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Course:CONS200/2025WT2/Human-Plant Coevolution: Lessons for Conservation

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Introduction

Humans growing medicinal herbs

Coevolution has been at the forefront of agriculture as far back as humans began domesticating crops[1].Without a firm understanding of the mutualistic relationship between plant and human populations, the future of sustainable agricultural and conservation efforts would be at stake. For example, gaining an understanding of how genetic crop diversity has evolved over time with human intervention is key in determining how modern farming practices can be altered as climate change accelerates[1]. This article examines how traditional plant cultivation[2] for medicinal[3] and agricultural uses can be paired with growing scientific knowledge of coevolution to shape the future of sustainable agriculture.

Historical Context

What is Coevolution?

Evolution is described as changes in characteristics over long periods of time, a classic example being the human evolution from apelike ancestors into modern humans[4]. The term coevolution describes when two or more species have an effect on each other's evolution and usually happens when the two species have frequent interactions. These interactions can occur on multiple levels including predator-prey interactions, host-parasite interactions, and more importantly in regards to plant and human coevolution, plant-pollinator and plant-herbivore interactions[5]. These interactions can be classified into broader categories including predation, competition, and symbiosis. The relationship between humans and plants is categorized as a symbiotic relationship, a close and beneficial association between two species. Although the complex human-plant relationship has changed, and continues to change, over time it can be viewed more specifically as a mutualistic, a type of relationship that falls under the symbiotic category[5]. In mutualistic relationships both parties involved gain from the interactions using the other to acquire resources or services which it otherwise wouldn’t have access to[6]. We can even attribute  the existence of plants themselves to symbiotic relationships when a eukaryotic cell first evolved into chloroplast, a vital organelle for plants[5].

Context of the Relationship between Humans and Plants

For millions of years the relationship between humans and plants has been evident. Humans rely on plants for many things, like food, medicine, clothes, shelter, and even air! It is difficult to deny our close interactions with plants, in turn over the centuries it is further difficult to deny that we have, in fact, coevolved with plants[7]. Although this is a historically tricky relationship to clearly observe, scientists can examine physical traits, relationship interactions, and genetic evidence to investigate coevolution. Coevolution is also, indisputably, a large driver of diversity due to natural selection and adaptation in response to interactions. The influence of coevolution spans far back in time and without it we would not have the same earth we live in today[5].

Examples of Human-Plant Coevolution Dynamics in Conservation

Domestication and Agriculture

Four rows of side-by-side images comparing wild and domesticated crop varieties. Row A shows teosinte and domesticated maize (Zea mays). Row B shows wild and cultivated chilli pepper (Capsicum annuum). Row C shows wild and domesticated common bean (Phaseolus vulgaris). Row D shows wild and cultivated cotton (Gossypium hirsutum). Wild varieties appear smaller and less uniform, while domesticated forms are larger and selectively bred.
Comparisons of wild and domesticated forms of key crops, the first image of each row is the wild relative: a) teosinte and maize (Zea mays), b) chilli pepper (Capsicum annuum), c) common bean (Phaseolus vulgaris), and d) cotton (Gossypium hirsutum).

The domestication of plants is a foundational process in the coevolutionary relationship between humans and the natural world. Over time, people selected traits such as seed size and taste that influenced growth patterns, transforming wild plant species into harvestable crops. In turn, these plants reshaped human diets, settlement patterns, and cultural relationships with the land [1][8]. This reciprocal process unfolded independently across multiple regions, including the Fertile Crescent (wheat, barley, lentils), China (rice, millet, soybeans), Mesoamerica (maize, beans, squash), and the Andes (potatoes, quinoa)[9].

“Domesticated plants are cultural artifacts as much as biological organisms.” — Fuller et al., 2023

Reciprocal Dynamics

Photograph of a traditional milpa showing maize, beans, and squash growing together. Maize stands tall, beans climb the stalks, and squash spreads across the soil surface
A traditional milpa with maize, beans, and squash cultivated together using Indigenous and Mesoamerican intercropping methods.

As early humans began cultivating plants, they exerted evolutionary pressure that led to what biologists call domestication syndromes, which are defined as suites of traits that emerge in a domesticated species. These traits include larger fruit size, loss of natural seed dispersal mechanisms, synchronized germination, and a reduction in toxicity or bitterness [1][8]. While some traits were consciously selected, others emerged through unintentional processes, such as favoring plants that retained seeds longer, simply for the reason they were easier to harvest. Over time, these changes made plants more dependent on humans for their survival and reproduction.

Rather than viewing domestication as a one-directional process of human control, many scholars now emphasize its interconnected nature, being a long-term negotiation between species, shaped by cycles of care and experimentation that encouraged adaptation [9][8]. These alterations, however, came with significant trade-offs. The narrowing of genetic traits in domesticated crops led to events such as genetic bottlenecks, making many modern varieties more susceptible to a plethora of diseases, pests and overall climate variability. This loss of genetic diversity continues to present a major challenge for agricultural sustainability today[1]. The relationship between humans and plants was never one-sided. Just as humans shaped the evolution of plants, plants also played a significant role in reshaping human cultures and ways of life. The domestication of staple crops like maize, wheat, and rice enabled permanent settlements, catalyzed population growth, and also heavily influenced systems of governance and trade, along with spiritual traditions[9][2][7]. In many Indigenous cultures, these plants are more than food, they are seen as kin, teachers, and ancestors.

Emerging ecological thought paired with Indigenous teachings also challenge us to recognize plants as active participants in their coevolution with humans. Plants have shown that they are capable of responding to human presence, remembering seasonal patterns, and adapting their chemical and genetic expressions in ways that suggest conscious depth within their roles in these mutual relationships[2]. Kimmerer (2013) writes that the process of tending plants is a form of relational ethics, one rooted in reciprocal responsibility, caring for the land as it cares for us[2]. For example, in the Mesoamerican milpa system, maize, beans, and squash are grown together in mutual support: maize offers a climbing stalk, beans fix nitrogen, and squash suppresses weeds. This agricultural model exemplifies coevolution not only between humans and plants but among plant species themselves within a human-guided ecosystem.

Indigenous Stewardship and Agricultural Wisdom

Across what is now Canada, similar relational systems persist. Indigenous seed keepers practice ceremonial and cultural stewardship, preserving crop diversity and food sovereignty through community-based, intergenerational knowledge systems[10]. These traditions are not static, they are adaptive and fluid technologies that have been developed over generations, and finely tuned to local natural ecological rhythms. In contrast, modern industrial agriculture has prioritized efforts rooted in standardization and high-output efficiency. These advances have presented certain benefits such as increased global food production and reduced hunger in some regions, but often at the expense of biodiversity, soil health, and long-term sustainability. Heavy reliance on monocultures, synthetic inputs, and centralized seed systems has weakened ecological resilience and deepened dependency on human intervention[1][8]. Yet within this dependency lies opportunity. As we face ecological crises and rising food insecurity, revitalizing ancestral agricultural knowledge offers not only practical solutions but a shift in mindset, from control to collaboration, from extraction to reciprocity.

Medicine and Traditional Ecological Knowledge

The coevolutionary relational dynamic between humans and plants is evident in medicine and traditional ecological knowledge. We have gained medicinal and ecological knowledge through the study of plants, with studies covering a vast range of plants and diseases and human functioning. Many examples exist, but one example includes the use of plants against malaria. This particular example exists within a larger context, one that observes the selection of medicinal plants over time, especially with regards to Indigenous knowledge[3].

With the development of drug-resistant strains of malaria, anti-malarial drug research has increased dramatically. Included in this is the study of natural medicines. For many years, Indigenous groups have used medicinal plants against malaria. The types of plants these groups use have antimalarial activity based on an oxidant mode of action. Western research has just started to explore antiplasmodial plants as a treatment for malaria, including Indigenous pharmacopoeias. The selection of plants has evolved over many years, yet Western research on the use of medicinal plants could be much more developed. N.L. Etkin suggests the use of the antimalarial plant Artemisia Annua, which has been used for centuries in Indigenous medicine and is effective in many ways. Its prevention and treatment of malaria can be attributed to its oxidant action, a characteristic also found in other plants. The development and use of medicinal plants for malaria treatment exemplify how human cultural practices and plant properties have evolved together[3].

Artemisia Annua, used in the treatment of malaria by Indigenous groups

Plants not only aid in the treatment of disease, but in a nuanced way support the establishment of disease. In the Neolithic period, increased plant domestications fostered increased population size, ones that could support “crowd infections,” like malaria[3]. Thus, plant evolution and human culture have evolved together, demonstrated in the effects of plant domestication on disease.

Indigenous and Plant Relationship

Human-plant coevolution dynamics are evident in Indigenous practice and plant relationships. Many Indigenous forms of knowledge highly value reciprocity and gratitude, evident in gift economy and respectful harvesting, emphasizing care over exploitation. Gifts from the earth are not a commodity, but establish a particular relationship: the field gives, and humans are meant to give back, according to much Indigenous Knowledge.[11] Sustainability is critical in the TEK of Indigenous harvesters. Many Indigenous groups caution taking too much, something that is not common in Western culture, perhaps indicating why Western culture is caught in overconsumption. The canon of Indigenous principles is known as the Honorable Harvest. Included in this canon are asking permission before taking, leaving some for others, reciprocity, and sustaining the earth so that one might be sustained. Practically, this is leaving behind some harvest, not to waste it, but to use as seed for next year and leave some for other beings.[12] The Honorable Harvest recognizes that what is good for land is also good for people.[13]

Members of the Leech Lake Band of the Ojibwe Tribe harvest rice on Mud Lake

One particular example of interdependent, sustainable cultivation and coevolution evident in Indigenous agricultural knowledge is the aforementioned crop called the three sisters. This crop is the use of corn, beans, and squash to grow together in mutual benefit. For millennia, Indigenous groups have used the three sisters to feed the land and people. When colonists on the Massachusetts shore first saw Indigenous gardens, which were a sprawl of abundance instead of straight rows of species, they thought they didn’t know how to farm.[14] However, the Indigenous peoples there continued to grow their crops in abundance using the method of the three sisters. The beauty in this is that each plant does what it normally does, simultaneously contributing to the flourishing of the whole. Many Indigenous groups see this as a moral lesson humans can use, where the gifts of the individuals are more fully expressed when they are nurtured together.[15]

A similar example is seen in the relationship between humans and marine plants, especially seaweeds. The domestication of seaweed through TEK  highlights a deeply rooted relationship between humans and plants. Indigenous communities, like Native Hawaiians, have practiced sustainable seaweed harvesting, integrating ancestral knowledge with scientific advancements. Indigenous groups have sustainably utilized seaweed for many health benefits, underscoring the reciprocal relationship of the two. Overall, Indigenous knowledge in environmentally friendly seaweed consumption highlights their sustainable outlook.[16]

Looking Forwards

Without knowledge of coevolution, modern day conservation efforts would be nearly impossible to achieve in a sustainable and effective way. As such, many modern evolutionary biologists utilize the deep-rooted relationship between human and plant evolution to inform conservation efforts. One such example is how many cereals, such as maize, wheat, and rice, have become domesticated to the point where their rate of seed dispersal without human intervention in greatly reduced, with some even becoming unable to germinate without human intervention[17]. The result of this is that they are now being planted and spread within disturbed, anthropic environments, such as camp-following commensals, in order to ensure these plants continue to grow, indicating how modern day conservation practices are influenced by human plant coevolution.

Coevolution is also shaping marine conservation efforts; for example, conservationists are using traditional ecological knowledge (TEK) to inform how they are planning to protect seaweed populations around the world[18].By using a combination of ancestral knowledge and modern scientific advancements, sustainable seaweed farming is being reshaped into something that can be implemented in other areas of marine conservation.

Modern wheat farming

The historical and intrinsic dynamic between humans and plants remains something that continues to evolve as environmental change is accelerating, which is why a firm understanding of coevolution is so critical in informing future conservation efforts.

Conclusion

The mutualistic coevolution of humans and plants has shaped not only our past but also the future of sustainable agriculture, medicine, and conservation. From ancient domestication practices and traditional ecological knowledge to modern scientific advancements, the deep-rooted relationship between people and plants continues to grow and shape the ways humans interact with the world and resources. As challenges like climate change and biodiversity loss intensify, recognizing and integrating both ancestral and contemporary understandings of coevolution is crucial. By recognizing this reciprocal relationship, we can foster more resilient ecosystems and agricultural systems for generations to come.

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Alam, O., & Purugganan, M. D. (2024). “Domestication and the evolution of crops: variable syndromes, complex genetic architectures, and ecological entanglements.” The Plant Cell, 36(5). https://doi.org/10.1093/plcell/koae013
  2. ↑ 2.0 2.1 2.2 2.3 Kimmerer, R. W. (2013). Braiding Sweetgrass: Indigenous Wisdom, Scientific Knowledge and the Teachings of Plants. Milkweed Editions.
  3. ↑ 3.0 3.1 3.2 3.3 Etkin, N. L. (2003). “The co-evolution of people, plants, and parasites: biological and cultural adaptations to malaria.” Proceedings of the Nutrition Society, 62(2), 311–317. https://doi.org/10.1079/pns2003244
  4. ↑ Millstein, R. L. (2017). “Evolution.” Stanford Encyclopedia of Philosophy. https://plato.stanford.edu/entries/evolution/
  5. ↑ 5.0 5.1 5.2 5.3 Langerhans, R. B. (2008). “Coevolution.” In Jørgensen, S. E., & Fath, B. D. (Eds.), Encyclopedia of Ecology (pp. 731–738). Academic Press. https://www.sciencedirect.com/science/article/pii/B9780080454054004717
  6. ↑ Plant-Animal Interactions. (2021). In H. M. Torezan-Silingardi & K. Del-Claro (Eds.), Springer eBooks (1st ed.). Springer Cham. https://doi.org/10.1007/978-3-030-66877-8
  7. ↑ 7.0 7.1 Schaal, B. (2018). “Plants and people: Our shared history and future.” Plants, People, Planet, 1(1), 14–19. https://doi.org/10.1002/ppp3.12
  8. ↑ 8.0 8.1 8.2 8.3 Fuller, D. Q., Denham, T., & Allaby, R. G. (2023). “Plant domestication and agricultural ecologies.” Current Biology, 33(11), R636–R649. https://doi.org/10.1016/j.cub.2023.04.038
  9. ↑ 9.0 9.1 9.2 Angourakis, A., Alcaina-Mateos, J., Madella, M., & Zurro, D. (2022). “Human-Plant Coevolution: A modelling framework for theory-building on the origins of agriculture.” PLOS ONE, 17(9), e0260904. https://doi.org/10.1371/journal.pone.0260904
  10. ↑ Turner, N. J., Cuerrier, A., & Joseph, L. (2022). “Well grounded: Indigenous Peoples’ knowledge, ethnobiology and sustainability.” People and Nature, 4(3). https://doi.org/10.1002/pan3.10321
  11. ↑ Kimmerer, Robin Wall (2013). Braiding Sweetgrass: Indigenous Wisdom, Scientific Knowledge, and the Teachings of Plants. Minnesota: Milkweed Editions. p. 25. ISBN 9781571313560.
  12. ↑ Kimmerer, Robin Wall (2013). Braiding Sweetgrass: Indigenous Wisdom, Scientific Knowledge, and the Teachings of Plants. Minnesota: Milkweed Editions. p. 181. ISBN 9781571313560.
  13. ↑ Kimmerer, Robin Wall (2013). Braiding Sweetgrass: Indigenous Wisdom, Scientific Knowledge, and the Teachings of Plants. Minnesota: Milkweed Editions. p. 195. ISBN 9781571313560.
  14. ↑ Kimmerer, Robin Wall (2013). Braiding Sweetgrass: Indigenous Wisdom, Scientific Knowledge, and the Teachings of Plants. Minnesota: Milkweed Editions. p. 129. ISBN 9781571313560.
  15. ↑ Kimmerer, Robin Wall (2013). Braiding Sweetgrass: Indigenous Wisdom, Scientific Knowledge, and the Teachings of Plants. Minnesota: Milkweed Editions. pp. 132–140. ISBN 9781571313560.
  16. ↑ Cornish, M.L; Critchley, A.T.; Mouritsen, O.G. (2017). "Consumption of Seaweeds and the Human Brain". Journal of Applied Phycology. 29: 2377–2398 – via ProQuest.
  17. ↑ Fuller, Dorian Q.; Denham, Tim; Allaby, Robin (2023). "Plant domestication and agricultural ecologies". Current Biology. 33: 636–649 – via ScienceDirect.
  18. ↑ Cornish, M. L., Critchley, A. T., & Mouritsen, O. G. (2017). “Consumption of seaweeds and the human brain.” Journal of Applied Phycology, 29(5), 2377–2398. https://doi.org/10.1007/s10811-016-1049-3
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