miércoles, 28 de abril de 2010

Insect Survival

In studying evolutionary adaptations of insects, one interesting example is the corn borer Ostrinia nubilalis, or a worm that makes a living off of human grown corn. During the growing season, the worm spends its time towards the top of the stalk while feeding on the corn. However, when the corn is ready to be havested, the worm makes its way down the stalk before spinning its cocoon for the winter. The depth that it descends down the stalk often exactly parallels the height at which the stalk is cut by the farmer for harvest. Its close neighbor, whom scientists recently thought were the same species lives on non harvested crops and displays almost all of the same habits except for the descent down the stalk. Scientists speculate that the evolutionary pressures of harvesting have perpetuated a population that descended farther and farther down the stalk of corn.

Zach Ming


The Humans Are Coming: Adapt or Die

Maybe we don't give caterpillars enough credit...

The Ostrinia nubilalis and Ostrinia scapulalis are two very closely related species of pest caterpillars that only differ in their host plant. While Ostrinia nubilalis, which is commonly called the corn borer, "spends spring and summer feeding on its corn stalk before spinning a cocoon for the cold winter," the Ostrinia scapulalis has the same life cycle except it feeds on a weed known as mugwort. Up until recently these two caterpillars were classified as the same species, because the particular host plant seemed unimportant to scientists. After closer observation, however, scientists realized that the cultivation of corn has created a distinct difference between these two species. While mugwort is never harvested or grazed, corn stalks are cut down leaving only about 6 inches of the stalk in the ground. The harvested stalks are then burned or fed to livestock once the corn has been removed, either of which leads to the certain death of any caterpillar cocoons attached to the harvested stalk. The corn borer, however, has adapted in order to survive the harvest by climbing down the stalk before it spins its cocoon.

This example of evolution was very successful and occured fairly quickly relative to the evolutionary time scale, because of the fast turnover of generations (one each year) and the lack of contamination of the sample. There was no worry of a caterpillar who did not move down the stalk before spinning its cocoon of passing on its genes, because it would die before it got the chance. I also found this example interesting, because nature has almost given us a control with the Ostrinia scapulalis, which have not developed the same "descending behavior, called geotaxis," because it has no evolutionary advantage since mugwort is not cut down. This clearly shows evolution at work.

Darwin certainly wouldn't have taken these caterpillars for granted.

Full Article: http://www.nytimes.com/2010/04/27/science/27obborer.html

Darwin Rocks.


Darwinists, Moral Relativism, and Hitler

Hi everyone,

I was interested in looking at the arguments against evolution today, so I decided to pay a visit to the Discovery Institute ( www.discovery.org ). One of the first articles I found there was titled "Darwinists, Moral Relativism, and Hitler." The author recently had attended a Darwin convention in southern California, and was "appalled" by the claims of a few of the speakers that our morals are shaped by evolution rather than an objective moral standard. One philosophy major he sat next to told him that Hitler was not really right nor wrong, since it is all in the eye of the beholder. The author took this further, saying that any Darwinist could not really blame Hitler since he was just trying to help evolution along by cleaning up the gene pool. He also suggested reading both of his books on Darwin and Hitler: "Hitler’s Ethic: The Nazi Pursuit of Evolutionary Progress," and "From Darwin to Hitler: Evolutionary Ethics, Eugenics, and Racism in Germany."

While I disagree strongly on the connection between Darwinism and eugenics, I thought the author did bring up some interesting points on morality that many people struggle with. Do we have morals only to more effectively populate the earth? Or have we as an advanced society developed an objective moral code that is more interested in protecting the quality of life of our species? And, does it matter?


Darwin's Falkland Islands Fox

Hey everybody,

Remember when Darwin visited the Falkland Islands, and he noted a "wolf-like fox" as the only large native quadruped? It was about the size of a coyote, peculiar to the island, and apparently very tame, to the point of going into gauchos' tents at night to steal meat. Darwin thought that the tameness indicated that they had been brought over as pets when humans travelled to the island, and before leaving, predicted (correctly) its imminent extinction because it was so easy to kill (and then facilitated the process, of course, by taking samples). Recently, researchers at UCLA have looked at mitochondrial DNA from these samples and other samples, and determined that it was indeed a separate species, its closest relatives being South American canids. But it wasn't brought over by people, because the 5 samples they looked at had a common ancestor (one that was already speciated into their current form) 70,000 years ago, and people didn't even arrive in the New World until 13,000 years ago. Furthermore, the South American canids that it shares an ancestor with (the "toaster-like" bush dog and the maned wolf) separated off about 6 million years ago-- which is before dogs even show up in South America (2.5 mya). So apparently the ancestors of all three species (and some other ones, incluing a Patagonian canid) evolved in North America and then migrated south. Somewhat annoyingly, though, no fossils that look like the Falklands fox-wolf lineage have been found in North America.
As to how it got to the Islands: since the Falkland Islands were never connected with South America, the researchers think it must have floated over from the mainland on an iceberg, surviving the journey and subsequent stay on seals, penguins, seabirds, etc.
Apparently Darwin's notebooks associate the wolves with some of his first thoughts on evolution, since he mentions them in conjunction with the Galapagos finches and his idea that species change over time.

Full articles:


Depression Helped Darwin Focus?

According to Jonah Lehrer of the New York Times Darwin may have been able to concentrate on his work because of depression. Darwin wrote about many ailments he faced "fits, flurries, air fatigues and head symptoms" but the real Darwin downer was not lactose intolerance or Chagas disease. He wrote to a psychiatrist that sometimes he would erupt in "hysterical crying" when Emma would leave him alone. He noted that the race to discover is for the strong and he would be forced to watch other great men make huge advances in science. However, Darwin also talked of his work as a salvation from his sour moods. He is even quoted as saying that "work is the only thing that makes life endurable for me".

From an evolutionary standpoint depression should be seen as a malfunction of the mind that would make it less inclined to function in society or leave offspring and would therefore be selected against. However, depression is very prevalent throughout human history. While most mental illnesses remain in less than 1% of the population, clinically diagnosed depression is like the common cold. How can something that makes you lose sleep, your appetite, and your libido still exist in so pervasively?

Like the fever helps the immune system, depression may have an unknown effect on either performance at a given task or protection against sudden crises, but up to this date, I know of no experiments on the purpose of depression. It is always assumed that depression is a bad thing that needs to be cured with drugs. In conclusion, would Darwin have written "The Origin of Species" if he was depressed?

Spencer Castro

New York Times

martes, 27 de abril de 2010

How Far Would You Go To Connect With Darwin?

At times throughout this quarter I have been amazed at the different windows of science that can all be accessed through the lens created by Charles Darwin. I’ve marveled at his contributions to the scientific fields of geology, evolution, psychology and the list goes on and on. However, this cerebral journey seems to be satisfying my need to learn about the man who revolutionized the way people think about science.

For some Darwin enthusiasts this journey of contemplation isn’t enough. Last year in honor of Darwin’s 150th birthday and the 100th anniversary of the publishing of his masterpiece On the Origin of Species a replica of the HMS Beagle set out to retrace Darwin’s footsteps. These Darwinians traveled 24,000 nautical miles in hopes of connecting with the great scientist. Their epic journey came to a close on Sunday in Cape Town, South Africa and I hope they got out of it a new appreciation for Darwin. Personally I think you can get more for you money if you read his works, listen to expert opinions and develop your own opinions. The beauty of this is that most of it can be done from the comfort of your own home and when you get the chance to travel, you can trust that Darwin will be everywhere you look.

Full Article: http://www.eturbonews.com/15698/darwins-hms-beagle-heads-cape-town

Darwin Rocks.


"Arrival of the Fittest?"

It has now been over 150 years since Charles Darwin´s influential work "The Origin of Species" first espoused the ideas of evolution by means of natural selection, or "survival of the fittest." But as scientists more closely examine the idea that these evolutionary changes happen slowly over time, many object. Many are finding that incredibly complicated changes happen not through gradual change over time, but through relatively simple changes in the genetic code that have extremely un-simple effects on the organism. This field, known as eco-devo, is gaining popularity among evolutionary scientists after largely being ignored for the better part of the last century. This has lead scientists to now believe that while changes in life on a broader scale are "gradual over time," most specific changes just simply "arrive."

One example of this come from a gene responsible for the growth of the beak of a finch. Scientists have shown that by simply activating the gene BMP4, the birds grow beaks up to twice as large as ones without. The gene is present in all types of finches, but is only activated in some types. Dr. Sean B. Carroll says that these discoveries really "blow people´s minds to know that changes once thought to be extremely complex can really be quite simple mutations." This may not be THE driving force in evolution, but it´s presence as a major one is definitely gaining credibility among many scientists who study evolution.

Zach Ming


Darwin's Earthworms

Who knew that earthworms are an invasive species in the Northeast? Darwin sure didn't. He did, however, find out that earthworms bring benefits to their native environments through soil turning, enhanced decomposition, and nutrient-rich castings. His experiment involved placing coal in the feild behind his home in London and watching it become covered in soil by earthworms over the course of two or three decades. This is according to a recent article in the Bennington Banner that describess how the earthworms Darwin came to appreciate are now affecting the Northeastern United States. Earthworms disappeared from the region during the last ice age and have slowly been migrating back, at a rate of five yards per year, or about a total of 28 miles in 12,000 years. They have been helped along in this migration by hapless fisherman. Other earthworm species have also been introduced by European colonizers. Since then, they have been churning up the soil and hurting native species, such as the red-backed salamaders. Their offspring need a thick duff layer and a good number of ground insects, both of which diminish with increased numbers of earthworms. The uninvited earthworms also help non-ntive plant species invade the area through their introduction of nutrients to the soil. Darwin was right in thinking that earthworms play a beneficial role in habitats, not just the role of a pest. He did, however, miss the invasive potential of these tiny earthmovers.



Evolution of Bats

Hi all,
So as you may have assumed, bats required a lot of special adaptations to reach their current state-- echolocation, low-density bones like birds, giant ears, etc etc. But scientists recently discovered that they also (like flying birds, but unlike flightless birds) have genes that improve their metabolic efficiency-- 23% of their genes for breaking down nutrients have been modified since their last common ancestor with other mammals. This was an important step in the process of going from energy-free gliding to highly energy-intensive flapping and sustained flight. Since we don't see bats in the fossil record until their current form, it's hard to tell which adaptations came first, but probably having the energy to control their flight was pretty essential early on.
Darwin apparently spent a lot of time considering the evolution of bats, so it's a good thing that people are working on it now from a genetic perspective.

Full article: http://www.wired.com/wiredscience/2010/04/bat-flight-evolution/


The Search for Genes

Sometimes genes can come from the most unexpected places. For instance, researchers at the University of Texas are now combatting tumor growth via blood vessel genes not from humans, but from yeast. In yeast, a particular group of five genes works on the task of creating cell walls. However, these genes are applicable beyond their normal function. Learning how to shut these genes down has also been shown to stunt blood vessel growth in humans, and thus tumor growth. This is not the first unique link that scientists have found relating certain functions of different species. For instance, genes associated with deafness have been found in plants, and genes associated with breast cancer have been found in worms.

These connections all come from an evolutionary idea called ¨homology,¨ or the idea that all forms of life share a common ancestor. As species have mutated over time, patches of genes have hung around and adapted their function in the organism. An obvious example of this would be the similarities between a bat´s wing and the human hand. However, less obvious examples like identical series of genes also comes from the same idea. Scientists can use these similarities in genes to work towards better understanding humans´genes by distantly related ancestors. Many, like drugs against tumors, have many real applications.

Zach Ming

a link to the full article http://www.nytimes.com/2010/04/27/science/27gene.html?hpw

Cannabalism and Survival of the Fittest

I´m sure when you were younger your mother sighed exasperatedly "that´s why some animals eat their young" but Marion Mehlis of the University of Bonn in Germany has proven that the three spined Stickleback makes very precise decisions when it comes to eating its offspring. Mehlis concluded that male Sticklebacks that guard the eggs after fertilization eat only the eggs that are fertilized by another male. Sticklebacks are notorious for "sneak fertilizations" but apparently the males have evolved a sense of whose eggs are whose. Researchers speculate that the fish must use some type of odor to determine his own eggs when the paternal genes are activated during development.

The study replaced different percentages of the clutches of male Sticklebacks, including 100% of the eggs, and every time, the male ate all the eggs that he did not fertilize. This goes back to the idea of fitness, in which an animal´s ability to produce more offspring and leave behind more of its genome is the ultimate goal. The fish would be wasting valuable energy and time raising offspring with another competitor´s genes. Darwin, of course, is the father of the "survival of the fittest.

Spencer Castro

New York Times

How Chimps Deal with Death

This Associated Press article reports on the recent death of a chimpanzee in a London wildlife park and the reaction of its relatives and friends. Many of the actions taken and emotions expressed are quite similar to those of humans, further showing our close relationships with these animals. Some examples of these similarities are:

-- Comforting the dying chimpanzee with physical contact such as grooming, especially in the last 10 minutes of the animal's life.
-- Immediately after death, the three chimpanzees surrounding her checked for signs of life by shaking her and opening her mouth.
-- Two of the chimpanzees left her immediately after death, while her daughter stayed with her throughout the night.
-- The surviving chimpanzees lost appetite and had little energy the next few days.

According to the article, it is quite rare to see this reaction as most chimpanzees leave to find cover and protection before death, and animals in zoos are usually separated from the others when sick. Thus, while the sample size is clearly very small, I found it interesting to see that other animals also have a strong emotional attachment with relatives and friends, and they show this in similar ways.

The full article along with some video can be found here: http://www.wtop.com/?nid=220&sid=1943277


Evolution: Debated Everywhere

I have always seen the debate in the United States between Evolutionists and Creationists as another one of the many battles between the Red and Blue States. My perception was that only the conservative, fundamentalist Christians were the driving force behind the Creationist movement and that it was only in states where these groups were a strong political force was the credibility of Evolution questioned. This article, however, drastically adjusted my perspective on the issue, because it was a school district in Weston, Connecticut that felt teaching 3rd, 4th and 5th graders about Evolution was too controversial. When I think of conservative strong holds in the U.S., Connecticut does not even enter my radar. What this proved to me is that Evolution is a controversial throughout the country and we cannot only think of this as an issue that only affects a few places. This also makes me think about the future of our country and how we should continue to move forward and create a more educated populace. To do this I think it is very important to educate the youth of this country about Charles Darwin and Evolution. I think disregarding this piece of history, because some people disagree with Evolution, is a great disservice to education, because even if a person disagrees with his findings, Charles Darwin changed the way people thought and that is a lesson that every child should be exposed to.

Full Article: http://www.thehour.com/story/485043

Darwin Rocks.


Making Darwin Accessible

Charles Darwin meticulously spelled out the Theory of Evolution in his most famous book, On the Origin of Species (1859). It was the first book on the subject of Evolution that presented the material in a clear and accessible manner that enabled not only scientists, but also the general educated populace to understand Evolution. 150 years later, however, Michael Keller and Nicolle Rager Fuller are helping to make Darwin’s masterpiece accessible to even more people by presenting the information in the form of a graphic novel. This medium is especially powerful for this book, because it was through seeing the world that Darwin was able to develop his Theory on Evolution. Presenting the material in this new and interesting way will help to bring Darwin’s research to the next generation and will hopefully inspire them through its words and images that Evolution is process by which the world has formed. It should also be noted that I stumbled upon this book, because of how well made it was, being recognized within the graphic novel community with a 2010 Eisner Award Nomination for Best Adaptation of Another Work.

Full Article about Eisner Awards: http://www.comic-con.org/cci/cci_eisners_10nom.php

Link to More Information about Charles Darwin´s On the Origin of Species: A Graphic Adaptation: http://www.amazon.com/Charles-Darwins-Origin-Species-Adaptation/dp/160529697X

Darwin Rocks.


The Window to the Soul

Charles Darwin’s research on the connection between the face and emotion was presented in, The Expression of the Emotions in Man and Animals (1872). This was a revolutionary concept, but at the time it was published it went relatively unnoticed and since then has been lost in history among his other marvelous contributions to science. Emotional expressions, however, have recently caught the attention of researches throughout the U.S. as they examine emotions with respect to people who have been born with facial paralysis. The interest begins, because leading studies have shown that facial mimicry is what allows people to interpret each other’s emotions, while a person with facial paralysis is not able to interact in this way. This explains why a person with facial paralysis would struggle interacting in the “normal” manner, because the people they are interacting with feel disconnected from them, because they cannot determine the person’s emotions. People with facial paralysis, however, are just as good as people without it at identifying emotions, which proves that there is some other mechanism that a person can use to identify emotions other than facial mimicry. Scientists hope to apply this discover to helping people who suffer from conditions such as autism, which make them unable to determine facial cues. Their thought process is that if they can figure out how to teach someone to use this other mechanism of identification of emotions, then they will be able to teach these people how to emotionally connect with the world.

Full Article: http://www.nytimes.com/2010/04/06/health/06mind.html

Darwin Rocks.

miércoles, 21 de abril de 2010

Orchid evolution

Hey everybody,

so you know those orchids that emit scents that mimic insect pheromones to attract pollinators? well, these two species of orchid in southern France have different flowers that attract different species of bees and trick them into pollinating with different mechanisms, but it turns out that some bees mess up the system and go to both flowers! wtf. furthermore, the hybrids that they produce don't produce a scent in between the two parent flowers', but rather one that attracts a THIRD species of bee, so if they weren't sterile, the system would be a big evolutionary speciating mess.
Full article: http://news.bbc.co.uk/2/hi/science/nature/8632814.stm


martes, 20 de abril de 2010

New Bat Species in Britain!

A country-wide study recently found a species of bat not previously thought to be present in Britain: Myotis alcathoe. They are very small ("the size of the end of a thumb") and are more commonly found in Greece and mainland Europe. They are migratory, but scientists thought they couldn't make it over the English Channel-- turns out they can. They had not been noticed before now because they look very similar to some of the other 16 species of bat found in England, which is not very surprising because it's hard to see what bats look like anyway.

Full article: http://news.bbc.co.uk/2/hi/uk_news/england/8632121.stm



Charles Darwin´s "The Origin of Species", first published in 1859, has been called the biggest single idea in the history of thought.

This is the story of how it came to written.

This is the opening of the film "Creation", which is going to be released to DVD June 16th. This film created quite a bit of controversy as it tackled Creationism and Evolution as opposing sides in a black and white battle of right and wrong. I watched this film online and took a few notes about interesting scenes. Also, there are a few interpretations/ artistic liscense abuses that give the movie its drama. However, this film brings Darwin back to the front of a mainstream audience. It had difficulties finding a distributor within the United States, but was eventually picked up by Newmarket Films, the same distributor that released "The Passion of the Christ" in the U.S.

If anybody would like to watch the movie, here is the link: