Question

scenario #3: there are two types of mice that live in rocky terrain in hawaii. these mice, called rock pocket mice, come in two variations of fur color, light tan fur and dark brown fur. the mice live in pockets in a light - colored rocky terrain. they have a natural predator of birds and owls. these birds and owls tend to hunt the mice more easily spotted against the light - colored terrain. each female mouse has about 11 mice per litter but only about 5 survive to adulthood.
what is the heritable variation in this population? what is the overproduction in this population?
what is the trait that is being selected for? selected against? what is the selective pressure in this example?
make a prediction: how will the population evolve over time?
environmental changes! a volcano erupted in hawaii and the lava cooled into a dark magma rock over the original light - colored terrain in hawaii. the rock pocket mices environment has now changed from a light rock to a dark rock. predict how the population of the mice will change over time as new traits will be selected for and new traits will be selected against. use evidence to support your claims.

Explanation:

1. Heritable variation: The two fur - color variations (light tan and dark brown) are heritable traits passed from parents to offspring.
2. Overproduction: Each female mouse has about 11 mice per litter but only about 5 survive to adulthood, indicating overproduction of offspring.
3. Trait selected for: Dark - brown fur is selected for as it is less visible against the light - colored rocky terrain. Trait selected against: Light - tan fur is selected against as it is more easily spotted by predators.
4. Selective pressure: The natural predators (birds and owls) are the selective pressure as they hunt the more visible mice.
5. Prediction: Initially, the proportion of dark - brown furred mice in the population will increase over time as they have a higher survival rate. After the volcanic eruption and change to dark terrain, light - tan fur may become more advantageous and its proportion may increase.

Answer:

1. Heritable variation: Light tan and dark brown fur color.
2. Overproduction: Each female has 11 offspring but only 5 survive to adulthood.
3. Trait selected for: Dark - brown fur; Trait selected against: Light - tan fur.
4. Selective pressure: Birds and owls.
5. Prediction: Initially more dark - brown furred mice; after volcanic eruption, shift may occur towards light - tan fur if it becomes more advantageous.