Preface

This course has been designed to teach the interested college-level student the fundamentals of evolution. 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. 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 talks about the origins of life and explains what we know about how life has evolved on earth throughout the ages. As you will learn 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.

No study of evolution would be complete without a discussion of the history of evolutionary theories, which is the topic of chapter one in the course. We will discuss some of the early evolutionists who gave rise to what we currently believe about how evolution works. We then talk in more detail about evolutionary thought throughout time, including modern evolutionary thinking. The story of Charles Darwin is a good one and will help 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 is 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 will see in this chapter, natural selection relates to fitness in a given environment and an organism s reproductive success. Examples of natural selection are given as well as 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 talks about the evolutionary relationships between the different types of living things. It starts 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 will see, newer findings in biology and microbiology have changed the way these phylogenetic trees are arranged.

Chapter four discusses 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 will talk about Mendelian genetics, the science of mutations, and the advantages and disadvantages that come with certain genetic situations.

Chapter five in the course introduces 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 talks 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 is 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 is discussed in this chapter. Because evolution happens to populations rather than to individuals, it is important to also talk about the evolution of individuality. There are advantages to evolving in a social environment, which is also covered in this chapter.

The major topics of chapter seven in the course are species and speciation. Earlier chapters talk about evolution and its role in the diversity of species on earth. In this chapter, we talk 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 talk 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 talks 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 will see 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 is 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 will talk 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 discusses 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 will be compared in this chapter. With sexual reproduction, in particular, there are complex variables involved in mate selection, which will also be 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 are discussed in the chapter. Social behaviors are complex but have genetic and evolutionary influences. Topics also included in the chapter are the Hardy-Weinberg Principle and the evolution involved in finite populations.

Chapter twelve focuses 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 hostparasite relationship. There are two other types of coevolution discussed in this chapter, including antagonistic coevolution and mosaic coevolution, which involve specialized relationships between two or more species.

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

Chapter fourteen looks at the future of evolution, particularly of humans and of the planet itself. We will talk 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 are discussed in the chapter. Human extinction is covered as a possibility as is the future of the planet with the progress of global warming, which will affect the earth itself and the humans on it.