DOC PREVIEW
UW-Madison BOTANY 940 - FOSSILS AND PLANT PHYLOGENY

This preview shows page 1-2-3-4-5-6 out of 17 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 17 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 17 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 17 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 17 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 17 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 17 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 17 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

1683American Journal of Botany 91(10): 1683–1699. 2004.FOSSILS AND PLANT PHYLOGENY1PETERR. CRANE,2,5PATRICKHERENDEEN,3ANDELSEMARIEFRIIS42Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK;3Department of Biological Sciences, The George WashingtonUniversity, Washington DC 20052 USA;4Department of Palaeobotany, Swedish Museum of Natural History, Box 50007, S-104 05Stockholm, SwedenDeveloping a detailed estimate of plant phylogeny is the key first step toward a more sophisticated and particularized understandingof plant evolution. At many levels in the hierarchy of plant life, it will be impossible to develop an adequate understanding of plantphylogeny without taking into account the additional diversity provided by fossil plants. This is especially the case for relatively deepdivergences among extant lineages that have a long evolutionary history and in which much of the relevant diversity has been lostby extinction. In such circumstances, attempts to integrate data and interpretations from extant and fossil plants stand the best chanceof success. For this to be possible, what will be required is meticulous and thorough descriptions of fossil material, thoughtful andrigorous analysis of characters, and careful comparison of extant and fossil taxa, as a basis for determining their systematic relationships.Key words: angiosperms; fossils; paleobotany; phylogeny; spermatophytes; tracheophytes.Most biological processes, such as reproduction or growthand development, can only be studied directly or manipulatedexperimentally using living organisms. Nevertheless, much ofwhat we have inferred about the large-scale processes of plantevolution, and much of what we know about the plant diver-sity to which those processes gave rise, is based on preservedsamples taken from living organisms. These samples, broughttogether in the collections of museums and herbaria aroundthe world, are crucial to attempts to name, characterize, sys-tematize, and understand the origin of the variety of plant life.They are also the starting point for any investigation of plantphylogeny. Preserved specimens are the essential samples andindispensable reference points on which knowledge of botan-ical diversity and large-scale processes of plant evolution arebased.Fossils, like herbarium specimens and leaf fragments keptin silica gel for DNA analysis, are the remains of once-livingorganisms gathered at a particular time and from a particularplace. There is no essential difference between a dried speci-men collected a decade ago and a fossil specimen entombedwithin rocks for millions of years. Neither is a perfect sampleof a complex living organism, but combined with knowledgefrom other samples of plant diversity and supplemented byinformation from living plants, both can help answer questionsabout the form of the botanical tree of life and the processesby which it has come about.Even relatively recently, paleontological data have beenconsidered by some (e.g., Hughes, 1976, 1994) to be the finalarbiters in any effort to understand plant phylogeny. We donot subscribe to this view. Recent advances in systematic the-ory have developed a more sophisticated perspective and havehelped to clarify exactly what information fossils can and can-not deliver (e.g., Hill and Crane, 1982; Crane and Hill, 1987;Patterson, 1981; Doyle and Donoghue, 1987; Gauthier et al.,1988; Donoghue et al., 1989). The result is a straightforwardand uncompromising view of paleontological data. In a cla-1Manuscript received 21 January 2004; revision accepted 17 June 2004.The authors thank Jeffrey A. Palmer, Douglas E. Soltis, and Mark W. Chasefor the invitation to contribute to this special issue and James A. Doyle forhis valuable comments on the manuscript. Many of these issues have beendiscussed during meetings of the ‘‘Deep Time’’ Research Coordination Net-work (NSF grant RCN-0090283).5E-mail: [email protected] context, neither fossils nor their stratigraphic positionhave any special role in inferring phylogeny, and althoughmore complex models have been developed (see Fisher, 1994;Huelsenbeck, 1994), these have not been widely adopted. Butfossils do provide additional information on the diversity ofplants, which must be accounted for by any comprehensiveunderstanding of plant phylogeny and evolution (e.g., Doyleand Donoghue, 1987). They also provide evidence on the tim-ing of evolutionary events that is useful to develop and testideas on how the variety of plant life may have arisen (e.g.,Doyle and Donoghue, 1993; Crane et al., 1995).In this paper, we discuss the contributions of paleobotanicaldata to understanding large-scale evolutionary patterns in theplant kingdom. We begin with a brief consideration of thenature of the paleobotanical record and the temporal infor-mation it provides. We then review three key areas of plantphylogeny with a particular focus on the contributions of pa-leobotanical data: the origin and diversification of vascularplants, the origin and diversification of seed plants, and theorigin and diversification of flowering plants. The many othercontributions of paleobotanical data, to areas of science as di-verse as global environmental change, biostratigraphy, and pa-leogeography, are not considered in this paper.FOSSIL PLANTS AND CHARACTERS FORPHYLOGENETIC ANALYSISFossil plants are generally more poorly known than theirliving counterparts. However, perhaps surprisingly, they aresometimes exquisitely well preserved. In many cases, theyprovide a level of structural detail that cannot be retrievedfrom living plants without significant investment of time andeffort. For example, permineralized plant fossils from classiclocalities such as the Eocene Princeton Chert preserve near-perfect anatomical details of stems, fruits, and seeds (e.g.,Cevallos-Ferriz and Stockey, 1991; Pigg and Stockey, 1996;Stockey et al., 1998). Equivalent information for the extantrelatives of these plants is frequently not readily available.Similarly, the quality of preservation of morphological andanatomical details in charcoalified flowers from Cretaceousfossil floras may exceed that seen in standard herbarium spec-imens (e.g., Friis, 1990; Herendeen et al., 1994, 1995; Kelleret al., 1996; Magallo´n-Puebla et al., 1997, 2001; Scho¨nenber-1684 [Vol. 91AMERICANJOURNAL OFBOTANYger et al., 2001; Friis et al., 2003b). In both these cases, de-tailed comparison of fossil and extant material often requiresextensive morphological and


View Full Document

UW-Madison BOTANY 940 - FOSSILS AND PLANT PHYLOGENY

Documents in this Course
Maize

Maize

29 pages

Phylogeny

Phylogeny

39 pages

Lecture 2

Lecture 2

23 pages

Load more
Download FOSSILS AND PLANT PHYLOGENY
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view FOSSILS AND PLANT PHYLOGENY and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view FOSSILS AND PLANT PHYLOGENY 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?