Chapter 4 Evolution and Biodiversity MORGAN MARTIN & ABI FUNK 4 TH H O U R APRIL 14, 2011 VOCABULARY 1. Artificial selection- Process by which humans select one or more desirable genetic traits in the population of a plant or animal species and then use selective breeding to produce populations containing many individuals with the desired traits. Compare genetic engineering, natural selection. 2. Background extinction- Normal extinction of various species as a result of changes in local environmental conditions. 3. Biological evolution- Change in the genetic makeup of a population of a species in successive generations. If continued long enough, it can lead to the formation of a new species. Note that populations not individuals evolve. See also adaptation, differential reproduction, natural selection, theory of evolution. 4. Biopharming- Use of genetically engineered animals to act as biofactories for producing drugs, vaccines, antibodies, hormones, industrial chemicals such as plastics and detergents, and human body organs. 5. Chemical evolution- Formation of the earth and its early crust and atmosphere, evolution of the biological molecules necessary for life, and evolution of systems of chemical reactions needed to produce the first living cells. These processes are believed to have occurred about 1 billion years before biological evolution. Compare biological evolution. 6. Coevolution- Evolution in which two or more species interact and exert selective pressures on each other that can lead each species to undergo various adaptations. See evolution, natural selection. 7. Differential reproduction-Phenomenon in which individuals with adaptive genetic traits produce more living offspring than do individuals without such traits. See natural selection. 8. Domesticated species- Wild species tamed or genetically altered by crossbreeding for use by humans for food (cattle, sheep, and food crops), pets (dogs and cats), or enjoyment (animals in zoos and plants in gardens). Compare wild species. 9. Ecological niche- Total way of life or role of a species in an ecosystem. It includes all physical, chemical, and biological conditions a species needs to live and reproduce in an ecosystem. See fundamental niche, realized niche. 10. Endemic species- Species that is found in only one area. Such species are especially vulnerable to extinction. 11. Extinction- Complete disappearance of a species from the earth. This happens when a species cannot adapt and successfully reproduce under new environmental conditions or when it evolves into one or more new species. Compare speciation. See also endangered species, mass depletion, mass extinction, threatened species. 12. Fossils- Skeletons, bones, shells, body parts, leaves, seeds, or impressions of such items that provide recognizable evidence of organisms that lived long ago. 13. Fundamental niche- The full potential range of the physical, chemical, and biological factors a species can use if there is no competition from other species. See ecological niche. 14. Gene pool- The sum total of all genes found in the individuals of the population of a particular species. 15. Generalist species- Species with a broad ecological niche. They can live in many different places, eat a variety of foods, and tolerate a wide range of environmental conditions. Examples are flies, cockroaches, mice, rats, and human beings. 16. Genetic adaptation- Changes in the genetic makeup of organisms of a species that allow the species to reproduce and gain a competitive advantage under changed environmental conditions. See differential reproduction, evolution, mutation, natural selection. 17. Genetic engineering- Insertion of an alien gene into an organism to give it a beneficial genetic trait. Compare artificial selection, natural selection. 18. Genetically modified organism (GMO)- Organism whose genetic makeup has been modified by genetic engineering. 19. Geographic isolation- Separation of populations of a species for long times into different areas. 20. Invertebrates- Animals that have no backbones. 21. Macroevolution- Long-term, large-scale evolutionary changes among groups of species. Compare microevolution. 22. Mass depletion- Widespread, often global period during which extinction rates are higher than normal but not high enough to classify as a mass extinction. Compare background extinction, mass extinction. 23. Mass extinction- A catastrophic, widespread, often global event in which major groups of species are wiped out over a short time compared with normal (background) extinctions. 24. Microevolution- The small genetic changes a population undergoes. 25. Mutation- Random change in DNA molecules making up genes that can alter anatomy, physiology, or behavior in offspring. 26. Natural selection- Process by which a particular beneficial gene (or set of genes) is reproduced in succeeding generations more than other genes. The result of natural selection is a population that contains a greater proportion of organisms better adapted to certain environmental conditions. See adaptation, biological evolution, differential reproduction, mutation. 27. Realized niche- Parts of the fundamental niche of a species that are actually used by that species. See ecological niche, fundamental niche. 28. Recombinant DNA- DNA that has been altered to contain genes or portions of genes from organisms of different species. 29. Theory of evolution- Widely accepted scientific idea that all life forms developed from earlier life forms. Although this theory conflicts with the creation stories of many religions, it is the way biologists explain how life has changed over the past 3.6-3.8 billion years and why it is so diverse today. 30. Vertebrates- Animals that have backbones. Compare invertebrates. 31. Wild species- Species found in the natural environment. Compare domesticated species. 32.Adaptation- Any genetically controlled structural, physiological, or behavioral characteristic that helps an organism survive and reproduce under a given set of environmental conditions. It usually results from a beneficial mutation. See biological evolution, differential reproduction, mutation, natural selection. 33.Adaptive radiation- Process in which numerous new species evolve to fill vacant and new ecological niches in changed environments, usually after a mass extinction. Typically, this takes millions of years. How do scientists account for the development of life on earth? Scientific evidence indicates that the earth’s life is the result of about 1 billion years of chemical change to form the first cells, followed by about 3.7 billion years of biological change to produce the variety of species we find on the earth today. What is biological evolution by natural selection, and how can it account for the diversity of organisms on the earth? Biological evolution by natural selection involves the change in a population’s genetic makeup through successive generations. Note that populations- not individuals- evolve by becoming genetically different. How can geologic processes, climate change, and catastrophes affect biological evolution? The very slow movement of huge solid plates making up the earth’s surface, volcanic eruptions, and earthquakes can wipe out existing species and help form new ones. The locations of continents and oceanic basins greatly influence the earth’s climate and thus help determine where plants and animals cam live. The movement of continents has allowed species to move, adapt to new environments, and form new species through natural selection. The changes in climate throughout the earth’s history have shifted where plants and animals can live. Asteroids and meteorites hitting the earth and large upheavals of the earth’s crust from geological processes have wiped out large numbers of species and created opportunities for the evolution by natural selection of new species. What is an ecological niche, and how does it help a population adapt to changing environmental conditions? It is a species way of life or role in a community or ecosystem and includes everything that affects its survival and reproduction. The species will always know their role, so when the environment is changing they will be able to adapt to the new way of life. How do extinction of species and formation of new species affect biodiversity? A new species can arise when members of a population are isolated from other members for so long that changes in their genetic makeup prevent them from producing fertile offspring if they get together again. If the environment is changing then then some species may not be able to handle and they may die off, while others will adapt and change to fit the environment. What is the future of evolution, and what role should humans play in this future? We selectively breed members of populations to produce offspring with certain genetic traits and use genetic engineering to transfer genes from one species to another. Biologists are learning to rebuild organisms from their cell components and to make identical copies or clones or organisms. Genetic engineering has great promise for improving the human condition, but it is an unpredictable process and raises a number of privacy, ethical, legal, and environmental issues. There are arguments over how much we should regulate genetic engineering research and development. How did we become such a powerful species in a short time? We have thrives as a species mostly because of our strong opposable thumbs, ability to walk upright, and complex brains. Like many other species, we have certain traits that allow us to adapt to and modify the environment to increase our survival chance.