Reconstructing The Plants

Paleobotanists who have been trained primarily as biologists are interested in research directions which include all aspects of the organisms themselves. Because the majority of fossil plants are generally preserved in rocks as disarticulated plant parts (FIG. 1.2), that is leaves (FIG. 1.3), stems, pollen, or reproductive structures, a major aim of paleobotany is to reconstruct the whole plant, that is to say, to put the pieces of the puzzle back together. Once this is accomplished,

Figure 1.2 Impression of angiosperm leaf from the Dakota Formation (Cretaceous). Bar = 2cm.

Figure 1.1 Lester Ward. (Courtesy H.N. Andrews.)

Figure 1.2 Impression of angiosperm leaf from the Dakota Formation (Cretaceous). Bar = 2cm.

the research can turn to other areas, such as determining the group of living plants, if any, to which the fossil is most closely related. Some paleobotanists are interested in aspects of plant life history that can be determined from fossils. For example, how did these plants reproduce, and how and what types of propagules were disseminated? Are their reproductive strategies similar to those of closely related living plants, or have there been major modifications in the reproductive systems of certain types of plants through geologic time? If so, how did this happen and when? What can we determine about the environment in which the plants lived millions of years ago, based on features of the fossil plants? For example, fossil wood collected from the Permian and Triassic of Antarctica (FIG. 1.4 ) indicates that the climate was quite favorable for tree growth, based on the analysis of tree rings (FIGS. 1.5, 1.6). General circulation models of Permian paleoclimate, however, have proposed that these high paleo-latitudes were very cold and not favorable for plant growth. Some paleobotanists are interested in what strategies these plants, and the animals that lived among them, developed to survive in the extreme seasonality at polar latitudes.

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