The problem
LOOK AROUND YOU. The world is brimming with the diversity of life. The great assortment of species is so much a part of our world that we take it for granted. It’s easy to say that diversity results from the theory of evolution and be done with it. But why is there such a wide gamut of life and how does diversification actually unfold? The question isn’t ‘Does evolution happen?’ but rather ‘How does evolution happen?’
When we look back in time we see that evolution has been punctuated by bursts of spectacularly rapid diversification during which many new species suddenly appeared. This process (called adaptive radiation) is very fast compared to the usually steady march of evolution, but it’s still too slow for scientific study.
The researcher
Rees Kassen is the University of Ottawa’s Research Chair in Experimental Evolution. When it comes down to it, Kassen wants to know the answer to a straightforward question: Why are there so many different kinds of living things in the world?
The project
To study the process of biodiversity, Kassen needs to watch evolution take place in his laboratory. He can do this by studying microbes. Since microbes live for only a short time, Kassen can observe changes that occur over generations in only a matter of days. This makes microbes an ideal model for studying adaptive evolution.
The key
When Kassen places colonies of microbes in a beaker of nutrient-rich broth, the colonies choose to live at the centre where there’s the most food. Early on the colony is smooth and round. After a while, resources become scarcer and competition becomes more fierce. Some of the colonies realize that if they stop fighting for control of the centre and move to the fringes they will have an ecological niche all to themselves. And so some colonies fall to the bottom of the beaker where they evolve into brush-shaped colonies. Others rise to the top where they change into very wrinkly colonies.
The new ecosystem offers the microbes opportunities to specialize and to a certain extent determines the form of the diversity. On the other hand, it is competition for resources that drives the specialization. Kassen suspects that these two factors cause adaptive radiation to occur quickly and helps explain why diversification happens in bursts.
Showing posts with label Biology. Show all posts
Showing posts with label Biology. Show all posts
Monday, March 28, 2011
Sunday, January 23, 2011
Tanning turtles
The problem
NORTHERN MAP TURTLES (that’s Glyptemys geographica for those of you who like Latin) are found in northern states and southern Ontario and Quebec. They hibernate through the coldest parts of the year in communal groups on the floor of lakes and rivers. They don’t come up to breathe for the entire hibernation. Since they spend a lot of time in the sun during the summer, Map Turtles like areas that have fallen trees or other objects to bask on near large bodies of water. Basking sets their body temperature, but the more important question is just how energetically vital is sun-basking to these northern turtles?
The researcher
University of Ottawa professor Gabriel Blouin-Demers studies the physiological ecology of reptiles. He integrates laboratory experiments with field observations to better understand how phenotypes or biological traits—especially behavioural—are set by reptiles’ physiologies.
Blouin-Demers hopes that the research coming out of his laboratory can contribute to reptile conservation. Reptiles are in fact the most threatened vertebrates in Canada.
The project
The northern Map Turtles that Blouin-Demers studied were from Lake Opinicon (100 km south of Ottawa). He implanted thermometers into the abdomen of juvenile turtles to continuously monitor their body temperature for two years. Using their body temperature, Blouin-Demers can calculate the turtles’ metabolic rates to estimate how important thermoregulation is to the energy available for growth and reproduction.
The key
Blouin-Demers determined that basking has a huge impact on the energy budgets of northern Map Turtles. The turtles spend three-quarters of their day basking in the sun.
More importantly, he found that if northern Map Turtles don’t bask, their metabolic rate slows by as much as a third. This amounts to a huge loss in available energy for growth, reproduction, and everyday turtlely business. Despite the clear importance of basking, Blouin-Demers discovered that the turtles bask a little less than the theoretically expected optimal amount. Blouin-Demers speculates that this is because basking is a mutually exclusive behaviour: Turtles can’t multi-task while basking. They bask on land but do all their other important activities (like foraging and mating) in the water, so they must compromise.
Mercury munching microbes (om nom nom)
The problem
THE MAJORITY OF MERCURY in the atmosphere is generated by human industries like coal combustion and gold mining. The rest comes from natural sources such as volcanoes and forest fires. Either way, when mercury is dispersed into the atmosphere, it is carried poleward where it is oxidized and becomes heavier, falling into sensitive Arctic regions as a toxic contaminant.
Mercury binds to proteins and then accumulates in organisms, causing mercury compounds from the environment to enter the Arctic’s atmosphere when they get soaked up by the tiny microbes that form the ecosystem’s foundation. Since there’s nowhere for it to go, mercury is passed from prey to predator. Eventually, high levels of mercury accumulate in the top of the food chain—that’s us, friend.
The researcher
Alexandre Poulain, a professor at the U of O, studies how microbes alter the mobility and the toxicity of metals and metalloids in the environment. He focuses on aquatic systems in polar regions and ventures out into the Arctic to bring samples home for analysis in his lab.
The project
Anaerobic microbes, bacteria that don’t use oxygen, alter the nature of the mercury. Some make metals more toxic by turning ordinary mercury into very harmful methylmercury. Dissimilarly, other bacteria break down methylmercury, making a gas and venting it out of the ecosystem. Poulain looks at the difference between the rates of these two processes by analyzing the production of proteins (ribonucleic acid or RNA) that control whether microbes create toxic mercury or whether they detoxify the Arctic atmosphere.
The key
Upon sensing mercury in their environment, certain northern microbes activate genes naturally encoded in their DNA. Poulain can determine which of these genes are active in biomass samples from polar regions and can even tell exactly which genes are needed to defend against the toxic nature of mercury.
Poulain’s goal is to bridge global-scale environmental science and microscopic biology The reduction of Arctic mercury by tiny microbes plays a major role in regulating the toxicity of the Far North and could possibly be used in integrated approaches to environmental management.
THE MAJORITY OF MERCURY in the atmosphere is generated by human industries like coal combustion and gold mining. The rest comes from natural sources such as volcanoes and forest fires. Either way, when mercury is dispersed into the atmosphere, it is carried poleward where it is oxidized and becomes heavier, falling into sensitive Arctic regions as a toxic contaminant.
Mercury binds to proteins and then accumulates in organisms, causing mercury compounds from the environment to enter the Arctic’s atmosphere when they get soaked up by the tiny microbes that form the ecosystem’s foundation. Since there’s nowhere for it to go, mercury is passed from prey to predator. Eventually, high levels of mercury accumulate in the top of the food chain—that’s us, friend.
The researcher
Alexandre Poulain, a professor at the U of O, studies how microbes alter the mobility and the toxicity of metals and metalloids in the environment. He focuses on aquatic systems in polar regions and ventures out into the Arctic to bring samples home for analysis in his lab.
The project
Anaerobic microbes, bacteria that don’t use oxygen, alter the nature of the mercury. Some make metals more toxic by turning ordinary mercury into very harmful methylmercury. Dissimilarly, other bacteria break down methylmercury, making a gas and venting it out of the ecosystem. Poulain looks at the difference between the rates of these two processes by analyzing the production of proteins (ribonucleic acid or RNA) that control whether microbes create toxic mercury or whether they detoxify the Arctic atmosphere.
The key
Upon sensing mercury in their environment, certain northern microbes activate genes naturally encoded in their DNA. Poulain can determine which of these genes are active in biomass samples from polar regions and can even tell exactly which genes are needed to defend against the toxic nature of mercury.
Poulain’s goal is to bridge global-scale environmental science and microscopic biology The reduction of Arctic mercury by tiny microbes plays a major role in regulating the toxicity of the Far North and could possibly be used in integrated approaches to environmental management.
Goldfish on Prozac
The problem
WHEN YOU THINK of pollution, what jumps to mind? Heavy metals, BP oil spill, carbon tax? What about the words antibiotics, the pill, nicotine, or Prozac? These so-called pharmaceutical pollutants are seeping out of our medicine cabinets and into our rivers and lakes.
Drugs are only partially metabolized in your body; the rest of them are flushed down the toilet. To make matters worse, traditional sewage treatment plants fail to cleanse the water of these chemicals, allowing them to flow right into rivers and lakes.
Last year Canadians filled 483 million prescriptions (that’s 14 prescriptions per person and doesn’t count the large amounts of antibiotics given to livestock).
So what happens when all the fish in the pond are on Prozac?
The researcher
Vance Trudeau is a neuroendocrinologist at the U of O and the Centre for Advanced Research in Environmental Genomics. He studies how hormones control brain function and how, in turn, the brain regulates sexual development.
The project
Fluoxetine, the trade name for Prozac, can be found in the brain and liver tissues in wild fish, and, just like in people, increases fishes’ serotonin levels. To understand how the drug upsets sex hormone levels in wild fish populations, Trudeau studies normal goldfish whose food intake, seasonal growth rates, and reproduction have been previously well studied.
The key
When Trudeau’s research group studied female goldfish injected with flouxetine, they found that multiple genes in the brain were affected, causing a decrease in estrogen levels in the blood. Some of these genes are known to have an impact on the reproductive and social behavior of fish. To make matters worse, fluoxetine has an impact on the secretion of growth hormones, causing the fish to feed less and to become underweight.
To simulate the levels of Prozac detected in the environment, another test was done where fluoxetine was added directly to the tanks of male goldfish. Trudeau’s team then added potent female sex pheromones to the water. This should have stimulated the healthy, normal males to release their sperm and fertilize the eggs. However, male goldfish that had been exposed to the fluoxetine completely fail to release their sperm.
Poor goldfish.
WHEN YOU THINK of pollution, what jumps to mind? Heavy metals, BP oil spill, carbon tax? What about the words antibiotics, the pill, nicotine, or Prozac? These so-called pharmaceutical pollutants are seeping out of our medicine cabinets and into our rivers and lakes.
Drugs are only partially metabolized in your body; the rest of them are flushed down the toilet. To make matters worse, traditional sewage treatment plants fail to cleanse the water of these chemicals, allowing them to flow right into rivers and lakes.
Last year Canadians filled 483 million prescriptions (that’s 14 prescriptions per person and doesn’t count the large amounts of antibiotics given to livestock).
So what happens when all the fish in the pond are on Prozac?
The researcher
Vance Trudeau is a neuroendocrinologist at the U of O and the Centre for Advanced Research in Environmental Genomics. He studies how hormones control brain function and how, in turn, the brain regulates sexual development.
The project
Fluoxetine, the trade name for Prozac, can be found in the brain and liver tissues in wild fish, and, just like in people, increases fishes’ serotonin levels. To understand how the drug upsets sex hormone levels in wild fish populations, Trudeau studies normal goldfish whose food intake, seasonal growth rates, and reproduction have been previously well studied.
The key
When Trudeau’s research group studied female goldfish injected with flouxetine, they found that multiple genes in the brain were affected, causing a decrease in estrogen levels in the blood. Some of these genes are known to have an impact on the reproductive and social behavior of fish. To make matters worse, fluoxetine has an impact on the secretion of growth hormones, causing the fish to feed less and to become underweight.
To simulate the levels of Prozac detected in the environment, another test was done where fluoxetine was added directly to the tanks of male goldfish. Trudeau’s team then added potent female sex pheromones to the water. This should have stimulated the healthy, normal males to release their sperm and fertilize the eggs. However, male goldfish that had been exposed to the fluoxetine completely fail to release their sperm.
Poor goldfish.
Subscribe to:
Posts (Atom)