Welcome to the 2016-2017 school year.
As part of your AP Biology course, you’ll read, comment, and participate in a community moderated by me, your Biology teacher. This virtual community–which exists since early 2013–has a very important mission: the development of scientific literacy, via the proper use of the Internet.
Hydrothermal vents near the Galápagos, via Getty Images & NYT
Given that this is a blog for a Biology course, and this is the first blog post of the school year, I’ve decided to share with you the following New York Times article: Meet Luca, the Ancestor of All Living Things. A brief excerpt from the piece is posted below:
“Deep sea vents are surrounded by exotic life-forms and, with their extreme chemistry, have long seemed places where life might have originated. The 355 genes ascribable to Luca include some that metabolize hydrogen as a source of energy as well as a gene for an enzyme called reverse gyrase, found only in microbes that live at extremely high temperatures”
Classwork:
– Read the NYT article.
– Access your Edline page and read the rubric posted in the Assignment folder.
– Write your first intervention in this community (i.e. comment), following the guidelines of the aforementioned rubric .
The Hypertextual Lounge 
I find it very interesting and impressive how this organism is able to metabolize hydrogen to maintain its energy. As said in the article, LUCA uses this ability to be able to survive at extremely high temperatures, which is an example of homeostasis and its adaptation to stimuli.
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It’s impressive how organisms can adapt to the environment they live in. For example, we metabolize glucose because it is available for us in food. But where LUCA lived there was no glucose available so it learned to metabolize hydrogen which is very strange.
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Hopefully, we’ll be able to find something like LUCA in the subsurface ocean of Europa. I suggest you do a Google search of this galilean moon.
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LUCA is extremely impressive but just because it is the last universal ancestor does not mean that it was the first, right? They’re may have been many before it. Earth was already 560 million years old when LUCA emerged so the debate on where life began, whether it be in a normal setting or in an extreme environments is still viable in a way, regardless of LUCA and where and how it was ‘born’. Not to discredit anything in the article, just a thought.
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It is possible that life emerged on Earth more than once–meaning that extractions, massive ones, are unavoidable.
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The fact that Luca can metabolize hydrogen to use it as energy is amazing. Such a complex organism with 355 genes which have adapted it to live at extremely high temperatures and to use hydrogen as a source of energy. It gives us an amazing insight at how life was billions of years ago.
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Check out this image of the highly complez metabolic pathway of hydrothermal vents: https://upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Deep_sea_vent_chemistry_diagram.jpg/1024px-Deep_sea_vent_chemistry_diagram.jpg
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I find it very interesting how two well known scientists are refuting about LUCA being the first living organism. Both scientist make excellent points and have scientific facts to back them up. For example, LUCA metabolizes hydrogen to get the energy it needs just like the organs in other living things metabolize food to become energy, which proves the possibility of LUCA being an independent organism which takes advantage of it’s enviroment to carry out it’s own chemical processes to “stay alive”. However, Dr. Sutherland states that it would be impossible for life to begin in the depths of the ocean because sunlight is a very important part of living processes. Seeing how much evidence each of the professionals have to back up their opinions on the dispute, it makes it clear that they should spread these facts across the scientific community and finally come to a conclusion on the debate.
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All living things owe their life to LUCA, the way it evolved from a unicellular bacterium-like organism and for now to be the common ancestor for all living things is simply surprizing. For LUCA to have the ability of synthesizing proteins gives this organism an advantage; it means that it can give and translate information such as DNA. For organisms to emerge this factor is crucial because every aspect of life relies on proteins.
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The fact that Luca can live in such an extremely hot environment and metabolize hydrogen to use it as fuel is amazing to me. Such a complex organism with 355 genes, which have allowed it to have all of these traits. It also gives us an amazing insight at how life was billions of years ago.
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Since the beginning, people have questioned from were did life originated. This article suggest that LUCA is very close to the origin of life because it is missing genes important for life and it also relies on chemical components. It might be true, but take us for instance, don’t we need chemical components to live such as water, oxygen, and carbon? That is why I personally agree more with Dr. Sutherland, because he puts into perspective other scenarios and possibilities about how life not necessarily originated from deep sea vents. On the other hand, Dr. Martin has interesting facts but in my opinion it’s still missing. However, I do agree that there has to be a common ancestor. In the end, the universe is huge and the origin of life in my opinion will remain a mystery.
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I agree. The article, more than anything, is a good reflection on what science can do–it can update. And conflicting hypotheses–or theories–do not mean that the scientific method is less viable. I suggest you do a Google search on the nature of science. You’ll see cases like the LUCA arguments are common in all major natural sciences.
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According Dr. Sutherland in the article, life couldn’t have begun without the help of ultraviolet light from the sun. Therefore, he concluded that land-based pools, not the ocean, are the most likely environment in which life arose. However, I found this article about a study that proves that life originated at deep sea vents: https://www.whoi.edu/news-release/study-tests-theory-that-life-originated-at-deep-sea-vents
We can’t be 100% certain (at least for now) about which of these theories is correct, but
future technology and studies might help us better understand the origins of life.
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It would be interesting to see how geothermic LUCA hypotheses are doing in the next couple of decades. This is what actually allows for scientific explanations–theories, hypotheses–to flourish or perish: time. I’m inclined to back up Dr. Sutherland’s conventional hypothesis for the origin of life, but hydrothermal vent LUCA–especially after Europa’s plumes have observed–can gain acceptance in the next few decades, especially if we find life there.
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According to the article, by comparing the sequence of DNA letters, genes could be arranged into evolutionary family trees. This led to the finding of 355 genes that probably originated n Luca. It’s very interesting and fascinating that just by locating specific gene sequences, scientists could determine where and how an organism lived, in this case where Luca lived. This is due to the ability of a gene that adapts to an organisms environment.
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Amazing what a few monomers can tell us about life.
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The orgins of life are still uncertain. However according to this website: ” In order for life to have begun, there must have been a genetic molecule capable of passing along blueprints for making proteins, which are essential molecules of life.” This site states the theories that Dr. Sutherland conculded where the conditions in which life originated.
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The fact that metabolism can happen at such deep places, begs for further explanation. This is why hydrothermal LUCA hypotheses exist. A lot of compelling data out there. Because of this, we can be sure that the next few decades of the 21st will be an exiting time for biochemical and interdisciplinary research.
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LUCA is an amazing organism just because of the fact that it can maintain its energy by metabolizing hydrogen. It surprises me that so may years ago there was LUCA that could do all those things like synthesizing proteins and adapting to its environment really is simply amazing. It’s stated that it is “half alive” because it cannot live without its environment which shows us how important is the environment even though it is one with extreme temperatures. It also drew my attention that billions of years ago, that organism went through the same process that we go through now a days like homeostasis.
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“Life” is clearly defined in our AP Bio textbooks. But keep in mind that the global scientific community is made up of thousands of scientists that have different takes of what is actually “alive”. Our idea of “life” can be challenged in the next few decades. So I would think that a responsible scientists should be aware of emerging hypotheses such as the on described in the NYT article of this blog post.
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I found it really interesting how LUCA had the ability to metabolize hydrogen to use it as its source of energy, but this made me doubt if we really descended from it. Although I have my doubts if LUCA is our ancestor, I wouldn’t discard the possibility because in Dr. Martin’s data he did establish that LUCA could synthesize proteins, which is something very necessary for human life.
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This is why data is important. Yes, Dr Stherland’s data shows very compelling results, but data in Science is currency. So a lot more has to be gathered. Certainly, this is a very good fist step. These hypotheses can be combined with actual ones. Maybe both types of origins of life happened. But, to be sure of that, we need more data.
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It’s intersting how this singled-cell bacterium-like organism (LUCA) can be part of creating life for every single type of species. Also, I find it interesting and amazing how this organism can survive in completely opposite temperature and how it can adapt in both land and in water by learning to metabolize hydrogen. Overall, LUCA is a very interesting organism, but even known its the oldest life universal comon ancestor we have seen, its imposible that it was the first life creator. Technically he needs the help of other organisms in order for it to complete the life creating cycle. In my opinion, this fact makes LUCA not the organism that created life for the first time.
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I suggest you do research–a Google search should be fine–on another hyothesis for the origin of life, which has to do with nucleotides and complexity; the RNA world hypothesis.
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During the experimental process of deep sea vents and whether or not this was where life began, scientists thought they would find a lot of methanethiol in the place of origin. They thought this because methanethiol is essential to life. This organ sulfur compound found in blood and other parts of the body, is found in hydrogen-high environments. Scientists hypothesized that lots of methanethiol would be found in these deep sea vents. They believed it could have been a sort of “starter dough” for life to emerge. But what they found was surprising. Methanethiol is CH4S and therefore scientists believed they would find metyhanthiol where there were large amounts of hydrogen. But they found out,surprisingly, the opposite. Where there was a rich amount of hydrogen, there were few amounts of methanethiol and when there was a hydrogen-low environment they found large amounts of methanethiol. This not only changed the hypothesis and ideas of the deep sea vents but also changed what scientists knew about how methanethiol forms. Here is a link where you can find more information on studies and experiments about the origin of life in the deep sea vents: https://www.whoi.edu/news-release/study-tests-theory-that-life-originated-at-deep-sea-vents
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A 20 year hypothesis is not that much, considering that some theories are centuries old. A lot can happen in the next 20: either the LUCA hypothesis gains popularity in the scientific community, or the UV/surface pool hypothesis–along with the RNA world explanation–will gain more data. I suggest you do research on the Urey-Miller experiment, which suggests that the atmosphere had a central role to play in the origin of life.
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The discovery of Luca has further more supported the theory that life was created under extreme living conditions. I find it really interesting that with only 355 genes identified that originated Luca they could determine that this organism lived in an extreme envioronment, a deep sea vent, and also that it is able to metablolize hydrogen for a source of energy. Even though Luca may have nothing to do with the origin of life it is a very fascinating organism that has given scientists the opportunity to study and gain more information about organisms that live in extreme environments.
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It is possible that both events–surface polled water, UV, and LUCA–were responsible for the origin of life. One theory doesn’t necessarily outranks the other. But, as with all things scientific, one hypothesis could prove to be better the the other one. ANd it would not be the first nor the last time that this will happen in Science. Fortunately, this will keep happening–a healthy competition of ideas.
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It is amazing how life emerged from a single-cell organism, 4 billion years ago. And how a gene can adapt to the organism’s environment, making LUCA possible to metabolise hydrogen. One thing i find very interesting is that LUCA is missing so many genes necessary for life that it must still have been relying on chemical components from its environment. Also, the way he depended on hydrogen and metals, supports the idea that life originated from the deep sea vent, according to Dr. Martin. On the other hand, Dr. Sutherland said that LUCA came from meteorites and that it was impossible that life originated from the deep sea.
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Life finds its way. If the LUCA hypothesis does not explain the origin of life, it could nevertheless be very useful for astrobiologists trying to find life in our own Solar System — i.e. the Galilean moon, Europa.
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Even though LUCA seems to be a plausible ancestor to life on Earth, I am not convinced that life on Earth can be traced to a single type of organism in a specific environment because it would fundamentally lack an explanation on the current variety of life. There must have been many place that had the conditions for life to happen simultaneously for such a diverse amount of life that is accounted for in our planet. I genuinely believe that it is very likely that life on Earth, especially animal life, came from space due to the fact that if life started out as organisms that were autotrophs then there would have never been a need for them to evolve and become heterotrophs.
That being said, at least two simultaneous ways of life must have present to account for the ridiculous difference in the approach organism take to stay alive; one that depended on other organisms to survive, while another could survive on its own. Even though life might not have one specific ancestor, it is pretty obvious to why organisms would have similar genes because all organisms would essentially have to perform metabolism, protect themselves, and reproduce, which should cause them to create similar way to achieve those goals.
It is also important to consider animals such as the tardigrade, which can survive conditions that are not even present in our Earth. Why would any native specie of Earth need to survive conditions not present here? It could very well be the first animal and extraterrestrial to live on Earth and evolve into other species over time after natural selection deemed that its extreme survival capabilities were not necessary allowing it to take other forms of life over time.
Overall, I believe scientist shouldn’t be looking for one specific ancestor, but, instead, to look for various parallel settings that would have allowed for life to happen and transform into what it is today.
http://www.sciencealert.com/the-tardigrade-genome-has-been-sequenced-and-it-has-the-most-foreign-dna-of-any-animal
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The search for a common ancestor pretty much underlines the most important aspects of Biology–genetics, ecology, biochemical pathways, etc. In other words, I think that this aspect of biological research should not be abandoned. We know that all life has a common ancestor. That is a scientific fact. What we don’t know is how that ancestor came to be. I suggest you do a brief Google search of the Urey-Miller experiment. There you will see that complexity and evolution can be traced back to molecular settings.
Given the sheer amount of time, biological information, and almost infinite permutations of 20 amino acids–in addition to code of life; will see more of that during the second semester–the king of polymers, DNA, can give rise to the varieties of life we now have.
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I find it very impressive that Luca survives in such an extreme environment and that it metabolizes hydrogen in order to maintain its energy, but, I’m not convinced that it is the common ancestor of all living things. Life is too diverse to just have one common ancestor. I also don’t believe that all living things originated in one specific environment, because not all living things nowadays live in the same conditions. Even if Luca is a possible ancestor, it don’t believe it was the only one. There must have been many other places where life originated, and these ancestors might have shared some characteristics, but they must have had differences as well, just like all the living things nowadays have differences that make them unique from each other. Plus, as Dr. Sutherland stated, sunlight is a very important part of life, and it’s impossible for life to exist without it, which means that life might not have even orignated in the deep sea, where sunlight doesn’t reach. And there is also the possibility that Luca might not even be one of the ancestors of all living things, since the Earth was already 560 million years old when Luca emerged. So, all in all, I believe that maybe Luca isn’t even a part of the origin of life, but a piece of the puzzle to finding the true ancestor or ancestors of all living things, whether they came from outer space or originated here on Earth.
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The search for LUCA is more an exercise of Science that an actual search. It would be a huge deal if we could literally pin point the origin of all life, but at this moment, it remains a Holy Grail–probably impossible to find, but nevertheless necessary, because of the huge amount of information and results we have gotten from the research.
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I found impressive how a single-cell bacterium known as Luca, could survive and live four billion years ago in that extreme environment. Genes are adapted to an organism’s environment and this organism has 355 genes, meaning that Luca had to adapt to various environments. An example is that it had to metabolize hydrogen as a source of energy, amazing and it could help us of an idea if things get too extreme in the future. The fact that this could be an ancestor of living things is very interesting and the tools that we humans have to find all these kind of information are incredible.
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We will discuss a great deal about metabolic pathways, how cells get energy. The most important aspect of LUCA ressearch is that we now know that life has alternative ways of, well, living.
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Looking for a common ancestor is like looking a needle in a haystack, its very difficult to exactly pinpoint the exact common ancestor of every living organism. But nonetheless its good that scientists dedicated themselves to the search of the common ancestor, thanks to their efforts they discovered chemo-synthesis and in Luca the metabolization of hydrogen. Its possible that life started in the bottom of the ocean or in a warm pond on land like Darwin said but what matters is that the information gathered on every scientific field, should be used to better our lives and the enviroment. Who knows? Maybe in a few years technology could evolve to be able to use the chemical energy in the vents on the ocean floor as a possible energy source.
Below is a link to a business model to exploit the natural and renewable resource that is CO2 negative energy. In the webpage there are various graphs of future big structures built on the ocean that are auto sustainable and look amazing like something from a science fiction page which i found awsome.
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http://climatecolab.org/contests/2015/industry/c/proposal/1314307
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It’s really astonishing how a single-celled bacterium survived in such extreme and harsh conditions Earth was encountering 4 billion years ago. This bacterium is known as LUCA (Last Universal Common Ancestor) and it lived in deep sea vents, where temperatures could reach up to 400 degrees celsius. How could that bacterium survive under in that state? It contained 355 genes precisely pointing to it living in extreme conditions caused by the scorching hot hydrothermal vents and was able to metabolize that hydrogen to produce a source of energy. It is possible that this is the common ancestor of life and that every organism evolved from this bacterium.
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Sources:
http://www.nytimes.com/2016/07/26/science/last-universal-ancestor.html
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We should keep an open mind about the origin of life—we know very little about it. Fortunately, there are many brace scientists out there willing to give the compelling LUCA hypothesis a chance.
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