Crayfish Unit Review

Before the 1800s in the city of Leeds, England, peppered moths that lived in trees were mostly white or mostly black. In the 1800s, many factories sent a lot of black coal smoke into the air. The smoke turned the white-trunked trees black. After many years, the population of moths was mostly black.

Which statement most likely explains why there were more black moths after coal started being used?

• Adult moths that were mostly black survived, laid eggs, and had offspring that looked like their parents.

• The white moths learned how to change their color to hide from predators.

• The moths that were mostly white knew they would be easy prey, so they flew away to a place with cleaner air.

• The white moths were covered with coal smoke, so they turned black.

A teacher asked a class, “Would it be a good idea to let a family of plant-eating frogs from South America into the environment represented in the food chain?”

• Yes, because with more frogs, the snakes and owls will have more to eat.

• Yes, because I read that frogs keep caterpillars under control so they don’t eat up too many leaves.

• No, because our teacher told us not to let animals from other places go in our area.

• No, because when the new frogs eat plants the other animals might have less to eat.

About 100 years ago, farmers on a few islands in Hawaii

brought mongooses from Asia to kill the many rats in their sugarcane fields. Which is the best advice for farmers on other Hawaiian islands who are thinking about controlling rats with mongooses?

• It is a bad idea. Mongooses are active during the day and rats are active at night.

• It is a great idea. Mongooses love to eat rats. Then you will have fewer rats.

• It is a bad idea. Mongooses are not native to Hawaii and might eat animals other than rats, too.

• It is a great idea. Mongooses live under the ground, so you won’t see them often.

Populations of brown, green-brown, and green walking sticks lived in the forest. Then the environment changed. Students collected data about five generations of walking sticks in the new environment.

From the data in the table, you can make the claim that the new environment probably had _____.

• mostly green leaves

• more brown leaves than green leaves

• an even mix of green leaves and brown leaves

• more green leaves than brown leaves

In class we learned that crayfish often hide under rocks so predators won’t see them. Frogs hide under lily pads during the day. The most likely reason frogs hide under lily pads is that _____.

• they don’t like sunlight

• they find food to eat there

• they are protected from predators

• they see better in dark places

In the spring, a water insect that lives in streams lays eggs. The eggs hatch, and there are many baby insects. Then it is unusually hot for a few weeks. Check the box next to each statement that will most likely happen as a result of the change in temperature.

• All the insects will die.

• Some insects will die.

• Some insects will move to cool shady spots in the stream to live.

• Some insects will grow faster in the warmer stream water.

Some animals lay a huge number of eggs _____.

• so enough survive and grow into adults

• because they like having big families

• so the babies will have brothers and sisters to play with

• because they want other animals to have plenty of food to eat

Chameleons can change color to hide from predators. Snails pull their soft parts into their hard shells when they sense nearby danger. They can do this because _____.

• their parents taught them how to survive

• they inherited these behaviors from their parents

• they like to play hide and seek with predators

• they think about the best way to hide from predators

Emperor penguins are among the most social of all birds. The males care for the eggs, while females go to the sea in search of food. The males carry the eggs on their feet. While caring for the eggs, the males huddle together in very large groups. The penguins change places every 30 to 60 seconds so that every penguin gets to move through the central part of the huddle. When the females return from the sea with a full belly of food, they take care of and feed the newly hatched chicks. The males, having done their duty, take to the sea in search of food for themselves.

Check the box next to each way that huddling helps the Emperor penguins survive.

• It helps all the penguins stay warmer.

• It helps all the penguins hide from seals.

• It helps penguins find food.

• It helps penguins escape the wind.