Summary

This course was designed to teach the interested college-level student the fundamentals of evolution. As you have come to understand, evolution is a field of science that is continually changing as more is understood about cell biology, genetics, and the study of the early earth environment. You ve learned that the process of evolution involves the adaptation of organisms to their environment and the ways in which organisms find their niche or surpass other organisms in the process of natural selection. The course talked about the origins of life and helped you understand what we know about how life has evolved on earth throughout the ages. As you hopefully learned from the course, evolution is not just a historic event but is a process that continues in today s time and will continue to be part of life on earth in the future.

After studying evolution, you now know that no study of evolution would be complete without a discussion of the history of evolutionary theories, which was the topic of chapter one in the course. We talked about some of the early evolutionists who gave rise to what we currently believe about how evolution works. We then discussed in more detail about evolutionary thought throughout time, including modern evolutionary thinking. The story of Charles Darwin is a good one and hopefully helped you understand how his major breakthroughs in the understanding of evolution as a naturalist in the Nineteenth Century helped to pave the way for modern evolutionary thought.

The focus of chapter two was natural selection. It is a key evolution-related process involving the ability of different organisms in a population to adapt to its environment and to pass on this adaptability to their offspring. As you have seen in this chapter, natural selection relates to fitness in a given environment and an organism s reproductive success. Examples of natural selection were given as well a discussion of how natural selection relates to complex behaviors in higher-order animals—a phenomenon known as evolutionary psychology.

Chapter three in the course talked about the evolutionary relationships between the different types of living things. It started with a discussion of taxonomy, which is the naming convention used to describe all living things. Every form of life falls under one of three domains, Bacteria, Archaea, and Eukarya. There are other subdivisions that describe these types of arrangements. Exactly how to describe the relationships between life forms involves a discussion of phylogenetic trees. As you have seen, newer findings in biology and microbiology have changed the way these phylogenetic trees are arranged.

Chapter four was a discussion of genetics and genetic variation. Genetics works on a small scale in the inheritance of certain traits by a descendant from a direct ancestor. It also works on a large scale because it is through a series of genetic mutations that new species are ultimately created. We talked about about Mendelian genetics, the science of mutations, and the advantages and disadvantages that come with certain genetic situations.

Chapter five in the course introduced topics related to the origin of life on earth. Life on earth in the beginning of time was very different than it is now. This is partly due to the fact that the early conditions of earth as a planet were vastly different from that of present-day time. The chapter talked about the evolution of viruses and of prokaryotes, which were the first cells to represent life on this planet.

There is more to be said about evolution than the evolution of single-celled organisms so this was the topic of chapter six. Eukaryotes are infinitely more complex than prokaryotes—even those that are unicellular. Many eukaryotic organisms are multicellular; for this reason, the evolution of multicellularity was discussed in this chapter. Because evolution happens to populations rather than to individuals, it was important to also talk about the evolution of individuality. There are advantages to evolving in a social environment, which was also covered in this chapter.

The major topics of chapter seven in the course were species and speciation. Earlier chapters talked about evolution and its role in the diversity of species on earth. In this chapter, we talked about how species are defined and the different methods in which speciation or the formation of a different species occurs. Historically, species were

defined by their similar characteristics but, in this chapter, we talked also about how the knowledge of genetics has changed the definition of what exactly is meant when referring to an organism being of a certain species in today s scientific terms.

Chapter eight talked about the evolution of the human species. From an evolutionary perspective, humans have not been around very long. Even so, there have been many changes that have taken place over the course of about 400,000 years. As you have learned in the chapter, there have been changes in brain size and gait, among other things, that have been a part of the processes necessary to turn ancient species into modern man.

The topic of chapter nine in the course was extinction, which is the final termination of a specific organism type or species. This has occurred to 99 percent of all species that have ever lived on earth. We talked about background extinction, which happens over a period of time for a variety of reasons, as well as extinction events that have occurred in the earth s history, leading to the mass extinction of many of the species on earth at roughly the same time.

Chapter ten discussed those issues related to the evolution of reproduction. There are basically two broad categories of reproduction, which are asexual reproduction and sexual reproduction. There are evolutionary advantages and disadvantages of both that were compared in this chapter. With sexual reproduction, in particular, there are complex variables involved in mate selection, which were covered along with the evolutionary issues related to human sexuality and human sexual reproduction.

The focuses of chapter eleven in the course are evolution within populations and the evolution of social behaviors. Anytime there is a group of individuals in a population, there will be issues of conflict and cooperation, which were discussed in the chapter. Social behaviors are complex but have genetic and evolutionary influences. Topics also included in the chapter were the Hardy-Weinberg Principle and the evolution involved in finite populations.

Chapter twelve focused on the subject of coevolution. Coevolution is a phenomenon that happens when two or more species affect each other s evolutionary processes. This can happen when two species have a mutualistic relationship or when there is a host-

parasite relationship. There are two other types of coevolution that were discussed in this chapter, including antagonistic coevolution and mosaic coevolution, which involve specialized relationships between two or more species.

The focus chapter thirteen in the course was evolution and disease. Diseases affecting all species have been around since the beginning of time. The way in which diseases have originated was discussed in this chapter, including how some human diseases have crossed species to affect humans. Also covered in the chapter was the evolution of senescence or aging. There are several theories as to how and why humans age, which were discussed in the chapter.

Chapter fourteen looked at the future of evolution, particularly of humans and of the planet itself. We talked about what s already happened with the Holocene extinction, often called the sixth mass extinction event on earth. Exactly how humans will evolve is unknown but scientists can make some speculations, which were discussed in the chapter. Human extinction was covered as a possibility as was the future of the planet with the progress of global warming, which will affect the earth itself and the humans on it.