Evolution by Natural Selection - Serendip （通过自然选择的进化锡兰）.pdf

Evolution by Natural Selection1 I. Mice Living in a Desert These drawings show how a population of mice on a beach changed over time. 1. Describe how the population of mice is different in figure 3 compared to figure 1. Explain what happened to cause this difference. In discussing evolution, fitness is defined as the ability to survive and reproduce. 2. For the mice in the figure, which characteristic increased fitness? 3. The term fitness can have two different meanings, depending on what subject you are discussing. Answer the following questions to show the two different meanings of fitness. What does the term fitness mean when biologists are discussing evolution? What does the term physical fitness mean? 1 Adapted from the University of California, Los Angeles, Life Sciences 1 Demonstration Manual by Drs. Ingrid Waldron and Jennifer Doherty, Dept Biology, University of Pennsylvania. © 2017. Teachers are encouraged to copy this Student Handout for classroom use. A Word file (which you can edit if you want), a one-habitat version of the activity, and Teacher Preparation Notes with instructional suggestions and background information are available at /exchange/waldron/naturalselection 1 A characteristic which is influenced by genes and passed from parents to offspring is called a heritable trait. For example, fur color is a heritable trait for mice. An adaptation is a heritable trait that increases fitness. 4. This table describes the characteristics of a population of mice living on gray sand. Color of Fur White Gray Black Average running speed 5 cm/sec. 6 cm/sec. 8 cm/sec. Average number of offspring 5