The Tree of Life: An Article on the World’s Most Powerful Metaphor

An Enduring Metaphor for All Life

In 1837, in a small, leather-bound notebook, the young naturalist Charles Darwin drew a simple, spindly sketch of a branching diagram. Above it, he scrawled two tentative words: “I think”.¹ This humble drawing, a mere thought experiment, would grow to become the central organising metaphor for all of modern biology. It was a visualisation of a radical idea: that all life on Earth is related, diverging from common ancestors over immense spans of time, just like twigs and branches from the trunk of a great tree.²

Thousands of years earlier and thousands of miles away, an artisan in ancient Assyria carved a delicate scene onto a piece of ivory. It depicts a griffin, a mythical creature with the body of a lion and the head of an eagle, nibbling at the leaves of a stylised, sacred tree.³ This image, one of countless similar depictions from cultures across the globe, represents an idea just as profound as Darwin’s: that the tree is a cosmic source of life, a symbol of divine order, and a bridge connecting the heavens, the earth, and the underworld.³

These two images—one a scientific hypothesis, the other a mythological archetype—both invoke the “Tree of Life.” That the same metaphor can serve as both a rigorous tool for scientific inquiry and a universal symbol for spiritual understanding is no coincidence. The Tree of Life is arguably the most potent and enduring metaphor in human history precisely because it resonates with fundamental truths that both science and mythology strive to explain: ancestry, interconnectedness, growth, and the cyclical nature of existence.⁴ This article explores these two parallel histories—the mythic and the scientific—to reveal a deeper, unified story about life itself and our unending quest to understand our place within it.

The Mythic World Tree — Roots of a Universal Symbol

Long before it became a diagram in a biology textbook, the Tree of Life was a foundational archetype in human mythology, religion, and philosophy.¹⁰ Appearing in civilisations from Mesopotamia to Mesoamerica, it served as a powerful tool for organising the cosmos, explaining creation, and contemplating the mysteries of life, death, and immortality. Its power lies in its intuitive structure, which provides a tangible framework for abstract spiritual concepts.¹¹

The Cosmic Axis: Connecting Heaven, Earth, and Underworld

Across a remarkable diversity of cultures, the Tree of Life is imagined as a cosmic pillar, or axis mundi, that stands at the centre of the universe, physically and spiritually connecting different planes of existence.⁹ The very form of a tree lends itself perfectly to this conception. Its roots delve into the hidden, mysterious depths of the earth, its sturdy trunk occupies the physical world we inhabit, and its branches reach upward toward the heavens and the light.⁶ This tripartite structure provides a natural and powerful metaphor for the common cosmological view of a universe divided into an underworld, a terrestrial plane, and a celestial realm.⁷

The quintessential example of this World Tree is Yggdrasil from Norse mythology. Described as a colossal ash tree, Yggdrasil is the structural scaffold of the cosmos, its branches and roots holding together the nine worlds of Norse belief.³ These realms include Asgard, the home of the gods in the highest branches; Midgard, the world of humans around its trunk; and Niflheim, the land of the dead among its roots.³ Yggdrasil is not a passive structure; it is a dynamic centre of cosmic activity. At its base lies the Well of Urd, where the Norns—the fates—weave the destiny of all beings.⁹ It is also the site of the god Odin’s great sacrifice; he hung himself from its branches for nine days and nights to gain the knowledge of the runes, cementing the tree’s role as a source of profound wisdom and a conduit between the mortal and the divine.³

A strikingly similar concept appears in Mesoamerican traditions. The Maya revered a great world tree, the Wacah Chan, often represented by the towering Ceiba tree. This tree was also seen as the centre of the universe, its roots plunging into the underworld of Xibalba, its trunk in the human world, and its branches reaching into the heavens, providing a pathway for gods and ancestral spirits to travel between the realms.¹⁶

The consistent recurrence of this “cosmic axis” motif suggests that the Tree of Life is more than just a decorative symbol; it functions as a powerful cognitive model. Faced with a complex and often frightening reality, early cultures developed this model to impose order and meaning on the universe. The tree provided a mental map that organised the known physical world, the mysterious spiritual realm of the gods, and the unseen underworld of ancestors and spirits. By making abstract cosmological ideas tangible and relatable, the World Tree made the universe comprehensible.

The Fruit of Immortality: A Quest for Eternal Life

Another pervasive theme in Tree of Life mythology is its role as a source of divine power, often in the form of sacred fruits that grant immortality, eternal youth, or profound knowledge.³ This motif speaks to the universal human confrontation with mortality and the deep-seated desire to transcend it.

The most famous example comes from the Abrahamic religions. In the biblical Book of Genesis, the Garden of Eden contains two mystical trees: the Tree of the Knowledge of Good and Evil and the Tree of Life.¹⁹ The fruit of the Tree of Life grants eternal life, a state of perfect communion with God.¹⁰ The foundational narrative of humanity’s fall centres on Adam and Eve eating the forbidden fruit of knowledge, after which they are exiled from Eden. God places an angel with a flaming sword to guard the way back, specifically to prevent them from eating from the Tree of Life and becoming immortal in their fallen state.³ This story frames mortality not as a biological fact but as a spiritual condition, with the Tree of Life representing a lost paradise. In later Christian theology, this symbolism is powerfully repurposed: the cross on which Jesus was crucified is often referred to as the new Tree of Life, with Christ himself as the fruit that restores the promise of eternal life to humanity.³

This quest for immortality-granting fruit is not unique to the West. In Chinese Taoist mythology, a sacred tree is said to produce the pantao, or peaches of immortality, only once every three thousand years. Consuming one of these peaches grants eternal life, and they are the food of the immortals.³ Similarly, Norse myths tell of sacred apples guarded by the goddess Idun, which the gods must eat to maintain their youth and vitality.³

In some traditions, the “gift” of the tree is not physical immortality but spiritual liberation. In Buddhism, the sacred Bodhi tree is revered as the place where Siddhartha Gautama sat in meditation until he achieved enlightenment (Bodhi), becoming the Buddha.¹⁰ By attaining this state, he broke free from samsara, the endless cycle of death and rebirth. Here, the tree provides a different kind of eternal life—not the continuation of the physical body, but the transcendence of suffering and the attainment of a timeless state of peace and wisdom.⁴

The Web of Being: Symbolising Interconnection and Ancestry

Perhaps the most profound and universal meaning of the Tree of Life is its role as a symbol of interconnectedness.¹³ Its branching structure provides a perfect visual metaphor for genealogy, showing how a family or a people can trace their lineage back to a common trunk and shared roots.⁶ On a grander scale, it represents the idea that all forms of life are part of a single, unified web of being, stemming from the same essential source.

This theme is central to Celtic traditions. The Celtic Tree of Life, or Crann Bethadh, was often a great oak or ash tree that stood at the heart of a settlement. It was the tribe’s spiritual and social centre, a symbol of their integrity, security, and connection to the land.⁷ The tree connected them to their ancestors through its deep roots and to the divine world through its high branches. Its seasonal cycle of death and rebirth mirrored the cycles of human life, reinforcing beliefs in reincarnation and the eternal nature of the spirit.⁴ The importance of this connection was so absolute that one of the most devastating acts of war was to cut down an enemy’s sacred tree, as this severed their connection to their heritage, their land, and their gods.⁷ Celtic art often depicts the Tree of Life with its branches and roots woven together in intricate, unending knotwork, a direct visual representation of the eternal and interconnected nature of all existence.⁹

An even more complex and metaphysical vision of the tree as a map of connection is found in Jewish mysticism, or Kabbalah. Here, the Tree of Life (Etz Chaim) is an intricate diagram composed of ten spheres, called Sephirot, connected by 22 paths.⁴ Each sphere represents a divine emanation or an attribute of God, such as Wisdom (Chokhmah), Mercy (Chesed), and Beauty (Tiferet).²⁰ The tree is not merely a symbol of life but a cosmic blueprint of creation, a map of the human psyche, and a guide for the soul’s journey back to union with the divine.¹¹ The entire structure is designed around principles of balance and harmony, with pillars of Mercy and Severity mediated by a central pillar of Equilibrium.¹⁷ It teaches that no aspect of reality exists in isolation; everything is part of a single, living, interconnected system through which divine energy flows.¹⁷

These examples, though diverse, draw their symbolic power from the physical form of the tree itself. The roots represent our past, our ancestors, and our connection to the Earth, providing stability and nourishment.⁶ The trunk symbolises our present strength, the path of life that links past and future.⁶ The branches, reaching for the sky, embody our aspirations, our growth, and our connection to the future and the divine.⁶

Table 1: The Tree of Life Across Cultures

To consolidate these diverse yet convergent interpretations, the following table summarises the key features and meanings of the Tree of Life in several major cultural and religious traditions.

The Scientific Family Tree — Charting the Course of Evolution

While the Tree of Life was taking root in the world’s mythologies, a very different way of understanding the world was slowly developing. The scientific revolution brought with it a new emphasis on observation, classification, and empirical evidence. For centuries, these two worlds—the mythic and the scientific—remained separate. But in the 19th century, the ancient metaphor of the tree was adopted by science, where it was transformed into the single most powerful explanatory diagram in biology: the evolutionary tree.

From a “Great Chain” to a Branching Tree

Before Charles Darwin, the dominant Western view of the natural world was not a tree but a ladder. Known as the Scala Naturae or the Great Chain of Being, this concept originated with ancient Greek philosophers and was deeply embedded in medieval Christian thought.²⁶ It depicted a static, linear, and hierarchical order of all existence. God sat at the top, followed by angels, humans (with kings above peasants), animals (with lions above worms), plants, and finally minerals at the bottom. This was not a model of history or relationship, but of fixed, unchanging rank. Every creature had its designated rung on the ladder, and there was no concept of movement or transformation between them.

The first cracks in this rigid worldview appeared in the early 19th century. As geologists and paleontologists unearthed more and more fossils, it became clear that life on Earth had a history and had changed over time. Early naturalists began to sketch diagrams that looked less like ladders and more like branches. One of the first was the “paleontological chart” in Edward Hitchcock’s 1840 book Elementary Geology, which showed branching relationships among ancient plants and animals.²⁶ This represented a monumental conceptual shift. It replaced the static, vertical ladder with a dynamic, historical model based on divergence from common origins. The stage was set for a revolutionary new idea.

Darwin’s “I Think”: The Birth of an Evolutionary Icon

That revolution was ignited by Charles Darwin. He was intimately familiar with the tree as a metaphor for genealogy, and he realised it was the perfect way to visualise his theory of evolution by natural selection.¹ In his 1859 masterpiece, On the Origin of Species, he articulated the idea with poetic clarity:

“The affinities of all the beings of the same class have sometimes been represented by a great tree. I believe this simile largely speaks the truth. The green and budding twigs may represent existing species, and those produced during each former year may represent the long succession of extinct species… As buds give rise by growth to fresh buds, and these, if vigorous, branch out and overtop on all sides many a feebler branch, so by generation I believe it has been with the great Tree of Life, which fills with its dead and broken branches the crust of the earth, and covers the surface with its ever-branching and beautiful ramifications.” ²

The only illustration in the entire book was an abstract diagram showing this process. It was not a complete “Tree of Life” but a model demonstrating how, over thousands of generations, varieties within a single genus diverge from a common ancestor. Some lineages branch out and thrive, while others are outcompeted and go extinct, becoming dead branches on the tree.²

It was the German biologist Ernst Haeckel who took Darwin’s abstract concept and gave it its iconic visual form. A fervent supporter of Darwin and a gifted artist, Haeckel published a series of stunning and detailed diagrams that were the first to depict the entire known history of life as a literal tree.² His 1866 tree, for instance, showed three great limbs for the kingdoms Plantae, Protista, and Animalia, all originating from a common trunk of “Monera”.² These images were enormously influential, cementing the “Tree of Life” in the scientific and public consciousness.

However, these early scientific texts also reveal a fascinating tension between the new science of evolution and old cultural biases. Darwin’s theory implies that humans are but one small twig among millions on a vast and sprawling tree. Yet Haeckel’s famous diagrams are almost invariably drawn with “Man” (Menschen) placed triumphantly at the very top, the pinnacle of creation.² This anthropocentric arrangement is a holdover from the pre-evolutionary “Great Chain of Being,” a lingering ghost of the ladder on the branches of the new tree. While Haeckel’s work was revolutionary in visualising common descent, it also inadvertently reinforced the popular misconception of evolution as a linear march of “progress” toward humanity. Much of the development of modern phylogenetics can be seen as a scientific effort to correct this bias and to depict the tree as it truly is: a vast, undirected bush with no predetermined goal or pinnacle species.

Drawing the Tree: The Art and Science of Phylogenetics

Today, the science of reconstructing the Tree of Life is called phylogenetics, and the trees themselves are known as phylogenetic trees or cladograms.²⁶ A modern phylogenetic tree is a hypothesis—a scientist’s best estimation of the evolutionary relationships among a group of organisms based on the available evidence.²⁹ The process of building one is a rigorous, multi-step investigation.

First, it is essential to understand the basic anatomy of a phylogenetic tree. The tips of the branches represent the organisms being studied (these can be species, genes, or larger groups, collectively called taxa). The lines themselves are the branches, representing the lineages through evolutionary time. Where two branches meet, there is a node, which represents the inferred most recent common ancestor of the lineages descending from it. The entire diagram traces back to a single root, which represents the common ancestor of all the taxa on the tree.²⁶

The modern process for constructing a tree, especially using molecular data, generally follows these four steps:

1. Identify and Acquire Data: Scientists first choose the group of organisms to study and the characteristics they will use to compare them. While early trees relied on morphology (physical traits like bones, teeth, or feathers), today’s research is dominated by molecular data.³⁰ The process typically begins by acquiring homologous DNA or protein sequences—that is, genes that are shared between different species because they were inherited from a common ancestor.³⁷ These sequences are often downloaded from massive public databases like GenBank.³⁷
2. Align the Sequences: The homologous sequences from the different species are then aligned. This involves arranging them in a grid so that corresponding positions in the gene or protein are lined up in columns. This crucial step allows scientists to see exactly where the sequences are identical and where they have changed (mutated) over the course of evolution.³⁷
3. Estimate the Tree: This is the core of the analysis. The aligned sequences are fed into a computer program that builds the tree. To do this, scientists must identify shared derived traits, also known as synapomorphies.⁴¹ A derived trait is a novel feature that was not present in distant ancestors but appeared in a specific common ancestor and was then passed down to all of its descendants.³⁶ These shared innovations are the evidence of close evolutionary relationships. For example, the presence of hair is a shared derived trait that unites all mammals and distinguishes them as a distinct group, or clade.⁴⁴ By identifying nested sets of these traits in the molecular data, scientists can infer the branching pattern of the tree.³¹
4. Apply an Optimality Criterion: Often, the data can support several different possible tree shapes. To choose the best hypothesis, scientists apply an optimality criterion. One of the most common is the principle of parsimony, a version of Occam’s Razor.⁴⁶ This principle states that the simplest explanation is probably the best one. In phylogenetics, this means the preferred tree is the one that requires the fewest evolutionary changes (e.g., the minimum number of DNA mutations) to explain the observed data.³¹ The program evaluates many possible trees and selects the most parsimonious one. Finally, statistical methods like bootstrapping are used to assign confidence levels to the various branches of the tree, indicating how strongly the data supports that particular grouping.³²

A New Map of Life: Woese and the Three Domains

For the first century after Darwin, the broad shape of the Tree of Life seemed relatively stable. Biologists generally divided life into a handful of kingdoms, such as plants, animals, and fungi, with all single-celled organisms lacking a nucleus lumped into a group called prokaryotes.⁵¹ This picture was based almost entirely on what organisms looked like and how they functioned. In the late 20th century, however, a revolution in molecular biology would redraw the map of life from its very roots.

The architect of this revolution was an American microbiologist named Carl Woese. In the 1970s, Woese and his colleague George Fox pioneered a new method for peering deep into evolutionary history. They decided to compare the genetic sequences of a molecule found in all living cells: ribosomal RNA (rRNA).⁵¹ Because rRNA is essential for building proteins, its sequence changes very slowly over evolutionary time, making it an excellent “molecular clock” for measuring the most ancient relationships.

As Woese and his team sequenced the rRNA from a wide variety of microbes, they made a stunning discovery. The organisms everyone had been calling “prokaryotes” were not one group, but two. While one group comprised the familiar bacteria, the other was a collection of microbes that were as different from bacteria as bacteria are from humans. Many of these newly identified organisms were “extremophiles,” thriving in boiling hot springs, intensely salty water, or deep-sea vents. Woese initially called them “Archaebacteria”.⁵¹

By 1990, the evidence was overwhelming. Woese, along with Otto Kandler and Mark Wheelis, formally proposed that life was not divided into prokaryotes and eukaryotes, but into three fundamental “domains” of equal rank.² They named these domains Bacteria, Archaea (the new group), and Eukarya (which includes all animals, plants, fungi, and protists).² This three-domain system, based entirely on genetic evidence, fundamentally reshaped our understanding of biodiversity and redrew the very base of the Tree of Life. It revealed that the greatest diversity of life on our planet is microbial, and that the visible world of plants and animals is just one small, albeit spectacular, branch on a much larger tree.

A Tangled Bank — The Tree of Life in the Genomic Era

The 21st century has brought another revolution: genomics. The ability to sequence the entire genetic blueprint—the genome—of any organism has provided an unprecedented flood of data with which to reconstruct the Tree of Life. Yet, this firehose of information has not simply refined the existing branches; it has revealed a picture of life’s history that is far more complex, interconnected, and “tangled” than Darwin or Haeckel could have ever imagined.⁵² This new knowledge has led some to question the very adequacy of the tree metaphor itself.

Shaking the Trunk: The Challenge of Horizontal Gene Transfer

The classical Darwinian model of the Tree of Life is built on a simple assumption: genes are passed down “vertically” from parent to offspring. This is overwhelmingly true for complex organisms like animals and plants. However, among microbes, there is another, more chaotic, way to acquire genes: Horizontal Gene Transfer (HGT), also known as lateral gene transfer.⁵³ This is the direct transfer of genetic material between contemporary, often unrelated, organisms.

Prokaryotes (Bacteria and Archaea) have several ways of swapping DNA ⁵³:

• Transformation: A cell picks up fragments of “naked” DNA from its environment, often released by dead cells.
• Transduction: A virus accidentally packages a piece of DNA from one host cell and injects it into another.
• Conjugation: Two cells form a direct physical connection, and one passes a copy of a piece of its DNA to the other.

HGT is a powerful evolutionary force. It allows microbes to acquire new genes and functions in a single leap, rather than waiting for them to evolve through gradual mutation. This is how traits like antibiotic resistance can spread so rapidly through bacterial populations.⁵³ From a phylogenetic perspective, HGT is a major complication. It means an organism’s genome can be a mosaic, with some genes inherited vertically from its parent and others acquired horizontally from a completely different species.⁵⁶ This blurs the clean lines of descent that a tree diagram assumes. A tree built using one gene might show one set of relationships, while a tree built from another gene—one that was transferred horizontally—might show a completely different pattern.⁵⁷

From a Tree to a Web (or a Ring)

The discovery of HGT’s prevalence, especially in the early history of life, has led some scientists to argue that the single-trunked tree is a fundamentally flawed model for life’s origins.⁵⁸ In the 1990s, influential biologists like W. Ford Doolittle proposed that we should instead think of a “Web of Life”.⁵⁸ This model suggests that the earliest life forms existed as a global community of primitive cells that freely and frequently exchanged genetic material. In this view, the three domains did not emerge from a single common ancestor (the “trunk”) but rather coalesced from this interconnected network of gene-swapping cells.⁵⁸ The history of early life, therefore, looks less like a neatly branching tree and more like a tangled thicket or a complex web with connections crisscrossing between the major lineages.⁵⁸

An even more radical alternative is the “Ring of Life” model. This hypothesis, supported by some genomic analyses, suggests that the domain Eukarya did not arise as a sister branch to the Archaea but was born from a massive fusion event between an ancient archaeon and an ancient bacterium.⁵⁸ This endosymbiotic merger would have combined two distinct genomes to create the first complex eukaryotic cell. Such an event cannot be represented by a branching tree; instead, it is best visualised as a ring, where two ancient lineages fuse to give rise to a third.⁵⁸

What is striking about this scientific shift is how it seems to echo the ancient mythological understanding of the tree. For millennia, the spiritual Tree of Life has symbolised the profound interconnectedness of all being.¹³ Now, through the lens of genomics, science is revealing a physical basis for a similar concept at the dawn of life. The discovery of a primordial genetic commons, where genes flowed freely between lineages, provides an empirical foundation for an idea that has long been a part of human spiritual intuition. Our most advanced tools are revealing a reality—a web-like, interconnected origin—that resonates deeply with our most ancient symbols.

The Genomic Revolution: Sequencing All of Life

The debate over the shape of life’s history is being fueled by an explosion of data from massive international collaborations aiming to sequence the genome of every known species on Earth. Projects like the Earth BioGenome Project and its regional affiliates, such as the Darwin Tree of Life Project in Britain and Ireland, are undertaking the monumental task of creating a complete genetic catalogue of our planet’s biodiversity.⁵⁹ The goal is to generate high-quality reference genomes for millions of eukaryotic species, providing an unparalleled resource for conservation, medicine, biotechnology, and fundamental biology.⁵⁹

This endeavour faces immense challenges—technical, logistical, computational, and ethical.⁶⁰ But as the data pours in, it is revealing a profound paradox. One might intuitively assume that having more data—indeed, the complete genetic data for all of life—would lead to a final, perfectly resolved Tree of Life. Instead, the opposite is happening. The flood of genomic information has illuminated the full, bewildering complexity of evolutionary history. It has been confirmed that processes like HGT, ancient gene duplications, and the random sorting of genes in large populations (a phenomenon called incomplete lineage sorting) are not rare exceptions but common features of evolution.⁶⁴

The result has been described as “phylogenetic chaos,” with different studies using different subsets of genes or different analytical methods producing “divergent and even contradictory evolutionary hypotheses” about the relationships between major groups of life.⁶⁵ The ultimate dataset, far from yielding a simple, clean picture, has revealed that the “tangled bank” Darwin spoke of is even more tangled than he knew. This suggests that the idea of a single, perfectly bifurcating tree may have been, in part, an artifact of having limited data. The true history of life is inherently messy, and our technology is finally powerful enough to appreciate that complexity in its full glory.

Is the Tree Dead? The Ongoing Debate

Given these challenges, some have declared that the Tree of Life metaphor is obsolete. They argue that HGT is “the essence of the phylogenetic process” and that the history of life is a “jumbled network” that cannot be forced into a tree-like structure.⁵⁶

However, this may be an overstatement. Other researchers argue that while HGT was likely rampant among primitive cells at the dawn of life, its evolutionary impact became more constrained as organisms grew more complex.⁶⁶ In modern eukaryotes like animals, plants, and fungi, barriers have evolved that make the successful transfer of genes between distant species a very rare event. For these vast and diverse branches of life, traditional vertical inheritance is overwhelmingly the dominant mode of evolution. As a result, even with whole-genome data, a clear, tree-like phylogenetic signal of common descent shines through the “noise” of more complex processes.⁶⁶

The most accurate modern view, therefore, is that the Tree of Life is a powerful and useful model, but its applicability is scale-dependent. At the base of the tree, among the microbial domains of Bacteria and Archaea, the history is indeed a tangled web of vertical and horizontal inheritance. But as we move up into the major branches of eukaryotes, the lineages become more distinct, the influence of HGT diminishes, and the tree metaphor remains an exceptionally accurate and indispensable tool for understanding the grand sweep of evolution.⁶¹

Conclusion: One Metaphor, Two Histories, One Truth

The journey of the Tree of Life—from a sacred symbol carved on ancient artifacts to a complex hypothesis rendered by supercomputers—is a story about humanity’s enduring quest for connection and understanding. The metaphor’s unparalleled persistence across both cultural and scientific history stems from its profound ability to represent a fundamental truth: that all life is a product of its past and is deeply interconnected with everything around it.⁶

The world’s mythologies captured this truth through spiritual intuition. They saw in the tree a cosmic axis connecting all realms, a source of eternal life, and a web of being that unites all of creation in a single, sacred whole. The tree’s form—with its roots in the past, its trunk in the present, and its branches reaching toward the future—provided a perfect map for both the cosmos and the human soul.

Science, arriving much later, approached the same truth from a different direction. Through the painstaking work of observation, classification, phylogenetics, and now genomics, it has demonstrated this interconnectedness through the cold, hard evidence of a shared genetic history. Darwin’s “great Tree of Life” is a hypothesis of common descent, a testable model of how the magnificent diversity of life arose from a single origin.

That these two great traditions of human thought—the mythic and the scientific—converged on the very same metaphor is a testament to its power. The modern challenges to the simple tree model, such as the discovery of horizontal gene transfer and the proposal of a “Web of Life,” do not diminish this power. On the contrary, they enrich it. They show that the scientific picture is evolving to look more like the ancient intuition: a vision of life not as a set of discrete, isolated lineages, but as a deeply interwoven and collaborative network.

Whether viewed as a spiritual map or a scientific model, the Tree of Life tells the same essential story. It reminds us that we are not separate from the natural world, but an integral part of it. It speaks of our shared ancestry with every other living thing and our shared destiny on this planet. It tells us that we are all, in the end, leaves on a single, ancient, and extraordinary tree.

Disclaimer

This article presents information from two distinct domains of human knowledge: scientific theory and cultural/religious belief. The sections on the scientific Tree of Life are based on the modern theory of evolution, which is the cornerstone of biology and is supported by overwhelming evidence. However, it is a dynamic field of research, and specific hypotheses about evolutionary relationships are subject to ongoing investigation and revision. The sections on the mythic World Tree describe beliefs, symbols, and mythologies from diverse cultures around the world. These are presented for their historical, cultural, and symbolic significance and are not intended as statements of scientific fact.

Reference

1. Reconstructing the tree of life | NSF – National Science Foundation, accessed on October 21, 2025, https://www.nsf.gov/news/reconstructing-tree-life
2. Tree of life (biology) – Wikipedia, accessed on October 21, 2025, https://en.wikipedia.org/wiki/Tree_of_life_(biology)
3. Tree of life | Meaning, Symbol, Biology, Name, & Movie | Britannica, accessed on October 21, 2025, https://www.britannica.com/topic/tree-of-life-religion
4. Tree of Life Meaning, Symbolism, and Influence – Saffron Marigold, accessed on October 21, 2025, https://www.saffronmarigold.com/blog/tree-of-life-meaning-symbolism/
5. The Tree of Life: A Universal Symbol of Growth, Connection and Transformation -, accessed on October 21, 2025, https://gettherapybirmingham.com/the-tree-of-life-a-universal-symbol-of-growth-connection-and-transformation/
6. The Meaning of the Tree of Life in Different Cultures – Luuckk, accessed on October 21, 2025, https://luuckk.com/en-us/blogs/articles/meaning-of-the-tree-of-life-in-different-cultures
7. Tree of Life Symbolism Explained – History and Meaning – FARUZO, accessed on October 21, 2025, https://www.faruzo.com/blog/tree-of-life-meaning-symbolism/
8. The Symbolism of the Tree of Life – Hippie Shop, accessed on October 21, 2025, https://hippieshop.com/blogs/the-tribe/the-tree-of-life
9. Tree of Life Meaning: A Deep Dive Into Symbolism – Xenos Jewelry, accessed on October 21, 2025, https://xenosjewelry.com/blogs/posts/tree-of-life-meaning
10. The tree of life – Green Earth, accessed on October 21, 2025, https://www.green.earth/blog/tree-of-life
11. The Tree of Life in Religions: Symbols and Interpretations – Luuckk, accessed on October 21, 2025, https://luuckk.com/en-au/blogs/artikel/the-tree-of-life-in-religions-symbols-and-interpretations
12. Tree of Life Meaning, Symbolism, and Mythology | UniGuide, accessed on October 21, 2025, https://www.uniguide.com/tree-of-life
13. The Tree of Life: A Symbol of Interconnectedness and Growth – Ystradgynlais Volunteer Centre, accessed on October 21, 2025, https://ystradgynlaisvc.org.uk/component/content/article/the-tree-of-life-a-symbol-of-interconnectedness-and-growth?catid=25&Itemid=101
14. Pagan symbolism, the Tree of Life – CelticWebMerchant.com, accessed on October 21, 2025, https://www.celticwebmerchant.com/en/blogs/info/pagan-symbolism-the-tree-of-life/
15. TREE OF LIFE: SYMBOLISM ACROSS CULTURES · Mexicali Blues, accessed on October 21, 2025, https://www.mexicaliblues.com/blogs/our-stories-mexicali-blues-blog/tree-of-life-symbolism-across-cultures-and-time
16. The Tree of Life: Universal Symbol of Connection and Rebirth, accessed on October 21, 2025, https://treeurn.eu/the-tree-of-life-universal-symbol/
17. Tree of Life – Pardesco, accessed on October 21, 2025, https://pardesco.com/blogs/news/tree-of-life
18. Tree of Life Connects the World – ClothRoads, accessed on October 21, 2025, https://www.clothroads.com/tree-life-connects-world/
19. The Tree of Life, accessed on October 21, 2025, https://scalar.usc.edu/works/mysteries-of-the-grail/the-tree-of-life
20. What is the Tree of Life – Everything You Need to Know About Its Meaning and Symbolism, accessed on October 21, 2025, https://www.dublez.com/what-is-the-tree-of-life-everything-you-need-to-know-about-its-meaning-and-symbolism-a16
21. THE TREE OF LIFE, A Connection to Everything | We are all Interconnected even with the Universe, accessed on October 21, 2025, https://rodger-ricketts.com/2021/06/17/the-tree-of-life-a-connection-to-everything/
22. The Tree of Life: Symbol, Connection, Growth, Renewal, accessed on October 21, 2025, https://senay-johnson.mykajabi.com/blog/the-tree-of-life
23. Symbolism of the Tree of Life – The Goddess Garden, accessed on October 21, 2025, https://thegoddessgarden.com/symbolism-of-the-tree-of-life/
24. CELTIC TREE OF LIFE SYMBOLISM – CELTIC ART STUDIO, accessed on October 21, 2025, https://celticartstudio.com/celtic-tree-of-life-symbolism/
25. Tree Symbolism: Discover Its Meaning, accessed on October 21, 2025, https://www.arnua.com/post/exploring-the-symbolism-behind-the-tree-of-life
26. Phylogenetic tree – Wikipedia, accessed on October 21, 2025, https://en.wikipedia.org/wiki/Phylogenetic_tree
27. Icon 2 — Darwin’s Tree of Life | National Center for Science Education, accessed on October 21, 2025, https://ncse.ngo/icon-2-darwins-tree-life
28. What is a Tree of Life? (video) | Khan Academy, accessed on October 21, 2025, https://www.khanacademy.org/partner-content/amnh/human-evolutio/x1dd6613c:evolution-by-natural-selection/v/what-is-a-tree-of-life
29. www.khanacademy.org, accessed on October 21, 2025, https://www.khanacademy.org/science/biology/her/tree-of-life/a/phylogenetic-trees#:~:text=A%20phylogenetic%20tree%20is%20a,a%20series%20of%20common%20ancestors.
30. Phylogenetic trees | Evolutionary tree (article) | Khan Academy, accessed on October 21, 2025, https://www.khanacademy.org/science/biology/her/tree-of-life/a/phylogenetic-trees
31. Phylogenetic Trees | Biological Principles, accessed on October 21, 2025, https://bioprinciples.biosci.gatech.edu/module-1-evolution/phylogenetic-trees/
32. Understanding Phylogenetics – Geneious, accessed on October 21, 2025, https://www.geneious.com/guides/understanding-phylogenetics
33. Biology Basics: Phylogenetic Trees – Dummies.com, accessed on October 21, 2025, https://www.dummies.com/article/academics-the-arts/science/biology/biology-basics-phylogenetic-trees-169115/
34. Common Methods for Phylogenetic Tree Construction and Their Implementation in R – PMC, accessed on October 21, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC11117635/
35. Understanding and building phylogenetic trees (video) | Khan Academy, accessed on October 21, 2025, https://www.khanacademy.org/science/ap-biology/natural-selection/phylogeny/v/understanding-and-building-phylogenetic-trees-or-cladograms
36. www.khanacademy.org, accessed on October 21, 2025, https://www.khanacademy.org/a/building-an-evolutionary-tree#:~:text=A%20phylogenetic%20tree%20may%20be,those%20of%20the%20group’s%20ancestor).
37. Building Phylogenetic Trees from Molecular Data with MEGA – Oxford Academic, accessed on October 21, 2025, https://academic.oup.com/mbe/article/30/5/1229/992850
38. How to build phylogenetic species trees with OMA – PMC, accessed on October 21, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC9194518/
39. Phylogenetic Tree Construction – James White Laboratory – Sites@Rutgers, accessed on October 21, 2025, https://sites.rutgers.edu/james-white-laboratory/phylogenetic-tree-construction/
40. Build Phylogenetic Trees – Geneious, accessed on October 21, 2025, https://www.geneious.com/tutorials/phylogenetic-trees
41. www.ck12.org, accessed on October 21, 2025, https://www.ck12.org/flexi/biology/phylogeny-and-cladistics/what-are-shared-derived-traits/#:~:text=Shared%20derived%20traits%2C%20also%20known,determine%20evolutionary%20relationships%20among%20species.
42. Flexi answers – What are shared derived traits? | CK-12 Foundation, accessed on October 21, 2025, https://www.ck12.org/flexi/biology/phylogeny-and-cladistics/what-are-shared-derived-traits/
43. Building a phylogenetic tree (article) | Khan Academy, accessed on October 21, 2025, https://www.khanacademy.org/a/building-an-evolutionary-tree
44. [University evolutionary biology] What’s the difference between homologous structures and synapomorphies? ELI5 please! : r/HomeworkHelp – Reddit, accessed on October 21, 2025, https://www.reddit.com/r/HomeworkHelp/comments/19biupp/university_evolutionary_biology_whats_the/
45. Shared Derived Character – Biology As Poetry, accessed on October 21, 2025, http://biologyaspoetry.com/terms/shared_derived_character.html
46. Parsimony principle – (General Biology I) – Vocab, Definition, Explanations | Fiveable, accessed on October 21, 2025, https://fiveable.me/key-terms/college-bio/parsimony-principle
47. To apply parsimony to constructing a phylogenetic tree. Choose t… | Study Prep in Pearson+, accessed on October 21, 2025, https://www.pearson.com/channels/biology/asset/b7af0f38/to-apply-parsimony-to-constructing-a-phylogenetic-tree-a-choose-the-tree-that-as
48. Principles of Parsimony Analysis, accessed on October 21, 2025, https://www.mun.ca/biology/scarr/2900_Parsimony_Analysis.htm
49. Maximum parsimony – Wikipedia, accessed on October 21, 2025, https://en.wikipedia.org/wiki/Maximum_parsimony
50. Maximum Parsimony on Phylogenetic networks – PMC – PubMed Central, accessed on October 21, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC3377548/
51. The evolution of the tree of life | Philosophical Transactions of the Royal Society B – Journals, accessed on October 21, 2025, https://royalsocietypublishing.org/doi/10.1098/rstb.2024.0091
52. Rethinking the Tree of Life with new tools – College of Chemistry – UC Berkeley, accessed on October 21, 2025, https://chemistry.berkeley.edu/news/rethinking-tree-life-new-tools
53. Horizontal Gene Transfer and the History of Life – PMC, accessed on October 21, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC4817804/
54. Inferring Horizontal Gene Transfer – PMC, accessed on October 21, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC4462595/
55. Biology, Evolutionary Processes, Phylogenies and the History of Life, Perspectives on the Phylogenetic Tree | OER Commons, accessed on October 21, 2025, https://oercommons.org/courseware/lesson/15038/student/?section=3
56. Evolution of genes and organisms: the tree/web of life in light of horizontal gene transfer – PubMed, accessed on October 21, 2025, https://pubmed.ncbi.nlm.nih.gov/19845634/
57. Student Question : What is horizontal gene transfer and how does it affect phylogenetic tree construction? | Biotechnology | QuickTakes, accessed on October 21, 2025, https://quicktakes.io/learn/biotechnology/questions/what-is-horizontal-gene-transfer-and-how-does-it-affect-phylogenetic-tree-construction
58. 20.3D: Web, Network, and Ring of Life Models – Biology LibreTexts, accessed on October 21, 2025, https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/General_Biology_(Boundless)/20%3A_Phylogenies_and_the_History_of_Life/20.03%3A_Perspectives_on_the_Phylogenetic_Tree/20.3D%3A_Web_Network_and_Ring_of_Life_Models
59. Darwin Tree of Life – Reading the genomes of all life: a new platform for understanding our biodiversity, accessed on October 21, 2025, https://www.darwintreeoflife.org/
60. The Earth BioGenome Project Phase II: illuminating the eukaryotic tree of life – Frontiers, accessed on October 21, 2025, https://www.frontiersin.org/journals/science/articles/10.3389/fsci.2025.1514835/full
61. Tree of Life – Wellcome Sanger Institute, accessed on October 21, 2025, https://www.sanger.ac.uk/programme/tree-of-life/
62. Darwinian genomics and diversity in the tree of life – PNAS, accessed on October 21, 2025, https://www.pnas.org/doi/10.1073/pnas.2115644119
63. Sequence locally, think globally: The Darwin Tree of Life Project – PMC – PubMed Central, accessed on October 21, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC8797607/
64. Challenges in Assembling the Dated Tree of Life | Genome Biology …, accessed on October 21, 2025, https://academic.oup.com/gbe/article/doi/10.1093/gbe/evae229/7850940
65. Troubles with the Tree of Life | Science and Culture Today, accessed on October 21, 2025, https://scienceandculture.com/2022/05/troubles-with-the-tree-of-life/
66. Horizontal gene transfer: A critical view – PNAS, accessed on October 21, 2025, https://www.pnas.org/doi/10.1073/pnas.1632870100