Saturday, September 10, 2005

Ice belt 'encircled Mars equator', etc

Here are science news items with my comments in square brackets:

Ice belt 'encircled Mars equator', BBC, Paul Rincon, 8 September 2005. ... Europe's Mars Express probe may have found evidence for a band of ice that once spanned the Martian equator. A frozen sea and patterns of glacial activity on the planet may be a relic of this ancient belt of ice, says a top scientist. The ice may have formed just before five million years ago due to a change in the tilt of Mars. This change caused moisture from the poles to be deposited as snow at the equator. The idea is based on work by a team of scientists led by astronomer Jacques Laskar ... Laskar's team has shown that the tilt of Mars on its axis can vary between 15 degrees and 40 degrees, largely because of its lack of a significant moon. By contrast, the Earth varies little from its tilt of 23.5 degrees ... [See also Science Daily. Note what would happen if Earth did not have such "a significant moon." See section PE of my "Problems of Evolution" book outline, "Earth's fitness for life ... Moon ... Stabilises Earth's axial tilt".]

Genes Show Signs Brain Still Evolving, ABC/AP, Lauran Neergaard, September 8, 2005. ... The human brain may still be evolving. So suggests new research that tracked changes in two genes thought to help regulate brain growth, changes that appeared well after the rise of modern humans 200,000 years ago. ..."We, including scientists, have considered ourselves as sort of the pinnacle of evolution," noted lead researcher Bruce Lahn ... whose studies appear in Friday's edition of the journal Science. ... Lahn and colleagues examined two genes, named microcephalin and ASPM, that are connected to brain size. ... Scientists attempt to date genetic changes by tracing back to such spread, using a statistical model that assumes genes have a certain mutation rate over time. For the microcephalin gene, the variation arose about 37,000 years ago, about the time period when art, music and tool- making were emerging, Lahn said. For ASPM, the variation arose about 5,800 years ago, roughly correlating with the development of written language, spread of agriculture and development of cities, he said. .... That the genetic changes have anything to do with brain size or intelligence "is totally unproven and potentially dangerous territory to get into with such sketchy data," stressed Dr. Francis Collins ... "There's just no correlation," said Duke's Wray, calling education and other environmental factors more important for intelligence than DNA anyway. ... [See also: BBC. It does not follow that just because there are variants in these genes that "The human brain may still be evolving", i.e. it could just be fluctuations around a mean. The fact is that the human brain reached its current size in anatomically modern Homo sapiens ~100,000 years before behaviourally modern Homo sapiens appeared ~40,000 ago.]

Fossils reveal prehistoric flying giants, ABC/Reuters, September 9, 2005. The giant reptiles [pterosaurs] that flew above the earth until about 65 million years ago could have grown to twice the size originally thought with wingspans of at least 18 metres, a palaeontologist says. That would be almost the same width as the 19.5 metre fully-extended wingspan of an F-14 Tomcat fighter aircraft and roughly five times bigger than an albatross, which ranks among the birds with the largest wingspans in the modern world. Dr David Martill ... says his research on pterosaur wings appeared to solve the problem of how such enormous creatures managed to take to the skies and stay there... Flying reptiles just got bigger, BBC, onathan Amos, 8 September 2005 ... But there was nothing ugly about the way they moved through the air, according to expert Dr David Martill ... Their ability to utilise air currents, thermals and ground effects would astonish aeroplane designers, he said. "Pterosaurs were beautifully engineered," ... "Their skeletons were exceedingly light: their bones were very thin and hollow, and those hollows were filled with an air-sack system. They'd also got rid of their reptilian scales and their wing membrane was very, very thin. "All this meant there wasn't that much weight to get off the ground, and so they probably flew really rather well," ... there is evidence from rare fossil eggs containing pterosaur embryos which suggests the creatures could fly soon after hatching. If this was the case, scientists say, it was a remarkable achievement because the wings would have had to have grown from just a few tens of centimetres in length to several metres without interrupting the animals flying capability. "The equivalent of an aircraft engineer trying to convert a Eurofighter into a jumbo jet while it was still flying," enthused Dr Martill. ... [More evidence that pterosaurs were primarily gliders from high points, since otherwise there would seem no point, and in fact a major disadvantage, to having such a huge wingspan? The language of intelligent design is again noted!]

Scientists given go-ahead for 'dual mother' embryo, ABC, September 9, 2005. ... A team of scientists in Britain have been granted official approval to create a human embryo using genetic material from two women, raising the future prospect of babies with a pair of mothers. The group from Newcastle University in Britain has been given the green light by the Human Fertilisation and Embryology Authority (HFEA)... The scientists will transfer the pro-nuclei - the components of a human embryo nucleus - made by one man and woman into an unfertilised egg from another woman. This technique is intended to help prevent mothers from passing on so-called mitochondrial diseases on to their unborn babies, genetic conditions caused by DNA outside the nucleus of a cell, in the mitochondria. .... Professor John Burn ... stressed that the new tests would not lead to "designer babies". "From a philosophical or medical point of view there is no reason why we should not do this," he said. "I would use the analogy of simply replacing the battery in a pocket radio to explain what we are doing. You are not altering the radio at all -- just giving it a new power source. .... However, campaigners expressed concern at the project. "This shows once again that the HFEA does not have any regard for public consultation and the views of the public," Josephine Quintavalle from the Comment on Reproductive Ethics group ... Embryo May Be Created From Two Women, ABC News, September 9, 2005 ... The application was initially rejected because of legislation prohibiting the alteration of the genetic structure of a cell while it is forming part of an embryo, the [HFEA] ... said ... he scientists eventually were given permission after reviewing the legislation. ... No treatment exists for mitochondrial diseases, which arise from DNA outside the nucleus and are inherited separately from DNA in the nucleus. ... The research does not involve human cloning. It would use normal IVF procedures, but before the sperm and egg fused, components would be implanted into a healthy female egg. ... [See also BBC & The Guardian. Agreed that this is not to create "designer babies" in the sense of improving humans (which I am against), but treating a disease, i.e. restoring humans back up to the normal level (which I am for). If mitochondria are all identical (apart from disease) then it is hard to see what is wrong with inserting disease-free mitochondria from another woman into an embryo. However, it worries me that from a scientific materialist "philosophical ... point of view" we are all just spare parts cobbled together by a `blind watchmaker', so then there would be no reason why we should not further interchange spare parts, like "simply replacing the battery in a pocket radio."]

Stephen E. Jones, BSc (Biol).
"Problems of Evolution"

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