Sexual Selection: Big-brain vs. Small-brain

Gianna Amatucci, Nick Mulvey, Caitlin Welsh, & Cayleigh Shufelt (Stonehill College, BIO 323 Evolution, Fall 2019)

Predominantly residing in the tropics of South America, guppies are small and colorful freshwater fish. They are omnivorous animals, primarily consuming algae and brine shrimp. Unfortunately, guppies are preyed upon by a number of larger creatures, including birds, larger fish and mammals. While constantly having to avoid such predators, guppies are always in search of a suitable mate to spread their gene pools to future offspring. Alberto Corral-López and colleagues studied how predation pressure, in addition to cognitive ability and brain size, affected sexual behavior and sexual selection in guppies. The actions of both large-brained and small-brained female and male guppies were observed by Corral-López in order to study this phenomenon.

Domestic male guppy in an S-curve mating display. Image credit: “older guy 22feb08” by Alice Chaos is licensed under CC BY-NC-SA 2.0
Continue reading “Sexual Selection: Big-brain vs. Small-brain”

Salty Cetaceans

By: Emma Foster, Ana Alcantara, Apsara Gurung (Stonehill College, BIO 323 Evolution, Fall 2019) 

While humans can taste a variety of flavors, this is not true for all mammals. Researches Dr. Kangli Zhu and other collaborators recently published the research article “The loss of taste genes in cetaceans,” and found that they are only able to detect one out of five sensations of taste. These tastes include sweet, salty, bitter, umami, and sour, but they can only taste salt. Taste is important to mammal adaptations, particularly in cetaceans, which are a group of organisms including whales, dolphins, and porpoises. Umami and sweet taste sensations are important for finding and eating nutritious protein- and energy-rich foods. Salt is also an attractive taste and helps animals maintain sodium levels. Bitter taste is beneficial for aversion to prevent ingestion of toxic or harmful foods. Sour taste also prevents the ingestion of potentially unripe or decayed foods.  

Bottlenose Dolphin
Image credit: “A little smile for you” by San Diego Shooter is licensed under CC BY-NC-ND 2.0
Continue reading “Salty Cetaceans”

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: by Dogbertio 14 is licensed under CC BY 3.0
Continue reading “How to break a sweat”