Extinction

According to most scientists, what is the ultimate cause of most mass extinctions?

• overhungtin

• the evolution of new species to replace old ones

• major changes in the environment

• asteroid impacts

What is a scientific theory? Choose the best answer.

• an explanation that makes a lot of sense

• an explanation that's backed up by evidence

• an explaination that's popular among the public

• an explanation that's thought up by a scientist

How has the expanding human population led to an increasing rate of extinction?

• humans kill and eat too many other species

• humans re-shape their environment, putting pressure on other species

• humans have been forced to destroy dangerous, violent species

• humans consume too much oxygen, preventing other species from breathing

How can the extinction of a plant species have such a drastic effect on a food chain?

• Food chains are all composed of several types of plants and animals so if one plant dies out, the chain breaks down

• plants are the main source of food for carnivores, so if plants go extinct, bears will starve

• food chains rely on certain plants to function properly, so if a plant does out, all other species in the food chain will die out too

• If the extinct species was the main food source for another animal, that animal will have to find a new way to survive

What can humans do to make sure that fish species don't go extinct?

• destroy sharks and other predators in the ocean

• stop the practice of overfishing

• stay away from oceans entirely

• stop eating fish altogether

Why do many scientists believe that the growing level of extinctions is a problem?

• extinctions affect entire ecosystems

• zoos will begin to lose money

• humans will no longer be able to own pets

• humans will no longer be able to eat meat