Posted on 02/08/2005 3:50:43 AM PST by PatrickHenry
A group of four-footed mammals that flourished worldwide for 40 million years and then died out in the ice ages is the missing link between the whale and its not-so-obvious nearest relative, the hippopotamus.
The conclusion by University of California, Berkeley, post-doctoral fellow Jean-Renaud Boisserie and his French colleagues finally puts to rest the long-standing notion that the hippo is actually related to the pig or to its close relative, the South American peccary. In doing so, the finding reconciles the fossil record with the 20-year-old claim that molecular evidence points to the whale as the closest relative of the hippo.
"The problem with hippos is, if you look at the general shape of the animal it could be related to horses, as the ancient Greeks thought, or pigs, as modern scientists thought, while molecular phylogeny shows a close relationship with whales," said Boisserie. "But cetaceans – whales, porpoises and dolphins – don't look anything like hippos. There is a 40-million-year gap between fossils of early cetaceans and early hippos."
In a paper appearing this week in the Online Early Edition of the Proceedings of the National Academy of Sciences, Boisserie and colleagues Michel Brunet and Fabrice Lihoreau fill in this gap by proposing that whales and hippos had a common water-loving ancestor 50 to 60 million years ago that evolved and split into two groups: the early cetaceans, which eventually spurned land altogether and became totally aquatic; and a large and diverse group of four-legged beasts called anthracotheres. The pig-like anthracotheres, which blossomed over a 40-million-year period into at least 37 distinct genera on all continents except Oceania and South America, died out less than 2 and a half million years ago, leaving only one descendent: the hippopotamus.
This proposal places whales squarely within the large group of cloven-hoofed mammals (even-toed ungulates) known collectively as the Artiodactyla – the group that includes cows, pigs, sheep, antelopes, camels, giraffes and most of the large land animals. Rather than separating whales from the rest of the mammals, the new study supports a 1997 proposal to place the legless whales and dolphins together with the cloven-hoofed mammals in a group named Cetartiodactyla.
"Our study shows that these groups are not as unrelated as thought by morphologists," Boisserie said, referring to scientists who classify organisms based on their physical characteristics or morphology. "Cetaceans are artiodactyls, but very derived artiodactyls."
The origin of hippos has been debated vociferously for nearly 200 years, ever since the animals were rediscovered by pioneering French paleontologist Georges Cuvier and others. Their conclusion that hippos are closely related to pigs and peccaries was based primarily on their interpretation of the ridges on the molars of these species, Boisserie said.
"In this particular case, you can't really rely on the dentition, however," Boisserie said. "Teeth are the best preserved and most numerous fossils, and analysis of teeth is very important in paleontology, but they are subject to lots of environmental processes and can quickly adapt to the outside world. So, most characteristics are not dependable indications of relationships between major groups of mammals. Teeth are not as reliable as people thought."
As scientists found more fossils of early hippos and anthracotheres, a competing hypothesis roiled the waters: that hippos are descendents of the anthracotheres.
All this was thrown into disarray in 1985 when UC Berkeley's Vincent Sarich, a pioneer of the field of molecular evolution and now a professor emeritus of anthropology, analyzed blood proteins and saw a close relationship between hippos and whales. A subsequent analysis of mitochondrial, nuclear and ribosomal DNA only solidified this relationship.
Though most biologists now agree that whales and hippos are first cousins, they continue to clash over how whales and hippos are related, and where they belong within the even-toed ungulates, the artiodactyls. A major roadblock to linking whales with hippos was the lack of any fossils that appeared intermediate between the two. In fact, it was a bit embarrassing for paleontologists because the claimed link between the two would mean that one of the major radiations of mammals – the one that led to cetaceans, which represent the most successful re-adaptation to life in water – had an origin deeply nested within the artiodactyls, and that morphologists had failed to recognize it.
This new analysis finally brings the fossil evidence into accord with the molecular data, showing that whales and hippos indeed are one another's closest relatives.
"This work provides another important step for the reconciliation between molecular- and morphology-based phylogenies, and indicates new tracks for research on emergence of cetaceans," Boisserie said.
Boisserie became a hippo specialist while digging with Brunet for early human ancestors in the African republic of Chad. Most hominid fossils earlier than about 2 million years ago are found in association with hippo fossils, implying that they lived in the same biotopes and that hippos later became a source of food for our distant ancestors. Hippos first developed in Africa 16 million years ago and exploded in number around 8 million years ago, Boisserie said.
Now a post-doctoral fellow in the Human Evolution Research Center run by integrative biology professor Tim White at UC Berkeley, Boisserie decided to attempt a resolution of the conflict between the molecular data and the fossil record. New whale fossils discovered in Pakistan in 2001, some of which have limb characteristics similar to artiodactyls, drew a more certain link between whales and artiodactyls. Boisserie and his colleagues conducted a phylogenetic analysis of new and previous hippo, whale and anthracothere fossils and were able to argue persuasively that anthracotheres are the missing link between hippos and cetaceans.
While the common ancestor of cetaceans and anthracotheres probably wasn't fully aquatic, it likely lived around water, he said. And while many anthracotheres appear to have been adapted to life in water, all of the youngest fossils of anthracotheres, hippos and cetaceans are aquatic or semi-aquatic.
"Our study is the most complete to date, including lots of different taxa and a lot of new characteristics," Boisserie said. "Our results are very robust and a good alternative to our findings is still to be formulated."
Brunet is associated with the Laboratoire de Géobiologie, Biochronologie et Paléontologie Humaine at the Université de Poitiers and with the Collège de France in Paris. Lihoreau is a post-doctoral fellow in the Département de Paléontologie of the Université de N'Djaména in Chad.
The work was supported in part by the Mission Paléoanthropologique Franco-Tchadienne, which is co-directed by Brunet and Patrick Vignaud of the Université de Poitiers, and in part by funds to Boisserie from the Fondation Fyssen, the French Ministère des Affaires Etrangères and the National Science Foundation's Revealing Hominid Origins Initiative, which is co-directed by Tim White and Clark Howell of UC Berkeley.
Although I do not wish to debate the merits of intelligent design, this forum seems an apt place to correct several factual inaccuracies in the Wall Street Journal’s Op Ed article by David Klinghoffer, “The Branding of a Heretic” (Jan. 28, 2005).Because Dr. von Sternberg has filed an official complaint with the U.S. Office of Special Counsel, I cannot comment as fully as I would wish.
1. Dr. von Sternberg is still a Research Associate at the National Museum of Natural History, and continues to have the usual rights and privileges, including space, keys, and 24/7 access. At no time did anyone deny him space, keys or access.
2. He is not an employee of the Smithsonian Institution. His title, “Research Associate,” means that for a three year, potentially renewable period he has permission to visit the Museum for the purpose of studying and working with our collections without the staff oversight visitors usually receive.
3. I am, and continue to be, his only “supervisor,” although we use the term “sponsor” for Research Associates to avoid personnel/employee connotations. He has had no other since Feb. 1, 2004, nor was he ever “assigned to” or under the “oversight of” anyone else.
4. Well prior to the publication of the Meyer article and my awareness of it, I asked him and another Research Associate to move as part of a larger and unavoidable reorganization of space involving 17 people and 20 offices. He agreed.
5. I offered both individuals new, identical, standard Research Associate work spaces. The other accepted, but Dr. von Sternberg declined and instead requested space in an entirely different part of the Museum, which I provided, and which he currently occupies.
6. As for prejudice on the basis of beliefs or opinions, I repeatedly and consistently emphasized to staff (and to Dr. von Sternberg personally), verbally or in writing, that private beliefs and/or controversial editorial decisions were irrelevant in the workplace, that we would continue to provide full Research Associate benefits to Dr. von Sternberg, that he was an established and respected scientist, and that he would at all times be treated as such.
On behalf of all National Museum of Natural History staff, I would like to assert that we hold the freedoms of religion and belief as dearly as any one. The right to heterodox opinion is particularly important to scientists. Why Dr. von Sternberg chose to represent his interactions with me as he did is mystifying. I can’t speak to his interactions with anyone else.
Sincerely yours,
Jonathan Coddington
You're right. It requires faith.
Not directed to me, but here gos...
Anything said in the Bible that contradicts the best scientific reasoning must be considered a miracle, and believed or not believed on faith. There are miracles recorded in the Bible that have left no physical imprint on the earth, and the Flood is one of these. Belief in the Flood as a miracle makes sense as an article of faith, but it is nonsense to assert that it has left a physical record.
IIRC, there's a variety of chromosome counts among horses.
That may be true, but then again it may be because Kepler's laws are derived from (in content, not historically) Newton's laws of motion and his law of universal gravitation. One of the fundamental postulates of general relativity is that the laws of physics are the same in all reference frames. I would suspect that, using a geocentric reference frame, that it would be entirely possible to use Newton's laws of motion and gravity to derive the orbits of the sun, moon and all the other planets around the earth, and probably some set of laws that describe the motions of these bodies would emerge.
Talk origins has some nice papers on why the Noah story and other literalist crapola are silly. Go here:
www.talkorigins.org/index.html
Here is an excerpt from one of my sermons on the Gospel:
(I don't normally do this online, so you are very blessed)
The Rev. Billy Graham tells of a time early in his career when he arrived in a small town to preach a sermon. Wanting to mail a letter, he asked a young boy where the post office was. When the boy had told him, Dr. Graham thanked him and said, “If you’ll come to the Baptist church this evening, you can hear me telling everyone how to get to heaven.”
“ I don’t think I’ll be there.” The boy said, “ You don’t even know your way to the post office.”
[Big SNIP!!!]
Jesus Sent to Us! Jesus Crucified for Us! Jesus Died for us! Jesus Resurrected!-this is the GOOD NEWS!
For God sent his Son, who has always existed, to us to show us His sacrifice on the Cross. This act expunges our sins so that God can look at us as pure and holy, although we can never deserve this consideration. This is called God’s Grace, the unmerited favor.
We cannot earn this, but we are imputed with sinlessness or righteousness because of Jesus dying on the Cross. But this is still not enough to get us into Heaven. This may only be enough to get us to the Post Office. Jesus had to conquer death in His resurrection after 3 days in the tomb and ascend to Heaven. Then he came back and appeared to the apostles and disciples and many others so that they could believe in these events. It is only in the belief that Jesus is God’s Son, that he died, that he resurrected and that the testimony of those that saw Him alive after His death reinforces our belief that we can find Heaven. God gives us the directions to Heaven by his gift to us of these events. Then he leads us to Heaven by the gift of the Holy Spirit- all this is God’s Grace.
Now is there anything you want to know about evolution, or do you still insist on questioning my Christianity?
I was wondering if you could figure it out. It is mystifying to me. I think he is talking about something to do with the great odds of biological evolution taking place at the molecular level or some other argument from personal incredulity.
There is also the fact that there is no evidence for a global flood in the geological record. At every place on earth that has not eroded in the last 10,000 years we should see the same indication of flooding in each cross section (like we do for regional flooding).
What does belief in a non-existent global flood have to do with faith? What reason would there be to put all animals in a boat to save them if it were just a regional flood?
Why couldn't God just take the animals and Noah's family out of time and put them back after the flood? Why would God need Noah to build a boat when God could have saved him the trouble?
There is a difference between believing in miracles and taking as fact utter nonsense extracted from an early pagan myth.
mmm... no.
what it requires are data pertaining to God which are themselves not apocryphal testimony of men talking about God.
After looking for the better part of twenty years, I find it difficult to not conclude that such data do not exist.
would this be an appropriate time to bring up the possible problems of Physics brought up by the Genesis definition of the rainbow and its first appearance?
Any god that would allow his existence to be "proved" would be an idol.
Sure, but I think that too is covered at talk.origins.
really?
damn - I stumbled upon the possible problem on my own hook, too.
drat - there goes my notion of being uniquely clever... again!
bah. I don't buy that.
proof of existence in no way equates to proving you know what a god wants or intends. faith and free will would still have a place.
Does a global flood make the whole Bible less credible? Davis Young, an Evangelical and geologist, wrote [p. 163]:
"The maintenance of modern creationism and Flood geology not only is useless apologetically with unbelieving scientists, it is harmful. Although many who have no scientific training have been swayed by creationist arguments, the unbelieving scientist will reason that a Christianity that believes in such nonsense must be a religion not worthy of his interest. . . . Modern creationism in this sense is apologetically and evangelistically ineffective. It could even be a hindrance to the gospel.
"Another possible danger is that in presenting the gospel to the lost and in defending God's truth we ourselves will seem to be false. It is time for Christian people to recognize that the defense of this modern, young-Earth, Flood-geology creationism is simply not truthful. It is simply not in accord with the facts that God has given. Creationism must be abandoned by Christians before harm is done. . . ."
Another Christian scientist said, "Creationism is an incredible pain in the neck, neither honest nor useful, and the people who advocate it have no idea how much damage they are doing to the credibility of belief." [quoted in Easterbrook, 1997, p. 891]
I guess I was wrong about the rainbow reference. What are your ideas?
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.