Evolution and Diversity: From the Great Chain of Being to Niche Construction

This page is the Lavenda and Schultz textbook-anchored treatment of evolution and diversity from Introduction to Anthropology 2021, covering chapter 2 of Lavenda and Schultz’s Anthropology: What Does It Mean to Be Human? (Commissions earned) and Agustín Fuentes’s “Human niche, human behaviour, human nature” in Interface Focus (Fuentes 2017). The two embedded videos take the lecture from pre-evolutionary European thought through Darwin and Wallace, then through Mendel and the Modern Evolutionary Synthesis, to the Extended Evolutionary Synthesis and niche construction.

Architecture: this page is the canonical treatment on the site for the Lavenda and Schultz 2021 framing of evolutionary theory. For the live-curriculum concept canonical on evolutionary theory broadly — Darwin, Wallace, Spencer’s “survival of the fittest,” and descent with modification — see Evolutionary Theory: Goodbye to Survival of the Fittest. For the article-specific canonical on Agustín Fuentes on the human niche, see Human Niche Construction. For the L&S companion treatment of the scientific method, falsifiability, and what makes evolution a scientific theory, see Is Evolution a Myth?

Evolution and Diversity: From the Great Chain of Being to Niche Construction

This material followed Is Evolution a Myth? in the Intro to Anthropology 2021 sequence. The next lecture was Primates!

Key Concepts

Charles Darwin’s theory of evolution was “possible only because he was able to think about species in a new way” (Lavenda and Schultz 41). Variation, not eternal essences, is the ground condition of life.
Philosopher of science Philip Kitcher’s three criteria of a successful scientific theory: testability (uniting independent hypotheses), unification (explaining a wide range of evidence), and fruitfulness (continually generating new hypotheses) (Lavenda and Schultz 32-34).
For 2,000 years, European thought combined biblical creation and Greek essentialism into the Great Chain of Being — a hierarchical ordering of all creation, with God at the top and every creature in its assigned place (Lavenda and Schultz 33-34).
Carl Linnaeus (1707-1778) developed kingdom-phylum-genus taxonomy within the Great Chain of Being framework. He was “committed to an essentialist definition of natural kinds” (Lavenda and Schultz 37).
“Survival of the fittest” was Herbert Spencer’s phrase, not Darwin’s. Darwin preferred “descent with modification” and only later borrowed Spencer’s term (Lavenda and Schultz 42). The borrowing smuggled the Great Chain of Being back into evolutionary thinking.
Fitness has no absolute measure. What is adaptive in one environment becomes maladaptive in another as conditions change (Lavenda and Schultz 43).
Stephen Jay Gould’s concept of exaptation explains traits that gradual adaptation cannot build. Insect wings likely originated as thermoregulatory structures before becoming useful for flight (Lavenda and Schultz 43).
Pangenesis (Darwin’s blending-inheritance model) was wrong. Gregor Mendel’s discrete, recombinable units of inheritance preserve the variation evolution requires (Lavenda and Schultz 44). Their work was synthesized only in the 1940s-1950s as the Modern Evolutionary Synthesis.
Human skin color varies gradually across populations through polygenic inheritance, with no biological boundaries supporting discrete race categories (Lavenda and Schultz 50).
Niche construction treats organisms as active modifiers of their selection environment. Beavers, birds, algae, and especially humans reshape the conditions under which the next generation is selected (Lavenda and Schultz 55-56).
Agustín Fuentes defines the human niche as “expanded innovation and increased use of extra-somatic materials in a dynamic feedback between action, perception and neural structures” (Fuentes 2017, 2).
Richard Lewontin estimates that “99.999% of the species that once existed are no longer with us” (Lavenda and Schultz 58). Extinction is the typical outcome of environmental change, not adaptation.

Evolution as Scientific Theory: Kitcher’s Three Criteria

Building from the previous class on Is Evolution a Myth?, Lavenda and Schultz open chapter 2 by drawing on the work of philosopher of science Philip Kitcher (32). Kitcher’s framework: a successful scientific theory has three parts (Lavenda and Schultz 32-34).

Testable: A set of independent hypotheses supporting one another that match observations of the natural world. The theory as a whole survives sustained attempts at falsification.
Unified: It explains a wide range of material evidence — atomic theory and the theory of gravity work the same way, covering wide scope through relatively simple principles.
Fruitful: It continually generates new hypotheses and research possibilities. The Theory of Evolution has been enormously productive — visible in ongoing work on COVID variants, antibiotic resistance, and developmental biology.

To say that evolution is a scientific theory is to emphasize how successful it has been in these areas — the opposite of the popular sense of “theory” as a wild guess.

Pre-Evolutionary European Ideas: Essentialism, the Great Chain of Being, and Linnaeus

Before evolution emerged as a framework, European ideas about the natural world combined biblical texts and Greek philosophy. The two traditions were different in important ways. Greek philosophy “thought the world had been, and would be, around forever” (Lavenda and Schultz 33). Calculations from biblical genealogies produced a world about 6,000 years old — Bishop Ussher famously dated creation to October 23, 4004 BC.

Despite these differences, the Christian and Greek traditions shared the idea of essentialism: “a belief in an ideal world of perfect, eternal, unchanging forms that exist apart from the imperfect, changeable, physical world of living things” (Lavenda and Schultz 33). For the Christian tradition, species had essences unchanged since creation. For the Platonic tradition, living creatures were imperfect realizations of ideal forms. Either way, life did not change.

These traditions merged into the Great Chain of Being, “a comprehensive framework for interpreting the natural world” (Lavenda and Schultz 34) — a hierarchical ordering of all creation from lowest to highest. “Creatures farthest away from divine perfection were lowest in the hierarchy, whereas creatures most like God (such as the angels) ranked highest” (34). The framework was beautiful — and wrong, but its hold on Western thought has been hard to shake.

Within this framework, Carl Linnaeus (1707-1778), the 18th-century Swedish botanist, developed his system of biological classification. As Lavenda and Schultz note, Linnaeus “operated within this framework” (37) of the Great Chain of Being. He was “committed to an essentialist definition of natural kinds” (37), believing his taxonomic work documented God’s perfect and unchanging creation. The kingdom-phylum-class-order-family-genus-species hierarchy we still use today comes out of this essentialist project — but the underlying assumption of unchanging essences was about to be overturned.

New Material Evidence: Fossils and the Age of the Earth

What began undermining the Great Chain of Being was not new ideas but new material evidence. Beginning in the 17th-19th centuries, fossil discoveries showed creatures similar to but different from anything alive today, and creatures with no living counterparts (Lavenda and Schultz 39). The new evidence led to debates Lavenda and Schultz describe as Catastrophism versus Uniformitarianism (36-39), each attempting to explain the findings while preserving some aspects of essentialism.

The other crucial part of the new evidence was geological. Sediment layers, rock formations, and the slow processes shaping landscapes forced acceptance that the Earth was vastly older than 6,000 years (Lavenda and Schultz 38-41). The new calculations opened up the time depth that evolution required. Together, the fossil record and geological time forced a revision of essentialism and set the stage for evolutionary thinking.

Lamarck and Transformational Evolution

Jean-Baptiste de Monet de Lamarck (1744-1829) developed the idea of transformational evolution, where organisms “change physically in response to environmental demands” (Lavenda and Schultz 37) and pass these acquired characteristics to offspring. The classic example (in many textbooks if not in Lavenda and Schultz): giraffes stretching their necks to reach higher leaves and passing the elongated necks to their young. Lavenda and Schultz use the example of giraffes, and also discuss the “panda’s thumb” (37-38) to illustrate the difference between Lamarck and Darwinian thinking.

Lamarck’s idea was important because it broke with essentialism — species could change. But the mechanism (inheritance of acquired characteristics) was wrong. The transformation idea preceded Darwin and Wallace; evolution was already “in the water” by the time they published.

Darwin, Wallace, and Variational Evolution

Charles Darwin and Alfred Russel Wallace independently developed the idea of variational evolution through natural selection, or what Darwin preferred to call “descent with modification” (Lavenda and Schultz 38, 41). Darwin had collected evidence for decades but feared publishing. Wallace, working in the tropics, sent Darwin a letter with the same idea. They presented their first paper together in 1858. [For an interesting 2021 look at the Darwin-Wallace exchange as it relates to contemporary issues, see The Good, The Bad, and the Scientists Who Don’t Know the Difference by Jonathan Marks.]

Both observed that species varied over time and space, and concluded that similar but distinct species descended from shared ancestral species. This overturned essentialism by recognizing variation as the “ground condition of life” (Lavenda and Schultz 41). As Lavenda and Schultz emphasize, “Charles Darwin’s theory of evolution was possible only because he was able to think about species in a new way” (41). Diversity — another word for variation — is in fact the fundamental element that makes natural selection and evolution possible. We might see life itself as a proliferation of difference, diversity, and variation.

Crucially, for natural selection to occur we also need heredity, competition for resources, and differential reproduction (Lavenda and Schultz 40).

Spencer’s “Survival of the Fittest” and the Persistence of the Great Chain

It would be tempting to leave the story with Darwin and Wallace as heroes overturning essentialism. But the Great Chain of Being did not go away easily. Many old ideas about hierarchy, progressive evolution, and human perfectibility were imported into evolutionary thinking — and remain there.

Part of this came from Darwin himself. In The Descent of Man, he placed humans at the top of an evolutionary hierarchy that mirrored the Great Chain. And after originally using “descent with modification,” Darwin later borrowed Herbert Spencer’s phrase “survival of the fittest” (Lavenda and Schultz 42). Spencer was a sociologist who applied evolutionary metaphors to human society. The borrowing was a mistake, many anthropologists argue, because it enshrined wrong ideas about how evolution works.

We now know there is no such thing as absolute fitness (Lavenda and Schultz 43). Fitness is differential reproduction in a specific environment. What is adaptive in one environment becomes maladaptive in another as conditions change — and conditions are always changing. The Great Chain of Being also produced the long-running search for “missing links,” when what evolution actually predicts are most recent common ancestors. The search for missing links has taken anthropology in wrong directions because it assumes a hierarchical chain rather than a branching tree.

For comprehensive treatment of why anthropology says goodbye to “survival of the fittest” — including Darwin’s role in adopting Spencer’s phrase and the modern alternatives — see Evolutionary Theory: Goodbye to Survival of the Fittest.

Stephen Jay Gould on Exaptation

Stephen Jay Gould’s concept of exaptation (Lavenda and Schultz 43) explains traits that gradual adaptation alone cannot build. The classic example is wings. An organism cannot incrementally develop flight through natural selection alone, because minor changes in limb length confer no reproductive advantage until flight is actually functional. Instead, the appendages that became insect wings likely developed first for thermoregulation — cooling the body — and were gradually enlarged through selection for that function. Only then did a different selection process take over as flight became possible.

Exaptation describes this broader pattern: a trait adapted for one environment subsequently enabling organisms to exploit an entirely different niche. The concept matters because many observable traits across living organisms cannot be explained through strict gradualist adaptation. Recognizing exaptation distinguishes contemporary evolutionary thinking from earlier “survival of the fittest” models, which assumed traits must gradually improve some current function.

Pangenesis, Mendel, and the Modern Evolutionary Synthesis

During Darwin’s time, inheritance was understood as pangenesis — blended inheritance, as if traits combined like mixing paint (Lavenda and Schultz 44). If you crossed red and white, you got pink. The problem with blending inheritance is that variation washes out across generations. If tall and short pea plants always produced medium pea plants, eventually all the plants would be medium with light yellow flowers, and there would be nothing for evolution to work on.

Gregor Mendel, working in a monastery garden with his pea plants, demonstrated that inheritance comes in discrete, recombinable units. Traits could stay dormant in one generation and reappear in another. This preserved the variation that evolution requires. Darwin and Mendel were near contemporaries — both lived and died within the same decades — but their paths never crossed. Mendel’s work was not widely recognized until decades later.

In the 1940s and 1950s, biologists combined Darwinian natural selection with Mendelian genetics into the Modern Evolutionary Synthesis (Lavenda and Schultz 44) — sometimes called neo-Darwinian evolution. The synthesis is the version of evolution most of us learned in high school. It is hugely important and remains foundational. But we now know that genetics is far more complex than one-gene-one-trait models. In humans, many traits involve polygenic inheritance — multiple genes contributing to one phenotype (45-55).

The classic example is human skin color. As Lavenda and Schultz illustrate, human skin color varies gradually across a population so that there are no lines at which you can draw rigid boundaries (50). This is because skin color is polygenic, the product of many different genes interacting. There is no limited number of “skin types”; the variation is continuous from darkest to lightest, with no biological boundaries supporting discrete race categories. We also know that genes themselves are dynamic — turning on and off in response to environment and development. Epigenetics studies these regulatory switches, which can be inherited in ways distinct from genetic inheritance.

The Extended Evolutionary Synthesis and Niche Construction

In the last 20-30 years, some biologists have argued for an Extended Evolutionary Synthesis (Lavenda and Schultz 55-56) building on the Modern Synthesis. Some of these ideas are still debated. The one Lavenda and Schultz emphasize — and the one most central for anthropology — is niche construction.

Niche construction posits that organisms are not passive recipients of environmental selection pressures. As organisms live and act, they alter their environments — and those alterations change the conditions of selection for the next generation. Beavers reshape landscapes through dams and lodges. Birds build nests. Rodents dig burrows. Even algae and bacteria transform their environments through their metabolism, breaking down materials and reshaping the chemistry of their surroundings (Lavenda and Schultz 55-56). These changes may be intentional or unintentional. Either way, they shift the selection landscape for what comes next.

We are born into an environment shaped by past generations, but we also take action within that environment to change it for the next generation and for our own lives. Niche construction is bidirectional — organisms shape environments that shape organisms.

Agustín Fuentes on the Human Niche

Although niche construction operates across many species, humans have become expert niche constructors. This is where Agustín Fuentes on the human niche becomes central. Fuentes defines the human niche as “a niche involving expanded innovation and increased use of extra-somatic materials in a dynamic feedback between action, perception and neural structures, which in turn altered the potentials for information acquisition and problem solving” (Fuentes 2017, 2).

From an anthropological perspective, evolution is heavily influenced by human agency — “the ability of people to change things in their personal lives or collectively in their environment” (Lavenda and Schultz 57). Migration, environmental modification, technology, and mate selection all reshape evolutionary processes in ways that simple natural-selection models cannot capture. “Human culture and particularly complex human life-history patterns” (Fuentes 2017, 3) become central to evolutionary processes.

These realizations make straightforward application of natural selection models difficult for humans. Fuentes proposes rethinking human nature as “a suite of potentials generated from our evolutionary history, and present, and our flexible capacity to create and sustain human cultures and to be shaped by them” (Fuentes 2017, 1).

For the article-specific canonical on Fuentes and the human niche — including Joan Roughgarden’s variation work and Eben Kirksey on emergent ecologies — see Human Niche Construction: Fuentes and the Extended Evolutionary Synthesis.

Saying Goodbye to the Great Chain of Being: Lewontin on Extinction and the Anthropocene

It is time to let go of the Great Chain of Being and the idea that evolution is inevitable progress toward better creatures. Evolution is change over time in a changing environment. There is no measure of absolute fitness because the environment is always changing. What is adaptive in one environment becomes maladaptive in another.

Key points to remember about evolution and diversity:

Humans were not an inevitable outcome of evolution. “Indeed, the very notion that organisms are ‘going somewhere’ along a linear evolutionary ‘path’ has been questioned” (Lavenda and Schultz 56). If we replayed the tape of evolution with slightly different conditions — if the asteroid had not struck — humans might not be here at all.
Evolution does not always “work.” Richard Lewontin estimates that “99.999% of the species that once existed are no longer with us” (Lavenda and Schultz 58). Most species go extinct when environments change; the trait needed to survive does not always emerge in time.
There is no necessary path from simple to complex organisms. Sometimes simpler organisms are more adaptable to environmental change because they are not over-specialized.
We are still in the “Age of Bacteria” (Gould in Lavenda and Schultz). The number of bacteria cells in and on the human body roughly equals the number of human cells.

As Lavenda and Schultz emphasize, “The study of evolution in contemporary biology is very lively” (55-60). Lavenda and Schultz illustrate this with a figure showing variation, inheritance, and natural selection at the core, surrounded by the additions of the Modern Synthesis, and bordered by the potential additions of the Extended Evolutionary Synthesis. The picture is an invitation to participate in the ongoing work.

Anthropologists are particularly interested in human niche construction — how we transform environments in unprecedented ways. Fuentes describes how “the pace and diversity of cultural and material change ratchets up across the Holocene (last 10,000 years or so), exploding to an even greater pace in what many term the Anthropocene (last approximately 3-5 centuries)” (Fuentes 2017, 5). The Anthropocene names “this era in which human activity becomes the predominant driving force of what used to be the natural world” (Lavenda and Schultz 58). Understanding human niche construction at global scale is now central to whether we survive our own environmental modifications.

Frequently Asked Questions

What is variational evolution? Variational evolution is Darwin and Wallace’s framework, in which evolution proceeds through the natural selection of variations already present in a population. It overturns transformational evolution (Lamarck’s framework, in which organisms transform themselves and pass acquired characteristics to offspring). The key insight: populations must vary for natural selection to operate. Without variation, there is nothing for selection to work on. Lavenda and Schultz call variation the “ground condition of life” (41).

Did Darwin coin “survival of the fittest”? No. The phrase comes from sociologist Herbert Spencer (Lavenda and Schultz 42). Darwin borrowed it later, and many anthropologists argue the borrowing was a mistake because it reinforced older Great Chain of Being ideas of progress and perfectibility. Darwin himself preferred “descent with modification.”

What is niche construction? Niche construction is the idea, central to the Extended Evolutionary Synthesis, that organisms actively modify their environments and thereby alter the selection pressures acting on future generations (Lavenda and Schultz 55-56). Beavers, birds, algae, and especially humans reshape the conditions under which the next generation is selected. The modifications may be intentional or unintentional.

What is the Extended Evolutionary Synthesis? The Extended Evolutionary Synthesis is a set of proposed expansions to the Modern Evolutionary Synthesis, incorporating niche construction, epigenetic inheritance, developmental plasticity, and other dynamics that the 1940s-1950s synthesis did not address (Lavenda and Schultz 55-56). Some of these ideas are still debated. For anthropology, niche construction is the most central addition.

What is exaptation? Stephen Jay Gould’s concept of exaptation (Lavenda and Schultz 43) describes traits that originated as adaptations to one environment but enabled organisms to exploit an entirely different niche. The classic example: insect wings likely originated as thermoregulatory structures (for cooling the body) before becoming useful for flight. Exaptation explains traits that pure gradualist adaptation cannot build, because the intermediate forms confer no advantage for the final function.

Course Navigation

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🎓 Course home: Intro to Anthropology 2021 (Lavenda and Schultz)
🌍 Hub: Human Origins
📚 Live-curriculum theory canonical: Evolutionary Theory: Goodbye to Survival of the Fittest
📚 Live-curriculum niche construction canonical: Human Niche Construction (Fuentes)