by cofty 81 Replies latest watchtower beliefs
As I said more lurking JWs and ex-JWs who hang on to creationism will be made to think by this thread than by posting a link to an off-site pdf.
It has already led to some discussion and the chance to answer some questions.
Once this is finished I will probably go on to other similar books and then you can dismiss them too and tell me why that is also a waste of time.
Thanks for the links BTS. I will check them out later when I have a bit more time.
Cofty, please keep it coming. Since my time is limited, I have to be judicious in my selection of threads to spend my time on. I have my faves... this is one of them. I hope to read the book one day along with others such as Darwin's "On the Origin of Species".
Part 12
Chapter 6 - Missing Link, What Do You Mean Missing? Creationists love to crow on about missing links. They are never sure what they mean by that exactly but they tend to repeat things they heard from people who were repeating things they had heard from people who…
The first thing to take away from this chapter is that evolution does not depend on the fossil record. If not one single fossil existed it would make not a jot of difference to the evidence for evolution.
Dawkins returns to the illustration of examining a crime scene and weighing the evidence. There is solid proof of the identity of the culprit including fingerprints, footprints, DNA, and a solid motive. The prosecution is ready to go to trial with a watertight case when, right at the last moment somebody finds cctv footage recorded around the time and location of the crime. When it is examined it also points to the same person, but the defense lawyer points out that the film is incomplete and therefore the whole case against his client is wrong. The fossil record is a bonus; there is more than enough evidence for the fact of evolution in the comparative study of modern species, and their geographical distribution without a single fossil. (More on these specifics in later chapters) It’s paradoxical to use gaps in the fossil record as if it was evidence against evolution.
A scientific theory is one that is subject to disproof and yet is not disproved. A single Precambrian rabbit fossil would be devastating evidence against evolution, and yet not a single fossil has ever been found in anything other than the layers where evolution would predict it to be. This point bears repeating. Creationists should all be out in the field looking for anachronistic fossils.
This chapter will firstly challenge a number of the misconceptions about the world that underpin many of the misguided questions regarding the fossil record and then present some amazing examples of transitional fossils that seem to escape the notice of creationists.
Part 13
Chapter 6 - Missing Link, What Do You Mean Missing? ...continued
When you consider the process of how a fossil comes to exist it’s amazing we have any at all. The following paragraph is based on “Why Evolution is True” by Jerry A. Coyne p22.
First the remains of an animal must find their way into water, sink to the bottom and quickly get covered in sediment to prevent it from decaying or getting eaten. That’s why most fossils are of marine creatures; land animals don’t die in water too often. Once buried the hard parts of the creature gradually get replaced by dissolved minerals to form a cast of the original. As sediments pile on top it becomes compressed and eventually turns into rock. Over time it must survive the endless shifting, folding, heating and crushing of the Earth’s crust, processes that obliterate most fossils. Most fossils are buried deep in the earth’s crust, only when the sediments are raised and exposed by erosion can they be found and then, only for a short time before they are effaced by wind and water.
It is no surprise then that there are gaps in the fossil record. It is estimated that we have fossil evidence for between 0.1% and 1% of all the species that have ever lived.
Soft parts of plants and animals are not easily fossilized which creates a severe bias in what we can know about ancient species. Bones, teeth and shells are abundant but there was a time in earth’s history before creatures had any of these features. For the first 80% of the history of life all species were soft-bodied leaving a gap in the record before the so-called Cambrian Explosion 500 million years ago, which is so beloved of creationists.
To illustrate the impossibility of ever finding a fossil record of life before this time, consider the example of the flatworms. Today there are more than 4000 species of turbellarian worms, that’s as numerous as all the mammal species put together. They have been plentiful in water and on land for a very long time and yet not a single fossil of these creatures has ever been found. Nobody believes they were created by god just last week and yet there is absolutely no record of their past.
Likewise with the rest of the animal kingdom before the Cambrian, half a billion years ago something happened to allow animals to fossilize freely – the arising of hard, mineralised skeletons.
Missing Links
Frequently it is the links between humans and other primates that creationists have in mind when they refer to missing links. We will soon be looking at some examples of the rich supply of intermediate fossils connecting modern humans to our common ancestor that we share with chimpanzees. Interestingly, although we have lots of evidence on that line of descent we have no fossils on the line between that common ancestor and modern chimps. Probably this is because chimps live in forests which don't provide good conditions for fossilization.
Creationists also demand evidence of links between major groups of creatures. Again we will be looking at some excellent examples of transitional forms but Dawkin's first point is that its a mistake to respond to this sort of challenge by pointing to famous examples Archaeopteryx. The challenge is based on a misunderstanding of Darwin's theory, an outdated conception that used to be known as "The Great Chain of Being".
The medieval myth of the Great Chain of Being persists in the minds of many. God reigned from the top of the ladder above various ranks of angels, humans, assorted animals then plants and inanimate objects. (I seem to remember a watchtower equivalent) Of course in this male-centric worldview women and the various races of mankind each took their subjective places on the imaginary ladder.
Although this mental image may have been partially dismantled, there is still a casual assumption that living things have some kind of ranking. It seems natural to suppose that lower creatures evolved into higher ones and therefore it seems reasonable to ask, “Where are the missing links?”
For example, it seems obvious that chimpanzees are higher animals than earthworms doesn’t it? We may even assume that evolution makes this fact even clearer and justifies it. In fact such thinking is deeply flawed and antithetical to evolution.
Consider what we may actually mean when we assert that chimps are “higher” than earthworms.
1. Perhaps we have in mind that monkeys evolved from earthworms - This is a just plain wrong, chimps and worms share a common ancestor. It is this kind of thinking that causes creationists to ask daft questions like why are there still chimps today if they evolved into humans? Or, where are the fossils of all the crocoducks or fronkeys? Australian creationist John McKay has been touring British schools, masquerading as a geologist, and teaching children this kind of nonsense.
2. We may mean that the common ancestor of chimps and worms looked a lot more like a worm than a monkey – This may be true but it really tells us nothing useful about the two creatures we are comparing. It’s just as likely that both animals have diverged equally in different directions from their common ancestor. Also it is likely that different parts of an animal will be more or less “primitive” than other parts. For example a horses hoof is simpler than a human foot (it has a single digit to our 5) but it is the human foot that is more “primitive” our common ancestor had 5 digits.
3. Often there are any one of a number of odd assertions in our mind when we try to rank animals by some arbitrary scale – cleverer, prettier, bigger genomes, more complicated body plans etc. These are all pointless judgments. Animals may rank highly on one ladder and poorly on another. A salamander has a smaller brain than some mammals but it has a bigger genome!
4. Often we are in fact judging how much an animal is similar to us humans when we rank them in our minds. Why? This is a very important point that we need to get over if we are going to understand the world. Evolution had no point, it has not been slaving away all these years for the purpose of making you and I. This is why we find ourselves asking questions like “what is the point of cockroaches?” There is no point; they are gene machines just like us. Do not make the mistake of using humans as the gold standard of living things.
5. OK so at least are chimps are better evolved to survive than lower animals? This assumption just does not hold up. Insects rule the world while some of our most majestic creature teeter on the edge of extinction.
It is just nonsense to rank modern species on an imaginary ladder. It is this wrong-headed way of seeing the world that prompts demands for “missing links”. When paleontologists rush to offer fossils like Archaeopteryx in response they are in fact pandering to a fallacy.
Part 14
Chapter 6 - Missing Link, What Do You Mean Missing? ...continued
Up From The Sea One of the most amazing transitions in the history of life was the emerging of animals from the oceans. How a creature moves and breathes is so different in the two environments that radical shifts are required in almost all parts of the body.
There was a time when everything - plant and animal life -lived in the sea and then, at various points in evolutionary history creatures have succeeded in making the dangerous trek out of life's watery tomb. Fortunately the transitional stages of our exodus as fish emerged onto dry land, and the later trek back to water by the ancestors of whales, are beautifully documented in the fossil record. Fish-world can conveniently be divided in two; ray-finned fishes (every fish you have ever seen that isn’t a shark) and lobe-finned fish who have fins more like legs as we shall see shortly. Lobefins in the sea today have dwindled to the lungfishes and coelacanths. On land they have prospered; all land vertebrates including humans are aberrant lungfish.
It was believed that coelacanths were long since extinct, known only from 200 million year old fossils. Then in 1938 a South African trawler man caught one in his nets. Biologist J.L.B. Smith who examined it said “I would not have been more surprised if I had seen a dinosaur walking down the street”. 
Coelacanths are closer cousins to us than they are to most fish. Nevertheless we are not descended from lungfish, we share a common ancestor with them that would have looked more like them than it looked like us. To find this ancestor we need to look at the part of the fossil record known as Romer’s gap, named after American palaeontologist A.S. Romer. The gap stretches from the end of the Devonian 360 million years ago when fish ruled the oceans, to the early Carboniferous 340 million years ago when amphibians, often gigantic ones, roamed the swamps.
In recent years some amazing finds have bridged this gap…..
Some of what follows is taken from "Your Inner Fish" by Neil Shubin.
In 1925 a Canadian farmer called Joseph Landry shipped a crate of fossils to the Swedish museum of natural history Packed inside was a superb half-metre long specimen of Eusthenopteron, virtually complete and preserved in three-dimensions, a fish that died 380 million years ago, but in appearance not much different from one lying on a fishmonger's slab. Landry, who collected fish fossils for the museum on commission, was paid $50 for this specimen. 
Erik Jarvik took decades to examine the specimen grinding it down a fraction of a millimetre at a time mapping the conduit of nerves and blood vessels and the position and shape of glands, organs and braincase. From the 40’s through to the 90’s Jarvik published a series of papers on his findings. He showed that the skull matches closely those of early amphibians and that the teeth had features that are also present in primitive tetrapods.
The front fin was supported by bones identifiable as a humerus, ulna and radius, and the rear fins by a femur, fibula and tibia. Clearly, the fins of Eusthenopteron contained the bones of the paired limbs of all tetrapods, although bones distal to a wrist or ankle are not present. More than 2000 specimens of Eusthenopteron have been collected from the same location at the Miguasha cliffs. These were surface-hunting fish and probably never came onto the land but clear progress was evident towards an amphibian body plan.
Nearer the amphibian side of the gap 20 million years later comes Ichthyostega discovered in Greenland in 1932 and buried there in the days when Greenland was at the equator. Ichthy looked more like a giant salamander, it lived mostly in the water and probably made occasional forays onto land. It had the flat head so characteristic of amphibians and the same; big bone – two thinner bones – lots of little bones – digits; layout of it’s limbs. One obvious difference was its seven toes instead of what became the standard set of five. 
Another exciting discovery from Greenland from the same period was Acanthostega. It too had a flat amphibian like skull and tetrapod-like limbs but it had opted for eight digits. It too was mainly a water-dweller but it had lungs and could cope with land when necessary.
The fascinating story of its discovery by Jenny Clack the "Diva of the Devonian" is recounted in this excellent BBC documentary that was part of the "Beautiful Minds" series.
... All of these “links” can roughly be described as amphibian-like fish or fish-like amphibians.
A team of scientists from the University of Pennsylvania led by Neil Shubin set out to bridge the remaining gap.
He studied the geological maps for the right kind of rocks from the correct period and found a likely candidate at Ellesmere Island in northern Canada. For four arctic summers he and his colleagues searched and found a few tantalising clues but nothing definitive. In the fourth year of the expedition, the last one his sponsor was going to fund, he found one of the most important fossils in all of history. 
If you were asked to sketch the perfect transitional creature between a fish and a reptile you could not do better than Titkaalik. It’s got a crocodile-like head on a salamander’s trunk attached to a fish rear end with a tail. Unlike any fish it also had a neck! If you were asked to draw the perfect intermediate creature between a fish and an amphibian you could not come up with anything better than Titkaalik. It’s leg bones follow the tetrapod model and there is even evidence of muscle attachments for substantial pecs. This was a fish that could do push-ups! And it was discovered in rock of exactly the right age; evolution can make scientific predictions!
The story of life's transition from water to land is wonderfully preserved in the fossil record. The development of all sorts of anatomical features has been preserved with the sort of detail we have no right to expect.
Below is an illustration of the evolution of the structure of tetrapod limbs taken from the NCSE website.
Coming next - back to the sea ...
Ohhh! The pics! I actually had this on audio book, so I've never seen the pics.
The pics are not the originals in Dawkin's book but they illustrate the main points.
Part 14
Chapter 6 - Missing Link, What Do You Mean Missing? ...continued
Back to the sea Having spent at least 20 million years acquiring the machinery to survive on dry land and hundreds of millions more diversifying and exploiting every conceivable niche, a number of landlubbers made their way back to the sea.
Among these were pond snails, water spiders, water beetles, crocodiles, otters, sea snakes, water shrews, Galapagos flightless cormorants, marine iguanas, penguins and turtles. Of course the most impressive example of all are the whales and their little cousins the dolphins. These have gone all the way back to an aquatic existence as have dugongs and their close cousins the manatees jointly known as the sirenians, they don’t even come ashore to breed. They do however still breath air, having never developed anything resembling the gills of their ancestors. Seals and sea lions on the other hand have only gone part-way back and are a living example of what intermediate species must have been like. 
Manatee
When it was first suggested that whales had evolved from land mammals creationists were, not surprisingly, somewhat dismissive. In recent years the evidence from genetics and from the fossil record provides us with a rich record of their history.
Their genome shows that the closest living relative of whales are hippos. Molecular evidence shows that hippos are more closely related to whales than they are to cloven-hoofed animals like pigs and the ruminants. If anybody has seen hippos in deep water you cannot have failed to be impressed with how graceful these giants are. But as they have stayed at least partly on land, they still resemble their more distant cousins the ruminants, while their close cousins the whales took to the water and changed so drastically that their close affinity was only discovered by the molecular geneticists.
While the boffins were busy in the lab the palaeontologists were getting their hands dirty in the field. In Pakistan a rich seam of fossils has been discovered that sheds light on the evolution of the whale. A whole series of specimens beautifully demonstrates the gradual disappearance of the hind legs, the transformation of the front legs from walking limbs to swimming fins and the flattening of the tail into a fluke.
Pakicetus
Ambulocetus
Basilosauros
Dorudon
A few months ago a fascinating series of four documentaries on British TV showed in detail the dissection of 4 of natures giants including a giraffe, an elephant, a crocodile and a whale. The whale had become stranded on a beach and an expert flew in from Canada to lead the autopsy. The final scene showed her deep inside the body of the giant pointing at relatively tiny little pelvis and leg bones! 
Whale
I personally find this amazing. On the one hand (excuse the pun) we have astonishing fossils like Ichthyostega and tiktaalk showing the development from lobe fins to legs with their - big bone, two bones, lots of bones, 5 or more digits – body plan, and now we have the fossils for one branch of their vertebrate descendants going back the other way.
The journey from useful back legs to the vestigial ones we see today is so clearly depicted in the fossils that this alone should forever silence the demands of “where are the missing links”
The following diagram is from the book, “Why Evolution is True” by Jerry A. Coyne. 
Dawkins concludes the chapter with evidence from both the genetics and fossils of the kinship between sirenians and their close cousins the modern elephants via an outstanding fossil called pezosiren who had an unmistakably sirenian skull but four walking legs. Similarly a 20 million year old fossil of Pujilia darwini from the Canadian arctic bridges the gap in the ancestry of modern seals, sea lions and walruses.
Pezosiren - ancient dugong
Finally the fascinating history of turtles and tortoises is examined.... coming next
Love the pictures of the fossils.
Looking forward to the next chapter.
WOW!!! I'm building my library and looking for Cofty and Terry's book list so I can order books in addition to Dawkins.
