U5.2 Variations

Variations in Populations

Multiple Choice

Stone flounder are fish that have the ability tp hide from predators and prey by blending in with the graveland sand at the bottom of the ocean.

This ability is known as -

• natural selection

• mimicry

• imitation

• camouflage

Open Ended

What variations do you observe in this photo of tree snails?

Variations

In all species that reproduce sexually, offspring are different from their parents. For example, variations of a tree snail population can be observed in their shells, which are different sizes, colors, and have different patterns. These variations exist because tree snails reproduce sexually and receive genetic material from two parents. This creates diversity in population. Variation in organisms occur due to random changes to the genetic material of offspring. These changes create new variations that are passed to the next generation.

Multiple Choice

Variations in populations are important because -

• they allow some organisms to be pretty.

• they allow some organisms to be smart.

• they allow some organisms to survive better than others.

Effects of Variations

Some variations that arise from random changes to genetic material might harm an organism’s chances of survival. For example, a condition called albinism, which results in an animal being all white, is caused by a random change to genetic material. This trait can be especially harmful for animals that are prey because their predators can easily spot them. However, many random genetic changes, such as those that cause the unique pattern of spots on a giraffe, cause no harm.

Multiple Choice

An example of a variation in a population is -

• All of the population has fins.

• Some of the population has larger fins.

• Some of the population is dead.

Multiple Choice

What will happen if a food source is not suitable to be eaten by an animal?

• They will be able to change what they eat.

• They will stop eating.

• They will either move or die.

Some random changes to genetic material can benefit an organism. A variation might make an organism better able to find food, avoid predators, resist disease or reproduce more successfully. These things are very beneficial to a population.

Over generations, as more and more offspring are born with the variation, the occurrence of the variation increases, and it becomes a trait of the population.

Multiple Choice

How does migration help a population survive?

• Allows them to find food in another location.

• It makes them so tired they don't eat.

• Makes the weak ones die early.

Multiple Choice

How does hibernation help a population survive?

• It allows their prey to migrate away from danger.

• It allows them to stop eating in times of low food supply.

• It keeps them away from dangerous predators.