Amplify Natural Selection Unit

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 seals passed on the gene for thick blubber to their offspring.

• The water became colder. Seals with thick blubber are more likely to survive, so the seals with thin blubber changed to have thick blubber.

• The water became colder. Seals with thick blubber are more likely to survive, so both kinds of seals passed on the gene for thick blubber to their offspring.

• The water became colder. With each generation, more seals with thick blubber survived long enough to pass on the gene for thick blubber to their offspring.

Tags

NGSS.MS-LS1-5

NGSS.MS-LS2-4

NGSS.MS-LS4-4

The diagram above shows a population of guppies that lived in a river. Scientists had previously only seen guppies with medium or large spots in this river; they had never seen any guppies with any other spot sizes.

-Karina says the change in the guppy population was caused by a mutation.

-Miles says the change was caused by a change in the environment.

-Zora thinks both Karina and Miles are correct.

Who do you think is right? Explain what happened to the guppies over many generations.

Tags

NGSS.MS-LS1-5

NGSS.MS-LS2-4

NGSS.MS-LS3-1

NGSS.MS-LS4-4

Tree squirrels can have different fur colors.

Squirrels live in forests where foxes also live. Foxes hunt squirrels for food. Squirrels that have fur the same color as the trees are harder for the foxes to see and catch.

The diagram above shows a population of squirrels that lived in a forest. Scientists had previously only seen brown and gray squirrels in this forest; they had never seen squirrels of any other color.

The diagram below shows how the population changed after many generations.

How did the color of the trees in the squirrels’ environment change? Explain what happened to the squirrels over many generations.

Tags

NGSS.MS-LS2-4

NGSS.MS-LS4-4

Scientists measured the spot size of guppies (small fish) in two different populations. Which population has more guppies with large spots?

• They both have the same number of guppies with large spots.

• The population in Brazil has more guppies with large spots.

• The population in Venezuela has more guppies with large spots.

• These bar graphs do not show which population has more guppies with large spots.

If their environment changes to have warm water, which of the following seal populations will most likely survive?

(HINT: 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.)

• 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 seals will change the thickness of their blubber if they need to.

Tags

NGSS.MS-LS1-5

NGSS.MS-LS2-4

NGSS.MS-LS4-4

Scientists measured the spot size of all the guppies (small fish) that lived in a river 40 years ago. They measured the spot size of the guppy population again last year. When was there more variation in the spot size of guppies in the river?

• These bar graphs do not show the amount of variation in the population

• There was the same amount of variation in spot size 40 years ago and last year.

• There was more variation 40 years ago.

• There was more variation last year.

Tags

NGSS.MS-LS4-4

The population of ducks shown above lives in an environment that has always had very cold water. Could there ever have been ducks with thin feathers in this population?

• No ducks could have been born with the thin-feather trait because none of the adult ducks had that trait to pass down.

• No ducks could have been born with the thin-feather trait in the past, but some with that trait could be born in the future if the environment changes to be warmer.

• A duck could have been born with a mutation in its genes for the thin-feather trait and lived for a little while, but it would have been more likely to die before it had offspring.

• A duck could have been born with a mutation in its genes for the thin-feather trait, but having a mutation in its genes would have caused it to die when it was born.

Tags

NGSS.MS-LS3-1

NGSS.MS-LS4-4

Scientists measured the height of giraffes in two populations—one in the wild and one in a nature preserve. Which statement best describes the difference between the two populations?

• There is more variation in height of the giraffes found in the wild.

• There is more variation in height of the giraffes found in the nature preserve.

• The giraffes in the wild are mostly shorter than the giraffes found in the nature preserve.

• The giraffes in the wild are mostly taller than the giraffes found in the nature preserve.

Tags

NGSS.MS-LS1-5

NGSS.MS-LS4-4

Scientists measured the beak length of a population of birds in a lake in 1960. They measured the beak length of the bird population again in 2010. When was there more variation in the beak lengths of the birds by the lake?

• There was the same amount of variation in 1960 and in 2010.

• These bar graphs do not show the amount of variation in the population.

• There was more variation in 2010.

• There was more variation in 1960.

Tags

NGSS.MS-LS1-5

NGSS.MS-LS4-4

Scientists measured the spine size of a population of cactuses found in an area in 1970. They measured the spine size of the cactus population again in 2015. Which of the statements below best describes the difference in the cactuses at the two time points?

• The cactuses in 1970 had smaller spines than the cactuses in 2015.

• The cactuses in 1970 had larger spines than the cactuses in 2015.

• There were more cactuses in 1970 than there were in 2015.

• There was more variation in spine size in 1970 than there was in 2015.

Tags

NGSS.MS-LS1-5