Stations

P A R T 1 Define fitness Define adaptation Describe how the population of mice is different in figure 3 compared to figure 1. Explain what happened to cause this difference. For the mice in the figure, what characteristic was an adaptation that increased fitness? From an evolutionary point of view, which mouse in the chart would be the fittest? How do you know that this mouse would be the fittest? Use data from the chart to support your response. Ability to survive and reproduce Any characteristic that increases fitness #3 has more gray mice than white White mice were more noticeable so they got eaten by predators The white mice were also slower. They blended with the background and produced more offspring. Gray mice b/c they camouflaged well and it reproduced the most

P A R T 2 A characteristic which is influenced by genes and passed from parents to offspring Define heritable trait. Define adaptive heritable trait. Explain why the percent of mice with gray fur would increase from generation to generation Notice that population size increased from 6 mice in generation 1 to 28 mice in generation 2. Suppose that this population of mice lived on a small area of gray sand that only had enough food for ~30 mice and white, gray and black mice were equally good at competing for food. What do you think would happen to the numbers of white, gray and black mice in generation 3? Explain your reasoning. A population of mostly gray mice living on a patch of gray sand are asleep in their burrows. While the mice are sleeping, the gray sand is replaced by white sand. (Perhaps the owner of the desert has a plan to attract more tourists.) Think about what would happen to the population of mice on the white sand. After several generations, most of the mice would have _____________ fur. (white/gray/black) A heritable trait that increases fitness They camouflaged with their background. Generation 3 would have more kids, resulting in less food. Some mice will die off because of this and only the fittest will survive. White

P A R T 2 Explain how the change in the color of the sand could result in a change in the most common fur color in this population of mice. When mice live on gray sand, which color fur is an adaptive heritable trait? ______________________   When mice live on white sand, which color fur is an adaptive heritable trait?______________________ Is the same trait adaptive in both environments? ___________________________________________ Which ever color is able to blend in with the background will survive; while the others will be more noticeable and be eaten by predators. Gray fur White fur Yes, because in both environments the fur color is adaptable

P A R T 3 Define Natural Selection Why did the deer choose the cactus without spines? What adaptive heritable trait preserved the cactus? The adaptive heritable trait tends to become more common in the population It could eat the flowers with ease. The spines

P A R T 4 ✓ Depending on the background, some colors blend better Researchers have found differences in mortality for the speckled and black forms of the peppered moth in different types of environment. Which form of the peppered moth do you think had higher mortality in forests in unpolluted areas where tree trunks and branches are lighter? ___black ___ speckled Which form of the peppered moth do you think had higher mortality in forests in areas where air pollution had resulted in dark tree trunks and branches? ___ black ___ speckled Explain your reasoning. ✓ ✓ Depending on the background, some colors blend better

P A R T 4 100% speckled 0% speckled 75% black 25% speckled B=Black Looking at the Punnett squares identify the percentage of peppered moth offspring when: Both parents are homogeneous recessive __________ Both parents are homogeneous dominant __________ There are two heterozygous parents _________ Based on these Punnett squares, explain why peppered moths generally have offspring that look like their parents. 100% speckled 0% speckled 75% black 25% speckled B=Black b=speckled The peppered moths have the parents genes.

P A R T 5 Which trait was an adaptive heritable trait for peppered moths in industrialized areas with dark tree trunks and branches? ___ black form ___ speckled form Which trait is an adaptive heritable trait for peppered moths in unpolluted areas with lighter tree trunks and branches? ___ black form ___ speckled form Many people think of the process of evolution as "survival of the fittest". How do you think most people interpret "survival of the fittest"? Use the peppered moth example to illustrate the following generalization: Natural selection acts on individuals, but only populations evolve.  ✓ ✓ The organisms with the most favorable traits are able to survive for long periods of time and reproduce  passing along their traits The variation amongst species allows specific individuals to survive and reproduce, but over many years the whole population can evolve.