By: Moussa Abboud, Victoria Pinaretta, Jack Ryan, and Cameron Sarkisian (Stonehill College, BIO323: Evolution, Spring 2023)
Just as natural selection acts on land, the creatures of the sea experience the same selective pressures! As a mode of evolution, natural selection works by weeding out those who are not as fit as others, while promoting those who are most successful at survival and reproduction. If the history of evolution has taught us anything, it is that one important way to make sure your genes get passed on through your offspring is to become the best at adapting to your environment! A great example of such a concept is visualized in nine-spined sticklebacks (Pungitius pungitius), where the predatory avoidance behaviors of freshwater and marine populations provide insight into the differences in how they evolved this behavior from a common ancestor. Here, we summarize an article about these sticklebacks that was published recently in Evolution by researchers from the University of Helsinki.
By: Emily Almeida, Caroline Houghton, Nathan Skopas, and Jada Thornton (Stonehill College, BIO323: Evolution, Spring 2023)
Three-spined Sticklebacks, Location of Study, and Introduction The three-spined stickleback (Gasterosteus aculeatus) is a species of fish that can be found in temperate regions of the northern hemisphere and in seawater and freshwater habitats in the Atlantic and Pacific basins. Sticklebacks have long been considered a model organism for studying adaptive radiation, due to their parallel diversifications between freshwater sticklebacks and their marine ancestors. Adaptive radiation is defined as the rapid increase in the number of closely related species characterized by great ecological and morphological diversity. The driving force behind adaptive radiation is an organism’s adaption to a new environment. In this article from Ecology and Evolution, the population of three-spined stickleback fish studied were native to two Scottish islands, North and South Uist. Specifically, the diversity in the number and type of bony armor plates in species native to both islands were compared. Bony armor plates are structures on the fish that run along their backside and help to protect the fish from predators. Based on prior work, it was observed that the populations located on North Uist showed immense diversity, which was thought to be related to diversity of aquatic habitats within the area. On South Uist, evolutionary diversity within the stickleback population was significantly less, despite similar levels of diversity within the surrounding habitats. The diversity in pH on North Uist, and lack thereof on South Uist, has likely led to this drastic difference.
By: Jentry Allen, Isabella Caldarone, Jacqueline Foley, and Nicole Godbout (Stonehill College, BIO323: Evolution, Spring 2023)
Overview Dogs are said to be a man’s best friend as they are wonderful companions and can be trusted like no other pet; they are loyal to a fault. We find comfort in our dogs, maybe even purpose. Some people are willing to put their lives in the hands of dogs, allowing them to be their eyes, tell them if a food contains an allergy that may cost them their life, and inform a person if they are on the brink of an epileptic attack so that they may find a safe space and be prepared. An article from The American Naturalist titled, “High Investment in Reproduction is Associated with Reduced Life Span in Dogs”, discusses research on this ever-reliable friend and pet that shows a pattern in their life span in relation to offspring production. It was found that higher reproductive investment, or the work and energy that goes into reproduction, causes a decrease in canine life span. Additionally, it was discovered that this effect on life span was greater for larger dog breeds. With breeders today who want to breed more and larger puppies, we questioned the possible evolutionary effects of artificial selection, or the act of humans breeding animals to achieve a certain characteristic. If a breeder selects for a larger litter with larger puppies, the reproductive investment will be higher, and in theory, the life span of the mother will be decreased. Hear more about our discussion on this topic on the Everyday Evolution podcast!
By: Hailee Arena, Caitlin Swanson, Elizabeth Cravinho, and Matthew Healy (Stonehill College, BIO323: Evolution, Spring 2023)
Just like your ex, being toxic is not always obvious! Did you know that frogs can display warning signals that indicate their toxicity, known as aposematism? Aposematism is a strategy employed by organisms to advertise toxicity to deter predators through color patterns. While this is a common trait, conspicuous coloration does not always signal toxicity. What causes coloration to evolve? Can toxicity depend on other factors, such as body size or time of activity? Due to this knowledge gap between conspicuousness and toxicity, Drs. Roberts, Stuart-Fox, and Medina, from the University of Melbourne, conducted research titled, The evolution of conspicuousness in frogs: When to signal toxicity?, as published in the Journal of Evolutionary Biology. The researchers collected data on various frog species to determine whether toxicity is linked to coloration. They examined the chemical defenses in these species and sought to identify whether body size and daytime (diurnal) activity could be linked to conspicuousness in chemically defended frogs. Ultimately, the researchers hypothesized that the conspicuous coloration in diurnal species is directly related to toxicity.
By: Stephen Cobbs, John de Abreu, Clare Feeman, and Molly Turner (Stonehill College, BIO323: Evolution, Spring 2022)
On April 26, 1986, the world effectively changed in the blink of an eye. An accident during a technical test at the Chernobyl Nuclear Power Plant near the city of Slavutych, Ukraine, produced what would eventually be referred to as “the worst nuclear disaster in history”. The consensus on the immediate, short-term effect of the accident was undeniably poor, as all wildlife within the area suffered mass casualties. 36 years later however, and the consensus is rather murky. Scientists have recently visited the Chernobyl Exclusion Zone (CEZ) and were shocked to find that area today presents great biodiversity, playing host to a multitude of different species from a multitude of different clades. Why is that you may ask? Well, some scientists believe that the radioactive pollution from the nuclear fallout led to an increase in mutation rates within genes of the animals in Chernobyl, which partially offset the diversity which was initially lost. This raises the question if there is such a thing as too many mutations and is there a line at which mutation rates cross from beneficial to deleterious? The paper Unusual evolution of tree frog populations in the Chernobyl exclusion zone, by Clément Car and 11 others, works to classify those questions, specifically looking at populations of Eastern Tree Frogs (Hyla orientalis) both in and around the CEZ and using simulations for populations throughout Europe as a whole.
By: Patrick McLaughlin, Natasha Moniz, and Emma Tedeschi (Stonehill College, BIO323: Evolution, Spring 2022)
Crypsis, another term for camouflage, is a strategy that many organisms use to protect themselves from predators. Many organisms perform a process known as ‘environmental matching’, which is when an organism changes the color of their skin to match their habitat. Disruptive camouflage is a specialized type of camouflage that disrupts the organism’s outline by creating false edges, making it hard for the predator to find their prey. Studies have been conducted and results have been compiled into a scientific article called “Rapid Body Color Change Provides Lizards with Facultative Crypsis in the Eyes of their Avian Predators,” with research done by Kelly Lin Wuthrich, Amber Nagel, and Lindsey Swierk. This research has helped with understanding the ability of organisms to be able to rapidly change their body color and its effects on their survival. The experiments were conducted using receiver visual models, digital image analysis, and spectrophotometric tests. However, researchers have yet to reveal if rapid color change can alter the whole color of the body or patterns of an organism. When gathering research, many factors need to be taken into consideration, such as the predators’ visual systems, the rapidity of the color change, and the variety of microhabitats. Anolis lizards, or anoles, are known for their rapid color-changing abilities. Some species can change colors within minutes, going from light to dark and vice-versa. However, it has been discovered that going from dark to light seems to be more difficult for an organism than going from light to dark- it is more time-consuming. The researchers tested whether rapid body color change in water anoles (Anolis aquaticus) could provide benefits to the organism with proper camouflage between different microhabitats.
By: Abby Campbell, Molly Cannon, and Marissa Freitas (Stonehill College, BIO323: Evolution, Spring 2022)
Safety in numbers: How Color Morph Frequency Affects Predation Risk in an Aposematic Moth is an article with the main purpose of understanding polymorphic warning signals in aposematic systems. This article was published by the American Naturalist in July 2021, written by Swanne P. Gordon, Emily Burdfield-Steel, Jimi Kirvesoja and Johanna Mappes. Aposematic is defined as a defense strategy that combines a primary warning signal (aposematic) with a secondary chemical defense. This study evaluated how bird behavior influenced the survival of three morphs of the aposematic wood tiger moth (Arctia plantaginis) that coexist in the same environment to a predator located from the same area. The three morphs of the moth were white, yellow, and red/ orange coloration. It calls attention to the need to understand predator foraging in natural environments with variable prey defenses to better examine how behavioral interactions between predator and prey affect evolutionary change.
By: Kristina McEvoy, Eli Penza-Clyve, Amaya Toribio, and Lindsey Walsh (Stonehill College, BIO323: Evolution, Spring 2022)
Have you ever wondered how wildlife has been affected by the 1986 Chernobyl nuclear power plant explosion? The disaster has been a subject of fascination to many, inspiring media such as the 2012 horror film Chernobyl Diaries and HBO’s 2019 television miniseries, Chernobyl. Although the incident occurred a little over 35 years ago, the accident has left lasting effects on the creatures that inhabit the Chernobyl area, particularly in the realm of genetic mutations.
Researchers at the University of Stirling, in collaboration with the Ukrainian Hydrometeorological Institute in Kyiv, sought to determine how radiation affected genetic diversity in a freshwater crustacean living in lakes at varying distances to the disaster. Daphnia pulex, also known as water fleas, live in the seven lakes examined in this study; five lakes were within the Chernobyl Exclusion Zone, or the radioactive area surrounding the explosion site, and two were located outside this boundary. Water fleas are known to accumulate mutations and suffer from a reduced ability to survive and reproduce when exposed to radiation. Scientists investigated the variation between the water fleas at each location by extracting DNA and sequencing ten microsatellite gene locations on chromosomes. Essentially, microsatellites are short segments of repeated DNA motifs in many places within one’s genome. The variation in the length of these microsatellites can serve as a measure of genetic diversity. The radiation from Chernobyl can lead to the development of genetic mutations, which can, in turn, increase genetic diversity. However, this relationship can change drastically when taking other evolutionary factors into account. Considering the radioactive conditions, there are two possible outcomes: either mutations cause genetic diversity to increase, or natural selection eliminates individuals that cannot survive the cellular damage associated with radiation, thus decreasing genetic diversity.
By: Sarah Boles, Carly Russell, Tia Zephir, and Gabby Scarcella (Stonehill College, BIO323: Evolution, Spring 2021)
Have you ever wondered how your immune system just knows and acts on a variety of diseases? Especially now during COVID-19, it seems our immune systems are really being put to the test. The actions of your immune system are due to the major histocompatibility complex (MHC). In a recent article in BMC Evolutionary Biology, researchers from the University of Geneva and the Biomedical Primate Research Center wanted to see if MHC genes are conserved and evolving similarly in Western chimpanzees (Pan troglodytes verus) and humans. The MHC region, referred to as Patr in chimpanzees and HLA in humans, is a family of genes that plays a key role in a population’s adaptive immunity. MHC diversity could affect a population’s survival because these genes code for proteins that help combat viral infections and protect the organism from harmful pathogens. MHC genes are classified as class I genes or class II genes, which differ in structure and function. The class I genes are named A, B, and C, and target viral invaders, whereas class II genes, such as DPB1, DQB1, DQA1, and DRB1, target parasitic and bacterial invaders. The objective of this study was to determine if the genetic diversity at different Patr genes is significantly reduced in present day Western chimpanzees due to a past bottleneck effect, which is defined as the sudden decrease of a population from natural causes. The researchers also compared human and chimpanzee genetic diversity to determine if MHC molecular evolution mechanisms were conserved between the two species.