Tag: evolution

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When Environments Change

Can Algae save the world?

In today’s world with an increasing human footprint across the natural world, scientists believe we may be entering a sixth mass extinction. Fragmented habitats, introduction of invasive species, and climate change are just some of the factors leading to this mass extinction.  A lot of species still have yet to be recorded, so the number of extinctions of populations and species documented by scientists are likely to be large underestimates (Barnosky et al. 2011).  Climate change is one factor among many that is leading to the loss of biodiversity. Therefore, it is important for scientists to understand how populations respond to rapid environmental change. It is known that evolutionary history may affect risk of extinction within populations due to the accumulation of mutations, or pleiotropy. In one environment certain mutations will be favored, but in others they may have detrimental effects that reduce fitness, or reproductive success of a certain genotype in a population. (genotype being the genetic makeup of an individual) This would lower a population’s ability to withstand environmental change due to the accumulation of mutations which aren’t suited for the new environment. (MacLean et al. 2004) Understanding evolutionary history is crucial for understanding how populations will respond to environmental change caused by climate change. In the October edition of the Journal of Evolutionary Biology there was a study looking at how evolutionary history affects extinction probability.  Its title is “The effect of selection history on extinction risk during severe environmental change’. This study looked at how the extinction risk of populations of the green algae Chlamydomonas reinhardtii changed with various stressful environments (Lachapelle et al. 2017).

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Parasitic Limitations on the Size of American Cliff Swallows

Introduction to the Role of the Parasite:

A parasite is an organism that lives in or on another organism at that organism’s expense. For most people, the thought of a parasite is usually in the form of leeches, tapeworms, or ticks. Within populations, parasites have the power to dictate the health of a population and which individuals survive. From an evolutionary standpoint, this can determine who in a population survives due to a parasites ability to kill off the defenseless, and therefore allow individuals with only specific traits to survive. Under the basic concept of natural selection: those who survive, pass on their traits, while the unfit individuals die and fail to pass their traits to the next generation. Parasites act as a controlling factor for which hosts and genes survive for reproduction. With this in mind, Charles R. Brown and Mary Bomberger Brown began a study to investigate the effect of parasitic cimicid bugs on the brood size of cliff swallows (Brown and Brown 2017).

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Do girls rule the world? They just might in finch hybridization!

Background: what’s happening, and where?

Map of the Galapagos Islands, Floreana is present at lower center
Figure 1. Galápagos Islands, image from Google Maps

In 1998, one of Charles Darwin’s famous finches, the medium tree finch, was classified as threatened on the International Union for Conservation of Nature’s (ICUN) red list (BirdLife, 2018). The medium tree finch, otherwise known as Camahynchus pauper, was named for the size of its short, curved beak. It can be found living only on Floreana island, an island that is part of the Galapágos Islands archipelago (bottom center of fig. 1). Over the last couple hundred years, this finch has faced numerous threats to its survival in the form of habitat fragmentation and destruction, predation, and now specifically parasitism (Kleindorfer et al., 2014). In 2009, the species was bumped all the way up to being labelled as critically endangered, after its population numbers dipped, largely due to threats caused by humans (BirdLife, 2018).

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Attractive Dads Make Poor Parents

An overview of Alissa et al. (2017)

The debate over parental responsibility is a contentious one in our human society. Who should get parental leave? Whose responsibility is child protection and education? Such questions are often aimed at trying to get men more involved in the caring of a child or to split responsibility more evenly between two parents. Who would have thought that similar questions are being asked about spider societies?

It turns out that those intriguing 8-legged creatures that have plagued people’s nightmares and inspired fantasy from Charlotte’s Web to Harry Potter, also have very complex family dynamics. For most wild creatures the main purpose in life is to reproduce as successfully as possible. Thus, in some species, such as the harvestman spider, Serracutisoma proximum, investigated by Alissa et al. (2017), we see a trade-off between energy and time investment in mating effort and offspring care. Continue reading “Attractive Dads Make Poor Parents”

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The Chronicles of Evolutionary Weight in the Fight Against Cancer

Background

“Dad, you have to try it, don’t you?’ Mary insists again.

Enrique doesn’t answer his daughter. What she’s implying will make him spend even more time in the hospital, to help someone in the distant future whom he will never meet, maybe. When he was 70, Enrique was diagnosed with acute myeloid leukemia (AML). As he understands it, some of his blood cells will never mature and perform the correct functions in his body. This cancer can be cured through chemotherapy in 25% of cases, but in most cases cannot be treated or reversed (Kornblau 2014). Enrique is contemplating joining a drug trial. In any given trial there is only a 10% chance that a patient will respond to the specific drug tested (Kornblau 2014). Some therapeutic drugs work for some patients, but how to match a patient to a drug is unknown; this is what the study Enrique might join is trying to figure out. Continue reading “The Chronicles of Evolutionary Weight in the Fight Against Cancer”

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Evolutionary advantage of learning to cope with change

Background

Whether migratory birds will respond successfully to rapid climate change is unclear.  Birds migrate to take advantage of seasonal peaks in resource availability: Food and habitat become abundant quickly during summer at northern latitudes, but decline quickly in the fall.  Timely arrival on the summer range is vital for many species (Alerstam and Hedenström 1998). Continue reading “Evolutionary advantage of learning to cope with change”

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All is fair in (insect) love and war

mantis1
Let’s rock! (freakingnews.com)

Musicians alike, from Roy Orbison and Gram Parsons to Rod Stewart and classic rockers Nazareth have crooned woefully on that most powerful of feelings: Love hurts. Each of these fellas, though, had at least one thing going for him. Although they may have been jilted by former lovers, they can be thankful that none of them was a praying mantis! Scientists (and Tina Turner) may rightly question What’s love got to do with it? But there can be no doubt, mantis mating can be a very painful experience for the males involved. That’s because female predatory mantises practice sexual cannibalism, or the act of consuming a male mate before, during, or following a reproductive event. As many as one in four mantis sexual encounters may involve cannibalistic behavior. And while this bit of trivia knowledge has been known for quite some time now, two questions have continued to perplex evolutionary biologists:
How did sexual cannibalism evolve and why has it persisted in the face of natural selection? Continue reading “All is fair in (insect) love and war”

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Does it even matter that you’re not a monkey? Host Species vs Immunocompetence

INTRO:

Viruses and their hosts influence each other’s evolution. As selection acts on viruses to increase their ability to infect hosts, selection is acting on hosts to decrease their susceptibility to viruses, and the next generation of viruses is less effective at infecting hosts. But the viruses continue to evolve, as do the hosts–they coevolve and often demonstrate this pattern:

RQ dynamics

This is called the Red Queen Effect, after the Red Queen from Through the Looking Glass by Lewis Carroll.

“Now, here, you see, it takes all the running you can do just to keep in the same place. If you want to get somewhere else, you must run at least twice as fast!”

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Hot Bod!: Evolution of Australian Frog Body Shape

Photo Credit: Autumn Fish, an Australian Hylid
Photo Credit: “Emotions of a Nocturnal Frog (an Australian Hylid) ” Autumn Fish

Convergent evolution. Oh gosh, you might be thinking, here we go again, another lesson on convergent evolution. If you’ve been in an evolution class, you probably know the definition: the independent origin of similar phenotypes in distantly related species. You most likely spent a whole lecture on the topic or have encountered numerous papers on the subject. With so much emphasis put on convergent evolution, it must be an important concept in evolutionary biology. But why does it matter? What is its importance?

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Spring 2016

A  year has passed since we started this blog and now we have a whole new crop of fantastic posts from our Evolution Honors students and Graduate students. Stay tuned over the next week as we highlight some recent research in Evolutionary Biology.