U5.2 Variations

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.

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.

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.