Bristolia insolens
Bristolia bristolensis
Olenellus mohavensis
Olenellus fremonti
From the Lower Cambrian Lantham Shale of the Marble Mountains, southern California, U.S.A. Illustrations are from: Levi-Setti, R., 1993. Trilobites, 2nd. Edition. University of Chicago Press:Chicago, 342pp.
The fossils are arranged in standard stratigraphic order - oldest at the bottom, youngest at top. These specimens are only the cephalon - the "head" of a trilobite. Other changes are observed in the shape of the thoracic segments of these species.
Eocoelia (a Silurian brachiopod)
Click for big version (58 Kbytes).
Eocoelia is a small (about 1cm long) brachiopod ("lamp shell") from lower Silurian-age (Upper Llandovery and lower Wenlock) rocks. It is found world-wide, including Britain, Nova Scotia, Pennsylvania, Iowa, Siberia, Norway, and South America. In several of these locations, a succession of 4 species has been recognized (see above), which is found consistently over wide areas (all of North America and Europe at least). Besides the species succession, statistical variations in the properties of the species can be observed. These are best documented in the illustration presented above, modified from:
Zeigler, A.M., 1966. The Silurian Brachiopod Eocoelia hemisphaerica (J. de C. Sowerby) and related species. Palaeontology, v.9, part 4, p.523-543.
In this case, the variation in "rib strength" - the distinctiveness of the ribs - is depicted. Similar "progressive" variations occur in other characteristics within this lineage.
Other brachiopod lineages within the same interval of the Silurian also show consistent morphological change with time, although this may be due to paleoenvironmental changes in some cases. See:
Johnson, M.E., 1979. Evolutionary brachiopod lineages from the Llandovery series of eastern Iowa. Palaeontology, v.22, part 3, p.549-567.
Baarli, B.G., 1986. A biometric re-evaluation of the Silurian brachiopod lineage Stricklandia lens/S. laevis. Palaeontology, v.29, part 1, p.187-205.
Feist, R. and Clarkson, E.N.K., 1989. Environmentally controlled phyletic
evolution, blindness, and extinction in Late Devonian tropidocoryphine
trilobites. Lethaia, v.22, p.359-373.
Johnson, J.G., 1982. Occurrence of phyletic gradualism and punctuated equilibria through geologic time. Journal of Paleontology, v.56, no.6, p.1329-1331.
MacLeod, N., 1991. Punctuated anagenesis and the importance of stratigraphy to paleobiology. Paleobiology, v.17, no.2, p.167-188. [I recommend this one in particular]
Sorhannus, U. and Fenster, E.J., 1989. Speciation and morphological divergence between two Neogene diatom lineages. Neues Jahrbuch fur Geologie und Palaontologie, Monatshefte, v.12, p.726-736.
Geary, D.H., 1990. Patterns of evolutionary tempo and mode in the radiation of Melanopsis (Gastropoda; Melanopsidae). Paleobiology, v.16, no.4, p.492-511.
Lineages within the irregular echinoids, described in chapter 5 ("Fossil Lineages") of:
Smith, A., 1984. Echinoid Palaeobiology. Allen and Unwin: London, p.1-190. ISBN 0-04-563001-1
Destined to be a classic, the land mammal to whale transition, originally predicted by Darwin in the "Origin of Species" on the basis of anatomical similarities between the two groups:
[ Pakicetus -- latest Early Eocene]
Gingerich, P.; Wells, N.A.; Russell, D.E. and Ibrahim Shah, S.M., 1983. Origin of Whales in Epicontinental Remnant Seas. Science, v.220, p.403-406.
Thewissen, J.G.M., and Hussain, S.T., 1993. Origin of Underwater Hearing in Whales. Nature, v.361, p.444-445.
[ Ambulocetus natans -- Early to Middle Eocene, 120m above Pakicetus]
Thewisson, J.G.M.; Hussain, S.T. & Arif, M., 1994. Fossil evidence for the
origin of aquatic locomotion in archaeocete whales. Science, v.263, p.210-212.
[ Indocetus ramani -- earliest Middle Eocene]
Gingerich, P.; Raza, S.M.; Afif, M.; Anwar, M.; and X. Zhou, 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, p.393-416.
[ Basilosaurus -- middle Eocene and younger]
Gingerich, P.D.; Smith B.H. and Simons, E.L., 1990. Hind limbs of Eocene Basilosaurus: evidence of feet in whales. Science, v.249, p.154-157. [Basilosaurus has been known for a long time, and was the earliest known whale (as old as middle Eocene), but no whales or land-mammal transitions were known from earlier rocks -- an obvious gap. That is, until recently (see above).]
NO. The sequence of fossils is an empirical observation with no assumptions based on evolutionary theory. The fossils are simply observed in a vertical sequence of rock, which, by the principle of superposition, is oldest at the bottom of the stratigraphy, and youngest upwards (when restored to its original orientation by independent means -- e.g., wave ripples which indicate "stratigraphic up"). That the sequence of fossils is not dependent upon evolutionary theory is demonstrated by William Smith, an engineer who used sequences of fossils to construct detailed geological maps in southern England in 1815 and earlier -- decades before Darwin's evolutionary theory existed.
Here is a copy of Smith's map:
And futher details about it (including the origin of the image): caption
Most of the commonly-known periods of time in the geologic time scale were described in the 1700s and early 1800s, also before Darwin's theory was published. For example, the Cretaceous was proposed in 1822 by J.J. d'Omalius d'Halloy for the (mainly) chalk units in the area of northern France.
See: Harland, W.B.; Cox, A.V.; et al., 1982. A Geologic Time Scale. Cambridge University Press: Cambridge, p.1-131, ISBN 0-521-28919-X.
Chapter 2 provides documentation of the origin of all the major time intervals. A very large proportion pre-date by decades the 1859 publication of Darwin's "Origin of Species".
Well, they were not a problem to explain in the 19th century, and are still not a problem now. John William Dawson (1868) described a classic Carboniferous-age locality at Joggins, Nova Scotia, where there are upright giant lycopod trees up to a few metres tall preserved mainly in river-deposited sandstones. These trees have extensive root systems with rootlets that penetrate into the underlying sediment, which is either a coal seam (i.e. compressed plant material), or an intensely-rooted sandstone or mudstone (i.e. a soil horizon). Dawson considered and rejected anything but an in situ formation for these fossils, and his interpretation is closely similar to current interpretations of sediments deposited on river floodplains. An interesting feature of these examples is the presence of vertebrate fossils (mostly small reptiles) within the infilling of the stumps.
The reason I am using Dawson rather than a more recent reference is to
emphasize that many supposed "problems" with conventional geology were
solved more than 100 years ago using very basic principles. The people
suggesting these "problems" exist are so out of date that even
19th-century literature refutes their presentations.
"1.=Shale. 2.=Shaly coal, 1 foot. 3.
Underclay with rootlets, 1 foot 2 inches. 4. Gray sandstone
passing downwards into shale, 3 feet. Erect tree with Stigmaria
roots (e) on the coal. 5. Coal, 1 inch. 6. Underclay with
roots, 10 inches. 7. Gray sandstone, 1 foot 5 inches.
Stigmaria rootlet continued from the bed above; erect
Calamites. 8. Gray shale, with pyrites. Flattened
plants."
Here is a more detailed post on
polystrate fossil trees,
previously presented in talk.origins.
Here is some information on the occurrence of
fossil trees in Yellowstone National Park
The occurrence of a
"fossil whale standing on its tail"
from Lompoc, California is a classic. This is an article by Darby South.
References:
Dawson, J.W., 1868. Acadian Geology. The Geological Structure,
Organic Remains, and Mineral Resources of Nova Scotia, New Brunswick,
and Prince Edward Island, 2nd edition. MacMillan and Co.: London, 694pp.
Coal is a rock consisting almost entirely of organic material. The structure
of this material can be observed by looking at thin sections of coal under
the microscope in either transmitted or reflected light. Coal consists of
fragments of land plant material, including wood, cuticle (the waxy
surface found on some leaves), sap (amber), and spores and pollen. Each
of these can be present in varying degrees of degradation due to decay
near the surface and "cooking" due to burial in thick sediments. The
progenitor of coal is peat like that found in modern swamps and bogs (although
older coals look a little different because the plants were different types).
Some people have proposed coal forms from floating mats of dead plant material
deposited in deep water in a short amount of time. Although not too far
from the conventional explanation (dead plant material, sometimes transported),
it can not explain the majority of coal deposits. Most coals are found in
sedimentary rocks deposited in terrestrial river floodplains. They have
river channels, levees, and fossil soil horizons. Often soil horizons are
found immediately below coal seams, and these are often filled with plant
roots (see the "polystrate trees" entry above, for example). All these
structures are similar to modern peat-forming environments. The common
occurrence of rooted upright trees that can not be transported (because
they have delicate rootlets embedded in the sediment) is compelling
evidence that most coals form near the surface in terrestrial
environments (see the "polystrate trees" above). However, even more
convincing is the co-occurrence of dinosaur footprints and upright trees
on the top surface of several coal seams at a Cretaceous-age locality near
Price, in southeast Utah:
It is impossible to interpret these deposits as formed by a single
event of short duration. The plants that form coal take time to grow,
coal takes time to accumulate and decay, and trees take many years to grow.
There are multiple coal seams and multiple tree and footprint horizons, and
this is only in one short interval of the geologic record in one area.
There are many other areas of similar coal deposits (e.g., Joggins,
Nova Scotia). Rather than being a significant problem for conventional
geology, coal is explained quite easily by analogy to modern peat environments.
Coal deposits and associated sediments are an immense problem for any
interpretation involving a "global flood".
Metazoans are commonly found in an interval known as the Ediacaran, named for the location in Australia where fossils of this age were first found. Examples of Cnidaria ("jellyfish", "sea anemones", and "sea pens") are common, as well as other groups of uncertain affinities (possible annelid worms, lophophorates, etc.). The Ediacaran fauna is found world-wide in rocks of late Precambrian age, and is entirely soft-bodied.
Charnia masoni - a pennatulacean or "sea pen"
Dickinsonia costata - thought by some to be an annelid worm.
Specimens are from the Khatyspyt (northern Yakutia) and Ust-Pinega
(White Sea region) formations in the former U.S.S.R.
Illustrations are from: Fedonkin, M.A., 1990. 1.3. Precambrian metazoans.
IN: Briggs, D.E.G. and Crowther, P.R. (eds.) Palaeobiology: A Synthesis.
Blackwell Scientific Publications:Oxford, p.17-24. It contains citations
of several other references on the subject of Precambrian animals.
A more complete, but slightly older introduction is:
Glaessner, M.F., 1984. The Dawn of Animal Life; A Biohistorical Study.
Cambridge Earth Science Series. Cambridge University Press: Cambridge, p.1-244.
ISBN 0-521-31216-7
Although a classic, this work advocates an interpretation that is still
a subject of current research, so you should look at some more recent
publications too.
Here are some
claims by Ted Holden about large sauropods.
The scientific literature does not support his claims.
See, as one example:
Hokkanen, J.E.I., 1986. The size of the largest land animal.
Journal of Theoretical Biology, v.118, p.491-499.
Abstract:
The upper mass limit to terrestrial animals is studied using physical
arguments and allometric laws for bone and muscle strength and animal
locomotion. The limit is suggested to lie between 10^5 and
10^6 kg. A possibility for a still higher mass, in case of new
adaptations, is not excluded.
Ted has recently addressed the claims in Hokkanen's paper.
Go to
Ted's comments. WARNING -- he has quite a few inlined images. You
may want to turn off automatic image loading until you read the captions.But the rocks are dated by fossils, and the sequence of fossils is dated by evolution. Isn't this circular?
Map -- BEWARE!! THIS IS 588 Kbytes!Are "polystrate" fossils a problem for conventional geology?
An upright tree preserved
in the cliffs at Joggins, Nova Scotia. Figure 35 of Dawson (1868).
Stratigraphy in association with an upright tree stump, Joggins, Nova Scotia.
Figure 41 of Dawson (1868). Figure Caption:Could coal deposits be explained by a global flood?
What are those "fossil polystrate trees" found near Kingston, Ontario?
"polystrate trees" at Kingston, OntarioAre there any Precambrian metazoan animal fossils?
What is the theoretical maximum mass for a land animal?
Is the claim there are "pyramids" on Mars a reasonable one?
Here are Ted Holden's claims about this issue.
And here are an image and comments .
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