Environmental Expression This presentation includes examples of traits affected by environmental factors.

3.2.3 Develop a cause and effect relationship between environmental factors and expression of a particular genetic trait.

Influences on Phenotype Internal Hormone differences in males and females Age External Temperature Nutrition Light Chemicals Infectious agents

Sun Exposure Causes different colors in the skin. UV radiation can lead to skin cancer or cause the break down of folate in the body which is needed for growth and repair. Is needed for Vitamin D production which allows our body to absorb calcium for bone strength.

Temperature In most turtles, there is only a small range in temperatures that will allow both males and females to hatch from the same brood of eggs. Extreme temperature changes either up or down may produce all male turtles or all female turtles.

Day Length In snowshoe hares, long days cause white fur; while short days cause dark-colored fur. How does this help the snowshoe hare? Allows the snowshoe hare to camouflage in with its environment.

Nutrition The types and amounts of foods and drinks you consume affect your weight and can also play a small role in your height. Not to mention, lack of certain nutrients can lead to problems and over consumption of certain nutrients can lead to problems.

Diabetes Caused by too much glucose in the blood. Type 1- the body does not produce enough insulin to regulate blood glucose levels. Type 2- cells become resistant to insulin action. Both types have genetic interaction, but type 2 is most commonly related to diet and exercise.

PKU Caused by the absence of an enzyme that converts the amino acid phenylalanine to tyrosine. Diets must be altered or the disorder may result in brain damage.