Category: Human evolution

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How Body Size and Proportionality are Influenced by Climate Change

By: Cameron Ward, Kellie Guerette, Meghan Doherty, and Benjamin Clark
(Stonehill College, BIO323: Evolution, Fall 2023)

Overview

Climate change is defined as long-term shifts in temperatures and weather patterns. Shifts can be natural, however, since the 1800s, human activities have been the main driver primarily due to the burning of fossil fuels. An article titled, “Climate Change Predictive of Body Size and Proportionality in Humans”, discusses how these changes have impacted the evolution of the human body over time. A relationship has been established between climate change and the human body shape and size, driven by natural selection in response to thermoregulatory demands. The studies suggested that smaller bodies with more of their weight distributed to the limbs dissipate heat better than larger and more rotund bodies with less relative surface area. This leads to larger species (endomorphic) in cooler geographic regions and smaller (ectomorphic) in warmer climates. Fossil records have shown that this trend holds true for a variety of species. Invertebrates, insects, and mammals all shrunk during past periods of global warming. Periods of global cooling have had the opposite effect, in which species increased in size to become better fit for their environment. There are several factors that could lead to the observed changes in body weight/ proportionality, however, climate change seems to be a major driver.

A short podcast summarizing the article.
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How to break a sweat

By: Adam Ziegler, Matthew Papp, Shivam Gandhi, Nikolas Steege, Bio323 Evolution, Fall 2019, Stonehill College

Let’s face it, we all sweat. Despite sweat being such a common and prominent aspect of everyday life, not many people understand what causes sweating, or why not all mammals sweat. A recent paper explored the difference in human sweat compared to other primates from compiled data sets across three phylogenetic models. The research focused on the two glands that are primarily involved in sweating, the apocrine and eccrine glands. By combining glycogen concentration, climate, and distribution of glands, the authors were able to predict the eccrine gland ancestral relationship. The results show exactly how humans have come to evolve the current gland distribution and offer a previously unstudied insight into our ancestors. 

Demonstration of Sweat. Image credit:  https://en.wikipedia.org/wiki/Perspiration#/media/File:Demonstration_of_Sweat.jpg by Dogbertio 14 is licensed under CC BY 3.0
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Bitterness on the Brain

Bitterness on the Brain

by: Alex Baryiames, Cassie Daisy, Mohini Patel & Olivia Peterson (Stonehill College Evolution Fall 2017)

Eating something bitter isn’t a great experience. The moment the taste hits your mouth can be an unpleasant one, and often causes you to avoid that particular food in the future. In an effort to understand this phenomenon, researchers discovered that the ability to detect these bitter tastes might have some evolutionary benefits! Read on to discover how the ability of vertebrates to detect bitter tastes can be a protective mechanism against toxic materials, and greatly contributes to our survival!  

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The Evolution of PMS

The Evolution of PMS

by: Lydia Blodgett, Alexandra Calafiore, Rachel O’Donnell (Stonehill College Evolution Fall 2017)

Premenstrual syndrome, commonly known as PMS, affects the majority of women and can cause an array of unwanted symptoms. Although up to 80% of women are affected by the symptoms of PMS, not much is known about exactly why it began and continues to happen in humans. Our podcast, “Evolution of PMS”, attempts to highlight the evolutionary basis of PMS. Using Michael Gillings’ article, “Were there evolutionary advantages to premenstrual syndrome?”, as a foundation, we explore the idea that the persistence of PMS is an outcome of its selective advantage to women. Although PMS has previously been considered maladaptive—with severe forms being classified as a diagnosable mental disorder—-Gillings proposes three main hypotheses that there are reproductive advantages for its persistence throughout evolutionary history.

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