Stories tagged Diversity of Organisms

Mar
20
2010

Clonal grove of trees considered oldest and heaviest living organism

Aspen grove might be clones
Aspen grove might be clonesCourtesy Al_HikesAZ

I wrote about Earth's tallest, biggest, and oldest trees about four years ago. This week Wired Science had a wonderful gallery of photos and information about Earth's oldest trees.

One of them, Pando, is a 105-acre colony is made of genetically identical trees, called stems, connected by a single root system. This organism is believed to be 80,000 years old (and maybe a million) and weighs 6,615 tons, making Pando the heaviest living organism on earth.

Oldest and largest organism debate

You can read a debate about how other organisms might be larger and older here.

Other candidates for oldest or heaviest living organisms include the possibly larger fungal mats in Oregon, the ancient clonal Creosote bushes, and strands of the clonal marine plant Posidonia oceanica in the Mediterranean Sea.

Mar
16
2010

Old school way of thinking: This idea of man as the be-all, end-all of evolution- the unchanging, final edit of nature- is exactly what the Smithsonian's new exhibition hall is trying to negate.
Old school way of thinking: This idea of man as the be-all, end-all of evolution- the unchanging, final edit of nature- is exactly what the Smithsonian's new exhibition hall is trying to negate.Courtesy wikimedia
The Smithsonian Institute will open a new exhibition hall tomorrow (March 17, 2010), the David H. Koch Hall of Human Origins (this opening coincides with the institute’s 100-year anniversary). The 15,000-square-foot hall will focus on what it means to be human, examining how our defining characteristics emerged over time. One cool thing about the new exhibition (in addition to…everything) is the highlight (in the form of bronze statues) of a-typical hominid species. There’s a statue of Homo heidelbergensis, Paranthropus boisei, and even Homo floresiensis (the “hobbit” species). Now, I know what you’re thinking, “What?! Where’s the Australopithecus africanus?!!” Well, it’s not in this exhibition (at least not in the form of a shiny effigy). The reason for this is to emphasize that our ancestry is not a straight line (as A. africanus might imply because it is a possible direct ancestor of Homo sapiens). Instead, our lineage is much less tidy; there’s species overlap, some species die off… the diagrams are messy. The David H. Koch Hall of Human Origins is trying to get at the fact that we Homo sapiens are just another iteration in our branch-laden tree, not the pinnacle of evolutionary development. I think that’s a great point to remind people of.

Other features of the exhibition include forensically reconstructed life-sized faces of some of our ancestors, 75 skull reproductions, key events in humanity’s evolution (environmental changes, behavioral innovations, etc.), a human family tree, and virtual tours of important research sites. I haven’t had the chance to visit it yet, but the American Museum of Natural History in New York also has a relatively new human origins exhibition. I think it’s exciting that more and more museums are taking on this topic. In the past museums have shied away from it for fear of stirring up controversy. The Milwaukee Public Museum, for example has an exhibit about evolution- it’s on a tiny wall in a dark corner…but at least they have one. It’s important for museums to present scientific research, and the exciting exploration of human evolution is no exception. So if you’re in the D.C. area, be sure to check out the new Smithsonian Hall of Human Origins.

Mar
15
2010

Cool, it is a baby mammoth: A new traveling museum exhibit features a frozen baby mammoth, found in the ice of Siberia in 2007.
Cool, it is a baby mammoth: A new traveling museum exhibit features a frozen baby mammoth, found in the ice of Siberia in 2007.Courtesy Field Museum
A few years ago, I posted a story about the find of a frozen baby mammoth in Siberia. You can refresh your memory of that discovery here.

Now, an exhibit on mammoths and mastodons has opened at the Field Museum of Chicago and visitors have the chance to see the frozen mammoth baby up close and in person (and right now you can look at the photo of it on exhibit right next to this paragraph). The Field Museum hosts the exhibit through Sept. 5 and then an international tour begins, running through 2014.

Here's an interesting story about what researchers have been able to learn about mammoths based on their findings from the mammoth baby, as well.

Feb
25
2010

An Instant Classic: Hey, Aesop, what if I told you Mr. Hare won the race?
An Instant Classic: Hey, Aesop, what if I told you Mr. Hare won the race?Courtesy Milo Winter

You’re probably familiar with Aesop’s classic fable The Tortoise and the Hare: Mr. Hare challenges Mr. Tortoise to a foot race. Mr. Tortoise accepts. Mr. Hare dashes from the start line, but stops just before the finish line to take a nap. In the meantime, Mr. Tortoise plods along to win the race!! The moral of the story? University of Minnesota professor and Institute on the Environment resident fellow, Dr. Peter Reich’s award-winning take on the fable may surprise you.

Dr. Peter Reich: This guy studies leaves for a living.
Dr. Peter Reich: This guy studies leaves for a living.Courtesy Regents of the University of Minnesota

Dr. Reich studies leaves. In particular, Dr. Reich has discovered three characteristics of leaves that allow researchers to identify where and how plants live: longevity, productivity, and nitrogen content. Longevity measures how old a leaf lives. Did you know leaves in the tropics live only 5-6 weeks whereas Canadian spruce leaves can live up to 18 years old? Productivity measures how much sugar the leaf makes (yes, leaves make sugar called “glucose,” which nearly every animal uses to fuel their body – that’s why your momma tells you to eat your vegetables!). Finally, nitrogen is like a vitamin for plants: they need it to grow big and strong. How much nitrogen a leaf has is important because it determines how much energy a plant can make.

Canadian Spruce: If these leaves were human, they could be legal adults!
Canadian Spruce: If these leaves were human, they could be legal adults!Courtesy Steven J. Baskauf

Tropical Leaves: These guys may look BIG, but they are not going to be around for long.
Tropical Leaves: These guys may look BIG, but they are not going to be around for long.Courtesy Flickr

What about the moral of The Tortoise and the Hare? Dr. Reich’s research says there are basically two types of leaves: ones that are like Mr. Tortoise and ones like Mr. Hare. Tortoise-like leaves work slowly, but steadily. They’re the marathon runners of the leaf world. Hare-like leaves work really fast! But they can’t keep it up for long. They’re sprinters. Could you run a marathon at your top sprinting speed? Probably not, and neither can leaves be both ultra-fast and long-lasting at the same time. Instead, leaves “tradeoff” speed for endurance. Like human runners, leaves don’t have to be all fast and short-lived or all slow and long-lived; they can fall somewhere inbetween and be medium speed and medium-lived.

So who cares about marathon and sprinting leaves anyway? Lots of people! Dr. Reich just won the BBVA Frontiers of Knowledge Award in recognition of this important research. Being able to group the thousands of plants out in the world into a handful of groups is allowing scientists to do incredible research that can be used around the world.

For example, Dr. Reich’s newest research is looking at the different responses of tortoise-leaves versus hare-leaves to changing environments, such as higher levels of carbon dioxide in the air caused by climate change. As each generation of leaves reproduces, new genetic combinations are created. New genetic traits that are helpful to the plant’s survival are passed on to the next generation. The more genetic combinations created, the better chance a species has of “finding” the right traits in a changing environment. This is where Dr. Reich’s interpretation of the moral of The Tortoise and the Hare may surprise you: because hare-leaves have fast, short lives, they reproduce more genetic combinations and are better able to deal with change. Tortoise-leaves will struggle more to adapt. That is, for leaves, slow and steady does not always win the race!

Want to know more?? Dr. Reich recently gave a lecture as part of the Institute on the Environment’s Frontiers on the Environment series. You can hear it here.

Feb
17
2010

Ibex: Capra ibex
Ibex: Capra ibexCourtesy Nino Barbieri
A recent article in the Journal of Archaeological Science reminded me of the importance of the Scientific Method Often we hear new and exciting scientific theories that seem plausible, especially if these ideas are presented in prestigious journals. However, the beauty of the Scientific Method is its verifiability, whether or not the data can be recreated through repetitive testing (If we truly believed everything the first time, our budding young scientists would have nothing to do!)

Michael Campana from the University of Cambridge and colleagues from across the UK and Ireland recently ran a sequence of DNA tests on 18th and 19th century parchments made from animal skins in order to reveal the complexities of ancient parchment analysis. Parchment is one of the most valuable archaeological and historical artifacts that can be used to understand not only language and history, but DNA testing on it can reveal clues to animal population studies, animal husbandry, different historical animal breeds, and provenance (where the animal or skins originated from). In the case of the Dead Sea Scrolls, DNA testing on the parchment could reveal what type of animal was used and possibly where it came from, providing additional data for questions regarding who wrote the scrolls.

Campana and colleagues analyzed both mitochondrial and autosomal genetic data using stable isotope, genetic, phylogenetic and ion beam analysis. All samples were considered to be well preserved and ideal samples for accurate testing. All but one parchment produced multiple DNA sequences that matched several different species including cow, goat, sheep, and even human. In other words, a parchment assumed to be made from one individual of one species, gave conflicting results as more than one species or more than one individual. Of course it can be assumed the parchment was not made of human skin and therefore human genetic data must have came from handling and processing of the parchment, but parchments can also be contaminated in long-term storage or contact with each other. Testing results can also be skewed by glues and inks or other preparatory treatments used to improve the surface. All of these factors need to be considered when testing truly ancient parchment like the Dead Sea Scrolls.

Previous DNA test results from 2001 and 1996 on the Dead Sea Scrolls produced results pointing to a single species, either ibex (Capra ibex) or domestic goat. While these results may indeed be correct, the likelihood that the results were so exact, when testing such as Campana's and colleagues on better preserved and more recent parchment were so complex, questions the accuracy of the earlier DNA testing. Of course we must not forget, precious artifacts like the Dead Sea Scrolls can not be needlessly dissected to offer unlimited samples for DNA testing labs. But as, Campana states, “Improving our understanding of parchment's DNA content would allow us to develop a predictive model for sampling of historic manuscripts.”

So the messages for today, bravo for the Scientific Method and go see the Dead Sea Scrolls at the Science Museum! Learn the science, archaeology, history and more that surround these amazing artifacts. Ask questions like: did the scroll writers choose ibex for some scrolls over goat because they thought these documents were so special or was ibex as readily available as any other animal species? Did the handling of the scrolls by shepherds who supposedly found them contaminate the actual scroll DNA with sheep, human or goat DNA? What can DNA testing tell us about other ancient artifacts? As long as there are unanswered questions, no matter how small, there will be a need for scientific investigation; which is good news for our future scientists!

Feb
14
2010

Naked Mole Rat: a mighty survivor both hairless and nearly blind
Naked Mole Rat: a mighty survivor both hairless and nearly blindCourtesy MissTessmacher
The naked mole rat (Heterocephalus glaber) is truly one of the most remarkable animals on this earth. On average 3 inches long and weighing just over an ounce, one would not think this creature so high and mighty. However, its unusual traits have brought it under more medical scrutiny and established an ever increasing presence in research laboratories. Stories have rung for years about how the only species to survive a world Armageddon would be cockroaches and rats. My money is on the naked mole rat.

While called a rat, they are one of 37 species of mole rats globally and are more closely related to guinea pigs and porcupines than other Rodentia. Limited to parts of East Africa, they spend their lives under ground in a highly social commune of individuals, all governed by a queen. This is very similar to the eusociality seen in bees and ants. The queen is the only female to breed, with all other individuals serving as guards or workers. This unusual social life for a mammal in a colony can lead to fierce competitions among females when the old queen dies. It may take days or weeks of power struggle before life in the colony returns to normal.

In search of plant tubers for sustenance, they dig through the dirt with their teeth, developing a system of burrows that can carry on for miles. One of the naked mole rats remarkable features is its ability to survive in the high carbon dioxide environments of these tunnels. Their extremely low metabolic rate and high absorption of oxygen allow them to overcome the limitations of the cramped and congested space. Research has found that these mole rats are void of a pain transmitter called Substance P found in other mammals, and have an uncanny resistance to the oxidative stress of daily metabolism.

Researchers hope this could lead to new insights into the process of aging. Captive research colonies have had individuals live as long as 28 years. That is more than nine times as long as a research mouse! This longevity and unique durability lead even more scientists to consider the naked mole rat for captive study populations in the fight against other afflictions like stroke and cancer. If these superman-like traits haven’t given you a deeper appreciation for such a tiny hairless creature, perhaps you just need a clever ditty to sing their praises. Oh! …you so UGLY!

Jan
28
2010

Elysia chlorotica: You think you're so special, don't you?
Elysia chlorotica: You think you're so special, don't you?Courtesy lauredhel
Some of you may already know my feelings on mollusks. In short, I’m against them.

It’s not that I necessarily want them all exterminated, or anything. It’s just that mollusks, with their tentacles and beaks and pseudopodia and large brains, freak my Schmidt out. And I tend to live under a “you’re either with us or against us” credo, and mollusks obviously aren’t “with us.” (They aren’t with me, anyway. Frankly, most things aren’t.)

But I get by. I know that there are mollusks out there, doing… I don’t know what. Probably something utterly horrible. But we leave each other alone, and more or less leave it at that. It’s a workable arrangement.

Now and again, however, a mollusk stretches its squishy neck out and, by its very existence, makes cracks in the already fragile JGordon/Mollusca peace. It’s like the cold war, really—if one side does something strange, or develops a fantastic new piece of technology, the other side gets a little nervous. So, naturally, I’m a little cagey about this news:

There’s a marine slug (a mollusk, of course, that feeds itself through photosynthesis.

Are you kidding me? I’m all, “I think I’ve got chronic anxiety!” and this lousy slug is like, “That’s too bad. Also, I feed myself with sunlight.” I can’t even get groceries because my car battery died (there’s a very scary tree near my bus stop, so that’s out), and this little jerk is a phototroph. If I had laser eyes, or something, the situation would be a little more balanced, but last time I checked I didn’t have laser eyes.

I have to give it to the slug, though—it’s a pretty neat trick. Early in its approximately one-year-long lifecycle, the slug eats some photosynthetic algae. From that point on, the slug is photosynthetic; it feeds itself by using sunlight to convert CO2 and water into sugar, just like plants do. What’s more, the photosynthesis isn’t being performed by algae inside the slug (some organisms, like lichen contain algae, which feeds them). The slug itself has genes for photosynthesis, and the photosynthesizing genes from the algae are just required to kick-start the slug’s own abilities. And then, BAM, a photosynthetic animal.

The leaf-shaped slug, which lives in salty swamps in Eastern Canada and grows to be about an inch long, is remarkable not only for its photosynthetic abilities, but also for something unique in the process written above. Getting those kick-starting genes from the algae requires gene transfer. Passing genes from one species to another is a rare and complicated thing, but some microscopic, single-celled organisms have been known to do it. This is the first time gene transfer has been observed between two multi-cellular organisms (the slug and the algae, of course).

Aside from being, well, just sort of weird, the slug’s gene transferring abilities might turn out to be useful in the future of gene therapy, where new genes are inserted into cells to combat diseases. A practical application whatever transferring mechanism the slug and algae use is a long way off, though. And, anyway, I’ll be damned if I ever use anything that came from a mollusk.

Dec
22
2009

art in a petri dish
art in a petri dishCourtesy Eshel Ben-Jacob
Take a close look at the image pictured here. Do you think it's the work of an artist, a scientist, or some other living organism?

The answer is: all of the above.

Eshel Ben-Jacob, an Israeli artist who is also a scientific researcher, created the image in collaboration with tens of billions of microorganisms, a colony of bacteria living in a petri dish. Why did he do it?

He was curious about how bacteria cope with stress in their environment, for example when humans try to eliminate them using antibiotics. One way he found to study the coping strategies of these persistent microbes was by creating stressful petri dish environments and studying how the living organisms respond. The results are beautiful and complex patterns like this one, which also tell a story about how living organisms adapt.

Turns out that bacteria actually cooperate to solve challenges, communicating to exchange genetic information that tells them how to survive as a group. It's a kind of underlying social intelligence, one that can make it difficult for us humans to keep up. In the case of the image here, you can see how the colony branches out in search of nutrients. That's just one of the things these researcher were able to learn more about by studying petri dish patterns.

Eshel Ben-Jacob realized that in addition to loads of interesting scientific data, these colonies make thought provoking artworks, reminding us never to underestimate the adaptive powers of living organisms. He added a bit of color to the patterns and has compiled a series of the resulting images in an online gallery. Take a look, and let me know what you see!

Ben-Jacob's work is also part of a fascinating collection cataloged on the website Microbial Art, which features artworks by scientists and artists from around the world who use a wide variety of taxa and techniques. You may not see it hanging in an art museum, but it's one of the most interesting examples of science-art collaborations that I've ever seen.

Oct
27
2009

Help this little boy find his parents: Sorry. I couldn't find any pictures from Encino Man.
Help this little boy find his parents: Sorry. I couldn't find any pictures from Encino Man.Courtesy cote
It’s a weird suggestion, I know, because you probably give a lot of thought to whom the various cavemen had sex with anyway, regardless of the weather. But give it a little extra thought today. Because it’s nice out, and the dark corners of your brain could use the sunlight.

So, you guys all know that we aren’t the only human species ever to exist, right? The human family tree had other branches before it got to us (take a look at our Human Spark feature for more on that), and there were times when more than one species lived in the same area, and—in all probability—had interactions with each other. Neanderthals, for instance, lived alongside modern humans for many thousands of years in ice age Europe. Keep in mind, “Neanderthal” isn’t just a synonym for “cave-man.” Neanderthals were a distinct species—they had heavier, longer skulls, and thick, strong bodies. The modern humans of ice age Europe would have looked, more or less, like us. And because the two species were living in the same area for so long, it seems pretty likely that they interacted. But did those interactions include, you know, dinner, dancing, and romantic music?

Svante Paabo of the Max Planck Institute for Evolutionary Anthropology in Germany says yes, for sure they were having sex.

On one hand, these are sort of fightin’ words. People have suggested that Neanderthals faded into extinction as they interbred with modern humans, but when human DNA was compared with a sequence of Neanderthal DNA, it didn’t look like there was any overlap. That is, if there was any interbreeding, the Neanderthal contributions to our genes have been so diluted with human genes that it doesn’t appear that we have any Neanderthals in our family at all.

On the other hand… Well… I mean… People do all sorts of stuff… We all just want someone to love, right? Or, you know, just think of what a puppy will do to a piece of furniture. And humans and Neanderthals are a lot more similar to each other than puppies and ottomans. Too much? I don’t think so. Look at ligers. Or tigons. Or mules. Similar animals interbreed all the time, but very often they have infertile offspring. And that would explain why we don’t see any Neanderthal genes around today—everybody could have been doing it like it was 2012, but if the offspring couldn’t reproduce it wouldn’t matter to future generations.

Another factor that could explain the lack of genetic overlap (despite Paabo’s certainty of caveman/Neanderthal sexiness) is that our Neanderthal DNA sample just isn’t good enough. Mitochondrial DNA from Neanderthals doesn’t show up in modern humans, and while that’s an incredibly valuable genetic marker, it only makes up a tiny fraction of an organism’s total DNA. The Neanderthal genome hasn’t been completely sequenced yet, and that’s what Paabo means to do. Once we can fully compare the genomes, we can see if the two species became at all mixed.

Because they were definitely doing it.