Archive: September, 2011
A critical reader commented on a previous column that I’ve been blind to something obvious when it comes to abiogenesis – the formation of life from non-life:
Once you bring up abiogenesis, that's a loser for naturalists/atheists. You need some type of genetic code, a method of replication, and metabolism all at the same time for a group of chemicals to survive for natural selection to work. I'm skipping over a bunch of other things, like all the amino acids have to have left-handed chirality, etc. And we keep having discoveries that push the sudden appearance of life (once conditions permitted) to just a blink of the eye in geological terms. "What could be the alternative to life coming from nonliving matter?"
(He’s quoting me there)
So blind in assuming certain assumptions... it's not about the need for matter. The heart of the matter is the need for intelligence to organize matter.
One thing my previous columns have been lacking is the perspective of Jack Szostak, a Harvard professor, Nobel Laureate, and a world expert on the origin of life. He’s a hard man to track down, but I intercepted him earlier this week at Penn State, where he was visiting, to get his perspective on the question of life's origin. Szostak and colleagues are trying to get inanimate matter to organize itself into living cells in a test tube. In Monday's column and post, I’ll have more about Szostak’s attempt to create life, and his view on the need for a God to do this.
Legend has it that when asked by a theologian what the living world could tell us about a creator, biologist J.B.S. Haldane remarked that, “If He exists the creator has an inordinate fondness for beetles.” In his writings, Haldane, who died in 1964, noted that there are 300,000 species of beetle and only 10,000 species of mammals.
Some doubt has been cast on the exact wording and context of this quote, but according to Wikipedia, Haldane’s friend, Kenneth Kermack, told Stephen Jay Gould that the actual quote was “God has an inordinate fondness for beetles”, elaborating that, “Haldane was making a theological point that God is most likely to take trouble over reproducing his own image, and his 400,000 attempts at the perfect beetle contrast with his slipshod creation of man.”
Whether it’s 300,000 or 400,000 species, some of these beetles are extraordinarily beautiful. Even 47 million years ago, they shone in glorious colors, according to a paper published this week in the Proceedings of the Royal Society B. More pictures and an explanation of the science can be found in this story from wired.com.
The researchers told wired.com that the colors come not from pigments but from the interplay between different wavelengths of light with nanometer-sized physical structures. And despite their tiny size, these structures have been preserved as fossils, the original exoskeletons of the beetles replaced by minerals, allowing the researchers to approximate the original colors.
Evolution is such a hot topic that it was the subject not only of yesterday’s Doonesbury, but of this week’s Savage Love column. For those who aren’t familiar with it, Savage Love is an extremely well-informed sex column. So if you’re offended by sex, please stop here.
In response to a query from a woman who couldn’t experience orgasm, columnist Dan Savage turned to Salon.com writer Tracy Clark-Flory, who drew on evolutionary biology for insights. She pointed to the theory that female orgasms evolved because they were advantageous in males, just as nipples evolved in many male mammals because they were advantageous in females, and didn't do the males any harm. Such anatomical crossovers happen because the sexes share the same genes, with the exception of some on the Y chromosome. And developmental biologists say we start out in utero with proto-versions of both types of genitalia, so every part in one sex has an analogue in the other.
In a male, orgasm is clearly adaptive. A male who didn’t experience them might quit before he was finished, which would be detrimental to his reproductive success. Or in some cases, he might stay with the act too long at the expense of his own survival.
I learned a lot about this topic during the three years I wrote my previous column, Carnal Knowledge, which was always about sex and, usually, also about evolution. There, I explained various theories purporting that female orgasm improves reproductive success, as well as the theory that it rode along with the male one as a byproduct.
The byproduct view was extolled by Stephen Jay Gould, who took some flak for it, but it served to make an important point about evolution: Everything isn’t here for a reason. Our bodies are full of byproducts – things that were adaptive in the opposite sex, or in our ancestors, whether they were other apes or even, going further back, fish.
Anthropologists study humanity and our evolution, but they don't agree on when we crossed over the threshold to status as full "human beings."
The question crops up often, as it did this month over some new scientific articles describing 2-million-year-old fossils of humanlike creatures from South Africa.
Called Australopithecus sediba, members of this group had brains little bigger than those of chimps, but they walked upright and possessed humanlike hands - which scientists say looked as if they were good at making and using tools.
If they were good tool users, they might need to be renamed as homo something - a member of our wider group, the genus Homo, which is Latin for human. The earliest known member of this group, Homo habilis, lived 1.8 million years ago and earned this qualification because their remains were found along with stone tools.
Does that make them human?
There’s a good way to be wrong in science and a bad way. When an international team of scientists announced last week they’d measured particles going faster than the speed of light, their colleagues thought they might be wrong, but in an honest way. Those surprising findings come from a European experiment described here, in which a beam of particles called neutrinos were sent 646 miles, from Switzerland to an underground detector in Italy. They arrived 60 nanoseconds faster than light should have travelled. Or so it appeared.
Physicists are skeptical because if this is confirmed, it would violate Einstein’s 1905 theory of special relativity, which showed that the speed of light is constant (in a vacuum), while time and space can expand and contract. According to Einstein, faster-than-light travel allows reversals of cause and effect. It would be possible, for example, to see a crime scene in which the victim collapsed from a bullet wound before the shooter fired.
Penn physicist Josh Klein said he was impressed with how careful the European team had been in checking their results. “They did a serious job of this,” said Klein, who has been studying neutrinos for more than a decade. If it’s wrong, it may not be any kind of obvious goof-up, he said. Perhaps there are subtle effects nobody knew about that threw off the accuracy of the measurements or gave the illusion the neutrinos had travelled faster than light.
“It will be something subtle and hard,” that explains the results, he said. Neutrinos are a very odd form of matter, first postulated by Enrico Fermi in the 1930s to explain why a small amount of mass seemed to be carried away from nuclear reactions. The first actual neutrinos were detected in the 1950s.
They’re generated in the sun and other stars in enormous quantities - 100 billion neutrinos zoom through a spot the size of your thumbnail every second. At night, they stream through the Earth and come out the other side. They’re not only invisible but they tend to pass through matter without leaving a sign.
It's a scenario worthy of any zombie movie: A virus infects a gypsy moth caterpillar and takes over its brain, putting it on a suicide mission. First, it's compelled to climb up high in the trees, where it dies in the midday sun. Then its body liquefies, and virus particles are spread downward with the first rain.
The behavior benefits the virus at the expense of the caterpillar.
Horror films borrowed the zombie concept from Haitian and African culture, where the term refers to a reanimated body that can be forced to do the bidding of a sorcerer. Nature shows the concept is not so far-fetched (though the victims aren't technically dead). The sorcerers can be viruses, fungi, or worms, and they don't need to use magic. They use evolution.
Among the most famous cases are those of "zombie ants," which get infected by a fungus that compels them to go where conditions are optimal to grow more fungus. And in corn earworm moths, a sexually transmitted virus can render the infected females not just more active in attracting males, but also irresistibly sexy.
In a new paper published Friday in Science, biologists showed how they pinpointed a gene that does the sorcerer's job in the gypsy moth virus, called baculovirus. The gene, egt, interferes with the moth's instinctive molting behavior, said Pennsylvania State University entomologist Kelli Hoover, the lead author.
Perhaps resistance to evolution is just a widespread case of being embarrassed by our parents. In a series of papers released today, paleontologists made a case that humanity descended from a species called Australopithecus sediba – a South African hominid that lived close to 2 million years ago, had small brains, long, tree-climbing arms, and short stature. The males stood about 4’6” and the females were just around 3’0”.
But they had great hands with long, graceful looking fingers. “These were tool making hands,” said anthropologist John Hawks of the University of Wisconsin.
The papers, presented in the journal Science, give the most complete description of a set of a. Sediba fossils found in 2008, which include remains from five different individuals. Hawks was not an author of the paper but he’s been out to the site, and to him, the fossils emerging could finally help us piece together when and how we became human.
Generally, anthropologists consider humanity to include not just Homo sapiens, but other relatives within the larger grouping of homo - including our probably ancestor Homo erectus, as well as the earlier Homo habilis and several others. Three general criteria distinguish these species as human: tool use, large brains and large bodies.
1.8 million year old Homo habilis has been considered the earliest species of human. To put that in perspective, humans branched off from chimps at around 7 million years, and the famous upright-walking small-brained hominid known as Lucy (Australopithecus afarensis) lived 3.2 million years ago. The first stone tools appear to be invented around 2.6 million years ago.
One of the many fascinating things about evolution is that it generates disputes that can help us all better understand what science is and how it differs from religion or other areas of human endeavor.
Just such an enlightening dispute cropped up recently between two readers who were kind enough to let me share some of their correspondence. It all started when Elisa Winterstein wrote a letter to The Inquirer, stating that scientists rely on faith just as religious people do by accepting the idea of abiogenesis - the notion that life arose from non-living matter.
Her contention is mirrored in dozens of other reader comments I've seen, stating that science, like religion, requires faith.
Her letter goes on to say that, while scientists are considering various scenarios for the origin of life, none is currently backed by any evidence, and therefore, "to believe in abiogenesis does indeed require faith."
This struck me as odd, since life couldn't exist at the big bang, and it certainly exists now. What could be the alternative to life coming from nonliving matter? That cells popped into existence from nothing?
This week scientists announced they’d sequenced the first genetic code of a reptile – an achievement that Harvard biologist John Losos expects to help clarify some open questions about the genetic changes that underlay evolutionary changes. The type of reptile they picked, an anole lizard, holds a particular fascination for biologists because on the Caribbean islands, different, unrelated species tend to evolve the exact same body-types and survival strategies, whether it’s hiding in brush or disguising themselves as twigs.
A few weeks ago I wrote this column about the way these lizards can help test Stephen Jay Gould’s thought experiment about running the clock back millions of years to see if evolution, if allowed to run again, would produce anything like the plants and animals we have today. Gould thought it certainly wouldn’t produce humans, or anything like humans, since evolution is too dependent on random and unpredictable events, including the asteroid impact that killed off the dinosaurs.
We can’t run the clock backwards but we can learn something by watching different populations of animals evolve independently on different islands. The end result is the extremely similar from one island to the next, said Harvard biologist Jonathan Losos, who was part of a collaboration of dozens of scientists involved in the genetic sequencing project. They know, for instance, that some of these lizards evolved short legs independently on different islands. Now they can start to ask how that happened – whether they modified the same genes or different ones to get there.
They might also learn why these lizards tend to evolve in parallel when other animals don’t. Is it something in their DNA?
The genome analysis, which was published this week in the journal Nature, looked at the green anole lizard – (Anolis carolinesis) which lives in the Southeastern United States. It’s one of about 400 species of anole. You can read more about the paper here.