Natural selection cj

Blue jays are birds that live in the forest. They can have beaks of different thicknesses.

Blue jays use their beaks to get to the seeds they eat. Blue jays with thinner beaks can easily reach and eat the seeds inside pine cones. Blue jays with thicker beaks can easily open and eat seeds with hard shells.

If their environment changes to have only seeds in pine cones, which blue jays will survive?

• Blue jays with thick beaks.

• Blue jays with thin beaks.

• Blue jays with long beaks.

• Blue jays with short beaks.

Blue jays are birds that live in the forest. They can have beaks of different thicknesses.

Blue jays use their beaks to get to the seeds they eat. Blue jays with thinner beaks can easily reach and eat the seeds inside pine cones. Blue jays with thicker beaks can easily open and eat seeds with hard shells.

If their environment changes to have only seeds in thick shells, which blue jays will survive?

• Blue jays with thick beaks.

• Blue jays with thin beaks.

• Blue jays with long beaks.

• Blue jays with short beaks.

Hummingbirds can have beaks of different lengths.

They use their beaks to reach to the nectar (their food) at the bottom of flowers. Hummingbirds with longer beaks can get food from long flowers. Hummingbirds with shorter beaks cannot reach the nectar in long flowers. If a hummingbird can't easily reach its food, it will die.

If their environment changes to have only long flowers, which hummingbirds will survive?

• Hummingbirds with thick beaks.

• Hummingbirds with thin beaks.

• Hummingbirds with long beaks.

• Hummingbirds with short beaks.

Guppies are small fish that live in South American rivers. They can have different-sized spots on their bodies.

The river bottoms are covered in rocks. Guppies with spots that are the same size as the rocks on the bottom are harder for bigger fish to see and catch.

If the river bottom is covered in big rocks, which guppies will survive?

• Guppies with large spots.

• Guppies with small spots.

• Guppies with no spots.

• No Guppies will survive.

Emerald tree boas are snakes that live in rain forest trees. The snakes have scales on their skin that can be different colors.

Eagles hunt the snakes in the trees. Snakes with scales that are the same color as the leaves around them are harder for the eagles to see and catch.

In the beginning there were equal amounts of red and yellow tree boas. After 50 generations, there were only red boas? What happened to the environment that caused this?

• The environment turned yellow.

• The environment turned green.

• The environment turned red.

• The environment turned white.

Emerald tree boas are snakes that live in rain forest trees. The snakes have scales on their skin that can be different colors.

Eagles hunt the snakes in the trees. Snakes with scales that are the same color as the leaves around them are harder for the eagles to see and catch.

In the beginning there were equal amounts of red and yellow tree boas. After 50 generations, there were only yellow boas? What happened to the environment that caused this?

• The environment turned yellow.

• The environment turned green.

• The environment turned red.

• The environment turned white.

Harbor seals live in northern oceans and have a layer of blubber (fat) that keeps them warm. Seals can have blubber of different thicknesses. Seals with thicker blubber are more likely to stay warm and survive in cold ocean waters. But, in warm ocean waters, thicker blubber can make the seals overheat and die. The population of seals once lived in an environment where the water was cold. The environment changed and now the water is very warm.

What will the population look like after many generations?

• Most of the seals will have thicker blubber.

• Most of the seals will have thin blubber.

• Most of the seals will have no blubber.

Harbor seals live in northern oceans and have a layer of blubber (fat) that keeps them warm. Seals can have blubber of different thicknesses. Seals with thicker blubber are more likely to stay warm and survive in cold ocean waters. But, in warm ocean waters, thicker blubber can make the seals overheat and die. The population of seals once lived in an environment where the water was warm. The environment changed and now the water is very cold.

What will the population look like after many generations?

• Most of the seals will have thicker blubber.

• Most of the seals will have thin blubber.

• Most of the seals will have no blubber.

Barrel cactuses live in the Mexican desert. They are covered in sharp spines. Cactuses can have spines of different lengths.

Their sharp spines help protect them from being eaten by bighorn sheep. Cactuses with longer spines are less likely to be eaten by the sheep.

If their environment changes to have many bighorn sheep, which of the following cactus populations will most likely survive?

• Those with shorter spines.

• Those with no spines.

• Those with longer spines.

Eider ducks live in the ocean and have a layer of warm feathers underneath their regular feathers. They can have feathers of different thicknesses. These feathers help the ducks stay warm in cold water. Ducks with thicker feathers are more likely to stay warm and survive in cold water. But, in warm water, thicker feathers can make the ducks overheat and die. If their environment changes to have very cold water, which of the following duck populations will most likely survive?

• Ducks with thicker feathers.

• Ducks with thinner feathers.