Natural Selection Critical Juncture Assessment

If their environment changes to have only seeds in pinecones, which of the following blue jay populations will most likely survive?

• Populations 1 and 2 will most likely survive.

• Populations 2 and 3 will most likely survive.

• Only Population 2 will survive because it is the only population with variation.

• All the populations will survive because the blue jays will change the thickness of their beaks if they need to.

Tags

NGSS.MS-LS4-4

Northern foxes can have different fur colors. The foxes hunt squirrels for food. Foxes that have fur the same color as their environment are better at getting closer to squirrels and catching them. The diagram below shows a population of foxes that live in one area. At time 1, the population had the same number of brown and white foxes. At time 2, after many generations, there were many more brown foxes and fewer white foxes in the population. How did the environment change between time 1 and time 2? How did the population change?

• You cannot tell how the environment changed. With each generation, more foxes passed on the gene for brown fur to their offspring.

• The environment became brown. Brown foxes are more likely to survive, so the white foxes changed to have brown fur.

• The environment became brown. Brown foxes are more likely to survive, so both kinds of foxes passed on the gene for brown fur to their offspring.

• The environment became brown. With each generation, more brown foxes survived long enough to pass on the gene for brown fur to their offspring.

Tags

NGSS.MS-LS2-4

NGSS.MS-LS4-4

Which prediction (Prediction 1 or Prediction 2) is more likely to happen if mostly long and medium flowers are present?

• Prediction 1

• Prediction 2

Tags

NGSS.MS-LS1-4

NGSS.MS-LS1-5

NGSS.MS-LS4-4

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. Based on this information, which type of beak would be most beneficial in an environment with mostly long flowers?

• Short

• Medium

• Long

Tags

NGSS.MS-LS2-1

NGSS.MS-LS4-4

Which prediction best shows what the population could look like after many generations? What caused it to change?

• Prediction 1 is best. Two hummingbirds with short or medium beaks had a baby with a mutation in its genes for the long-beak trait. Because long-beak hummingbirds are more likely to survive, that baby survived long enough to pass on its mutation, so the long-beak trait became more common over generations.

• Prediction 1 is best. Hummingbirds with long beaks are more likely to survive, so hummingbirds with short and medium beaks began to have offspring with a mutation in its genes for the long-beak trait so that their offspring would have a better chance to survive.

• Prediction 2 is best. A hummingbird could have been born with a mutation in its genes for the long-beak trait and lived for a little while. Because long-beak hummingbirds are more likely to die, it would have been more likely to die before it had any offspring, so the final population will only have medium or short beak hummingbirds.

• Prediction 2 is best. A hummingbird could have been born with a mutation in its genes for the long-beak trait, but having a mutation in its genes would have caused it to die when it was born, so the final population will only have medium or short beak hummingbirds.

Tags

NGSS.MS-LS3-1

NGSS.MS-LS4-4

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. The diagrams below show three possible guppy populations. If their environment changes to have only large rocks, which of the following guppy populations will most likely survive?

• Only Population 2 will survive because it is the only population with variation.

• All the populations will survive because the guppies will change the size of their spots if they need to.

• Populations 1 and 2 will most likely survive.

• Populations 2 and 3 will most likely survive.

Tags

NGSS.MS-LS2-4

NGSS.MS-LS4-4

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. The diagram below shows a population of snakes that live in a rain forest. At time 1, the population had the same number of yellow and red snakes. At time 2, after many generations, there were many more red snakes and fewer yellow snakes in the population. How did the environment change between time 1 and time 2? How did the population change?

• You cannot tell how the environment changed. With each generation, more snakes passed on the gene for red scales to their offspring.

• There were more trees with red leaves. With each generation, more red snakes survived long enough to pass on the gene for red scales to their offspring.

• There were more trees with red leaves. Red snakes are more likely to survive, so the yellow snakes changed to have red scales.

• There were more trees with red leaves. Red snakes are more likely to survive, so both kinds of snakes passed on the gene for red scales to their offspring.

Tags

NGSS.MS-LS2-4

NGSS.MS-LS4-4

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 image above shows what the population looked like then. The environment changed and now the water is very warm. Look at the diagrams below. Which prediction (Prediction 1 or Prediction 2) best shows what the population of seals will look like after many generations in the very warm water?

• Prediction 1

• Prediction 2

Tags

NGSS.MS-LS1-5

NGSS.MS-LS2-4

NGSS.MS-LS4-4

Which prediction best shows what the population could look like after many generations? What caused it to change?

• Prediction 1 is best. Two seals with thick or medium blubber had a baby with a mutation in its genes for the thin trait. Because thin seals are more likely to survive, that baby survived long enough to pass on its mutation, so the thin trait became more common over generations.

• Prediction 1 is best. Seals with thin blubber are more likely to survive, so seals with thick and medium blubber began to have offspring with a mutation in its genes for the thin trait, so that their offspring would have a better chance to survive.

• Prediction 2 is best. A seal could have been born with a mutation in its genes for the thin trait and lived for a little while, but it would have been more likely to die before it had any offspring, so the final population will only have seals with thick or medium blubber.

• Prediction 2 is best. A seal could have been born with a mutation in its genes for the thin trait, but having a mutation in its genes would have caused it to die when it was born, so the final population will only have seals with thick or medium blubber.

Tags

NGSS.MS-LS3-1

NGSS.MS-LS4-4

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

• Populations 1 and 2 will most likely survive.

• Populations 2 and 3 will most likely survive.

• Only Population 2 will survive because it is the only population with variation.

• All the populations will survive because the cactuses will change the length of their spines if they need to.

Tags

NGSS.MS-LS1-5

NGSS.MS-LS2-4

NGSS.MS-LS4-4