what evidence caused Darwin to doubt his own theory of evolution?
has the progress of science made the problem more, or less, problematic for naturalists?
why is the problem of the Cambrian explosion so significant in biology?
how many animal body plans are there in total?
how many animal body plans emerged suddenly in the Cambrian explosion?
If you haven’t yet read Meyer’s first book, “Signature in the Cell”, you should probably grab that one. It’s the best book on intelligent design that’s out right now. It talks about the origin of the first living cell, surveying all naturalistic explanations for it, and concluding that the best explanation – the one most consistent with what we know now – is intelligent design.
Darwin’s tree of life might be visible in DNA, if DNA didn’t conspire to scramble the signal.
Now that quite a few genomes have been published, a team from Australia and France went on a Darwin fishing trip in the gene pool. In the largest study of its kind to date, they examined microsatellite markers (tandem-repeated DNA motifs of 1-6 base pairs) that are widespread in eukaryotic genomes. If neo-Darwinism is correct, these non-coding stretches of DNA should reflect the tree of common ancestry by showing similar mutational patterns in related groups.
Well, they don’t. The paper by Meglecz, Neve, Biffin and Gardner in PLoS ONE is titled, “Breakdown of Phylogenetic Signal: A Survey of Microsatellite Densities in 454 Shotgun Sequences from 154 Non Model Eukaryote Species.” What went wrong?
As the title implies, the team checked 154 “non-model” species. Darwinian evolutionists tend to focus on the model species, like a particular roundworm, the fruit fly Drosophila melanogaster, and a species of watercress, because their genomes are complete and most researchers use them in experiments. Problem: they may or may not be representative:
Although information for model species is accumulating rapidly, it is insufficient due to a lack of species depth, thus intragroup variation is necessarily ignored. As such, apparent differences between groups may be overinflated and generalizations cannot be inferred until an analysis of the variation that exists within groupshas been conducted. In this study, we examined microsatellite coverage and motif patterns from 454 shotgun sequences of 154 Eukaryote species from eight distantly related phyla (Cnidaria, Arthropoda, Onychophora, Bryozoa, Mollusca, Echinodermata, Chordata and Streptophyta) to test if a consistent phylogenetic pattern emerges from the microsatellite composition of these species.
Sounds like a good test. After all, scientists shouldn’t generalize on overinflated signals, right? The team expected to find nicely behaved data interpolated between the model species. It wasn’t to be:
It is clear from our results that data from model species provide incomplete information regarding the existing microsatellite variability within the Eukaryotes. A very strong heterogeneity of microsatellite composition was found within most phyla, classes and even orders. Autocorrelation analyses indicated that while microsatellite contents of species within clades more recent than 200 Mya tend to be similar, the autocorrelation breaks down and becomes negative or non-significant with increasing divergence time. Therefore, the age of the taxon seems to be a primary factor in degrading the phylogenetic pattern present among related groups. The most recent classes or orders of Chordates still retain the pattern of their common ancestor. However, within older groups, such as classes of Arthropods, the phylogenetic pattern has been scrambled by the long independent evolution of the lineages.
There are two ways to interpret this anomaly. One is that microsatellites mutate too fast to maintain the phylogenetic signal. (This is known as a “post hoc rationalization.”)
The other is that Darwin was wrong. Data do not show a phylogenetic pattern; they show common design with some variation.
Read the rest here. I’m a skeptic on common ancestry, but not for religious reasons. I just don’t think that it’s compatible with the progress of science.
A recent article in Science begins by observing that the lack of evolutionary ancestors for the animal phyla that appear abruptly in the Cambrian explosion has been troubling to many evolutionary scientists:
Ever since Darwin there has been a disturbing void, both paleontological and psychological, at the base of the Phanerozoic eon. If his theory of gradualistic evolution be true, then surely the pre-Phanerozoic oceans must have swarmed with living animals — despite their conspicuous absence from the early fossil record.
(N. J. Butterfield, “Terminal Developments in Ediacaran Embryology,” Science, Vol. 334:1655-1656 (December 23, 2011).)
The articles goes on to explain that in 1998, tiny fossil animal embryos were reported that offered “palpable relief” to those evolutionary scientists worried about the lack of Precambrian ancestors.
However, new analyses of these microfossils now strongly suggest that they were not multicellular animals, and thus could not be Precambrian multicellular metazoa that have long been the holy grail for evolutionary paleontologists. Rather, they likely represent single-celled amoeba-like organisms.
[…]A Science Daily article on the study explains that many Darwinian scientists will be dismayed by the results of this study:
Professor Philip Donoghue said: “We were very surprised by our results — we’ve been convinced for so long that these fossils represented the embryos of the earliest animals — much of what has been written about the fossils for the last ten years is flat wrong. Our colleagues are not going to like the result.”
How did the investigators determine the nature of these ancient organisms? The fossils were exceptionally well preserved, such that, as the lead author on the paper stated, “the fossils are so amazing that even their nuclei have been preserved.” These allowed the authors to determine that these were in fact eukaryotic organisms, but not multicellular animals.
Casey goes on to answer the response by naturalists that “the fossil record is incomplete”.
I think it’s important, when deciding whether naturalistic evolution happened, to be aware of these problem areas. So often when discussing Darwinian evolution, people like journalists and philosophers and economists, etc. will just accept the theory because they trust in what experts tell them. There can be a lot of pressure in the university to not be seen as a dumb person, so that people will just go along with whatever their professor tells them to believe. And, that’s not necessarily a bad policy when time is short. However, that is taking evolution on blind faith. It’s a good thing, as we get older, to go back and revisit these things to see if they are really true.
For example, a really educated Darwinian should be able to finish a sentence like this: “People who doubt fully naturalistic evolution do so because of the following pieces of scientific evidence…” If you meet someone who cannot finish this statement, but who still espouses Darwinian evolution, then you know that you are dealing with someone who has jumped to the answer without really working through the problem by themselves. It can be very tempting, especially for artsy types, to just try to jump to the answer that all the smart people believe without really working through the problem. But that’s not a good way to decide what’s true. Everyone has to work through these problems themselves, and listening to the best people on both sides is the way to do that. People who question evolution nowadays don’t question that the universe is billions of years old or that scientific methods have to be used to answer scientific questions. By all means, let’s decide how we got here by appealing to science.
If you would like to see a nice hour-long video on the Cambrian explosion, then click here.
By the way, if you missed my previous post on the new discovery of oxygen in the early Earth’s environment, and the challenge it represents to naturalistic scenarios for the origin of life, then do check that out.
WINTERY KNIGHT 