Tag: paleontology

How Science is Reshaping the Race Debate


I’ve written about racism before. I think I’ve made it clear that I don’t think science can justify dividing us into “races.” The similarities among us are too great, and the differences within the “races” are also too great. As I have said, if you see races, you’re racist. Here’s a link to an article that covers the subject more thoroughly, including the admission that racists are not idiots. Not all of them, anyway. They know about the science too, and they know how to bend it to support their bias.

via How Science and Genetics are Reshaping the Race Debate of the 21st Century – The Seattle Star

Over the last decade, there have been hopes that the US has become a post-racial society, free of racial prejudice and discrimination. However, the most recent months indicate the contrary: race remains an incendiary issue. Race and racism are not new issues, but in today’s 21st century Trump-era, discussions about race are distinct from those of the past in that they possess an entirely new dimension: that of genetics and DNA.

Ancestry test kits are the new “it” item—and with their success is the tacit admission of our belief that our DNA can sort us into categories like the “five races:” African, European, Asian, Oceania, and Native American.

If separate racial or ethnic groups actually existed, we would expect to find “trademark” alleles and other genetic features that are characteristic of a single group but not present in any others. However, the 2002 Stanford study found that only 7.4% of over 4000 alleles were specific to one geographical region. Furthermore, even when region-specific alleles did appear, they only occurred in about 1% of the people from that region—hardly enough to be any kind of trademark.

In the biological and social sciences, the consensus is clear: race is a social construct, not a biological attribute.

… the broader public is not convinced of this. After all, if an Asian person looks so different from a European, how could they not be from distinct groups? Even if most scientists reject the concept of “race” as a biological concept, race exists, undeniably, as a social and political concept.

Despite the scientific consensus that humanity is more alike than unlike, the long history of racism is a somber reminder that throughout human history, a mere 0.1% of variation has been sufficient justification for committing all manner of discriminations and atrocities.

Mounting scientific evidence has shown that humans are fundamentally more similar than different from each other. Nonetheless, racism has persisted. Scientific findings are often ignored, or otherwise actively misinterpreted and misused to further racist agendas of extreme political groups.

If you’re interested in a synopsis of the current state of “race” and the science around it, follow the link to the original article.

via How Science and Genetics are Reshaping the Race Debate of the 21st Century – The Seattle Star

rjb

Alfred Wegener

Alfred Lothar Wegener was born in Berlin, Germany on November 1st, 1880. He was the youngest of the five children of Richard Wegener, clergyman, theologian and classical language teacher. The family was well-off enough to own a vacation home, as well as to afford to educate all their children. Alfred did very well in school and went on to study physics, meteorology and astronomy. He got a doctorate in astronomy in 1905, but had formed a strong interest in the growing disciplines of climatology and meteorology.

Public Domain

Wegener made four expeditions to Greenland in his study of the polar climate, the first in 1906. He built a weather station and made observations using kites and tethered balloons, in addition to the usual instruments. He had his first experience with the killing harshness of Greenland’s climate when the expedition leader and two others died while exploring. He returned to Germany in 1908.

His second expedition to Greenland in 1913 began with a calving glacier that almost wiped it out, and ended with a fortunate and unlikely rescue as their crossing of the interior resulted in their having to eat all of their dogs and ponies before its completion.

His military service in World War One lasted only a few months. He faced fierce fighting, was injured twice and declared unfit for duty. He spent the rest of the war in the meteorological service and published 20 papers by its end. Having published on his ideas about continental drift for the first time in 1912, Wegener followed up with a major work — “The Origin of Continents and Oceans” — in 1915. Interest was small.

After the war he worked as a climatologist and as senior lecturer at the University of Hamburg. In collaboration with Milutin Milankovich, he did pioneering work in a field that would become known as paleoclimatology, where they reconstructed ancient climates. He published the third edition of “The Origin of Continents and Oceans,” provoking discussion of his theory of continental drift, and disparagement by the experts of the day.

By 1924 he attained a position that provided stability for his family, and he was able to concentrate on his studies for the rest of the decade. In 1926 he presented his ideas on continental drift at a symposium in New York, to near-uniform rejection. In 1929 he published the fourth and final edition of “The Origin of Continents and Oceans,” and made his third expedition to Greenland.

Wegener led the 1930 Greenland expedition, his fourth, and his sense of personal responsibility ultimately led to his death. A combination of a late thaw and harsh conditions resulted in the failure of a re-supply mission and the death of Alfred Wegener. His body remains buried where he died.

Public Domain

Alfred Wegener was accomplished at astronomy, meteorology and climatology, but what he is known for today is continental drift. We’ll cover that in more detail in future posts.

rjb

Evolution – Part Three

Photo by Michael D. Gumert. – CC-BY – No larger image available

Some years ago I published a series of articles about evolution in my local newspaper. It generated some interest and a spate of letters to the editor, and my publisher liked it. There was even a creationist who challenged me to a debate over it. I decided to reproduce it here. This is part three, which I called Walk This Way. See also Part One and Part Two.

The first primates show up in the fossil record about 50-55 million years ago. They are part of the resulting explosion of new species that evolved to fill environmental niches vacated by the non-avian dinosaurs, after they went extinct sixty-five million years ago. Many of the new species are mammals, and we see a mammal-dominated landscape right now. Of the mammals, it is the primates which interest us the most, as they are our ancestors. Primates spread out and evolved into many different species, including lemurs, monkeys and apes. They can be found in most parts of the world, but it was in Africa where the line led to humans.

Between seven and eight million years ago a primate living in Africa split into two species. Such splits normally result when two populations of one species get separated somehow. Something like that happened to the common ancestor of chimpanzees and humans. A fossil from that period shows definite signs of an upright, two-legged gait, but the oldest hominin fossil with extensive bipedal adaptations is Ardipithecus ramidus. That was the beginning of the hominin, or human-like primate. Since then it evolved and radiated out into many different hominin species, most of which have gone extinct.

The first evidence of stone tools shows up at least 2.6 million years ago, with some evidence that pre-homo hominins were using them as early as 3.3 million years ago. Undoubtedly they were using tools made of other materials like wood and grass, but only stone can survive long enough for us to find.

Homo erectus is thought to have tamed fire by about 1.8 million years ago. Others put the use of hearths beginning later, at about 800,000 and even only 300,000 years ago. Much of the discussion revolves around whether we were simply burning grasslands to improve hunting, or actually sitting around a hearth cooking food on a regular basis. Those favoring the earlier date cite the shrinking jaw and growing brain of H. erectus as evidence that they were cooking their food. The pinnacle of upright hominids seemed to have been reached, but their brains were only about half the size of ours. Larger than the brains of similar-sized animals, but still too small by our standards.

Increasing brain size was the next big step. By the time we reach the age of Neanderthals, about four hundred thousand years ago, and modern humans at about half that, our brains were as big as they are now.

Since then it’s been a matter of social and technological evolution. The first jewelry shows up about 75-100 thousand years ago. The first garments appear to have been manufactured about 100 thousand years earlier, based on the evolution of body lice. The tool set became extremely sophisticated.

Neanderthals died out about thirty thousand years ago, leaving only a single hominid species on Earth for the first time in millions of years. Our cultural evolution continued to accelerate, as evidenced by sophisticated cave paintings, bringing us to the present state of high civilization.

Let’s hope we’re not due for another mass extinction.

rjb

Evolution – Part Two

Credit United States Geological Survey – Public Domain – Tap for large original

Some years ago I published a series of articles about evolution in my local newspaper. It generated some interest and a spate of letters to the editor, and my publisher liked it. There was even a creationist who challenged me to a debate over it. I decided to reproduce it here. This is part two, which I called Tough Life. See also Part One and Part Three.

Life started on Earth just about as soon as it could. When the Solar System condensed out of a vast cloud of dust and gas about four and a half billion years ago, Earth was a molten globule. It was kept molten for a few hundred million years by a continuing bombardment of comets and planetoids among the thick debris. Eventually, as fewer collisions occurred, Earth cooled and its crust formed and hardened. It was still so hot that the huge quantity of water delivered by the comets was kept vaporized. Only after about 500 million years had it cooled enough for standing water to form on the surface. Not long after that we begin to see fossils of tiny organisms.

There is a question whether life formed through the evolution of chemistry on this planet, or arose from space-borne particles. Either way it’s been here for almost four billion years. The fact that it took root as soon as it could and has survived for so long both show how tough and persistent life is. It has had to be. There have been at least five major extinctions that we know of in the interim. There were probably more, but we haven’t unearthed the evidence yet. Some of the extinction events extinguished over ninety percent of the species on Earth. Once in a long while everything changes forever.

The first creatures were tiny, simple, single-celled organisms. They didn’t even have a nucleus, their DNA floating freely within the cell. From them evolved more complex forms of life, with DNA in a nucleus and other structures performing ever more complicated tasks. About two and a half billion years ago evolution produced a radical change. A microbe appeared which could use sunlight to synthesize food from water and carbon dioxide. Unfortunately for the existing life forms, the oxygen produced as a byproduct was a deadly poison. Things were changed forever.

About five hundred forty million years ago the abundance of free oxygen provided the energy for another radical change. Multicellular life arrived and proliferated in an explosion of diversity. It was a matter of time before some of it found a way to live on land, away from the competition and sharp teeth in the sea. It wasn’t long, in geological terms, before the land was covered in a riot of life. Evolution filled every niche with a profusion of species, including the majestic dinosaurs. Then the most famous mass extinction happened sixty-five million years ago. Dinosaurs were out and mammals were in.

Life took hold here early and has persisted by evolving and adapting to a state of permanent change.

rjb

How Did Life on Earth Begin

Today life has conquered every square inch of Earth, but when the planet formed it was a dead rock. How did life get started?

We have probably been wondering for millennia how life started on Earth. At some point we decided that it must have been done by one or more gods, and we’ve elaborated that hypothesis as it evolved over the ages. We’ve never tested it, though. No one has ever done an experiment to see if a god could create life. We just sort of said that they must have because, well, how else could it have happened? The judicious application of exclusion, torture and execution kept the questions to a minimum.

Eventually we reached a point where inquiry could no longer be peremptorily quashed, at least not everywhere all the time, and we began to look at the question in a more naturalistic way. That is, could life have arisen on Earth through the natural workings of physical elements and forces? The linked BBC article is a long, comprehensive look at the evolution of this inquiry over the last two hundred years or so. I strongly recommend reading it, but in the case of TL;DR, here’s the condensed version: We haven’t settled on a single theory yet, but we’ve certainly shown that’s it’s plausible.

From the BBC article:

The oldest known fossils are around 3.5 billion years old, 14 times the age of the oldest dinosaurs. But the fossil record may stretch back still further. For instance, in August 2016 researchers found what appear to be fossilised microbes dating back 3.7 billion years.

This means we can define the problem of the origin of life more precisely. Using only the materials and conditions found on the Earth over 3.5 billion years ago, we have to make a cell.

Before the 1800s, most people believed in “vitalism”. This is the intuitive idea that living things were endowed with a special, magical property that made them different from inanimate objects.

… the big biological breakthrough of the 19th Century was the theory of evolution, as developed by Charles Darwin and others.

The idea that life formed in a primordial soup of organic chemicals became known as the Oparin-Haldane hypothesis. It was neat and compelling, but there was one problem. There was no experimental evidence to back it up. This would not arrive for almost a quarter of a century.

The Miller-Urey experiment.

Miller connected a series of glass flasks and circulated four chemicals that he suspected were present on the early Earth: boiling water, hydrogen gas, ammonia and methane. He subjected the gases to repeated electric shocks, to simulate the lightning strikes that would have been a common occurrence on Earth so long ago.

And five more chapters follow. It’s really worth the read. But I think I can safely guarantee that the creationists won’t be convinced. They prefer the age of vitalism.

Source: The secret of how life on Earth began

For your interest, see my previous posts on Panspermia and life in the Solar System.

rjb

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