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.

Anthropology is the study of humanity, in all its biological and cultural aspects, past and present. It is a four-field discipline comprised of biological anthropology, cultural anthropology, archaeology, and linguistic anthropology. The focus of this book is biological anthropology, which explores who we are from biological, evolutionary, and adaptive perspectives.

Where did we come from? What were our ancestors like? Why do we differ from other animals? How do scientists trace and construct our evolutionary history? The History of Our Tribe: Hominini provides answers to these questions and more. The book explores the field of paleoanthropology past and present. Beginning over 65 million years ago, Welker traces the evolution of our species, the environments and selective forces that shaped our ancestors, their physical and cultural adaptations, and the people and places involved with their discovery and study. It is designed as a textbook for a course on Human Evolution but can also serve as an introductory text for relevant sections of courses in Biological or General Anthropology or general interest. It is both a comprehensive technical reference for relevant terms, theories, methods, and species and an overview of the people, places, and discoveries that have imbued paleoanthropology with such fascination, romance, and mystery.

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

Describe the features that characterized the earliest animals and approximately when they appeared on earth
Explain the significance of the Cambrian period for animal evolution and the changes in animal diversity that took place during that time
Describe some of the unresolved questions surrounding the Cambrian explosion
Discuss the implications of mass animal extinctions that have occurred in evolutionary history

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

Define species and describe how scientists identify species as different
Describe genetic variables that lead to speciation
Identify prezygotic and postzygotic reproductive barriers
Explain allopatric and sympatric speciation
Describe adaptive radiation

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

Describe pathways of species evolution in hybrid zones
Explain the two major theories on rates of speciation

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:

Compare homologous and analogous traits
Discuss the purpose of cladistics
Describe maximum parsimony

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

Discuss the need for a comprehensive classification system
List the different levels of the taxonomic classification system
Describe how systematics and taxonomy relate to phylogeny
Discuss a phylogenetic tree's components and purpose

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

Describe horizontal gene transfer
Illustrate how prokaryotes and eukaryotes transfer genes horizontally
Identify the web and ring models of phylogenetic relationships and describe how they differ from the original phylogenetic tree concept