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2.1: The Beginnings of Evolutionary Thinking

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    Throughout our evolutionary history, humans have developed an understanding of the natural world as they interacted with and extracted resources from it. To survive, our earliest ancestors possessed an understanding of the physical environment, including weather patterns, animal behavior, edible and medicinal plants, locations of water, and seasonal cycles. Many ancient cultures, including those of the Americas (Dunbar-Ortiz 2014), Mesopotamia, and Egypt, left writings, hieroglyphics, and stories passed down through oral tradition detailing their understanding of the natural environment, human and zoological anatomy, botany, and medical practices (Moore 1993).

    There are also over 2,000 years of organized thought and writing regarding evolution, including contributions from Greek, Roman, and Islamic scholars. Three examples of note are included here. The Greek philosopher Aristotle (384–322 BCE) studied the natural world, publishing several volumes on animals based on systematic observations, rather than attributing what he observed to divine intervention, as his contemporaries were doing (Figure 2.1). Aristotle’s system for the biological classification of nearly 500 species of animals was based on his own observations and dissections, interviews with specialists such as beekeepers and fishermen, and accounts of travelers. His nine book History of Animals, published in the 4th century BC (n.d.), was one of the first zoological taxonomies ever created. Aristotle’s primary contribution to the classification of biological species was to recognize that natural groups are based on structure, physiology, mode of reproduction, and behavior (Moore 1993, 39).

    Large orange octopus on ocean floor.
    Elephant half-submerged in a body of water with a ferry of human watchers behind.
    Figure 2.1a-b: Aristotle was the first to publish that a. octopuses can change their colors when disturbed and b. elephants use their trunks as a snorkel when crossing deep water. Credit: a. Octopus macropus by SUBnormali Team (originally from Yoruno) is under a CC-BY-SA 3.0 License. b. Elephant swimming, Botswana (cropped) by Jorge Láscar from Australia (uploaded by Peter D. Tillman) is under a CC BY 2.0 License.
    Rows of organisms, with plants and animals at the bottom and humans, angels, and God at top.
    Figure 2.2: The Great Chain of Being by Didacus Valades. Credit: Great Chain of Being by Didacus Valades (Diego Valades 1579), print from Rhetorica Christiana (via Getty Research), is in the public domain.

    Aristotle’s History of Animals also placed animals in a hierarchy, ranking animals above plants due to what he claimed were their abilities to sense the world around them and to move. He also graded animals according to their modes of reproduction. Those giving birth to live young were placed above those who laid eggs. Warm-blooded animals ranked above invertebrates. This concept of “higher” and “lower” organisms was expanded upon by scholars in the Medieval period to form the Scala Naturae (Latin for “ladder of being”). This “Great Chain of Being,” depicting a hierarchy of beings with God at the top and minerals at the bottom (Figure 2.2), was thought by medieval Christians to have been decreed by God; in this Great Chain, humans were placed closer to God than other species. Aristotle’s works were rediscovered by Islamic scholars in the ninth century and translated into Arabic, Syriac, Persian, and later into Latin, becoming part of university curriculum in 13th-century Europe (Lindberg 1992), allowing Aristotle’s works and ideas to influence other thinkers for 2,000 years.

    A person leading a giraffe on a leash, with text written in Arabic below.
    Figure 2.3: An image from Kitāb al-ḥayawān (Book of the Animals) by Al-Jahiz. Credit: Al-Jahiz by Al-Jahiz [in Kitāb al-ḥayawān (Book of the Animals), 15th century] is in the public domain.

    Science also owes a debt to many Arabic scholars. One such Islamic scholar and writer, who built upon the ideas of Aristotle, was Abū ʿUthman ʿAmr ibn Baḥr al-Kinānī al-Baṣrī / al-Jāḥiẓ, known as Al-Jahiz (776–868 CE), who authored over 200 books (El-Zaher 2018; Figure 2.3). His most well-known work was the seven-volume Kitab al-Hayawan or Book of Animals, in which he described over 350 species in zoological detail. Importantly, Al-Jahiz introduced the idea and mechanisms of biological evolution 1,000 years before Darwin proposed the concept of natural selection in 1859 (Love 2020). For instance, Al-Jahiz wrote about the struggle for existence, the transformation of species over time, and environmental factors that influence the process, all ideas that were later espoused by western European scientists in the 19th century. Al-Jahiz wrote:

    Animals engage in a struggle for existing, and for resources, to avoid being eaten, and to breed. Environmental factors influence organisms to develop new characteristics to ensure survival, thus transforming them into new species. Animals that survive to breed can pass on their successful characteristics to their offspring. [Masood 2009]

    A person with a full beard and turban looks into the distance.
    Figure 2.4: Drawing of Ibn al-Haytham. Credit: Ibn al-Haytham by Sopianwar is under a CC BY-SA 4.0 License.

    Another important early Islamic scientist is Ibn al-Haytham (965–1040), a 10th-century Islamic scholar who contributed a great deal to our understanding of optics and how human vision works (Figure 2.4; Lindberg 1992, 177–180). Born in what is now Iraq, al-Haytham was a scholar of many disciplines, including mathematics, physics, mechanics, astronomy, philosophy, and medicine. He authored some 200 books in his lifetime and was an expert on Aristotle’s natural philosophy, logic, and metaphysics. In relation to evolution, al-Haytham’s methodology of investigation—specifically, using experiments to verify theory—is similar to what later became known as the modern scientific method. He is most famous for discovering the laws of reflection and refraction over 1,000 years ago and inventing the camera obscura, which was incredibly important for the eventual development of photography. His work is credited for its influence on astronomy, mathematics, and optics, inspiring Galileo, Johannes Kepler, and Sir Isaac Newton (Tasci 2020). As an inspirational scientific figure, al-Haytham was celebrated in 2016 by UNESCO as a trailblazer and the founder of modern optics (Figure 2.5). An International Year of Light was named in his honor and a scholarly conference on his contributions was held to coincide with the 1,000th anniversary of the publication of his Kitāb al-Manāẓir (Book of Optics; 2015).

    Labeled diagram of the eye and optic nerves.
    Figure 2.5: Diagram of the Human Eye by Ibn al-Haytham. Credit: Diagram of the eye by Ibn Al [Alhazen] Haitham (16th Century) has been modified (cropped) and is under a CC BY 4.0 License. This image is available from Wellcome Images 3044 (under the photo number L0011969).

    The writings of these Islamic scholars as well as similar scientific texts from other cultures were unknown to or unacknowledged by Western scientists until recently. Fortunately, many science teachers are now incorporating this content into their classes (Love 2020).

    This page titled 2.1: The Beginnings of Evolutionary Thinking is shared under a CC BY-NC 4.0 license and was authored, remixed, and/or curated by Joylin Namie (Society for Anthropology in Community Colleges) via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.