Tuesday, January 13, 2015
Black Widow Spider Venom Dangers
http://www.livescience.com/49333-why-black-widow-spider-venom-is-so-potent.html
In the article "Why Black Widow Spider Venom is so Potent," by Jennifer Viegas on Discovery News, she informs the readers about the potency of their venom. Over the years, the venom has developed into a powerful tool, allowing black widow spiders to triumph over many insects and sometimes animals. This lethal venom has evolved rapidly, and in doing so, equipped the spiders with an advantage, allowing them to create larger and stronger webs in efforts to handle even-bigger prey. This information, presented at the 2015 annual conference of the Society of Integrative and Comparative Biology in West Palm Beach Florida.
These spiders produce similar toxic compounds as others in the spider community, however, in their's, the most powerful neurotoxins called latrotoxins. Latrotoxins are named after a group of black widow spiders called Latrodectus. The most toxic latrotoxins is the alpha-latrotoxin, which hijacks the victim's own nervous system. Jessica Garb of UMASS Lowell, determined that latrotoxins are actually more popular in the arachnid community than previously believed, as many other types of spiders produce their own watered down versions helpful in hunting, but nontoxic to humans.
So the question then becomes, why do female black widow spiders have this feature? Garb and her team of scientists think it was to expand their diet. These spiders are able to eat small mammals and reptiles, in addition to typical smaller prey.The females also eat the males, and because their diets are quite open ended, it begs the question, was there a time when this species had a strict diet and was forced to adapt to its surroundings, therefore prompting the venom toxicity to increase to broaden its options.
Monday, January 12, 2015
Modern Genetics Confirm Ancient Relationship between Fins and Hands
http://www.sciencedaily.com/releases/2014/12/141222165441.htm
This article describes how scientists have finally made a conclusive link between the fins of aquatic animals and the human counterpart (comprising of wrists/fingers or ankles/toes) called the autopod. In the past, scientists had studied teleost fish in comparison with human bone structures, which comprise most of the world's commercial fish. However, they were barking up the wrong tree, so to speak. They never found a signatory connection between the two, and a lack of expression of necessary limb-forming genes called Hox genes confirmed this. The Hox genes function using genetic switches that can turn them on and off. While scientists found these genes in teleosts, they did nothing went turned on. The reason behind teleost fish not activating the necessary genes was due to an ancestral split millions of years ago, where speciation made them a separate group from more bony fishes that maintained a similar structure to the autopod. Scientists then studied a fish called the spotted gar, a North American fish with more bony structures than the teleosts. Scientists found that when the gar's Hox genes were activated, autopod-like structures were formed as compared to transgenic rats. This breakthrough showed a direct genetic/evolutionary connection between aquatic life bone structures and human/mammal bone structures, thus strengthening existing ideas about the origin of mammal/human life.
This relates to our current topic of evolution because it shows how homologous structures evolved, and what possible common ancestry might occur between fish and humans. It also relates to genetics in that scientists used methods of genetic fingerprinting to discover this connection (PCR and Gels were most likely used).
This article describes how scientists have finally made a conclusive link between the fins of aquatic animals and the human counterpart (comprising of wrists/fingers or ankles/toes) called the autopod. In the past, scientists had studied teleost fish in comparison with human bone structures, which comprise most of the world's commercial fish. However, they were barking up the wrong tree, so to speak. They never found a signatory connection between the two, and a lack of expression of necessary limb-forming genes called Hox genes confirmed this. The Hox genes function using genetic switches that can turn them on and off. While scientists found these genes in teleosts, they did nothing went turned on. The reason behind teleost fish not activating the necessary genes was due to an ancestral split millions of years ago, where speciation made them a separate group from more bony fishes that maintained a similar structure to the autopod. Scientists then studied a fish called the spotted gar, a North American fish with more bony structures than the teleosts. Scientists found that when the gar's Hox genes were activated, autopod-like structures were formed as compared to transgenic rats. This breakthrough showed a direct genetic/evolutionary connection between aquatic life bone structures and human/mammal bone structures, thus strengthening existing ideas about the origin of mammal/human life.
This relates to our current topic of evolution because it shows how homologous structures evolved, and what possible common ancestry might occur between fish and humans. It also relates to genetics in that scientists used methods of genetic fingerprinting to discover this connection (PCR and Gels were most likely used).
How Culture Has Shaped Human Evolution
http://www.apa.org/science/about/psa/2011/11/human-evolution.aspx
The article above gives reasoning and evidence for how human culture and/or society has shaped the evolution of our species. The author organizes his evidence into three main points:
1)Culture, cultural transmission, and cultural evolution come from genetically evolved psychological adaptations in humans to acquire information/skills from observation and inference
2)These adaptations allow for a second system of inheritance in humans(and other highly intelligent organisms) that operates by different rules than those observed by genetic inheritence.
3)Inherited information/practices can affect the processes of natural selection and other forms of evolution(Ex. Domestication of cows led to lactase persistence being selected for in certain human societies)
This relates to our current unit as it shows how human society and artificial selection can influence the evolution of our species.
Evolution is happening right now
https://www.youtube.com/watch?v=mq9A9OctSts
The most common argument against evolution is that there is no proof because you can't see it happening. Evolution is a process that spans over many generations of a species and takes a very long time but it doesn't mean you can't see it happening. In the last 25 years, the population of African and Asian elephants has decreased by as much as 50% due to poachers killing them for their tusks. The elephants have naturally selected to be tuskless. The African and Asian populations use to have as little as 5% tuskless elephants but now they are as high as 30%. The tuskless elephants are less likely to be killed by poachers and are thus more likely to pass on that gene. This is relevant to the material we are learning in class about the process of natural selection and evolution.
The most common argument against evolution is that there is no proof because you can't see it happening. Evolution is a process that spans over many generations of a species and takes a very long time but it doesn't mean you can't see it happening. In the last 25 years, the population of African and Asian elephants has decreased by as much as 50% due to poachers killing them for their tusks. The elephants have naturally selected to be tuskless. The African and Asian populations use to have as little as 5% tuskless elephants but now they are as high as 30%. The tuskless elephants are less likely to be killed by poachers and are thus more likely to pass on that gene. This is relevant to the material we are learning in class about the process of natural selection and evolution.
Can returning crops to their wild states help feed the world?
http://www.sciencedaily.com/releases/2014/12/141216140743.htm
This article talks about how returning crops to their wild states might help feed the world in the near future. They discuss how experimentally breeding with these crops has made them lose some of their important properties. A scientist in the article suggested a way that fixes weaknesses that have sprung up by accident in the process of traditional crop breeding over the course of thousands of years. The scientist suggested that we replace those lost properties by isolating them from related plants, or using precision methods to repair the faulty genes. The one problem with this is, by definition, these methods of replacing the lost properties is genetically modifying the plants. That is a problem because just being categorized with the word genetically modified usually has a negative connotation, and people are not going to like it, even though it's not really genetically modifying these crops.
This article relates to our curriculum because learning about GMO's, and if they could feed a growing population was a key part of our unit about genetic engineering, and we even had a debate about it.
This article relates to our curriculum because learning about GMO's, and if they could feed a growing population was a key part of our unit about genetic engineering, and we even had a debate about it.
Evolution of Color in Plants and Animals
http://www.sciencedaily.com/releases/2015/01/150109093727.htm
Published: January 9th, 2014
This article looks into why color variants occur in populations, a question that scientists are still trying to solve. One color should eventually replace the other through natural selection as it becomes more beneficial to the species, but that is not what happens. Instead, these differences continue to exist. In order to answer this question, scientists studied fish of the same species that varied in color, a darker fish and a gold fish, with the gold color being dominant but the darker color more common. They placed the fish on both dark and light surfaces and recorded changes in the shade of their color. The results of their experiment were that the darker fish could alter its color to better fit its environment while the gold colored fish could not. This shows that differences in the ability to change colors to match environments could be an important way that color frequencies are created and maintained in the wild.
This article relates to our curriculum because natural selection and evolution are two main points in our current unit, and it is about the study of evolution of color in animals and why natural selection does not appear to occur in some populations.
Published: January 9th, 2014
This article looks into why color variants occur in populations, a question that scientists are still trying to solve. One color should eventually replace the other through natural selection as it becomes more beneficial to the species, but that is not what happens. Instead, these differences continue to exist. In order to answer this question, scientists studied fish of the same species that varied in color, a darker fish and a gold fish, with the gold color being dominant but the darker color more common. They placed the fish on both dark and light surfaces and recorded changes in the shade of their color. The results of their experiment were that the darker fish could alter its color to better fit its environment while the gold colored fish could not. This shows that differences in the ability to change colors to match environments could be an important way that color frequencies are created and maintained in the wild.
This article relates to our curriculum because natural selection and evolution are two main points in our current unit, and it is about the study of evolution of color in animals and why natural selection does not appear to occur in some populations.
Sunday, January 11, 2015
Evolution in the human body
http://www.sciencedaily.com/releases/2014/12/141211141833.htm
This article talks about how studies of many primate species (including humans) has shown us how we have evolved to fight infectious bacteria in the bloodstream. The bacteria feeds off of the iron in the bloodstream. It talks about how scientists have only been aware of nutritional immunity for 40 years, but over the past 40 million years of primate evolution, this battle for iron between bacteria and primates has been a determining factor in our survival as a species. The human body has evolved to have a runny nose, sneeze, become inflamed in order to rid the body of the bacteria. The body also does a variety of things under the skin to fight the bacteria it can "starve the bacteria out" by hiding the circulating iron. The article also talks about how the harmful pathogen has also evolved, and in certain cases can find where the iron is being hidden and take it causing diseases such as meningitis, gonorrhea, and sepsis. The main point of the article is that evolution is constant and continues to happen in the body over generations as pathogen and host evolve to fight off the other one, and by observing these changes over time scientists can take successful things that have happened and apply them to different situations.
This article talks about how studies of many primate species (including humans) has shown us how we have evolved to fight infectious bacteria in the bloodstream. The bacteria feeds off of the iron in the bloodstream. It talks about how scientists have only been aware of nutritional immunity for 40 years, but over the past 40 million years of primate evolution, this battle for iron between bacteria and primates has been a determining factor in our survival as a species. The human body has evolved to have a runny nose, sneeze, become inflamed in order to rid the body of the bacteria. The body also does a variety of things under the skin to fight the bacteria it can "starve the bacteria out" by hiding the circulating iron. The article also talks about how the harmful pathogen has also evolved, and in certain cases can find where the iron is being hidden and take it causing diseases such as meningitis, gonorrhea, and sepsis. The main point of the article is that evolution is constant and continues to happen in the body over generations as pathogen and host evolve to fight off the other one, and by observing these changes over time scientists can take successful things that have happened and apply them to different situations.
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