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.
Really????? You think that shubi?
It is not fanatical to try to keep science classrooms clear of silly superstitious heretical nonsense.
I think you are fanatical about straddling the fence.
LOL
Yep.
3a is close:
The technical definition is:
Change in allele frequency in populations over time.
Do you know what an allele is?
Exactly my point. Yet you follow her doctrines as regards the Flood of Noah.
Christians went along for a solid one hundred years not only being advocates, but often authors, of old earth geology. This was no mere accommodation or reluctant toleration. Book after book, and sermon after sermon, were eagerly written and delivered to show that the "record of the rocks" was testament to God's creation and governance of nature.
"Flood Geology," OTOH, was not elaborated until 100 years after the origination of geology as a science, and was specifically formulated to accommodate the writings of Ellen G. White.
in a minor point of concession: the whole Canis Family is a mess, as the species designations not only predate genetics but are derived from traditional non-scientific discrimination.
Canis Lupus certainly can interbreed successfully and viably with Canis Familiaris. Both can also interbreed with Canis Latrans.
I wish this mess would get cleaned up in the literature, so as to remove a weapon-of-mass-BS from the creationist arsenal.
WildTurkey -- you enjoy calling people liars and then adding the typical ad hominem attack, don't you? Your condemnation of people with that phrase "bearing false witness" is so predictable. Can you try communicating with a bit less ad hominem attacks?
Shubi wrote, "No Almighty God would have been so stupid as to come up with this design." Shubi used the word "stupid" to describe the design (and therefore the Designer) of the eye. In fact, the eye represents an ingenious design, only "stupid" to those who have an axe to grind against the Designer or a bias against Intelligent Design.
I don't understand the mindset of someone who says that the Creator exists, but that somehow this Creator is not the Designer. The eye is an accident? The Creator received the blueprints from someone else? The eye just sort of developed without any input from the Creator? What kind of foolishness is this? -- and coming from someone who has a degree in Ministry and directs an inner-city ministry? Just boggles the mind to try to imagine the director of a ministry who has such a impotent estimation of the Creator.
Shubi -- specifically, how is it that you call the eye stupidly designed? Did God make a mistake? Did he withold his hand during the creation of the eye? Did it devolve? Is God a little boy who sets something in motion and it then spirals out of his control? How is it that you are calling evil something that is truly good? It really is puzzling to hear such ridicule of God's handiwork from a minister.
Umm, no, I dont follow Ellen G. White, where in the world did you get that?
Ichneumon? Narby? Do you believe that that the lack of a common ancestor would contravene the underpinnings of evolution?
It does not matter if it is possible they can interbreed, but if they actually do in nature. Thus, it would be rare that coyote and wolf would breed in the wild. This is more true today since the wolf has almost been eliminated due to human fear.
These statements are not irrrelevant at all, they are truth.
These doctrines are historically the position of the Church.
Just because you can find a liberal version of protestantism abandoning the Bible doesnt prove THE CHURCH held to those beliefs as a whole.
In fact, the abandonement of these doctrines about 100 years ago WAS A NEW THING and very short lived until RA TORREY'S "THE FUNDMENTALS" came out.
To make the claim that the Churches didnt hold to a young Earth 100 years ago, is to make a broad statement about what was actually a minority position of only a few churches. The Fundamentals was widely read by all denominations, not just Baptists.
And ever since, those who rejected THE FUNDAMENTALS have slid to the mere shadow of the Christian churches they once were.
RECENT CREATION
In his gospel, Luke, the beloved physician, recorded 75 generations from Jesus to Adam.26 Using the numbers found in the Old Testament, Theophilus and others 27 added up the number of years from the creation of the world. Theophilus concluded,
There are not two myriads of myriads (28) of years, even though Plato said such a period had elapsed between the deluge and his own time, . . . The world is not uncreated not is there spontaneous production of everything, as Pythagoras and the others have babbled; instead the world is created and is providentially governed by the God who made everything. And the whole period of time and the years can be demonstrated to those who wish to learn the truth. . . . The total number of years from the creation of the world is 5,695.29
Regarding the total number of years, Theophilus acknowledged,
If some period has escaped our notice, says 50 or 100 or even 200 years, at any rate it is not myriads, or thousands of years as it was for Plato . . . and the rest of those who wrote falsehoods. It may be that we do not know the exact total of all the years simply because the additional months and days are not recorded in the sacred books."30
Origen (b. 185), the great theologian of the Greek churches, defended "the Mosaic account of the creation, which teaches that the world is not yet ten thousand years old, but very much under that."31
And Augustine (b. 354), the great bishop of the Latin churches, wrote, "the Scripture . . . has paramount authority, . . . to which we yield assent in all matters."32 "That God made the world, we can believe from no one more safely than from God Himself."33
On the age of man and the earth, Augustine wrote, Some hold the same opinion regarding men that they hold regarding the world itself, that they have always been . . . . And when they are asked, how, . . . they reply that most, if not all lands, were so desolated at intervals by fire and flood, that men were greatly reduced in numbers, and . . . thus there was at intervals a new beginning made. . . . But they say what they think, not what they know. They are deceived . . . by those highly mendacious documents which profess to give the history of many thousand years, though reckoning by the sacred writings, we find that not 6,000 years have yet passed.34
Care to recent?? You stated that it is only a RECENT thing to believe in a young eqarth...
See? All you have to do is Believe what the Bibel says, and it all falls into place.
If there is no proof, then you need to stop claiming Evolution is true.
Got ya.
God didn't design the eye, natural selection did.
The human eye receptors do not face directly toward the image as hawks or eagles do. We have a bundle of nerves right in the middle of the retina that causes a blind spot that our brain learns to ignore.
The whole point of me mentioning this was to show you that it is ridiculous to accuse God of design flaws. I was not calling God stupid. Just the opposite. I respect God too much to think that He is not perfect.
You didn't get me. You got yourself.
Science is based on evidence and analysis, not proof.
Whenever someone starts talking about prove this or prove that, we can tell he is not a scientist.
Ignore the insults. WildTurkey loves to call people liars ("bearing false witness"). These "discussions" always end in ad hominem attacks....
Yes, the Creator is a cult leader.
I am not a biologist (though I did minor in Cell and Molecular Bio in college), so perhaps my understanding of the basic dividing line between species is incorrect. If so, please correct me:
I am given to understand that the principal absolute requirement for dividing specimens into different species is the capacity to interbreed and produce fertile offspring. If they cannot produce viable offspring, they are different species. If they can, they are the same species, though possibly of breeds having radical morphological differences.
NO, I believe God is the Creator. I know creation is not in the theory of evolution. There is no conflict.
Putting something in the Theory that is not there is dishonest and unchristian. It is also dumb to argue against a Theory that doesn't exist except in creationists minds.
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