The building blocks from which DNA is made are known as deoxynucleoside-5′-triphosphates (dNTPs), which are made up of the familiar four DNA bases – Adenine, Guanine, Cytosine, and Thymine – plus a deoxyribose sugar and three phosphate groups. dNTPs are produced by the enzyme ribonucleotide reductase (RNR), and the enzymes that replicate DNA must obtain these molecules from the solution around them.
Imagine you have a tower of randomly coloured lego bricks, which you are trying to construct an identical copy of. The problem is that the materials you are using are not orderly arrayed on the floor but are instead being thrown at you randomly and must be caught before use. Continue reading →
We have a new contender for the title of “oldest known galaxy”: it has a redshift of z = 7.51, corresponding to an age only 700 million years younger than the universe as a whole, and has been assigned the code z8_GND_5296. Discoveries like this happen fairly often, as there is a sustained effort of astronomers staring at little red dots with similarly arcane designations in the hope of teasing out a little more information about the early evolution of galaxies. Continue reading →
I’m feeling a rush of what seems to be nostalgia: I’m sure it’s been ages since we saw such a classic example of an attempt to prove that the Earth is young via the use of an overly simplistic understanding of geological processes as we have here in Counting Earth’s Age in Lightning Strikes, by Brian Thomas.
You no doubt still remember Friday’s post, in which we looked at an article by Brian Thomas and Frank Sherwin called Human-like Fossil Menagerie Stuns Scientists (screenshot) that horribly mangled the science around Dmanisi skull 5 to claim that it showed that all early Homo species were fully human in the modern sense, while Australopithecus and others were just apes. While they correctly noted that many species would have to be “wiped from the textbooks” – quoting from a Guardian article they couldn’t go too far wrong there – they went so far in their enthusiasm as to claim that human evolution itself should be similarly erased. For my part I suggested that the ICR may want some new science writers, as their article went over and above the call of duty when it comes to misrepresenting scientific results for creationist ends. Seriously: I could do much better.
Today, in a spectacular turnaround, Brian Thomas alone has published a second article on the same fossil called New ‘Human’ Fossil Borders on Fraud. Having previously argued that Dmanisi skull 5 was a problem for evolution, he now suggests (while not so much as acknowledging the previous article) that it’s really a fraud in some manner, perpetrated by researchers to prop up evolution. Thomas doesn’t seem to be claiming that the skull itself is a fraud, in the manner of Piltdown Man, but that it’s really just a Australopithecine that anthropologists are calling early Homo for their own ends. Continue reading →
Researchers recently studied a highly sophisticated cellular machine that acts as a guard for the genome against harmful mutations and that evolution cannot explain.
Grammar is a wonderful thing – does he mean that “evolution cannot explain” the protein or the mutations? I don’t know for certain, but we’re going to have to use the former as our working assumption. Continue reading →
I should post follow-ups on old posts more often. Minda Berbeco at the NCSE’s new blog, Science League of America, has tracked down the primary author, Morgan Kelly, of a paper that Brian Thomas misinterpreted back in June about adaptation in sea urchins. Kelly answered a few of Berbeco’s questions on her research, including:
Could you explain how the ICR article misrepresented your results?
There were a couple problems with their interpretation of my research. First of all, there is a difference between the potential to adapt and having already done so. It seems that they have misinterpreted our findings to say that urchins have already adapted. That’s not what we were looking at.
There’s more. Of course there’s more. I’ve emailed researchers in the past to notify them of ICR articles, and the typical response notes that the creationist piece does indeed horribly mangle their research and conclusions. Rarer is a detailed explanation of what is really going on – real scientists are busy – but when it happens it’s a treat. Read on!
Palaeontologists at Dmanisi, an increasingly famous village in Georgia, have made some quite interesting discoveries: a small collection of early Homo skeletons from people living in the same place at the same time that are nevertheless fairly variable in appearance, as exemplified by the recently-described “skull 5.” The usual rules of population dynamics say that you can’t have different species that have the same niche (i.e. they have same shtick – they live in the same way, eat the same food etc) living in the same place – one of them will quickly win out and exclude the others. If this hasn’t happened – and it doesn’t seem to have at Dmanisi – we must conclude that the organisms are or were of the same species. Continue reading →
Here’s a question that everyone seems to want an answer to: how did freshwater organisms survive a salty flood? A recent article at Your Origins Matter, Flood Survivors – derived from an Acts & Facts article by John Morris from 2011 called Fish in the Flood – tries to offer some solutions. After first acknowledging that survival would have been very difficult, and that most didn’t make it, Morris produces his first idea:
In the complex of events and conditions that made up the Flood, certainly there were pockets of fresh water at any one time. Remember, it was raining in torrents, and we can expect that the rain water was fairly fresh. Many studies have shown that waters of various temperatures, chemistries, and sediment loads do not tend to mix; they tend to remain segregated in zones. It would be unlikely for any one area to retain such zones for very long during the tumult of the Flood, but on a worldwide scale, some such segregated zones would have existed at any given time.
As should really be common knowledge, there’s no shortage of nitrogen in the atmosphere. This is, however, in the form of plain old N₂, which while it contains the right element is not very useful for life on Earth. This makes usable – “fixed” – nitrogen a major limiting factor for plant growth. Humans can fix nitrogen for fertiliser directly from the atmosphere via industrial-scale processes which aren’t readily available to the biosphere at large, but other sources do exist. Lightning, for example, is supposed to fix nitrogen into NO₂, but this probably isn’t an approach you can rely upon on the long term. Animals seem to have no difficulty in obtaining nitrogen for themselves – i.e. by eating other organisms – and in an unusual reversal of roles certain plants and fungi will actively capture and kill (small) animals for their nitrogen and other nutrients. Continue reading →