Notes Science

Variation refers to a variety or diversity of traits (different kinds) within any given population.

Example: Look around at the other students. Notice the unique traits that individuals have such as hair color, height, eye color, skin color, etc.

Likewise variations occur in nature in populations ofplants, animals, insects, fish, etc.

Variation in Populations

This is an example of variation within the student population

SPI 0807.5.3 Variation in Populations

Variation occurs due to natural selection and is theresult of the pairing of alleles from parental DNA

(dominant and recessive) and also from mutations.

Phase 1 Phase 2

Phase 3 Phase 4

4 Phases of Natural Selection

Questions ScienceSPI 0807.5.3 Variation in Populations

Note: This in only about insecticide two.

Insecticide 2

For population two, only 2 % survived, and with population four, zero % survived. They were the least resistant.

Also, this is about resistance (survival rate) and not about the percentages killed!

Questions ScienceSPI 0807.5.3 Variation in Populations

Note: Something beneficial happened in 1988 that enabled the population to increase. One logical explanation is that with

fewer predators, more rabbits survived.

Questions ScienceSPI 0807.5.3 Variation in Populations

Note: This charts shows the color variation in the summer. Brown is dominant in this summer as camouflage.In a snowy winter, white would be better camouflage.

Better in the summer

Better in the winter

Questions ScienceSPI 0807.5.3 Variation in Populations

Note: The new predator runs 40 KPH. Therefore the rabbits that can run faster than this have the best chance of surviving.

Questions ScienceSPI 0807.5.3 Variation in Populations

Note: After 5 generations, genotype Gg is only 5% of the population. One explanation would be that this type of grass

is producing fewer seeds that the other two types of grass.