Define fitness Ability to survive and reproduce Define

� Define fitness Ability to survive and reproduce � Define adaptation Any characteristic that increases fitness � Describe how the population of mice is different in figure 3 compared to figure 1. Explain what happened to cause this difference. #3 has more gray mice than white White mice were more noticeable so they got eaten by predators The white mice were also slower. � For the mice in the figure, what characteristic was an adaptation that increased fitness? P A R T They blended with the background and produced more offspring. � 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. Gray mice b/c they camouflaged well and it reproduced the most 1

Define heritable trait. A characteristic which is influenced by genes and passed from parents to offspring Define adaptive heritable trait. A heritable trait that increases fitness Explain why the percent of mice with gray fur would increase from generation to generation They camouflaged with their background. 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. Generation 3 would have more kids, resulting in less food. Some mice will die off because of this and only the fittest will survive. 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 White generations, most of the mice would have _______ fur. (white/gray/black) 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. 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. When mice live on gray sand, which color fur is an Gray fur adaptive heritable trait? ___________ When mice live on white sand, which color fur is an White fur adaptive heritable trait? ___________ Is the same trait adaptive in both environments? Yes, because in both environments the fur color is adaptable ______________________ P A R T 2

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

� 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

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

� 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"? The organisms with the most favorable traits are able to survive for long periods of time and reproduce passing along their traits Use the peppered moth example to illustrate the following generalization: Natural selection acts on individuals, but only populations evolve. The variation amongst species allows specific individuals to survive and reproduce, but over many years the whole population can evolve. P A R T 5