Stories tagged evolution
Author Jim Holt consults Darwin and Copernicus and declares: laughter will be mankind’s most enduring legacy.
Tags : The discovery of a new fossil of an ancient four-legged creature with both amphibian and fish traits has been reported in the scientific journal Nature.
Named Ventastega curonica, the extinct animal’s 365 million year old remains were discovered in Latvia in the near-shore marine sediments of the Ketleri Formation. It lived during the Late Devonian about 100 million years before dinosaurs. Only partial remains of Ventastega were recovered, including its skull, shoulder, and pelvis, but by studying the bones' structures scientists were able to determine that the creature had limbs rather than fins.
Fossils of other transition creatures have been found with similar degrees of advancement between fish and tetrapods (animals with four limbs), but those appear to be more fish than tetrapod, while Vestastega appears to be more tetrapod than fish.
Dr. Tatiana (Dr. Olivia Judson) sizes up the situation: The males in the audience may not have been amused.
Courtesy Mark RyanYesterday, I attended a public lecture at the Evolution 2008 conference at the University of Minnesota given by Dr. Olivia Judson, an evolutionary biologist who also brings the evolutionary biology of sex to the masses via her clever book and television show "Dr. Tatiana's Sex Advice to All Creation". The book has been translated into over 15 languages, and the three episodes of her humorous television show completed so far (with Dr. Judson starring as her alter-ego Dr. Tatiana) have played on the Discovery Channel in Canada, Britian, Australia, and also in France to high acclaim. Evidently, the show is considered too saucy for US broadcast. (Why are we considered an "open" society?)
Dr. Olivia Judson shares a video clip: "Dr. Tatiana's Sex Advice to All Creation".
Courtesy Mark RyanBut really this is an excellent way of teaching the sexual aspects of evolution to the general population. I haven't read her book yet, but from what I heard at the lecture and saw in the accompanying video clip (which included those mainstays of courtship, song and dance), Dr. Tatiana keeps things on a very comprehensible level, shying away from scientific terms, and explaining things clearly and as humorously (and frankly) as possible.
Judge for yourself. After the lecture I went to YouTube and discovered a number of clips have been posted there for viewing (not by young children but if you're an American adult, you should be okay):
Dr. Tatiana clip 1
Dr. Tatiana clip 2
Dr. Tatiana clip 3 (BBC report)
I guess this explains most of the comments on this blog...
Scientists witness evolution in lab
in Cells, Heredity, Biological Populations Change Over Time, and Flow of Matter and Energy
For decades, scientists have been growing microbes in their labs and watching them evolve new traits. Most of the changes tend to be simple things, like an increase in size or growth rate.
But Dr. Richard Lenski of Michigan State University (just 2 miles from my house!) recently witnessed a major evolutionary leap--as it was happening. Twenty years ago, he took a colony of E. coli, a common bacteria, and split it into 12 identical populations. He’s been watching ever since to see if the strains evolve in different directions.
A few years ago, one of them did. One of his study strains suddenly evolved the ability to eat citrate, a molecule found in citrus fruits. No other E. coli in the world can do this, not even the other strains in Dr. Lenski’s lab. Even given several extra years and thousands of extra generations, the other strains are still citrate-averse. What’s more, the bacteria evolved this mutation entirely on their own, without any prodding or genetic manipulation from the researchers.
Lenski had saved frozen reference samples of all of his strains at regular intervals. Going back and growing new cultures from these samples, he again finds that only those from one strain ever evolve the citrate-eating habit – and only those sample less than about 10 years old. Lenski figures that some mutation happened around that time in one strain – and one strain only – that would later lead to citrate eating. He and his lab are now working on figuring out exactly what that mutation is.
I'm too sexy for light feathers: Barn swallows with darker chest feathers do better with the ladies than those with lighter feathers, a study shows. On top of that, those that have their feathers darkened increase their production of testosterone.
Courtesy MdfSorry guys, but our perceptions of what makes us manly have taken a severe hit with this new scientific discovery.
Evolutionary biologists working with barn swallows in New Jersey have found that a little extra black make-up applied to the chest feathers of male swallows increases their “hook-ups” with female swallows.
The lighter colored males typically are smaller, less genetically attractive versions of the species and hence their low procreation rate. But as they say, a little dab will do you, and with the help of ink from a marker, life changes for the male swallows.
The researchers actually had done earlier testing that showed the feather coloring change to be an aid for male swallows. But in this latest round of research, they found that maleness-enhancing impacts from the color change. They treated males had increases in the amount of testosterone they produced and even trimmed down in weight.
Full details of the study are available here at the Current Biology website. I just hope that the Hair Club for Men and Grecian Formula yahoos don’t get wind of this new information.
The platypus
Courtesy Wikimedia CommonsWhen English zoologist George Shaw was presented with the first platypus from Australia in 1798, he was certain some smart aleck had pieced it together using various animal parts, so he began searching its pelt earnestly for signs of stitching. Of course he didn’t find any, but you can’t really blame Shaw for beingsuspicious; the platypus is an odd amalgamation of avian, reptilian, and mammalian features all crammed into one very bizarre-looking animal.
But today, some 200 years later, the stitching has finally been found –and not on the little freak show’s carcass – but in its gene sequence. This week a team of about 100 international scientists published the platypus genome in the journal Nature.
A skinned platypus: stranger looking yet
Courtesy Wikimedia Commons"Its probably the most eagerly awaited genome since the chimp genome because platypuses are so weird," said Jenny Graves, one of the paper’s authors, and head of the Comparative Genomics Group at the Australian National University.
Weird is an understatement.
The platypus (Ornithorhynchus anatinus) belongs to an order of animals known as monotremes, which are mammals that lay eggs. Not happy with just one act of non-conformity, the platypus crosses even more Class lines. Although it lays eggs like bird and walks like a reptile, it’s covered in fur and nurses its young like a mammal. One end of it sports a duckbill, and the other a beaver-tail. When swimming underwater the web-footed, cat-sized oddity closes down all normal sensory organs and relies on electrosensory receptors in its bill to detect weak electric fields send out by potential prey. Males of the species can inject enough venom from spurs on their back legs to kill a dog.
So I guess it’s not surprising then that the platypus’s genetic code appears just as strange as the creature itself does.
"You see genes that look reptile-like, genes that look bird-like and genes that look mammal-like. Its a pretty amazing picture," said Rick Wilson, director of the Genome Center at Washington University in St Louis. He also directed the platypus genome report.
This evolutionary Frankenstein is one strange dude. Or rather in this case: dudette. The study’s genome sequence was derived from a female platypus named Glennie, and compared with genomes found in humans, dogs, opossums, mice and chickens.
"It teaches us a lot about some of the biology that some of our earliest common ancestors might have had, in terms of immune systems and early nervous systems functions," said Wilson.
The platypus, it seems, has 10 sex chromosomes, five male and five female - whereas we humans have only one of each. Some share similarities to mammalian sex genes, some to avian sex genes. This could aid scientists in future studies of sex determination in mammals or human infertility. The platypus is also the only mammal without a scrotum. The male’s testicles are located safe inside the abdominal cavity, like those of frogs, birds, and reptiles.
Humans, frogs and platypus carry two copies of a gene passed down from a common evolutionary ancestor. Somewhere along the evolutionary path (and probably at different times) the genes mutated because in the frog even though they produce a similar protein, they function differently than they do in humans. One of the roles of these duplicated genes causes the human testes to descend into the scrotum away from the body for temperature regulation.
But what’s interesting is that one of these genes in the platypus resembles a human gene, and one resembles the frog variation, which lead scientists to regard the platypus as the link between frogs (and reptiles and birds) and humans. Just a single mutation in the platypus genes could have caused it to develop a scrotum like other mammals. Information like this could help solve human problems such as why the testes of nearly 30 percent of pre-pubescent boys fail to descend, as they should.
The platypus first branched off the mammalian line about 166 million years ago, and is found today along Australia’s east coast and on Tasmania.
LINKS
Reuters story
Nature news story
ABC News story
More on the platypus
Evolved geek: Are advances in technology dooming humans to become lapdogs with laptops?
Courtesy PipeHave you ever wondered what kind of effect all the recent advances in technology along with our geeky ways of dealing with them will have on the evolution of our species?
For example, two innovations alone – search engines and the Internet – have caused tremendous change in the way we gather, store, and retrieve information. Used to be if I wanted to find a local business address, I’d have to walk to the kitchen, pull open the middle drawer, heft the ten pounds of Yellow Pages up to the counter, then spend at least a couple minutes wracking my brain while paging through it. I was using all sorts of arm and leg and back muscles – not to mention excessive brainpower going through the alphabet – just to accomplish the simple task.
Nowadays, I hardly have to move at all. I remain seated at my computer, type in a couple keywords and click the mouse a couple times. Voila! I get more company information than I’ll ever need plus detailed maps and directions to the exact location.
Or, as pointed out in a recent article, will having all our critical numbers and information stored externally in our iPhones or Blueberries free up some of our brain space for more important tasks? Or will the size and dexterity of the human thumb evolve eventually to produce a race of super text-messagers (I don’t know that this will happen since keyboarding is an old technology that I suspect will someday disappear).
But, it’s kind of an interesting subject to ponder, and a forthcoming book by William Halal, a professor of science, technology and innovation at George Washington University looks into the phenomenon.
"All of the routine things we currently preoccupy ourselves with are going to disappear and people are going to do what? We will move up another notch in the level of evolution," Halal said.
In his book, Technology’s Promise, Halal predicts that advances in new technologies over the next dozen years will relieve our species from the bounds of many of our mundane jobs, allowing us to shift our priorities to more important issues.
But at what cost?
"We are the first humans to outsource jobs to technology, to automate that which is labor intensive or mentally tedious," said Patrick Tucker, senior editor of the Futurist magazine. "In the 21st century, this may result in people that are by and large less capable than we are today. Whether or not we seize all of those opportunities depends on how we mature in the coming decades."
Will this future diminishment of our mental and physical expenditure lead us to evolve into a species of torso-less heads suspended by wires inside bell jars? As long as my jar is within viewing range of the TV, and I can change channels through telepathy, I really don’t care.
MORE INFO
Speaking of geeks, here’s an interesting video of Clifford Stoll that may add some relevance to this subject. But then again, maybe not. Stoll is an astronomer who, if nothing else, is really interesting to watch (although some may say he’s completely nuts). I saw him speak at a conference a few years ago and was really taken by his point of view regarding our reliance on computers in schools and elsewhere. He does have some good points about our dependence on technology. Not that I followed his advice much but he’s worth a listen.
Laughing it up: Not just for humans anymore.
Courtesy premasagarA new study of contagious laughter among orang-utans could mean the emphatic response evolved from an ancestor common to both humans and primates.
This comes on the heals of the recent post about testosterone's link to humor. That's funny.
Well, maybe.
New fossil evidence indicates that the ancestors of modern kangaroos walked on four legs, had fangs and climbed trees -- a sobering thought. Meanwhile, scientists studying marsupial flatulence have discovered that kangaroo gas contains no methane, and thus does not contribute to greenhouse gasses. A spokesman for kangaroos said he was glad no kangaroos were involved in changing the Earth's climate.
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