Claim CC200:
There are no transitional fossils. Evolution predicts a continuum between
each fossil organism and its ancestors. Instead, we see systematic gaps
in the fossil record.
Source:
Morris, Henry M. 1985. Scientific Creationism. Green Forest, AR: Master
Books, pp.
78-90.
Watchtower Bible and Tract Society. 1985. Life--How Did It Get
Here? Brooklyn, NY, pp. 57-59.
Response:
- There are many transitional fossils. The only way that the claim of
their absence may be remotely justified, aside from ignoring the
evidence completely, is to redefine "transitional" as referring to a
fossil that is a direct ancestor of one organism and a direct
descendant of another. However, direct lineages are not required; they
could not be verified even if found. What a transitional fossil is, in
keeping with what the theory of evolution predicts, is a fossil that
shows a mosaic of features from an older and more recent organism.
- Transitional fossils may coexist with gaps. We do not expect to find
finely detailed sequences of fossils lasting for millions of years.
Nevertheless, we do find several fine gradations of fossils between
species and genera, and we find many other sequences between higher
taxa that are still very well filled out.
The following are fossil transitions between species and genera:
- Human ancestry. There are many fossils of human
ancestors,
and the differences between species are so gradual that it is not
always clear where to draw the lines between them.
- The horns of titanotheres (extinct Cenozoic mammals) appear in
progressively larger sizes, from nothing to prominence. Other head
and neck features also evolved. These features are adaptations for
head-on ramming analogous to sheep behavior (Stanley 1974).
- A gradual transitional fossil sequence connects the foraminifera
Globigerinoides trilobus and Orbulina universa (Pearson et
al.
1997). O. universa, the later fossil, features a spherical test
surrounding a "Globigerinoides-like" shell, showing that a feature
was added, not lost. The evidence is seen in all major tropical
ocean basins. Several intermediate morphospecies connect the two
species, as may be seen in the figure included in Lindsay (1997).
- The fossil record shows transitions between species of Phacops (a
trilobite; Phacops rana is the Pennsylvania state fossil;
Eldredge
1972; 1974; Strapple 1978).
- Planktonic forminifera (Malmgren et al. 1984). This is an example
of punctuated gradualism. A ten-million-year foraminifera fossil
record shows long periods of stasis and other periods of relatively
rapid but still gradual morphologic change.
- Fossils of the diatom Rhizosolenia are very common (they are mined
as diatomaceous earth), and they show a continuous record of almost
two million years which includes a record of a speciation
event (Miller 1999, 44-45).
- Lake Turkana mollusc species (Lewin 1981).
- Cenozoic marine ostracodes (Cronin 1985).
- The Eocene primate genus Cantius (Gingerich 1976, 1980, 1983).
- Scallops of the genus Chesapecten show gradual change in one "ear"
of their hinge over about 13 million years. The ribs also change
(Pojeta and Springer 2001; Ward and Blackwelder 1975).
- Gryphaea (coiled oysters) become larger and broader but thinner
and flatter during the Early Jurassic (Hallam 1968).
The following are fossil transitionals between families, orders, and
classes:
- Human ancestry. Australopithecus, though its leg and pelvis bones
show it walked upright, had a bony ridge on the forearm, probably
vestigial, indicative of knuckle walking (Richmond and Strait 2000).
- Dinosaur-bird transitions.
- Haasiophis terrasanctus is a primitive marine snake with
well-developed hind limbs. Although other limbless snakes might be
more ancestral, this fossil shows a relationship of snakes with
limbed ancestors (Tchernov et al. 2000). Pachyrhachis is another
snake with legs that is related to Haasiophis (Caldwell and Lee
1997).
- The jaws of mososaurs are also intermediate between snakes and
lizards. Like the snake's stretchable jaws, they have highly
flexible lower jaws, but unlike snakes, they do not have highly
flexible upper jaws. Some other skull features of mososaurs are
intermediate between snakes and primitive lizards (Caldwell and Lee
1997; Lee et al. 1999; Tchernov et al. 2000).
- Transitions between mesonychids and whales.
- Transitions between fish and tetrapods.
- Transitions from condylarths (a kind of land mammal) to fully
aquatic modern manatees. In particular, Pezosiren portelli is
clearly a sirenian, but its hind limbs and pelvis are unreduced
(Domning 2001a, 2001b).
- Runcaria, a Middle Devonian plant, was a precursor to seed
plants. It had all the qualities of seeds except a solid seed coat
and a system to guide pollen to the seed (Gerrienne et al. 2004).
- A bee, Melittosphex burmensis, from Early Cretaceous amber, has
primitive characteristics expected from a transition between
crabronid wasps and extant bees (Poinar and Danforth 2006).
The following are fossil transitionals between kingdoms and phyla:
- The Cambrian fossils Halkiera and Wiwaxia have features that
connect them with each other and with the modern phyla of Mollusca,
Brachiopoda, and Annelida. In particular, one species of halkieriid
has brachiopod-like shells on the dorsal side at each end. This is
seen also in an immature stage of the living brachiopod species
Neocrania. It has setae identical in structure to polychaetes, a
group of annelids. Wiwaxia and Halkiera have the same
basic
arrangement of hollow sclerites, an arrangement that is similar to
the chaetae arrangement of polychaetes. The undersurface of
Wiwaxia has a soft sole like a mollusk's foot, and its jaw looks
like a mollusk's mouth. Aplacophorans, which are a group of
primitive mollusks, have a soft body covered with spicules similar
to the sclerites of Wiwaxia (Conway Morris 1998, 185-195).
- Cambrian and Precambrain fossils Anomalocaris and Opabinia are
transitional between arthropods and
lobopods.
- An ancestral echinoderm has been found that is intermediate between
modern echinoderms and other deuterostomes (Shu et al. 2004).
Links:
Hunt, Kathleen. 1994-1997. Transitional vertebrate fossils FAQ.
http://www.talkorigins.org/faqs/faq-transitional.html
Miller, Keith B. n.d. Taxonomy, transitional forms, and the fossil
record. http://www.asa3.org/ASA/resources/Miller.html
Patterson, Bob. 2002. Transitional fossil species and modes of
speciation. http://www.origins.tv/darwin/transitionals.htm
Thompson, Tim. 1999. On creation science and transitional fossils.
http://www.tim-thompson.com/trans-fossils.html
References:
- Caldwell, M. W. and M. S. Y. Lee, 1997. A snake with legs from the
marine Cretaceous of the Middle East. Nature 386: 705-709.
- Conway Morris, Simon, 1998. The Crucible of Creation, Oxford
University Press.
- Cronin, T. M., 1985. Speciation and stasis in marine ostracoda:
climatic modulation of evolution. Science 227: 60-63.
- Domning, Daryl P., 2001a. The earliest known fully quadupedal
sirenian. Nature 413: 625-627.
- Domning, Daryl P., 2001b. New "intermediate form" ties seacows firmly
to land. Reports of the National Center for Science Education
21(5-6): 38-42.
- Eldredge, Niles, 1972. Systematics and evolution of Phacops rana
(Green, 1832) and Phacops iowensis Delo, 1935 (Trilobita) from the
Middle Devonian of North America. Bulletin of the American Museum of
Natural History 147(2): 45-114.
- Eldredge, Niles, 1974. Stability, diversity, and speciation in
Paleozoic epeiric seas. Journal of Paleontology 48(3): 540-548.
- Gerrienne, P. et al. 2004. Runcaria, a Middle Devonian seed plant
precursor. Science 306: 856-858.
- Gingerich, P. D., 1976. Paleontology and phylogeny: Patterns of
evolution of the species level in early Tertiary mammals. American
Journal of Science 276(1): 1-28.
- Gingerich, P. D., 1980. Evolutionary patterns in early Cenozoic
mammals. Annual Review of Earth and Planetary Sciences 8: 407-424.
- Gingerich, P. D., 1983. Evidence for evolution from the vertebrate
fossil record. Journal of Geological Education 31: 140-144.
- Hallam, A., 1968. Morphology, palaeoecology and evolution of the genus
Gryphaea in the British Lias. Philosophical Transactions of the
Royal Society of London B 254: 91-128.
- Lee, Michael S. Y., Gorden L. Bell Jr. and Michael W. Caldwell, 1999.
The origin of snake feeding. Nature 400: 655-659.
- Lewin, R., 1981. No gap here in the fossil record. Science 214:
645-646.
- Lindsay, Don, 1997. A smooth fossil transition: Orbulina, a foram.
http://www.don-lindsay-archive.org/creation/orbulina.html
- Malmgren, B. A., W. A. Berggren and G. P. Lohmann, 1984.
Species formation through punctuated gradualism in planktonic
foraminifera. Science 225: 317-319.
- Miller, Kenneth R., 1999. Finding Darwin's God. New York:
HarperCollins.
- Pearson, P. N., N. J. Shackleton and M. A. Hall. 1997. Stable
isotopic evidence for the sympatric divergence of
Globigerinoides trilobus and Orbulina universa (planktonic
foraminifera). Journal of the Geological Society, London
154: 295-302.
- Poinar, G. O. Jr. and B. N. Danforth. 2006. A fossil bee from Early
Cretaceous Burmese amber. Science 314: 614.
- Richmond B. G. and D. S. Strait, 2000. Evidence that humans evolved
from a knuckle-walking ancestor. Nature 404: 382-385. See also
Collard, M. and L. C. Aiello, 2000. From forelimbs to two legs.
Nature 404: 339-340.
- Shu, D.-G. et al., 2004. Ancestral echinoderms from the Chengjiang
deposits of China. Nature 430: 422-428.
- Stanley, Steven M., 1974. Relative growth of the titanothere horn: A
new approach to an old problem. Evolution 28: 447-457.
- Strapple, R. R., 1978. Tracing three trilobites. Earth Science
31(4): 149-152.
- Tchernov, E. et al., 2000. A fossil snake with limbs. Science 287:
2010-2012. See also Greene, H. W. and D. Cundall, 2000. Limbless
tetrapods and snakes with legs. Science 287: 1939-1941.
- Ward, L. W. and B. W. Blackwelder, 1975. Chesapecten, A new genus of
Pectinidae (Mollusca: Bivalvia) from the Miocene and Pliocene of
eastern North America. U.S. Geological Survey Professional Paper 861.
Further Reading:
Cohn, Martin J. and Cheryll Tickle. 1999. Developmental basis of
limblessness and axial patterning in snakes. Nature 399:
474-479. (technical)
Cuffey, Clifford A. 2001. The fossil record: Evolution or "scientific
creation". http://www.gcssepm.org/special/cuffey_00.htm
or
http://www.nogs.org/cuffeyart.html
Elsberry, Wesley R. 1995. Transitional fossil challenge.
http://www.rtis.com/nat/user/elsberry/evobio/evc/argresp/tranform.html
Godfrey, L. R. 1983. Creationism and gaps in the fossil record. In:
Godfrey, L. R. (ed.), Scientists Confront Creationism, New York: W. W.
Norton, pp. 193-218.
Morton, Glenn R. 2000. Phylum level evolution.
http://home.entouch.net/dmd/cambevol.htm
Pojeta, John Jr. and Dale A. Springer. 2001. Evolution and the Fossil
Record, Alexandria, VA: American Geological Institute,
http://www.agiweb.org/news/spot_06apr01_evolutionbk.htm
,
http://www.agiweb.org/news/evolution.pdf
, pg. 2.
Strahler, Arthur N. 1987. Science and Earth History, Buffalo, NY:
Prometheus Books, pp. 398-400.
Zimmer, Carl. 2000. In search of vertebrate origins: Beyond brain and
bone. Science 287: 1576-1579.
created 2001-4-29, modified 2006-11-5