The Biology I Course was developed through the Ohio Department of Higher Education OER Innovation Grant. The course is part of the Ohio Transfer Assurance Guides and is also named OSC003. This work was completed and the course was posted in October 2019. For more information about credit transfer between Ohio colleges and universities, please visit: www.ohiohighered.org/transfer.Team LeadCathy Sistilli                                         Eastern Gateway Community CollegeContent ContributorsLisa Aschemeier                                 Northwest State Community CollegeShaun Blevins                                     Rhodes State CollegeRachel Detraz                                     Edison State Community College                                     Sara Finch                                          Sinclair Community CollegeWendy Gagliano                                 Clark State Community College AJ Snow                                             University of Akron Wayne CollegeLibrarianAmanda Rinehart                               Ohio State UniversityReview TeamJessica Hall                                        Ohio Dominican UniversitySanhita Gupta                                    Kent State UniversityErica Mersfelder                                 Sinclair Community College

The theory of evolution is the unifying theory of biology, meaning it is the framework within which biologists ask questions about the living world. Its power is that it provides direction for predictions about living things that are borne out in ongoing experiments. The Ukrainian-born American geneticist Theodosius Dobzhansky famously wrote that “nothing makes sense in biology except in the light of evolution.” He meant that the tenet that all life has evolved and diversified from a common ancestor is the foundation from which we approach all questions in biology.

People did not understand the mechanisms of inheritance, or genetics, at the time Charles Darwin and Alfred Russel Wallace were developing their idea of natural selection. Scholars rediscovered Mendel’s work in the early twentieth century, and over the next few decades scientists integrated genetics and evolution in what became known as the modern synthesis—the coherent understanding of the relationship between natural selection and genetics that took shape by the 1940s. Natural selection can affect a population’s genetic makeup, and, in turn, this can result in the gradual evolution of populations. In the early twentieth century, biologists in the area of population genetics began to study how selective forces change a population through changes in allele and genotypic frequencies.  Adaptive evolution is the process by which natural selection increases the frequency of beneficial alleles in the population, while decreasing the frequency of deleterious alleles.

By the end of this section, you will be able to do the following:

Describe how scientists developed the present-day theory of evolution
Define adaptation
Explain convergent and divergent evolution
Describe homologous and vestigial structures
Discuss misconceptions about the theory of evolution

By the end of this section, you will be able to do the following:

Explain the different ways natural selection can shape populations
Describe how these different forces can lead to different outcomes in terms of the population variation

By the end of this section, you will be able to do the following:

Define population genetics and describe how scientists use population genetics in studying population evolution
Define the Hardy-Weinberg principle and discuss its importance

By the end of this section, you will be able to do the following:

Describe the different types of variation in a population
Explain why only natural selection can act upon heritable variation
Describe genetic drift and the bottleneck effect
Explain how each evolutionary force can influence a population's allele frequencies

By the end of this section, you will be able to:

Explain the basic principles of the theory of evolution by natural selection
Describe the differences between genotype and phenotype
Discuss how gene-environment interactions are critical for expression of physical and psychological characteristics