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Chapter

Cover The Evolution of Life

Adaptation and Evolved Design  

This chapter describes how both functional utility and ancestry contribute to adaptation and the evolved design of organisms. Evolved structures, unlike fabricated structures, are constrained by their origin as modifications of an ancestral state. Hence, structures in two species may be similar in form not because they operate in a similar fashion, but because their common ancestor had the corresponding structure. Characters that are similar among species because they are inherited from the common ancestor of the group are said to be homologous. The central principle of independent evolution leads to the recognition of homology at different phylogenetic levels. The chapter then looks at how evolutionary engineering combines utility and ancestry.

Chapter

Cover Evolution

All About Sex  

This chapter discusses the evolution of sex. Sex refers to copulation and a variety of other mechanisms related to the genes that organisms carry. The chapter then looks into the diverse ways organisms have sex, while also acknowledging that some organisms are asexual and do not need sex to reproduce. It explores female choice and male-to-male competition as modes of sexual selection, which results in the evolution of exaggerated secondary sexual traits that increase mating success but usually decrease survival.The chapter examines how inbreeding depression frequently causes the evolution of mechanisms that prevent self-fertilization and mating between close relatives.

Chapter

Cover The Evolution of Life

The Ancestry of Life  

This chapter details the evolutionary history of the modern groups discussed in the previous chapter and describes their ancient ancestors. The age of a group of organisms can be estimated from the age of the rocks in which the earliest fossils belonging to this group have been found. However, this is only the minimum age of the group because still earlier representatives may not have fossilized or their fossils may not have been found yet. If the rate of neutral mutation were constant over genes and lineages, DNA sequences could also be used to estimate absolute ages, independently of fossils. Ultimately, any given clade descends (to the exclusion of all other clades) from a most recent common ancestor that lived at some time in the past. The chapter considers the ancestry of Homo sapiens, Hominoidea, Primates, Eutheria, Mammalia, Amniota, Tetrapoda, Sarcopterygii, Osteichthyes (bony fishes), Gnathostomata, Chordata, Deuterostomia, Bilateria, Metazoa, Unikonta, and Eukaryota.

Chapter

Cover The Evolution of Life

Artificial Selection  

This chapter highlights artificial selection—the deliberate choice of certain individuals to propagate a line. This has been the mechanism for producing all the modern varieties of domestic animals and crop plants. Indeed, the application of evolutionary principles to practical problems has been essential to the great expansion of agricultural productivity on which modern civilization is based. At the same time, artificial selection is itself a powerful method for investigating these principles. The chapter then looks at how artificial selection produces rapid and predictable change in the short term and considers domestication as applied artificial selection. It also examines how artificial selection can produce extensive adaptive radiations.

Chapter

Cover Evolution

The Birth and Death of Species  

This chapter focuses on the birth and death of species, which has been referred to be the nature of evolution. It also notes the modern classification system based on Linnaeus' Systema Naturae, a framework featuring genus and kingdoms of species. The chapter also notes how reproduction isolation is required for speciation. Genetic isolation is the result of a physical or geographical barrier to gene flow during the process of allopatric speciation. Sympatric speciation is involved in the emergence of hybrids, especially among plant species. Extinction, the chapter explains, is an essential part of evolution as new niches and set of speciation take over.

Chapter

Cover The Evolution of Life

Cooperation and Conflict  

This chapter demonstrates how natural selection can lead to the evolution of helpful behaviour in certain kinds of society. Unqualified exploitation or aggression needs no special explanation: it is easy to understand that selection will often favour the selfish pursuit of individual interest. There are other features of organisms, however, that cannot be readily explained in this way. The most interesting involve social behaviour, and especially any behaviour that involves a degree of helpfulness or cooperation among individuals. The chapter begins with the simplest possible situation, involving bacterial cultures where social relations are of the simplest kind. Simple as they are, they show how much more complicated kinds of society can be understood. The chapter then considers how social interactions introduce a new aspect of adaptation and how altruism evolves only in family groups.

Chapter

Cover Evolution

Cooperation and Conflict  

This chapter examines the notion of cooperation and conflict in line with the evolution of social interactions. It notes how evolutionary biology provides a unique perspective into how and why families function as they do. Interactions within families allow us to examine cooperation, while other relationships exhibit the most extreme forms of conflict. Conflicts may exist among different genes in a species' genome and these are inherited by different pathways. The chapter also considers extreme examples of cooperation and altruism in eusocial species, most of which are governed by kin selection and policing by workers. It mentions how kin and group selection explain three of the major transitions in the evolution of life on Earth.

Chapter

Cover The Evolution of Life

The Diversity of Life  

This chapter evaluates biodiversity by tracing our own lineage backwards in time. Each clade comprises a group of lineages that have diverged from their common ancestor by adapting to different ways of life. This process of adaptive radiation may occur at any scale, from a small group such as ‘apes’ to a much larger one such as ‘vertebrates’. An innovation is a shared ancestral character that facilitates the adaptive radiation of a clade. The chapter then differentiates between potentiating innovations and implementing innovations. The separate phylogenetic trees of the clades can be fitted together so as to make a tree for the whole of life—although some branches will be much more detailed than others. The chapter describes Homo sapiens, Hominoidea, Primates, Eutheria, Mammalia, Amniota, Tetrapoda, Sarcopterygii, Osteichthyes (bony fishes), Gnathostomata, Chordata, Deuterostomia, Bilateria, Metazoa, Unikonta, and Eukaryota.

Chapter

Cover The Evolution of Life

The Dynamic Genome  

This chapter studies the genome itself, which is the source of all the hereditary information underlying the adaptation of organisms to their environment. The evolution of the genome is naturally one of the most pressing issues in evolutionary biology. Why are many genomes much larger than they need to be? How does the gain and loss of genes contribute to evolution? How do new genes come into being? Molecular genetics is beginning to provide answers to fundamental questions like these, and the answers have turned out to depend on the Darwinian rules that govern genome dynamics. The chapter then considers how evolving genomes diverge, how genes are modified at different rates, how eukaryotic genomes have evolved novel features, and how genetic elements may evolve cooperation or conflict.

Chapter

Cover The Evolution of Life

The Engine of Evolution  

This chapter discusses two basic processes that underlie evolutionary change: variation and selection. Mutations do not systematically lead to improvements, and mutation alone therefore cannot cause adaptation. Instead, mutation leads to variation so that a population contains many different kinds of individuals. A few of these may be better than the rest, at least in some circumstances, and are able to grow and reproduce more rapidly. This creates a process of selection that is responsible for driving evolution in a particular direction. The key is to realize that, at any given time, selection always modifies the changed state that has been produced by the previous episode of selection. This is the principle of cumulation. The chapter then looks at incorporation and evolution.

Chapter

Cover The Evolution of Life

The Evidence for Evolution  

This chapter provides an overview of the science of evolution, which explains how the vast diversity of living things is governed by a few simple natural principles. The outward diversity of animals and plants is based on a very restricted range of materials, body plans, power sources, and instructions, relative to those we use in everyday life. Evolution is modification through descent. All organisms are similar, not because they have been perfectly engineered, but rather because they all descend from the same common ancestor. The chapter is concerned mainly with descent—how we know that the diversity of living forms springs from a single root. The chapter then introduces the concepts of extinction, adaptation, development, sex, and diversity.

Book

Cover Evolution

Neil Ingram, Sylvia Hixson Andrews, and Jane Still

Evolution provides an introduction to evolution. It traces the history of the emergence of life, by contextualizing the development of evolutionary thought and discussing the implications of evolutionary processes on modern-day genomics, biochemistry, and ecology. The text explores topics that are familiar and also introduces new ideas. Chapters include an introduction to evolution, the birth and death of species, and an examination of the evidence. The latter half of the book looks at the evolution of a theory, human evolution, and the human story so far.

Book

Cover Evolution

Douglas J. Futuyma and Mark Kirkpatrick

Evolution offers expertise in evolutionary genetics and genomics, the fastest-developing area of evolutionary biology. The text emphasizes the interplay between theory and empirical tests of hypotheses, thus acquainting readers with the process of science. It addresses major themes — including the history of evolution, human evolution, evolutionary processes, adaptation, and evolution as an explanatory framework. In addition, it examines levels of biological organization ranging from genomes to ecological communities.

Chapter

Cover Evolution

Evolution and Development  

This chapter concepts the concept of evolution and development. Evolutionary developmental biology (EDB) seeks to integrate data from comparative embryology and developmental genetics with morphological evolution and population genetics while also determining the expression of genes as changes in phenotypes. During evolution, genes and developmental pathways have often evolved to serve additional new functions. The differences among species range between heterochronic and allometric changes in the relative developmental rates of different body parts or in the rates or durations of different life history stages. The chapter discusses how development affects morphological evolution. It also explores the notion of gene regulation, phenotypic plasticity, canalization, and genetic assimilation.

Chapter

Cover Evolution

Evolution and Society  

This chapter provides an overview of the interrelation of evolution and society. It explains that evolution simultaneously describes the history of species alongside the history of language and other cultural elements. According to biologists and social scientists, human behaviors are affected both by our genetic evolutionary heritage and by culture, the product of the extraordinary human ability to think, learn, imagine, and speak. Aside from the implications of nature and humanity, evolutionary science contributes to many aspects of medicine and public health, agriculture and natural resource management, pest management, and conservation. The chapter then explores the relationship between the science of evolutionary biology and social Darwinism.

Chapter

Cover Evolution

Evolution in Space  

This chapter covers the evolution of species in space. It starts with how genes involved with local adaptation are found in the genome while also acknowledging local adaptation as an important cause of genetic differences between populations. Studying spatial variation in phenotypes provides a further understanding of the interplay between selection, random genetic drift, and the movement of individuals. The chapter then explains how gene flows play important roles in evolution by equalizing and introducing allele frequencies. When both gene flow and local selection are at work, allele frequencies evolve toward a balance between them. The chapter also discusses the evolving range of species and their dispersal rates.

Chapter

Cover Evolution

The Evolution of Biological Diversity  

This chapter covers the evolution of biological diversity. It starts with the concept of biogeography, which is the scientific study of the geographic distribution of organisms. It is roughly divided between historical biogeography and ecological biogeography. Phylogenetic niche conservatism features, which evolutionary lineages retain adaptation to, and association with, certain ecological factors, rather than adapting to environmental change. The major historical factors that affected geographic distributions are extinction, dispersal, and vicariance. The chapter then discusses the impact and aftermath of five major mass extinctions, which include the extinction of many taxa and nonavian dinosaurs and the increase in diversity over time.

Chapter

Cover Evolution

The Evolution of Genes and Genomes  

This chapter tackles the evolution and origin of genes and genomes. New genes are an important source of evolutionary novelty and adaptation, which can either originate through eukaryotes, retrotransposition from mRNA to DNA, or horizontal gene transfer (HGT). The chapter considers how genome size and genome coding vary dramatically among species by referencing viruses, prokaryotes, animals, and plants. It also looks into the neutral theory of molecular evolution and the evolution of protein-coding genes by changes to their sequences and their expression. The chpater notes that whole genome duplication is responsible for the large differences in gene number among closely related groups of organisms.

Book

Cover The Evolution of Life

Graham Bell

The Evolution of Life provides an introduction to the central issue of evolutionary biology—adaptation through natural selection—in six sections. The first section looks at the basics, covering the evidence and engine of evolution. The second part looks at the history of evolution, examining the tree of life, the diversity of life, and ancestry of life. The next section focuses on the origins of variation, species, and innovation. Then the text moves on to adaptation and includes an evaluation of the dynamic genome. Section 5 focuses on selection and covers artificial selection, experimental evolution, and selection in natural populations. The final section considers sexual selection, cooperation and conflict, and symbiosis and struggle.

Chapter

Cover Evolution

The Evolution of Quantitative Traits  

This chapter discusses the evolution of quantitative traits through selection and environment. It notes how genotype and environmental factors determine an individual's phenotype. Most morphological and physiological characteristics of plants and animals are quantitative traits, and their evolution and inheritance can be studied through quantitative genetics. The chapter then explores evolution by directional selection and the evolution of genetic correlations, which reference that variation in quantitative traits can be caused by loci. It also explains that artificial selection, wherein people selectively breed animals and plants to improve them for food production and other purposes, became essential to civilization since many species of domesticated animals and plants evolved dramatically.