Claim CC216.1:

There are gaps between land mammals and whales.

Source:

Gish, Duane T., 1994. When is a whale a whale? Impact 250 (Apr.). http://www.icr.org/index.php?module=articles&action=view&ID=379

Response:

  1. The transitional sequence from a land mammal to whales is quite robust. See Babinski (2003) or Zimmer (1998) for pictures of some of these.

    1. Pakicetus inachus: latest Early Eocene (Gingerich et al. 1983; Thewissen and Hussain 1993).
    2. Ambulocetus natans: Early to Middle Eocene, above Pakicetus. It had short front limbs and hind legs adapted for swimming; undulating its spine up and down helped its swimming. It apparently could walk on land as well as swim (Thewissen et al. 1994).
    3. Indocetus ramani: earliest Middle Eocene (Gingerich et al. 1993).
    4. Dorudon: the dominant cetacean of the late Eocene. Their tiny hind limbs were not involved in locomotion.
    5. Basilosaurus: middle Eocene and younger. A fully aquatic whale with structurally complete legs (Gingerich et al. 1990).
    6. an early baleen whale with its blowhole far forward and some structural features found in land animals but not later whales (Stricherz 1998).

    The whale's closest living relative is the hippopotamus. A fossil group known as anthracotheres links hippos with whales (Boisserie et al. 2005). The common ancestor of whales and hippos likely was a primitive artiodactyl (cloven-hoofed mammal); ankle bones from the primitive whales Artiocetus and Rodhocetus show distinctive artiodactyl traits (Gingerich et al. 2001).

Links:

Babinski, E. T., 2003. Cetacean evolution (whales, dolphins, porpoises) http://www.edwardtbabinski.us/babinski/whale_evolution.html

Sutera, Raymond, 2001. The origin of whales and the power of independent evidence. Reports of the National Center for Science Education 20(5): 33-41. http://www.talkorigins.org/features/whales/

References:

  1. Boisserie, Jean-Renaud, Fabrice Lihoreau and Michel Brunet. 2005. The position of Hippopotamidae within Cetartiodactyla. Proceedings of the National Academy of Science USA 102(5): 1537-1541.
  2. Gingerich, P. D. et al., 1983. Origin of whales in epicontinental remnant seas: New evidence from the Early Eocene of Pakistan. Science 220: 403-406.
  3. Gingerich, P. D., B. H. Smith, and E. L. Simons, 1990. Hind limb of Eocene Basilosaurus: Evidence of feet in whales. Science 249: 154-157.
  4. Gingerich, P. D. et al., 1993. Partial skeletons of Indocetus ramani [Mammalia, Cetacea] from the Lower Middle Eocene Domanda Shale in the Sulaiman Range of Punjab [Pakistan]. Contributions from the Museum of Paleontology of the University of Michigan 28: 393-416.
  5. Gingerich, P. D. et al., 1994. New whale from the Eocene of Pakistan and the origin of cetacean swimming. Nature 368: 844-847.
  6. Gingerich, P. D. et al. 2001. Origin of whales from early artiodactyls: Hands and feet of Eocene Protocetidae from Pakistan. Science 293: 2239-2242. See also: Rose, K. D. 2001. The ancestry of whales. Science 293: 2216-2217.
  7. Thewissen, J. G. M. and S. T. Hussain, 1993. Origin of underwater hearing in whales. Nature 361: 444-445.
  8. Thewissen, J. G. M., S. T. Hussain and M. Arif, 1994. Fossil evidence for the origin of aquatic locomotion in archaeocete whales. Science 263: 210-212. See also Berta, A., 1994. What is a whale? Science 263: 180-181.
  9. Stricherz, Vince, 1998 (10 Oct.). Burke displays fossil of toothless whale. http://depts.washington.edu/uweek/archives/1998.10.OCT_29/_article2.html See also http://more.abcnews.go.com/sections/science/DailyNews/baleen980916.html

Further Reading:

Gould, S. J. 1995. Hooking leviathan by its past. In: Dinosaur in a Haystack. New York: Harmony Books, pp. 359-376.

Pojeta, John Jr. and Dale A. Springer. 2001. Evolution and the Fossil Record, American Geological Institute, Alexandria, VA. http://www.agiweb.org/news/spot_06apr01_evolutionbk.htm , http://www.agiweb.org/news/evolution.pdf .

Thewissen, J. G. M. (ed.). 1998. The Emergence of Whales: evolutionary patterns in the origin of Cetacea. New York: Plenum. (technical)

Thewissen, J. G. M., S. I. Madar, and S. T. Hussain. 1998. Whale ankles and evolutionary relationships. Nature 395: 452. See also Wong, K., 1999 (Jan.). Cetacean creation. Scientific American 280(1): 26,30.

Thewissen, J. G. M. and E. M. Williams. 2002. The early radiations of Cetacea (Mammalia): Evolutionary pattern and developmental correlations. Annual Review of Ecology and Systematics 33: 73-90. (technical)

Zimmer, Carl. 1995. Back to the sea. Discover 16(1) (Jan.): 82-84.

Zimmer, Carl. 1998. At the Water's Edge. New York: Touchstone, ch. 6-10.
Previous Claim: CC215   |   List of Claims   |   Next Claim: CC216.2
created 2001-4-29, modified 2006-2-25