6. 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? Notice that which trait is adaptive differs in different environments. 7. What is natural selection? As part of your answer, explain why an adaptive heritable trait tends to become more common in a population. II. Natural Selection in Action The Peppered Moth – Necessary conditions for evolution by natural selection. Variation in Characteristics: For natural selection to different individuals in a population must have different characteristics. For natural selection to occur, the different characteristics of different Differences in fitness: individuals must contribute to differences in fitness (i.e. differences in ability to survive and reproduce) For natural selection to occur, the characteristics that affect Heritability of characteristics: fitness must be heritable (i.e. passed by genes from one generation to the next) These photos both show the two major forms of the peppered moth. Can you find the speckled form of the peppered moth on the lichen-covered tree trunk shown below? Can you find the black form of the peppered moth on the tree trunk that has been darkened by air pollution? x Peppered moths are active at night. During the day peppered moths rest on tree trunks and branches. Some of these resting moths are eaten by birds. Researchers have found that mortality is higher for the speckled form of the peppered moth in one type of environment, and mortality is higher for the block form of the peppered moth in a different type of environment. 8a. 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 8b. Explain your reasoning.
6. 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? Notice that which trait is adaptive differs in different environments. 7. What is natural selection? As part of your answer, explain why an adaptive heritable trait tends to become more common in a population. II. Natural Selection in Action – The Peppered Moth Necessary conditions for evolution by natural selection. Variation in Characteristics: For natural selection to different individuals in a population must have different characteristics. Differences in fitness: For natural selection to occur, the different characteristics of different individuals must contribute to differences in fitness (i.e. differences in ability to survive and reproduce) Heritability of characteristics: For natural selection to occur, the characteristics that affect fitness must be heritable (i.e. passed by genes from one generation to the next) These photos both show the two major forms of the peppered moth. Can you find the speckled form of the peppered moth on the lichen-covered tree trunk shown below? Can you find the black form of the peppered moth on the tree trunk that has been darkened by air pollution? x Peppered moths are active at night. During the day peppered moths rest on tree trunks and branches. Some of these resting moths are eaten by birds. Researchers have found that mortality is higher for the speckled form of the peppered moth in one type of environment, and mortality is higher for the block form of the peppered moth in a different type of environment. 8a. 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 8b. Explain your reasoning.
NaturalSelection_Quests.docx