Ecology: Concepts and Applications

Citation

Sher, A. A., & Molles, M. C. (2026). Ecology: Concepts and Applications (2026 release). McGraw Hill.

Chapter Summary

The book has 23 chapters in six sections. It moves up the scale of ecological organisation: from natural history and evolution, through the adaptations of individual organisms, populations and species interactions, to communities, ecosystems and the ecology of landscapes and the whole planet. McGraw Hill publishes it as a continuously updated "release" rather than a numbered edition. It describes the content as written for a first undergraduate course in ecology lasting one semester.

Chapter 1: Introduction to Ecology: Historical Foundations and Developing Frontiers

The opening chapter introduces ecology as a discipline. As its title says, it covers both where the science came from and where current research is heading.

Chapters 2–4: Life on Land; Life in Water; Population Genetics and Natural Selection

Section I, "Natural History and Evolution", surveys the major environments of the planet, with one chapter on terrestrial life and one on aquatic life. It then turns to population genetics and natural selection. Evolution therefore comes before any of the ecological processes, as the frame for the rest of the book.

Chapters 5–8: Temperature Relations; Water Relations; Energy and Nutrient Relations; Social Relations

Section II, "Adaptations to the Environment", deals with single organisms. It covers how they cope with temperature and water, how they obtain energy and nutrients, and how they interact socially. Social behaviour thus gets a chapter of its own within the study of individual adaptation.

Chapters 9–12: Population Distribution and Abundance; Population Dynamics; Population Growth; Life Histories

Section III, "Population Ecology", covers where populations occur and how many individuals they contain, how populations change over time, how they grow and how life-history traits vary. This is the section where population models are introduced.

Chapters 13–15: Species Interactions and Competition; Exploitative Interactions: Predation, Herbivory, Parasitism, and Disease; Mutualism

Section IV, "Interactions", takes the main kinds of interaction between species in turn: competition; the exploitative relationships of predation, herbivory, parasitism and disease; and mutualism.

Chapters 16–20: Species Abundance and Diversity; Species Interactions and Community Structure; Primary and Secondary Production; Nutrient Cycling and Retention; Succession and Stability

Section V, "Communities and Ecosystems", first treats communities: how diversity is measured, and how species interactions shape community structure. It then treats ecosystems: production at the first and higher trophic levels, nutrient cycling and retention, and change over time through succession, together with the question of stability.

Chapters 21–23: Landscape Ecology; Geographic Ecology; Global Ecology

Section VI, "Large-Scale Ecology", widens the scale to landscapes, to geographic patterns and finally to ecology at the global level.

Key Concepts

Section I: Natural History and Evolution (Chapters 1–4)

• Terrestrial and aquatic environments: the major settings of life on land and in water, set out before ecological processes are analysed.
• Natural selection and population genetics: the evolutionary mechanisms that the book places at the start, before ecology proper begins.

Section II: Adaptations to the Environment (Chapters 5–8)

• Temperature and water relations: how individual organisms deal with heat, cold and water supply.
• Energy and nutrient relations: how organisms obtain the energy and materials they need.
• Social relations: interactions among members of the same species, treated as one aspect of adaptation.

Section III: Population Ecology (Chapters 9–12)

• Distribution and abundance: where a population occurs and how many individuals it contains.
• Population dynamics and growth: how population size changes over time.
• Life histories: how organisms differ in the timing and pattern of growth and reproduction.

Section IV: Interactions (Chapters 13–15)

• Competition: interactions in which species limit one another.
• Exploitation: predation, herbivory, parasitism and disease, in which one species feeds on or lives at the expense of another.
• Mutualism: interactions that benefit both partners.

Sections V–VI: Communities, Ecosystems and Large-Scale Ecology (Chapters 16–23)

• Species diversity: the number and relative abundance of species in a community.
• Primary and secondary production: how much energy enters an ecosystem through producers, and how much is transferred to consumers.
• Nutrient cycling and retention: how elements move through ecosystems and how they are kept in them.
• Succession and stability: how communities change after disturbance, and how stable they are.
• Landscape, geographic and global ecology: ecological patterns and processes at regional, continental and planetary scales.

Critical Analysis

Strengths

• A clearly stated audience. The publisher says the book was written for students taking their first undergraduate ecology course in a single semester. It assumes some basic chemistry and mathematics and a general biology course that covered evolution, physiology and biological diversity. Readers can judge their readiness before starting.
• A complete levels-of-organisation sequence. The six sections climb from organisms through populations and interactions to communities, ecosystems, landscapes and the globe. All the standard parts of an introductory ecology syllabus therefore fit into one book.
• Evolution and natural history first. Population genetics and natural selection come in Chapter 4, and life on land and in water in Chapters 2–3, before the ecology of individuals and populations. Students reach the later chapters with an evolutionary frame and a picture of the major environments already in place.
• Topics often squeezed in elsewhere get their own chapters. Social relations, mutualism, landscape ecology and geographic ecology each have a full chapter, rather than a section inside a broader one.
• Authors with field research careers. According to the publisher's biographies, Sher works on restoration ecology, invasive riparian plants and quantitative ecological methods, and Molles worked mainly on river and riparian ecology and on the ecological effects of climate variability.

Limitations

• A lot for one semester. Twenty-three chapters are more than most single-semester courses can cover in depth, so instructors and independent readers will need to choose among them.
• No chapter on conservation or applied ecology as such. The table of contents has no chapter on conservation biology, restoration or the management of natural resources. Readers who want an applied course should not expect a separate treatment of these subjects.
• Only one chapter on evolution. Population genetics and natural selection share a single chapter. Students without a solid evolution unit in their general biology course may need more background.
• A moving target. McGraw Hill's "evergreen" model updates content between releases, so page numbers, figures and exercises in one release may not match another. Students should check that they are using the release their course assigns.

Where It Fits in the Course

Among the ecology books on this list, this is a full-length textbook for a first course. Jaboury Ghazoul's Ecology: A Very Short Introduction is a brief overview of the discipline and its applications. It can be read before this book or alongside it to see how the parts fit together, but it cannot replace a textbook in a course with problem sets and exams. Bowman and Hacker's Ecology and Relyea's Ecology: The Economy of Nature are alternative first-course textbooks covering the same span from individuals to the biosphere. Bowman and Hacker build each chapter around running case studies and applied problems such as climate change and invasive species. Relyea frames topics around adaptation and evolution and adds exercises in working with ecological data. Sher and Molles share Relyea's emphasis on evolution. Students who need more practice with data analysis may find Relyea a useful companion.

After this book, Begon and Townsend's Ecology: From Individuals to Ecosystems is a broader and more detailed treatment along the same individuals-to-ecosystems path. It is a natural next step for students taking ecology further. Mittelbach and McGill's Community Ecology is a graduate-level synthesis that takes up the material of Chapters 13–17 in much greater depth, with mathematical models and recent theory.

How to Use This Book

The book suits first- or second-year biology and environmental science students who have completed introductory biology. Basic algebra and some chemistry will be needed for the population and ecosystem chapters. A practical approach:

• Core sequence: Chapter 1, then Chapter 4 on natural selection, then Sections III–V (Chapters 9–20). Populations, interactions, communities and ecosystems are the heart of most first ecology courses.
• Background chapters: Chapters 2–3 on life on land and in water work well as reference material: read them early for orientation and return to them when later chapters mention particular biomes or aquatic systems.
• Choose by interest: Section II (Chapters 5–8) suits students interested in physiological or behavioural ecology. Section VI (Chapters 21–23) suits those heading towards landscape, biogeographical or global-change work. In a short course, one or two chapters from each may be enough.
• Work actively: When the population chapters introduce growth models, write the equations out and try them with simple numbers. For each interaction type in Section IV, find an example from a local habitat.

Students who plan to continue in ecology should note which topics they found thin and follow them up in a fuller textbook such as Begon and Townsend.