Manly Noses Versus Womanly Noses

Manly Noses Versus Womanly Noses

David Chen
16 January 2014

University of Iowa
Published: 18 Nov 2013
http://phys.org/news/2013-11-men-noses-bigger-women.html

Summary:
            Why are men's noses larger than female's noses? A recent study from the University of Iowa seems to answer this question. After puberty, the male nose grows, on average, 10% larger than female noses in European descent. Researchers now believe that the difference in size correlates with the energy demand of the gender. Larger noses supply more oxygen, and males generally have more lean muscle tissue to support and grow, so the energy demand is higher. During puberty, males gain about 10% more weight in muscle mass than females. This also shows why other ancient humans, such as Neanderthals, had extremely large noses. They had more muscle and energy demand than modern humans, so the noses grew larger as a result of directional selection. Although the studies were only for people of European descent and ancient Europeans like the Neanderthals, the lead researcher says other populations of different origins should hold true, as the muscle mass in males versus females stays about the same throughout all the races.

Connection:
            This article connects with the evolution unit that we learned. The reason why men's noses were bigger throughout history was because of directional selection, a form of natural selection in which a trait got more and more expressed in a population because of it's advantages. In ancient humans, the males with bigger noses could support their large muscle mass better than others with smaller noses, and probably had a survival advantage, as they could hunt better or provide straight forward man-strength. This also connects back to our units on mitochondria and cellular respiration, as larger muscle mass meant more mitochondria, which went more oxygen was needed to proceed with aerobic processes.

How Many Cheers for Cheerios?

Anna Kramer
Mr. Matheui
Period 2/Honors Bio
January 15, 2014

Source: New York Times
Link: http://www.nytimes.com/2014/01/08/opinion/bittman-how-many-cheers-for-cheerios.html?ref=geneticallymodifiedfood&_r=0

Author: Mark Bittman

Published: January 7, 2014

Summary

     This article talks about the new label that is going to be present on Cheerio boxes. The Cheerio company is going to be soon adding a "No GMOs" label. The question is, do they truly care or is this a marketing ploy? Mark Bittman believes that this change could be the start of something big. He believes that this is not at all a difficult task for Cheerios, it is simply up to finding new sources for their main ingredients, such as oats. So, a small task for what they are hoping to be a boost in sales. Their are not many cereals that have this label, giving Cheerios the bragging right if added to the box. Mark Bittman believes that this doesn't change the content of the Cheerios in anyway. This is significant because it will probably start a switch for many farmers over to the cheaper non-GMO seeds. The benefits for the GMO seeds are outweighed by their cost, and the farmers have been told that the GMO seeds are supposed to produce a larger crop yield and a smaller food cost, which has yet to be fully believed.
     The three problems Bittman outlines: GMOs have slowed down the process of containing weeds, bugs, etc. That is a problem that needs to be looked at in a different way, and eliminating GMOs won't do much in that process. The next issue, people constantly want to know what is being put in their food, but GMOs are not all that bad. The last issue, non-GMO foods are being looked at over organic foods, which take far more effort but require a different and separate label, if you have an organic label you can't have a non-GMO label, but people may start to only look for non-GMO, while organic is the true better option.

Connection
     This article connects to the section where we studied GMOs and their presence in many common foods. We watched a clip of a protest against GMOs, probably instances such as these have led customer pleasing products, such as Cheerios, to change their ways from GMO to non-GMO. A point that Mark Bittman makes is that GMOs are not all that bad, as we learned in class. In fact, we also learned in class that they can be very beneficial to farmers, but Bittman also argues this by saying there are only small benefits that may not be worth the price of the GMO products. Lastly, Bittman talks about how GMOs have slowed the process of weeds, bugs, and more which is another topic we studied in evolution. My assumption would be that GMO products have only slowed and not stopped the rampage of weeds and bugs because these organisms have started to reproduce from some individuals in their species that are resistant to the gene that is in the GMOs that are supposed to kill them off. So, the weeds and bugs will continue to adapt and reproduce, therefore GMOs will not the be answer to that very relevant issue in farming.

Dolphin Species Created Through Natural Hybridization

Thanoshi Balasuriya
Mr. Mathieu
Period 2

Author: unknown; Source: Wildlife Conservation Society
Published: January 9, 2014
Link: http://www.sciencedaily.com/releases/2014/01/140109003754.htm

Summary:
       According to authors from the Wildlife Conservation Society, the American Museum of Natural History's Sackler Institute for Comparative Genomics, the University of Lisbon, and other groups, the clymene dolphin species was developed through the process of natural hybridization. Hybridization is when members of two distinct species produce offspring that are a new species. This has been occurring naturally between dolphins and producing unique dolphin species. The clymene dolphin is a hybrid of the spinner and striped dolphins. Ana R. Amaral, lead author of the study and research associate at the American Museum of Natural History said, "This [study] also provides us with an excellent opportunity to better understand the mechanisms of evolution." Taxonomists used to believe that the clymene species was a subspecies of the spinner dolphin, but in 1981, it was established as a separate species. In the study, scientists took the mitochondrial and nuclear DNA from clymene, spinner, and striped dolphins. For data, they amplified 6 nuclear DNA markers and 1 mitochondrial DNA marker in order to see the evolutionary relationship between the three species. The nuclear genome was more alike to the spinner dolphin, and yet, the mitochondrial genome was more similar to the striped dolphin. Continued hybridization could be possible. 

Connection:
       This article connects to the unit of evolution, as the scientists want to use the data from the study, and the study itself in order to be able to have a deeper understanding of evolution. One way to test the evolutionary relationship between organisms is molecular, or genetic analysis. You can get the exact and specific data needed to see the clear relationships that a certain organism has with another organism. In their study, they examined the DNA of the dolphins to see the correlation between the clymene, spinner, and striped dolphins. We also have been doing DNA amplification in our own labs as they have done to study these dolphins, using PCR to amplify the extracted DNA and then visualizing it through Gel Electrophoresis. The concept of hybrids is something we have also discussed in class, when talking about how individuals from different species should not be able produce fertile offspring.          
   

Everett Han
Mr. Mathieu
Period 2

Michael Angelo Francisco
January 15, 2014
http://www.gmanetwork.com/news/story/343965/scitech/science/cats-and-dogs-had-a-common-ancestor-and-here-it-is

Summary:
 Recently, a fossil was found that is thought to be the ancestor of both dogs and cats. This name of this animal is "Dormaalocyon". This animal was estimated to be about a foot in length and about a kilogram in weight and preys on smaller animals and insects. Scientists found that 280 of the nearly 14,000 teeth specimens that they found in Dormaal’s soil belonged to the ancient tree mammal. Based of of these findings, the primitive teeth and the age of them place it very close to the carnivoraforms’ evolutionary roots. Anklebones that were found pointed out that the creature spent most of its time scurrying from tree to tree in the warm, humid woodlands of its time. It has been confirmed to be one of the earliest carnivores. This animal helped scientists figure out that there may have been an even earlier group than the carnivoraforms from whom they descended from. The Dormaalocyon  provides information concerning the evolution of placental mammals after the disappearance of the largest dinosaurs. Their study showed that carnivoraforms were very diversified at the earliest Eocene, which allows hypothesizing that they were probably already diversified during the latest Paleocene.

Connection:
This relates to what we are discussing in class because it says that both dogs and cats evolved from the same ancestor. It is important to know that this article informs people that many animals, including stereotypical enemies such as cats and dogs can be descendants of the same ancestor. This also relates to how we have talked about different time periods because it was mentioned in the article that the Dormaalocyon appeared after the era known as Paleocene-Eocene Thermal Maximum.

Ancient Legged Fish

Doran Teverovsky
Mr. Mathieu
Period 2

Michelle Lograta
January 15, 2013
http://www.gmanetwork.com/news/story/343973/scitech/science/ancient-legged-fish-provides-missing-link-in-limb-evolution

Summary:
   Recently, a new fossil has been found in Canada of a type of fish, about 375 million years old, that had legs, and could possibly walk on land and water. This nine foot long fish also provided challenging to classify because it blurred the line between crocodile and fish. While this fish, named the Tiktaalik roseae, had a similar rib cage and lung structure to a crocodile, it also had gills and scales leading scientists to name it as a fish. This fish has given scientist much more conclusive proof that rear appendages evolved in water then gradually went to land. The massive pelvis of this fish was what gave it away is a walker. The pelvis was open, and was shaped for legs and possibly even a fin as well.

Connection:
    This recent fish find relates to evolution, classification, and phylogeny. Before, we were guessing as to where legs evolved, with this fish, we can much more easily place mammals and fish on the same phylogeny because of this ancestor. Also, this connects to classifying organisms, and how difficult it can be for scientists. Because this animal had such crocidillian, and fish like characteristics, people had to pool all of there resources to decide what to call the animal. This animal is a great example of how one thong leads to another in evolution, and how the slightest advantage, by getting on land first, leads to adaptive radiation in the extreme.

Iconic Australasian Trees Found as Fossils in South America

Sophie Antonioli

Mr. Mathieu

Period 2

14 January 2014

Author: unknown

Published: January 9, 2014

Link: http://www.sciencedaily.com/releases/2014/01/140109132650.htm

Summary:

Scientist have recently discovered a tree fossil native to Australian in South America. The tree is known as Dammar in Australia and Kauri in Asia but does not have a name in South America due to the fact that it was not grown there unless planted. This specific tree is 52 million years old and the most intact fossilized one that they have found anywhere. The scientists are predicting that these trees grew in Patagonia when the supercontinent Gondwana was formed. Gondwana was made of Australia, South America, and Antarctica. It is also thought that the Agathis (another name for the tree) must have also grown on Antarctica because it was not all ice when Gondwana was composed. However, the trees much have died because of the extreme temperatures that later undertook Antarctica. So, the Agathis tree moved away from the cold south and towards northern Australia and spread to Asia. In Patagonia, they died out due to the seasonal dryness. The inconsistancy of water availability made it hard for them to survive.

Connection:

In this unit, we learned about continental drift and adaptation. Continental drift plays a huge role in this discovery. We know that the tree was able to be on all three of these continents (South America, Australia and Asia) because the continents were once connected. Without this connection, if Gondwana was never formed, the Agathis tree would not be present in all these places because of geographic isolation. It is also important to notice that as Antarctica began to freeze, the trees were dying and natually migrated north, toward the equator where they could survive in the hot and wet environments. 

Parents don't approve of your boyfriend? Blame evolution

Evolution and Bad Boyfriends:
http://www.nytimes.com/2013/10/13/opinion/sunday/evolution-and-bad-boyfriends.html?_r=0

By: Piet van den Berg and Tim W. Fawcett
Published October 11, 2013

Summary:
Studies have shown that all over the world parents and children hardly agree on a suitable partner in life. When behavioral characteristics are shared throughout most of humanity it implies that the cause might be because of evolution. A simulation was designed and ran explaining how it is possible for evolution to lead to such an uncomfortable parent-child confrontation. Parents want as many grandchildren as possible, and to do so they split their available resources between their children equally so the most possible number of surviving grandchildren are produced. However, the children would care more about producing their own offspring than their siblings producing offspring, so they would try to gain as much resources as possible from their parents. In the study, a computer simulated model was built with a large number of males and females in a population. The males were given certain degrees of ability to provide resources for their children and the females were given a variable amount of preference for this quality in men. The model was ran with offspring inheriting resource providing abilities and preferences from their parents, with possible mutations. The parents of the female was allowed to have an opinion on her mate, and they were also allowed to distribute resources to their children. Over many generations, parents were found to invest more in children who had a mate who could not provide many resources so as to help her produce s many offspring as her sisters whose mates could provide more resources. The daughters would start to use this factor by choosing a less supportive mate to receive the help from their parents. This lowered the standards of the daughters, but raised the standards of the parents.

Connection:
This study connects to what we learned in class about evolution and the inheritance of traits. Although we did not study sexual selection, the concept is similar to natural selection: survival of the fittest. In sexual selection, males who were able to reproduce more because of certain characteristics were able to pass these down to many offspring and so on. In natural selection, if the organism had a trait that benefited them in their environment and further allowed them to grow and reproduced, their offspring would inherit these traits. This article shows how evolution cannot only lead to strange physical features of an animal, but also strange behavioral features in a human.

Tiktaalik, the missing link from water to land

Tiktaalik: Iconic fossil's rear parts described

author: Jonathan Amos

source: http://www.bbc.co.uk/news/science-environment-25713538

Summary: A now extinct fish that lived around 375 million years ago, which is called the Tiktaalik, is thought to be a species that most land mammals descend from. This fossil provides lots of insight into life's move from the water onto the land. Although the discovery of this species is not very new until, it was first discovered in Canada in 2004, now only the front parts of the fossil have been found. Recently, however, new fossils have been found that have the rear section still intact. The most interesting of this back half to look at are the tail fins and the pelvic bone because they show how the Tiktaalik propelled itself through the water. Although its appearance looked fishy because of its scales and fins much of its body resembles the land mammals to come after it. Its flat head and shoulders, its forearms, and wrist bones all show this relationship. The Tiktaalik was recently discovered to have two strong back fins that helped propel this organism along with its front fins. The scientists that discovered this species even speculated that it is possible that the Tiktaalik used these to push itself along a shallow bottom of a body of water or even to quickly move to another water course. It is easy to see how these fins may have developed into legs however the scientists say that this fish is by no means built to live on land because its sensory system, hunting and breathing all are reliant on the water. However this species does show an important connection between the land and the water

connection: This species connects to a lot of what we were learning about in class. This is a great example of evolution because it shows how an example of an organism could adapt to living on the land. This also shows homologous structures that have formed between the Tiktaalik and  many four legged mammals today. Finally this new discovery shows how species could adapt to a new niche because this species is going from the water to a new niche as an animal that lives on the land

Scientists Unlock Evolution of Cholera, Identify Strain Responsible for Early Pandemics that Killed Millions

Jonathan Liu
January 14th, 2014

Published: January 9th, 2014

URL: http://www.sciencedaily.com/releases/2014/01/140109003802.htm

Summary: Researchers at McMaster University and the University of Sydney discovered early strains of cholera in samples of preserved intestines that were in a medical-history museum. Cholera is a deadly water-borne pathogen that has caused the deaths of millions over the past couple hundred years. Researchers have now mapped the entire genome of the pathogen, hoping to be able to understand it more now that they have the complete genome. They nicknamed the early strain as the "classical" version, which they think has caused 5 of the 7 major outbreaks in the 1800s, which most likely came from the Bay of Bengal. Researchers hadn't been able to sequence early versions cholera before because cholera thrives in the instestines, and so skeletal remains have no traces of the pathogen. Then they stumbled onto the medical-history museum, which had preserved instestines that had the early cholera. Researchers think that by analyzing the early version, we will be able to better understand the current strain, called El Tor, better. The El Tor strain seems to have completely replaced the classical strain since the 1960s for reasons not known and was the cause of the outbreak in Haiti after the earthquake.

Relevance: One of the topics we studied this term was evolution. This article directly relates to evolution, as it discusses the evolution of the dangerous pathogen cholera. The classical strain and the El Tor strain are both strains of cholera, however they are different species, but they have the same ancestor. This also relates to our evolution topic as it talks about two different strains that have the same ancestor. Lastly, the article also talks about DNA and mapping the genome of the early strain, which relates to the earlier unit heredity and genetics that we did this term.

Human-Pathogen Coevolution

Helicobacter pylori strains that share ancestry with their human hosts are less likely to cause severe disease 

Author: Jef Akst

Source: http://www.the-scientist.com/?articles.view/articleNo/38845/title/Human-Pathogen-Coevolution/


Summary:

Helicobacter pylori is a bacterium that colonizes in the gut mucosa in nearly half the human population, causing gastric inflammation and sometimes stomach cancer. This is one of the second-leading causes of death by cancer in the world! The study of this bacterium shows that patients who contain this strain possess fewer severity of diseases compared to the distinct ancestor who had the bacterium in their body. Scientists and doctors say that this issue should be seen with both the host and microbe, or population and pathogen. After collecting samples from a Columbian Hospital with gastric cancer patients, doctors found out that the severity of the H. pylori is less severe compared to the distinct ancestors due to the evolutionary adaptation and change of humans. The idea was that if one coevolved with the bacterium, the strain becomes les and less virulent.


Connection:

This article talks about the idea of evolution and how coevolution or convergent evolution is something species, including bacterium, undergo. In this article, it shows how the bacterium Helicobacter pylori underwent coevolution with humans in different environments, causing the severity of its affects to be dampened. Another connection to the evolution unit is the idea of adaptive radiation. Due to humans adapting in various environmental conditions, humans on the African coast had a less virulent strain of the bacterium similar to humans living in the mountains. As a result, the bacterium adapted and varied itself to the environment as it was in the host, causing the severity to decrease.

A Living Time Capsule Shows the Human Mark on Evolution

Sonali Deshpande
Mr. Mathieu
Period 2
Jan 14, 2014

Author: Carl Zimmer
Published: Jan 8, 2014
Article: http://www.nytimes.com/2014/01/09/science/a-living-time-capsule-shows-the-human-mark-on-evolution.html?module=ArrowsNav&contentCollection=Science&action=keypress&region=FixedLeft&pgtype=article

Summary:
     Scientists have found the South Center Lake in Lindstrom, Minnesota, from which they have been able to resurrect organisms that are up to 700 years old.This lake was chosen because its chemistry has been documented for decades, which makes it easier for scientists to observe how changes in pollution affect the organisms. The tiny shrimp-like creatures are known scientifically as Daphnia, or more commonly, as "water fleas." In the fall, some species of these produce heavily-cased eggs that fall to the bottom of the lake; some hatch in the spring, while some get buried under the sediment. Dr. Lawrence J. Weider, an evolutionary ecologist, had figured out how to coax these eggs to hatch in the mid 1990s. In 2009, to gather eggs to resurrect, his colleagues and he pushed a tube three feet into the sediment of the lake-- the oldest eggs he had resurrected were surprisingly 700 years old. To date the eggs, the scientists measured levels of the radioactive isotope lead-210, and are now confirming the dates with another isotope: carbon-14.  
     Then, scientists determined that in the late 1800s, there was a dramatic shift from a lack of phosphorous in the lake to an abundance of phosphorous. This was due to the fertilizer running off from new, local farms. Coincidentally, a previously rare strain of water fleas took over the lake as this increase in phosphorous occurred; because of the excess phosphorous, this particular species did not feel the need to waste their energy feeding on phosphorus. The resurrected fleas, however, did need to feed on it in their time because of the lack of phosphorous.
Connection:
This article connects to our unit on evolution. Lamarck had the idea that organisms adapt to their surrounding environments and niches, which is the case for the water fleas. When there was a lack of phosphorous, they saved it, and when there was an abundance, the water fleas simply disregarded it. This article also relates to Darwin's idea of  "survival of the fittest." Though this research has nothing to do with competition, it can be inferred from the article that the newer strain of water fleas was more biologically "fit" than the resurrected species. Since they had did not have to use their energy on saving phosphorous, they had more energy than the resurrected fleas to survive to reproductive age, and more importantly, leave offspring. Another topic we learnt, genetic drift, the change in a gene pool by chance, was demonstrated when another species of water fleas took over. Finally, the dating of the Daphnia eggs relates to the radiometric dating--measuring radioactive isotope levels--explained in Chapter 15. An isotope's half-life is the number of years it takes for 50 percent of the original sample to decay. Since the Daphnia are relatively young in terms of the geological time scale, scientists would not have to use radioactive isotopes with long half lives. As radiometric dating is used mainly for rocks and fossils, they probably measured the ages of the rocks around the eggs. The article also mentions carbon-dating, which was talked about in the book as a method of dating recent fossils.

Creating More Kernels By Genetic Modification

Harshul Shukla

Mr.Mathieu

Period 2

1/14/2014

Author: Unknown, Information provided by Cold Spring Harbor Laboratory

Publish Date: February 3rd 2013

Article URL : http://www.sciencedaily.com/releases/2013/02/130203145600.htm

Summary

Scientists at the Cold Spring Harbor Laboratory (CSHL), have hypothesized a way to create corn that will produce more seeds (kernels). Doctor Peter Bommert said that by increasing the size of the inflorescence meristem, a "stem-cell reservoir” , it would in turn allow more space for the kernels to develop. This would be by making changes the Fasciated Ear2(FEA2) gene. The lab would need to create a weaker version of Fea2 which would  in turn allow the the maristem to enlarge and create more space for more ears. More ears means more kernels created. In a test, the corn with the genetic modification produced 13% more kernels than the more prevalent  Zea Mays corn crop that is used across America today. Next, the lab will try to cross breed some of the highest yielding genetically modified corn with this strand of the weakened FEA2 to create an even more efficient crop.

Connection

In this unit, we learned about genetically modified organisms. In this example, the corn is being genetically modified to have a larger yield of kernels, and in turn allow more food to be produced. If we did a GMO test on the corn from this new type of maize, much like the GMO lab we did in class, we would find GMO genes. Also, this would help humans sustain a larger population. We learned about this in chapter 14 from Thomas Robert Malthus and Charles Darwin. At our current state, we have a maximum population for how much food we can produce. If our population exceeds the number of people we are allowed by our food, there would be a struggle for existence. By developing techniques and technology to create more food, we are able to increase the population that our environment, Earth , can support without a widespread struggle for existence.

How Dogs Do the 'Dog Paddle': An Evolutionary Look at Swimming

Andrew Robbertz

January 14, 2014

Date of Publication: January 5, 2014

Article: http://www.sciencedaily.com/releases/2014/01/140105102502.htm

            Summary:Most teens and adults remember the time they learned how to swim and trying the silly looking doggie paddle. Scientist, Dr. Frank Fish, set out with his colleagues to understand how dogs themselves do the doggie paddle. Fish after mostly studying the swimming of marine mammals not has the opportunity to look at how many marine mammals have evolved from their walking terrestrial ancestors. For the study Fish used eight different dogs from six different species. They set out to a rehabilitation for horses, where they recorded the dogs swimming from one end to the other, in order to compare the swimming movements. When swimming the legs moved in the same style as a trot, with diagonal legs moving together, but at a faster pace when swimming. This means that many of the dogs use a basic function with slight modifications. Fish believed that many of the first ancestors of swimming mammals were uncoordinated, until eventually the limbs became more like paddles and the modern whales, dolphins, and porpoises. These dogs can be used as a model for precursors to early swimming mammals. Fish hopes to unravel the steps it took to form am mammal with complex swimming locomotion from a four legged terrestrial form.  

            Connection:This is relevant to our most recent unit on the evolution of life. IN this unit we talked about homologous structures. Both Marine mammals and dogs share homologous structures that point to them having shared a common ancestor. Watching the dog’s clumsy swim provided Fish with an idea of how the four legged land mammals came to be the marine mammals that they are today. This is also an example of divergent evolution, where the single common ancestor broke into multiple new species. We believe that the origins of wales came from hippopotamus related species, but now we can more accurately determine how the limbs made for walking turned into paddles and fins.

Dogs originated from wolves domesticated in Europe, 19,000-32,000 years ag

Dogs originated from wolves domesticated in Europe, 19,000-32,000 years ago: researchers

Author: Malcolm Ritter (AP)

Source: http://life.nationalpost.com/2013/11/14/dogs-originated-from-wolves-domesticated-in-europe-19000-32000-years-ago-researchers/

Summary: 

Scientists have been wondering where dogs have originated for years. Evidence from Europe suggests that fossils of bones show that the domestic dog originated and was first domesticated in Europe. A large DNA study is lining up with the discovered fossils suggesting that dogs originated in Europe some 19,000 to 32,000 years ago. Scientists agree that dogs emerged from wolves to become the first domesticated animal, and after a long time surrounded by human environment (garbage dumps and carcasses left by human hunters), becoming tamer. Scientists believe that people found them useful for hunting and guard duty. The latest attempt to figure out where this domestication happened was published Thursday by the journal Science.

Researchers gathered DNA from fossils of 18 ancient wolf- life and dog- like creatures that lived up to 36,000 years ago in Argentina, Belgium, Germany, Russia, Switzerland and the United States. Scientists compared the genetic material to modern samples from 49 wolves from North America, Asia, Europe, and the Middle East, and 77 dogs of a wide variety of breeds. The DNA of modern dogs showed similarities to the genetic material from ancient European specimens and modern day European wolves. Robert Wayne of UCLA said that the kind of wolf that gave rise to dogs is now extinct, by that they could conclude that Europe played a major role in the domestication process. However, this doesn't mean that this is the only place dogs were introduced, by it presents a strong argument for an origin in Europe.

Connection: 

This connects to our past chapter because it involves artificial selection, using human desired traits and years of evolution to domesticate wolves into dogs. Archaeology and fossils play a large part in determining whether the discovered specimens share homologous structures. The similarities in homologous structures of fossils in different areas. Genetics played a part as well, since over time a subspecies appeared due to artificial selection, prompting the split of domesticated dogs and wolves.

Natural Hybridization Produced Dolphin Species

Shaina Sikka

Mr. Mathieu

Period 2

January 14th, 2014

Author: Unknown. Materials provided by Wildlife Conservation Society

Published: January 9th, 2014

Article URL: http://www.sciencedaily.com/releases/2014/01/140109003754.htm

Summary:
Found in the Atlantic Ocean, the Clymene Dolphin is a sleek marine mammal that can grow up to seven feet in length. The mammal was originally thought to be a subspecies of the Spinner Dolphin, but through genetic analysis, the Clymene Dolphin was found to be a fertile natural hybridization of two closely related dolphin species, the Striped Dolphin and the Spinner Dolphin. It is the first documented result of natural hybridization in marine mammals. To find proof that the Clymene originated from the spinner and striped dolphins, the American Museum of Natural History’s Sackler Institute for Comparative Genomics examined the nuclear and mitochondrial DNA from skin samples from both free-ranging and dead dolphins of all three species. The researchers chose certain markers in both DNA samples to analyze the evolutionary relationship between the Clymene dolphin and its closest relatives. The results showed that the mitochondrial genome of the Clymene Dolphin was closest to the Striped Dolphin, while the nuclear genome resembled the Spinner Dolphin. Therefore, the occurrence is best described as natural hybridization. Researchers say that more hybrids may form, yet at low levels, however this occurrence will be an opportunity to extend the understanding of the mechanisms of evolution.

Connection: 
This article relates to our study on evolution. In lesson 15.1, we learned that species are populations whose members have the ability to breed with one another and produce fertile offspring, and that members of one species cannot successfully interbreed with members of another species. The natural hybridization of the two related dolphin species is an exception to definition of species. We know that different species are unable to produce fertile offspring, if any. Yet, in this case two closely related dolphin species did so. In addition, in lessons 14.2 and 15.4 we learned that molecular biology can be used to study the relationships between species. The more genes and protein sequences match up, the more closely related the species are. This article uses the method of molecular biology to determine the relatedness of the three dolphins species by sequencing and comparing their mitochondrial and nuclear genomes.

Discovery of New Tiktaalik Roseae Fossils Reveals Key Link in Evolution of Hind Limbs

Ronak Shah
1/14/14
http://www.sciencedaily.com/releases/2014/01/140113154211.htm
Author: University of Chicago Medical Center
Published: Jan 13 2014

Summary:
Recently the back part of the Tikaalik Roseae was discovered. The Tikaalik Roseae is a fish that resembles a fish/crocodile mix which is 325 million years old. After this back part of the body, scientists found what is the transitional species between fish and the first legged animals. A good analogy would be going from a 2 wheel drive in fish to a 4 wheel drive on land. A pelvic bone of the fish's was for the first time discovered along with "enhanced hind fins" that seem very similar to the first hind legs. The pelvis is the most interesting part. It is comparable to the pelvis of the first tetrapods and has, like them, a ball and hip socket. It was nearly identical size. Though no hind legs were  found the hind limbs were just as complex and strong as the animals fore fins. Scientists say it is clearly possible the fish used the hind fins to walk on the ocean floor. This fish also contains a primitive form of a lung, though scientists think it was not used. It is a great step in understanding how the first sea based eukaryptes, started to walk.

Connection:
This article connects to our most recent unit on evolution. We learned about how natural selection makes it so only the organisms in a population best suited to survive pass down more gametes that those who don't. We also learned that if their is an open niche in the environment, it is common for an organism to evolve until it can fill that niche and get all resources and food that come with it. This relates to the article because if the hind limbs of the Tikaalik Roseae's ancestors allowed to walk on the ocean floor and get food, it would have been the best allele constantly getting stronger and more common and soon after, becoming strong enough to walk out onto the land and fill that niche.
















Citation:
University of Chicago Medical Center. "Discovery of new Tiktaalik roseae fossils reveals key link in evolution of 
hind limbs." ScienceDaily, 13 Jan. 2014. Web. 14 Jan. 2014.

New Fossils Shed Light On the Origins of Lions, Tigers, and Bears

Jessica Lim
Mr. Mathieu
Period 2
January 14, 2014

No Author given
Published: January 6, 2014
Article: http://www.sciencedaily.com/releases/2014/01/140106160029.htm

Summary:   
     At the Belgian locality of Dormaal, new fossils of the species Dormaalocyon was discovered and it is said to be very close to the common ancestor of carnivoraformes; modern mammals. Scientists were able to infer that since it had ankle bones it moved around on trees and lived in them. This species was known to have over 250 teeth. Scientists were able to infer that it was "close to the origin of carnivoraforms" because when they inspected the baby teeth of the species, they were able to tell the scientists that it was from a very early time period.
     When they recreated the environment 55 million years ago, the environment turned out to be really warm and humid because it was after the Paleocene-Eocene Thermal Maximum, and the evolution of the carnivoraformes and many other species were affected by this. This fossil also shows that there are even more primary species that once lived in an earlier time period.

Connection:   
     This connects to our unit on evolution. We learned about how when there is a change in the environment, through natural selection, those that inherited the most suitable characteristics to survive and reproduce, evolved and adapted to the new environment. We also learned that through either reproductive isolation or geographical isolation, speciation occurs and therefore one species can diverge into multiple species. Connecting to the article, the common ancestor of carnivoraformes eventually diverged into multiple species that we see today, for example cats, dogs, bears, and seals.

Tiktaalik roseae fossil analysis provides new details on the origin of vertebrate legs

Isabelle Terranova


Author: University of Chicago- Medical Center
Source: http://phys.org/news/2014-01-discovery-tiktaalik-roseae-fossils-reveals.html
Published: January 13, 2014


Summary:

A group of scientists have discovered that the evolution of hind legs actually started as enhanced fins. This contradicts the theory that large, hind limbs were developed after vertebrates made the transition onto land. The scientists discovered that the transitional species discovered a decade ago, Tiktaalik roseae, actually had large hind limbs when they put together the back end of a prehistoric fossil. The fossil had a large hind fin which was previously believed to be a small appendage. Researchers believe that this fin was capable of walking on underwater surfaces, as well as propelling the fish through the water. The fossil showed that the fish had a large pelvic bone the size of it's shoulder. The pelvic bone is used to support the hind limbs, the fact that it was so large shows that the hind limbs were also large. This is a characteristic of early tetrapods; this relationship allows scientist to believe that the development of hind limbs started much earlier than they previously believed. They conclude that the fish were possibly able to walk before they made the transition onto land, and then the hind limbs were simply exaggerated as it made the transition to a tetrapod. 

Connection: 

In chapters 14 and 15 we discussed evolution. The discovery made was a turning point and changed what scientists believe about evolutionary history. The discovery of a pelvic bone and hind limbs in the Tiktaalik roseae are homologous structures to those of early tetrapods. This is a term that we discussed in class. It means that they are similar structures found in differnet species that came from the same ancestor. The fins on the fish  turned into the hind limbs of the tetrapods; this made the tetrapods better adapted to land. We also discussed the how scientists use the fossil records to determine when certain evolutionary changes and adaptations occurred. The scientists who discovered the fossil put it back together and analyzed it. When they found the fin and hind limb, they were able to adjust their theory; the fossils also helped them date the species back to 375 million years ago, right before when tetrapods would have been emerging. This also ties back to the scientific method in a way because they came up with an idea, found evidence and discovered something new. The article is very interesting and provides many ways in which our units tie back to real life discoveries. 

Overweight? Maybe You Really Can Blame Your Genes

Madhuri Raman
Mr. Mathieu
Period 2
January 14th, 2014

Author: Gina Kolata
Published: July 18th, 2013
Article: http://www.nytimes.com/2013/07/19/health/overweight-maybe-you-really-can-blame-your-metabolism.html?smid=pl-share

Summary
This article is about the discovery of a gene called MRAP2 that controls weight gain and how quickly calories are burned. It is a helper gene, sending signals from the brain to another gene that control's an individual's appetite. However, there are rare mutations of this gene that cause it to get "turned off" and leads to the organism gaining a lot of weight, even while on a normal diet. In one experiment, scientists kept two groups of mice on the same diet in order to compare their weights at the end of a given period of time. The first group of mice had the gene for the control of weight gain removed from their cells, but the other group of mice still possessed the gene. The scientists found that the group without the gene was getting fat, while the other group was not. This led them to believe that the presence of the MRAP2 gene determines a person's general weight, much more than the person's diet. Other researchers conducted a similar experiment in which they found that children without the gene gained weight, but still had normal appetites. But once the children matured into adults, their appetites grew tremendously. Now the question is, is this the cause of obesity?

Connection
This article directly relates to our studies of Heredity and Molecular Genetics throughout Term 2. In class, we learned a lot about inherited traits, and the article discusses how obesity and weight gain are a result of genes that have been passed down from generation to generation, not poor dietary habits. We also learned about the dangers that one could possibly face from having a gene mutation, although mutations are not always harmful. The rare mutation of the MRAP2 gene explained in the article is an excellent example of that. It was most probably the factor that has led to many cases of obesity in children, one of whom has already been found to have the mutation. All in all, the discovery of the gene controlling weight gain is important in understanding the actual causes of obesity.

Ancient fossil found in Canadian Arctic shows evolution from fins to feet: scientists

Author: Margaret Munro

Source: http://news.nationalpost.com/2014/01/14/ancient-fossil-found-in-canadian-arctic-shows-evolution-from-fins-to-feet-scientists/

Published: Jan. 14, 2014

Summary:

A 375-million-year old fish,  known as Tiktaalik roseae. uncovered in the Canadian Arctic a decade ago continues to provide information to evolutionary biologists. Scientists reported Monday that the back end of this extinct fish has helped to reveal a large factor in the evolution of fins to feet. Tiktaalik had sturdy, mobile hind fins that it may have used to walk on as it slithered around shallow water and mudflats, say paleontologists. Scientists also say Tiktaalik’s large pelvic bones indicate the evolution of four legged locomotion occurred less recently then we initially suspected. “It looks like this shift actually began to happen in fish, not in limbed animals,” the team leader Neil Shubin said in a summary of the findings. Along with these recent finding scientist have made many ground breaking observations when studying this particular fossil. It is not til just recently they have been studying the hind section of the fossil, but prior to this particular observation scientists have made many key observations about the organisms front half. Both its head which seems to be a cross between a crocodile and fish, and its large pelvic bones this organism is an important example of the shift from fish to tetrapods.

Connection: This connects to chapters 14 and 15 in our textbook which are about evolution. We talked a lot about how the reason after a mass extinction the remaining organisms thrived due to increased opportunities. The reason the first fish moving to land was a beneficial trait was because similar to after a mass extinction the land was full of new opportunities, so the fish that could obtain more and more of these resources had a distinct advantage over other members of their species which through natural selection (another topic of the chapters) there was a gradual shift towards certain fish becoming tetrapods.

Living On Islands Makes Animals Tamer

Carter Terranova

Author: University of California - Riverside
Source: http://www.sciencedaily.com/releases/2014/01/140110103720.htm
Published: Jan. 10, 2014

Summary: 

One of Darwin's ideas while he was on the HMS Beagle on an expedition around the world, was that organisms "evolve to lose structures, functions, and behaviors they no longer needed when environmental circumstances changed." He also noticed that island organisms acted more tame, which he believed was because they adapted to having less predators around them. Researchers from University of California - Riverside, Indiana University, Purdue University - Fort Wayne, and George Washington University concluded that island lizards are, in fact, tamer than mainland lizards. To conclude this, the researchers analyzed the flight initiation distances (the distance between the predator and the prey before the prey starts to flee) of island lizards and mainland lizards from around the world. The results show that the farther the island is from the mainland, the more tame the lizards are, and the flight initiation distance is reduced because there are less to no predators to flee from. Results also show that predator approach speed is important, as well as the size of the prey relative to the predator. If the prey is small, the predator will not attack that individual prey, resulting in a very small to no flight initiation distance.

Connection:

The connection from this article is to the evolution unit. In that unit we learned about natural selection. Natural selection on remote islands will favor animals with reduced flight initiation distances because there is no reason for animals to waste the time and energy on an unneeded escape from predators that are scarce or nonexistent on the island. The lizards will not go through natural selection of large flight initiation distances if that will not be something that helps the lizards survive and reproduce. This study also is important because it proves that Darwin's observation of animals being tamer on islands is true. Though the lizards and other animals are losing their extended flight initiation distance, they are still adapting and changing to better suit themselves in their new environment with few to no predators, rather than like animals living on the mainland who are adapting and changing to better suit themselves living with predators (natural selection).

A Living Time Capsule Shows the Human Mark on Evolution

Gabriella Ricciardone
January 13, 2014

Author: Carl Zimmer
Published: January 8, 2014
http://www.nytimes.com/2014/01/09/science/a-living-time-capsule-shows-the-human-mark-on-evolution.html?_r=1

Summary:

        In South Center Lake in the small town of Lindstrom, Minnesota, scientists have made a remarkable discovery by reviving Daphnia, shrimp-like animals more often known as water fleas.  Each fall, the Daphnia reproduce by laying eggs with tough cases, which then float to the bottom of the lake.  In the spring, many produce new water fleas, but some remain under the sediment, and do not hatch.  In 2009, Dr. Lawrence J. Weider, an evolutionary ecologist, and his team set out to dig up Daphnia eggs in lakes in Minnesota, expecting to find eggs a few decades old, reproducing research he had done in the mid-1990s in Germany.  They had figured out how to coax the eggs into hatching as well, and planned to do this again.  Once they successfully hatched the eggs they dug up in South Center Lake, they ran a DNA extraction, which determined that the eggs were approximately 700 years old.  Dr. Weider and his team also estimated the ages of the sediment to support their findings, and they did this by measuring levels of the radioactive isotope lead-210 and then confirming the results by measuring another isotope, carbon-14.   The paper documenting their discovery was published on January 8, 2014.

        The creatures the team found had been at the bottom of South Center Lake for an estimated 700 years, buried under sediment, which luckily had preserved these centuries-old specimens.  The resurrected water fleas provide insight to the changes that this lake has been through over the past several hundred years.  The scientists found that, about a century ago, a major evolutionary jump occurred, around the time when Europeans started to change the land they were settling on.  Previously for centuries, phosphorus was a scarcely found element in the lake, and the Daphnia had adapted and learned to feed on the phosphorus and hold onto it for days.  But around the late 1800s, the Europeans began using fertilizer on their farms, which dramatically increased the amounts of phosphorus in the area around them.  This affected the Daphnia population in the South Center Lake, as these organisms began to stop relying on their ability to hold on to phosphorus because there were now high levels of it in the environment.  This discovery shows that humans are indeed influencing the evolution of wild species.

Connection:

        During our studies of Chapter 14 and Chapter 15, we discussed evolution and adaptations.  We have also repeatedly talked about how humans influence the environment, including how humans affect evolutionary patterns of other species.  This article discusses how early European settlers in the late 1800s affected the evolutionary path of the Daphnia, due to their farming methods and use of fertilizers containing phosphorus.  We have also learned about radioactive isotopes in Chapter 4 and the dating of specimens using isotopes in Chapter 15.  DNA extraction was discussed earlier in the term in Chapter 13.  The scientists mentioned in the article used DNA extraction to calculate the ages of the Daphnia specimens they found at the bottom of South Center Lake.