Cetacean Evolution (Whales, Dolphins, Porpoises)
Evidence Of Common Ancestry of Cetaceans and Certain Species of Land Mammals
by Edward T. Babinski
(Reviews of several creationist articles that deny such evidence exists.)
REVIEW OF The Overselling of Whale Evolution
by Ashby L. Camp
The author complains about the dating scheme of the Archaeocetes (early whales): "In the standard scheme, Pakicetus inachus is dated to the late Ypresian, but several experts acknowledge that it may date to the early Lutetian.  If the younger date (early Lutetian) is accepted, then Pakicetus is nearly, if not actually, contemporaneous with Rodhocetus, an early Lutetian fossil from another formation in Pakistan. Moreover, the date of Ambulocetus, which was found in the same formation as Pakicetus but 120 meters higher, would have to be adjusted upward the same amount as Pakicetus. This would make Ambulocetus younger than Rodhocetus and possibly younger than Indocetus and even Protocetus. In the standard scheme, Protocetus is dated to the middle Lutetian, but some experts have dated it in the early Lutetian. If the older date (early Lutetian) is accepted, then Protocetus is contemporaneous with Rodhocetus and Indocetus. In that case, what is believed to have been a fully marine archaeocete was already on the scene at or near the time archaeocetes first appear in the fossil record.  "The fact that all of the above critters are clustered together in geologic time with similarly shaped skulls and intermediary earbones unlike modern day whales, and that they were all mammals adapted in varying degrees to a water habitat, and that they all preceded modern cetaceans, speaks louder than the author's reliance on dating haggles to make a case for creationism. Reminds me of the old joke about two men looking up at a tall skyscraper and arguing vehemently over whether it was exactly one hundred stories tall or one-hundred-and-one stories tall by each of their careful reckonings. Then a third man comes over, in this case the author of the above article, and argues that their disagreements prove that his hypothesis -- that the building is really only a SINGLE storey tall -- makes more sense.)
"It's tempting to build this story like a totem pole, with trotting Pakicetus at the base, Ambulocetus laying its humming jaw on top of it, and Rodhocetus, the earliest whale to swim like a whale, sitting above the two. It seems like such a smooth progression toward today's cetaceans that it must be right. But such a version would only be a vertical slice of the story. Life doesn't proceed from one point to another -- it forks and radiates like the cladograms that represent it. Paleontologists have found many other whale bones in Eocene rocks of Pakistan and India. Mostly they are teeth -- the rock surrenders a few skulls as well -- but even teeth clearly show that their owners were not clones of Pakicetus or the other better-known whales. Ambulocetus kept to brackish deltas and coastal water, but Thewissen has found whale teeth from about the same age in what at the time was the open ocean. Gingerich has found at least three contemporaries of Rodhocetus a few million years younger than Ambulocetus: Takracetus, with a wide, flat head; Gavinocetus, with a slender skull and loose hips; and Dalanistes, a whale with a head as long and narrows as a heron's set on a long neck, with hips cemented firmly enough to its spine to walk on land. If this is a confusing picture, it should be. As time passed, certain whale species emerged that were more and more adapted to life in the water, but other species simultaneoulsy branched away in many directions. Walking and swimming whales lived side by side, or in some cases traded homes as the buckling birth of the Himalayas shuffled their habitats. Some were only a minor variation on a theme that would carry through to modern whales, but others -- heron-headed Dalamistes, for example -- belonged to strange branches unilke anything alive today. "-- Carl Zimmer, At the Water's Edge
QUESTION: How did the whales's eco-location system evolve?
ANSWER: There is a fascinating discussion of what is presently known about the evolution of whale skulls and of cetacean eco-location in Carl Zimmer's book, By the Water's Edge.
QUESTION: How did whales evolve a process whereby the young whale could ingest milk from the mother through a water-tight sealed apparatus with the milk being pumped into the young whale instead of them having to suck by some type of random, evolutionary process?
ANSWER: "Randomness" does not phase atheistic evolutionists (who view natural selection as non-random), nor does it phase theistic evolutionists nor Intelligent Design advocates (for whom the evolutionary process is not random), yet who all agree that evidence for common ancestry exists. The fact that female whales birth their young and feed them via mammary glands reminds evolutionists that whales share their ancestry with mammals.
SUGGESTED READINGS IN WHALE EVOLUTION:Carl Zimmer, At the Waters Edge(1988) Carl Zimmer, Evolution: The Triumph of an Idea (2001)Creationist Mindblocks to Whale Evolution (By a scientist who addresses ICR concerns, and whom you can get in touch with via e-mail. If you shorten the web address below you can get to his home page featuring "news," that includes his brief description of visiting S.C. to see new cetacean fossils there).
The Origin of Whales and the Power of Independent Evidence (examines the evidence one category at a time: morphological, paleontological, embryological, etc.)
Ambulocetus as a Fossil Transitional by Lenny Flank (a response to Gish's analysis of Ambulocetus)
Introduction to the Cetacea (with links to Cetacean evolution sites at the bottom of the page)
The Evolution of Large Complex Brains Over Geological Time is Not Unique to the Human Species. It Has Now Been Documented in the Evolutionary Line of the Cetacea As Well
A new Emory University study (Release date: Oct. 22, 2004) maps how brain size changed in dolphins and their relatives the past 47 million years, and helps to provide some answers to how cetacean species evolved increasing encephalization (just as the primate line leading to human beings also evolved increasing encepahlization). Increasing encephalization over time is not a phenomenon unique to the human species and lineage.
Marino and her colleagues spent four years gathering the data and tracking down fossils at The Smithsonian Institution and other museums. A total of 66 cetaean fossil crania were scanned and measured. This subset was added to brain and body weight data from 144 modern cetacean specimens for a total sample of 210 specimens representing 37 families and 62 species. Their work produced the first description and statistical tests of the pattern of change in brain size relative to body size in cetaceans over 47 million years. They found that encephalization level increased significantly in two critical phases in the evolution of odontocetes. "[Modern] dolphin brains are four to five times larger for their body size when compared to another animal of similar size. In humans, the measure is seven times larger -- not a huge difference. Essentially, the brains of primates and cetaceans arrived at the same cognitive space while evolving along quite different paths" Marino says. "What the data say to me is that we, as humans, are not that special. Although we are highly encephalized, it's not by much or for that long compared with odontocetes." "A description of the pattern of encephalization in toothed whales has enormous potential to yield new insights into odontocete evolution, whether there are shared features with hominoid brain evolution, and more generally how large brains evolve," Marino says. Marino's previous research has shown how dolphins have the capacity for mirror self-recognition, a feat of intelligence previously thought to be reserved only for Homo sapiens and their closest primate cousins.
Other Links of interest:
Photo of a whale embryo's hind limb bud, while the following link is a pic of a cetacean's hind limb bud, namely that of a dolphin.
Photo of whale embryo hind limb bud
The following web article features clear full-color pics of hind limb buds on a modern day cetacean embryo.
EVOLUTION and DEVELOPMENT 4:6, 445-458 (2002)Limbs in whales and limblessness in other vertebrates: mechanisms of evolutionary and developmental transformation and loss Lars Bejder* and Brian K. Hall 1 Department of Biology, Dalhousie University, Halifax, Nova Scotia, CanadaB3H 4J1 *Author for correspondence (e-mail: firstname.lastname@example.org)
Both authors contributed equally to this article.
"We're working on a neat new website now, that shows the embryological data. Little dolphin embryos with hind limbs for instance. Suspected launch: fall 2003.Thewissen - Northeastern Ohio Universities
- J. G. M. Hans Thewissen, Ph. D.
Note: this link is provided as a resource for further study on Whale Evolution.
"The Emergence of Whales: Evolutionary Patterns in the Origins of the Cetacea"
(Advances in Vertebrate Paleontology) edited by J.G.M. Thewissen.
Plenum Press, ISBN 0306458535.
Review by James Acker
For Evidence of Vestigial Features on other Modern Day Creatures, see "29+ Evidences for Macroevolution. Part 2: Past History" by Douglas Theobald, Ph.D.
Vestigial features.The skeleton of a baleen whale, a representative of the group of mammals that contains the largest living species, contains pelvic bones. These bones resemble those of other mammals, but are only weakly developed in the whale and have no apparent function.
More links to further articles specifically related to the Evolution of whales