By: Nia Campbell, Chris Driscoll, Ethan Fultz, and Rachael McCabe (Stonehill College, BIO323 Evolution, Spring 2018)
Regressive evolution is the process where a trait is lost or becomes dysfunctional in a species over generations. This type of evolution is the opposite of constructive evolution, where a species evolves a new or more complex structure. Regressive evolution is a difficult method to use to classify species into evolutionary lineages because it often can only be identified by finding a genetic trace, such as a mutated or deleted gene in the species’s genome. In a paper published by Christopher A. Emerling in 2017, three traits found in relatives of snakes were examined in snakes for evidence of regressive evolution: presence of claw keratin, taste receptors, and light-associated genes.
Continue reading “Snaking Around Evolution”
By: Kaili Jackson, Yash Malai, Nina Parziale, and Nick Perry (Stonehill College, BIO323 Evolution, Spring 2018)
Despite the many great technological and scientific advances that have defined the 21st century thus far, there are many important questions that remain unanswered. Among them is the ultimate reason that Neanderthals went extinct while humans were capable of further survival. There are several theories as to why this occurred, and scientists continue to debate which factors may have contributed to Neanderthal extinction to the greatest extent. Some examples of suggested theories include the possibility that climatic fluctuations may have had a negative impact on Neanderthals; the hypothesis that modern humans’ shorter gestation period allowed for more rapid population growth; and the proposition that the intelligence and language capabilities of modern humans were superior to Neanderthals, allowing them to develop better hunting strategies such as the domestication of dogs to aid them during large animal hunts. Another potential theory, which the article An evolutionary medicine perspective on Neandertal extinction presents research on, is that viral disease transmission from modern humans may have contributed to the ultimate extinction of Neanderthals. This research was led by Alexis Sullivan from the Department of Biology at Pennsylvania State University. This theory is known as the differential pathogen resistance model.
Continue reading “Did a poor immune system contribute to Neanderthal extinction?”
By: Stefan Balestra, Adam Casey, Alessandro Puccio, and Walker Smith (Stonehill College, BIO323 Evolution, Spring 2018)
Spiders are considered by some as a source of fear, but many people find arachnids to be a cool group of arthropods. I mean, one of the most beloved superheroes is Spiderman, after all. Adding to the coolness factor associated with spiders, the spider discussed below is not only a jumping spider, but also a dancing spider with an interesting ritualized dance used to attract a mate. Additionally, the male individuals of the species exist in two morphs with different ritualized dances, competing in a spider dance battle of sorts to impress the ladies. Read on to learn more about the specific mode of sexual selection that contributes to the male morphs’ different looks and dance styles.
Continue reading “These Spiders Can Jump and Dance, but Can They Use Their Moves to Impress the Ladies?”
By: Katelyn Foley, Eileen Mello, Erica Shepherd, and Joe Varney (Stonehill College, BIO323 Evolution, Spring 2018)
When a species extends across large geographic ranges, it is often found that the individual populations of the species differ physically and genetically from one another, as these subgroups are exposed to a wide range of environmental conditions within the range. Typically, populations found at the edges of the geographic range, or peripheral populations, are more likely to have adaptations or evidence of new traits as a result of their environment. One peripheral population of interest, the elephants of the Namib Desert, demonstrate unique behaviors and physical adaptations in comparison to other African savanna elephant populations. Knowing this, researchers from the Department of Animal Sciences at the University of Illinois were interested in how these elephants might differ genetically, as they show different behaviors compared to populations that are nearby.
Continue reading “The Elephants of the Namib Desert”
by: Marissa Beachell, Stephen Kulka, Mackenzie Lachkey, & Katherine O’Malley (Stonehill College, BIO 323 Evolution, Spring 2018)
There isn’t much worse than walking in after a night spent outside in the summertime and seeing your arms and legs covered in mosquito bites! While not every species or type of mosquito needs to bite to obtain food, many species do get their nutrients from a blood meal. What if there were a way that we could never get bitten by mosquitoes again but the mosquitoes actually live… and even thrive? We spend so much time and money on mosquito repellents and tiki torches that supposedly ward off these pests, while those in some other parts of the world set up mosquito nets to avoid a bite. It’s easy to brush off a few mosquito bites in Massachusetts or another urban area of the U.S., but for those countries with preventative mosquito nets, a bite could mean life or death. This whole landscape could be changing, however, as recent scientific research has illuminated a possible solution in which humans and mosquitoes both win.
Continue reading “The Evolution of Nonbiting Mosquitoes”