep only fish that are above a certain size. Smaller fish that are caught must be thrown back into the water. While these laws were originally designed to protect fish populations, the evolutionary effects of these actions may be doing more harm than good. Which of these statements explains how such regulations will most likely impact the biodiversity in aquatic ecosystems where they are enforced?

• Fish size, genetic diversity, and species diversity will increase.

• Fish size, genetic diversity, and species diversity will decrease.

• Fish size will decrease, but genetic diversity and species diversity will increase.

• Fish size will increase, but genetic diversity and species diversity will decrease.

   

How did Darwin’s trip to the Galapagos Islands help define his ideas about evolution?

• The same species of finches were observed on all the islands, so he thought the finches must have evolved together.

• Each island had similar species with slightly different traits, so he thought each species adapted to its habitat.

• Different organisms were observed on each island, so he thought each island had only one species.

• One of the islands had only a few finch species, so he assumed all the islands had predators.

Which of a polar bear’s adaptations would be a disadvantage if the polar bear lived in a rain forest?

• sharp teeth

• very wide paws

• lack of hibernation

• layers of insulation

Fossils often show that organisms change over time. How can the law of superposition support the evidence for evolution?

• Each rock layer contains specific types of fossils.

• Only igneous rock layers contain fossils of simple life forms.

• Rock layers closer to the surface have fossils of simpler life forms.

• More complex fossils are found in rock layers closer to the surface.

PCBs are a toxic chemical that can kill fish, birds, and other organisms in aquatic ecosystems. Between 1947 and 1976, manufacturers released over one million pounds of PCBs into New York's Hudson River. While PCBs were eventually banned in 1979, the river continues to contain high levels of PCBs. Scientists have recently discovered that some populations of a fish species, the Atlantic tomcod, have developed a resistance to PCBs. Which of these statements best explains how the tomcod developed this resistance?

• Plankton in the water carried the PCB resistance gene from one tomcod to another.

• Exposure to PCBs caused a gene to mutate, providing the tomcod with resistance to the chemical.

• Tomcods with a genetic resistance to the affects of PCBs survived and passed their resistant genes to their offspring.

• Release of PCBs over time allowed the tomcods to get used to the chemical and eventually made them resistant to PCBs.

Endangered species, such as the great panda, are species with decreasing populations that are at risk of extinction.  Which fact would most likely contribute to the great pandas high risk of extinction?

• Pandas do not hibernate.

• Pandas have a single food source.

• Pandas raise their cubs alone.

• Pandas have very few natural predators.

   

How does the study of fossils support the theory of evolution? 

• Fossils allow scientists to look into the future and predict what organisms will look like in years to come.

• Fossils show evidence of the outside traits of an organism, which can show how the creature has changed.

• Fossils provide evidence of the past that shows relationships among organisms and how they have changed over time.

• Fossils give scientists information about the soft body structures of extinct organisms, which can show how a creature has changed.

How did Charles Darwin describe the process of natural selection?

• Individual organisms show how evolution has happened.

• Organisms evolve through traits that are passed on by chance.

• The environment helps all organisms stay alive so they can reproduce.

• Organisms evolve through favorable traits that help them survive to reproduce.