Chapter 18: Evolution of Populations

Essential Questions:

• How does natural selection contribute to biodiversity?

Content Objectives:

• Define evolution in genetic terms.
• Identify the sources of genetic variation.
• Explain what determines the phenotypes for a given trait.
• Explain how natural selection affect single-gene and polygenic traits.
• Define genetic drift.
• Describe the conditions required to maintain genetic equilibrium.
• Describe the types of isolation that lead to the formation of new species.
• Explain a current hypothesis about the speciation of the Galapagos finches.
• Identify where new genes come from.
• Describe the Hox genes might be involved in evolutionary change.
• Explain how molecular clocks work.

Language Objectives:

Students will:

• make a claim about a real world connection to evolutionary processes.
• support their claim using examples of projects.

Standards Addressed:

• HS-LS3-2. Make and defend a claim based on evidence that genetic variations (alleles) may result from (a) new genetic combinations via the processes of crossing over and random segregation of chromosomes during meiosis, (b) mutations that occur during replication, and/or (c) mutations caused by environmental factors. Recognize that mutations that occur in gametes can be passed to offspring.
• HS-LS3-3. Apply concepts of probability to represent possible genotype and phenotype combinations in offspring caused by different types of Mendelian inheritance patterns.
• HS-LS3-4(MA). Use scientific information to illustrate that many traits of individuals, and the presence of specific alleles in a population, are due to interactions of genetic factors and environmental factors
• HS-LS4-1. Communicate scientific information that common ancestry and biological evolution are supported by multiple lines of empirical evidence, including molecular, anatomical, and developmental similarities inherited from a common ancestor (homologies), seen through fossils and laboratory and field observations.
• HS-LS4-2. Construct an explanation based on evidence that Darwin’s theory of evolution by natural selection occurs in a population when the following conditions are met: (a) more offspring are produced than can be supported by the environment, (b) there is heritable variation among individuals, and (c) some of these variations lead to differential fitness among individuals as some individuals are better able to compete for limited resources than others.
• HS-LS4-4. Research and communicate information about key features of viruses and bacteria to explain their ability to adapt and reproduce in a wide variety of environments.
• HS-LS4-5. Evaluate models that demonstrate how changes in an environment may result in the evolution of a population of a given species, the emergence of new species over generations, or the extinction of other species due to the processes of genetic drift, gene flow, mutation, and natural selection.