History Of Discovery

Our understanding of early vascular plants has an interesting history that, to a large degree, has greatly influenced many areas of paleobotany. In 1859, the Canadian geologist and paleobotanist Sir John William Dawson (FIG. 8.6t published a report on a Devonian vascular plant collected from the Gaspe region of Nova Scotia. His reconstruction showed a horizontal rhizome bearing upright, leafless, dichotomizing axes, to which were attached pairs of sporangia. Dawson named this interesting plant...

Early Land Plant Evolution

During the evolution of land plants, the sporophyte generation has become increasingly more complex, both physiologically and morphologically. The gametophytes from the Rhynie chert demonstrate that during the Early Devonian gametophytes and sporophytes were more similar to each other than these generations are today. Some authors working with extant plant development suggest that the Rhynie chert gametophytes provide evidence of developmental genes being reassembled from the gametophyte phase...

Spores And Spore Tetrads

In recent years, isolated spores and spore tetrads of Ordovician and Silurian age have received considerable attention as potential proxy records for early land plants (Wellman and Gray, 1988b, 2000 Edwards and Wellman, 2001 Steemans and Wellman, 2004) (FIG. 6.23). Although spore-like microfossils have been reported from as early as the Middle Cambrian (Strother, 2000 Strother and Beck, 2000), to date the oldest spore assemblages believed to have been produced by some land-inhabiting plant...

Biological Correlation

Because radiometric dates are not available for all sequences of rocks in specific geographic regions, it becomes necessary to position a given rock unit accurately relative to its absolute age, a type of relative dating. One way in which a sequence of sedimentary rocks can be grouped according to age is through the use of index fossils. To be effective, an index fossil should (1) distinguishable from other fossils and easily identifiable, (2) have existed during a relatively short period of...

Info

FIGURE 2.1 International Stratigraphic Chart showing the Precambrian. (From the International Commission on Stratigraphy Courtesy F. Gradstein.) dynamic processes of plate tectonics, new crust is created and old subducted, and there are few rocks still available that formed in the Paleoarchean. Currently the oldest known rocks are from the Acasta gneisses of the Great Slave Lake area in Canada (Northwest Territories), dated at 4.03-4.0 Ga (previously 3.96Ga Bowring et al., 1989) based on...

Conclusions

We find no vestige of a beginning, no prospect of an end Although Hutton was speaking about the geology of the Earth in this famous quotation, it could equally apply to the presence of life on Earth. The past 10 years have seen an explosion of information on the origin of life and evidence for the earliest life on our planet. On the geologic side, this explosion has benefited from the applications of new or improved geochemical, isotopic, and microscopic techniques to Precambrian rocks. On the...

Eons Eons

Oldest calcareous algae Oldest traces of invertebrate animals Oldest spiny acritarchs 1.5 Ga -Oldest sphaeromorphic acritarchs 1.85-1.4 Ga Decline of uraninite -Major deposits of banded iron formations Cyanobacterial biomarkers and steranes (eukaryotes ) 2.7-2.6 Ga Barberton Greenstone Belt 3.5-3.2 Ga Oldest microbial fossils 3.5-3.4 Ga- Oldest stromatolites (Warrawoona Group) 3.5-3.4 Ga Oldest terrestrial rocks (Great Slave Lake, Canada) ' 4.03-4 Ga

Figure

Seem to represent true red algae (Aguirre and Barattolo, 2001), whereas others, again, are interpreted as chaetetid sponges today (Riding, 2004). The cells of Solenomeris are polygonal in outline, with those of adjacent rows forming a zigzag configuration. Formerly considered to be a red alga, today Solenomeris belongs with the incrusting foraminifera (Bassi, 2003). Marinella lugeoni (Late Jurassic-Oligocene) was originally described as a cyanobacterium but has more recently been included in...

P

Figure 7.19 Cross section of Cycas revoluta leaf showing papilla (P) and sunken guard cells (arrows) (Extant). Bar 50 pm. They suggested that a combination of cutin, waxes, and lipids from the interior of the plant may combine during diagenesis to form the so-called cuticle found on many fossils. The epidermis also contains stomata (sing. stoma), the openings in aerial plant parts that allow for exchange of O2, CO2, and water vapor during photosynthesis. The stomatal complex (FIG. 7.18)...

Acknowledgments

We are truly indebted to a large number of individuals and institutions who eagerly assisted us in the preparation of this book. This includes all of our colleagues both past and present, who readily contributed illustrations as well as the various professional journals, book publishers, and professional organizations that granted permission to use copyrighted material. We are also indebted to numerous colleagues who took the time to read chapters and sections of the book, and freely discussed...

Summary

Throughout this book there are numerous examples of many of the biological and geological questions being asked by paleobotanists today, and how the fossil record contributes to answering these questions. The field of paleobotany continues to advance, not only by the discovery of new fossils but also by the use of new methods applied to existing fossils and the application of techniques from other fields to paleobotany. Plant parts preserved in different ways or ones that show additional...

Anchorage And Water Uptake

Long before there was any real appreciation of the diversity of fossil plants, the French botanist Octave Lignier (1908) advanced a theory about the morphological changes necessary during the move onto the land and the evolution of roots. His hypothesis used an algal ancestor with a three-dimensional, dichotomously branched system that was periodically desiccated during fluctuations of available water. According to Lignier's scenario, one segment of the branching system became covered with...

Fungal Spores

Albugo Oogonia Image

Although fungal spores are known throughout geologic time, it is only beginning in the Late Jurassic that they constitute a significant and important fraction of the palynomorphs recovered from most rocks (Elsik, 1976). Spores of obvious fungal origin, however, are known as early as the Late Silurian. There is an extensive terminology applied to fungal palynomorphs based on living fungi (Elsik et al., 1983). Spores are often named based on the concept of morpho-genera (Elsik, 1989), in which...

Absolute Dating

One of the most frequent questions asked of paleobotanists is, How do you date fossil plants Most paleobotanists are familiar with the various groups of plants that lived at different points in geologic time. Consequently, when encountering FiguRe 1.75 Elaterocolpites castelaini (Cretaceous). Bar 20 im. (From Jardin and Magloire, 1965 courtesy M. S. Zavada.) Figure 1.76 Petrofilaments. Bar 25 im. (Courtesy A. Graham.) Figure 1.76 Petrofilaments. Bar 25 im. (Courtesy A. Graham.) a new assemblage...

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...

Background Reading

There are many approaches that one might take in the preparation of a volume dealing with fossil plants. Through the years there have been many excellent books on paleobotany that have covered the discipline from many perspectives. We have included a number of these in the bibliography so that the reader may obtain additional information on some of the plant groups presented here, or additional ones not discussed. The following volumes (and references cited therein) will provide supplemental...

Az

FIGURE 3.41 Protoascon missouriensis showing suspensor (S) with appendages and (a)zygosporangium (AZ) (Pennsylvanian). Bar 50 im. FIGURE 3.42 Suspensor appendages of the mucoralean fungus Protoascon missouriensis (Pennsylvanian). Bar 50 m. FIGURE 3.42 Suspensor appendages of the mucoralean fungus Protoascon missouriensis (Pennsylvanian). Bar 50 m. within the Zygomycota, and is now considered to be the sister group of the clade formed by the Ascomycota + Basidio-mycota, based on molecular...

Putative lycopsids

There are always fossils that remain impossible to place systematically. The enigmatic Devonian-Carboniferous plant Barinophyton is one of these. Members of the genus consist of alternately arranged naked branches with sporangia organized in two rows on laterally born (FIGS 9.122, 9.123), spikelike fructifications. Structurally preserved specimens of B. citrulliforme from the Devonian of New York include an exarch protostele (Brauer, 1980). The tracheids have a continuous secondary wall that is...

Entomophthoromycotina Harpellomycotina

- BLASTOCLADIOMYCOTINA (treated with chytrids here) FIGURE 3.1 Relationships of major fungal groups. (Modified from J. Taylor and Berbee, 2006.) are that more than 1.5 million species are yet to be discovered (Hawksworth et al., 1995). Other organisms that were historically included with the fungi, but are now placed in the Kingdom Chromista, include the Oomycetes (water molds), Hyphochytridiomycetes, and Labyrinthulomycetes. Of these three clades, only the water molds will be discussed here....

Lepidqdendrales

Fossil Lycopsid

The Lepidodendrales includes the arborescent lycopsids that were the most conspicuous elements of the Carboniferous landscape. Members of this group are responsible, to a large extent, for the extensive quantities of plant material that resulted in the formation of Carboniferous coal seams around the world. It is estimated that up to 70 of the biomass in the extensive Westphalian coal-swamp forests of Euramerica was produced by members of the Lepidodendrales (DiMichele et al., 1985). Toward the...

Classification Of Organisms

Each author has his or her own ideas concerning the way organisms should be organized, or in the case of plants, whether they represent a single kingdom or multiple kingdoms. With this in mind, the classification scheme in Appendix 1 is presented merely as a guide to the groups of algae, fungi, bryophytes, and vascular plants that are discussed in this book. In the case of some groups, such as the hyperdiverse flowering plants, there are so many families with a meager fossil record, or no...

Sclerenchyma

Collenchyma Figure

Sclerenchyma cells are characterized by relatively thick, lig-nified secondary cell walls. All plant cells initially have only figure 7.3 Cross section of Apium sp. petiole showing parenchyma (arrow), epidermal, and collenchyma cells (C). Bar 100 pm. figure 7.3 Cross section of Apium sp. petiole showing parenchyma (arrow), epidermal, and collenchyma cells (C). Bar 100 pm. figure 7.4 Astrosclereid (arrow) in Castalia sp. leaf (Extant). Bar 150 pm. figure 7.4 Astrosclereid (arrow) in Castalia sp....

Neoproterozoic

A greater diversity of eukaryotic algae begins to appear around the Mesoproterozoic Neoproterozoic boundary (1 Ga), and the divergence of the major clades of eukaryotes is also believed to have occurred about this time (Knoll et al., 2006b). There is an increasing diversity of ornamented acritarchs (Butterfield, 2000). Although the diversity of taxa and number of clades increase, it is not until the middle Neoproterozoic that the primary radiation of eukaryotes occurred (Porter, 2004), so that...

Prqtqlepidqdendrales

Members of the Protolepidodendrales extend from the Devonian into the Mississippian (Lower Carboniferous) and fit the definition of a true lycopsid. They were either herbaceous or subwoody plants or small trees, and possessed small, helically arranged microphylls that branched at their tips and were vascularized by a single vein (Berry, 1996). Although one genus has been found to bear ligules (discussed below), they have not been found in any other taxa. The generic name Protolepidodendron has...

Evolution Of Plant Groups

Paleobotanists are also interested in the origin and subsequent evolution of major groups of plants and their interrelationships. When did plants first inhabit the Earth and what did they look like When did the first representatives of different groups of plants first arise Other researchers want Figure 1.4 Permineralized wood extending from paleostream channel in the Triassic of Antarctica. Figure 1.4 Permineralized wood extending from paleostream channel in the Triassic of Antarctica. FiguRE...

Reproductive Biology

Lepidostrobus

The reproductive units of the lepidodendrids consist of stro-bili or cones borne on distal branches in the crown of the tree. In Synchysidendron cones occur on late-formed crown branches, whereas in Diaphorodendron they are borne on deciduous lateral branches (DiMichele and Bateman, 1992). Lepidodendrid cones could reach considerable size (FIG. 9.58), for example cones assignable to Lepidostrobus goldenbergii could be more than 50 cm long. The basic organization of lepidodendrid cones consists...

Systematics Of Fungi

In the last edition of this book Taylor and Taylor, 1993 , fungi and fungal-like organisms were described within a stratigraphic framework, and when possible, comments were offered on where they might fit within a modern classification of the Kingdom Fungi. With more information now available about fungal diversity through time, and many more specimens known in greater detail, many of the fossil taxa can now be discussed within the context of modern fungal groups. Phylogeny of the fungi was...

Biostratigraphy And Correlation

Paleobotany has also played a key role in many areas of geology, especially in biostratigraphy placing rock units in stratigraphic order based on the fossils within them. Pollen grains and spores one aspect of palynology have been extensively used as index fossils in biostratigraphy and in the correlation of rock units, as have various forms of algal cells and cysts. In some instances, megafossils, such as leaves and seeds, have also provided a method of correlating rock units which are widely...

Meristems

Although all parenchyma cells in a plant have the potential for growth and production of new cells, unless a plant has been wounded, cell production normally occurs in meristem-atic tissue, which consists of parenchyma cells that remain capable of dividing and producing daughter cells throughout the life of the plant. Because of these meristems, vegetative growth in plants is indeterminate, which means that the plant body is not fixed in its development but is potentially capable of continuous...

Cuticle And Cuticlelike Material

Isolated sheets of resistant material in the fossil record are routinely referred to as cuticle or cuticle-like sheets early records of this type of microfossil include specimens from the Early Ordovician of Tunisia Combaz, 1967 and early Middle Ordovician of Saudi Arabia Le H riss et al., 2007 . The affinities of the organisms that produced the cuticle were probably very diverse and included not only plants, but animals, fungi, and perhaps lichen-like associations. Although most cuticle sheets...

Sieve Elements

Sieve elements are thin-walled cells that are alive at maturity, although the protoplast is greatly changed, and they generally lack nuclei. Sieve elements are elongated and function as the basic photosynthate-conducting cell type in the phloem of vascular plants. The walls of sieve elements contain sieve areas, circular-to-elliptical parts of the wall that are thinner. Each sieve area FIG. 7.11 includes a number of sieve pores, which allow for transport from one sieve element to the next FIG....

Nomenclature Of Fossil Plants

Historically, paleobotanists have utilized a somewhat artificial classification system, since in almost all instances and discussed with other paleobotanists. The other reason is that some identical plant parts may be attached to different plants, for example the Carboniferous lycopsid rooting organ Stigmaria, a morphogenus, has been found attached to different genera of stems. In a case like this, the name of the part is maintained, even though the entire plant has subsequently been...

Trimerophyte Evolution

Trimerophyton

The trimerophytes demonstrate more complex morphology and anatomy than rhyniophytes, their presumed ancestors, although both groups are coeval. In the trimerophytes, plant architecture is monopodial or pseudomonopodial. Laterals are produced in a variety of patterns, including helical Psilophyton sterile branches , alternately and distichous Psilophyton fertile branches , tristichous Trimerophyton , and tetrastichous Pertica . In Pertica the ultimate branch-lets consist of slender,...

Sphenophyllales

Members of the Sphenophyllales were relatively small plants probably lt 1 m tall that formed a portion of the understo-rey in many Carboniferous forests. Sphenophyllaleans can be traced from the Devonian into the Triassic, but they are best known from petrified and compressed remains from the Carboniferous. Although the order was widespread in the late Paleozoic, Triassic representatives have only sporadically been documented from a few countries, including Japan Asama and Naito, 1978 Asama and...

Molds And Casts

In addition to two-dimensional plant parts, such as leaves, three-dimensional structures, such as stems, seeds, or fruits, can also be carried into sites where sediment is accumulating and buried. During flood events, massive trunks and tree branches can be moved some distance before they are eventually deposited. If these plant parts became crushed over time, they would be preserved as compression or impression fossils. If, however, the sediment surrounding the three-dimensional plant parts...

Je

Features Companion Cell Plants

Figure 7.14 Longitudinal section of Zea mays xylem showing annular A and helical thickenings B Extant . Bar 60 pm. figure 7.15 Sieve elements S and companion cells C in Cucurbita sp. Note conspicuous sieve plate Extant . Bar 50 pm. figure 7.15 Sieve elements S and companion cells C in Cucurbita sp. Note conspicuous sieve plate Extant . Bar 50 pm. At maturity companion cells exhibit dense cytoplasm and have numerous protoplasmic connections with their associated sieve tube member....

Glaophyton Major

Aglaophyton

The best known plant from the Rhyme chert is Aglaophyton major FIG. 8.13 , a macroplant originally described as Rhynia major, but transferred to a new genus by Edwards based on a reexamination of the original Kidston and Lang slides and the discovery of new specimens D.S. Edwards, 1986 . In a very real sense, A. major is the Arabidopsis of the Devonian, not because its genome is well known, but because the plant and its life history are known in such detail FIG. 8.14 . Aglaophyton major is now...

Leaf Evolution

True leaves appear to have evolved at least twice in plant evolution. Microphylls are believed to have evolved from enations Chapter 8 and represent a synapomorphy for the Lycophyta. They are generally, but not always, small, have a single vascular bundle, and a leaf trace that leaves no gap when it departs the stele. The evolution of microphylls is discussed in more detail in Chapter 9. Megaphylls evolved from branching systems generally have more complex vasculature and produce a leaf gap...

Coal And Charcoal

Chemical Composition Charcoal

Technically, coal FIG. 1.30 comes under the definition of a compression fossil, since it represents a complex, heterogeneous mixture of macromolecular organic compounds derived from plant material that has been compressed over time Scott, 1987 . In general, the lower the rank of the coal the degree of coalification , the more details of plant structure one can observe. The higher the rank, the more the coal has been metamorphosed and the higher the carbon content. Ranks from lowest to highest...

Nathorstiana Plant

Chaloneria

Despite the enormous amount of information that has been accumulated about fossil lycopods, there are still gaps in our understanding of their evolution. During the Carboniferous in Euramerica the lycopsids were well represented by at least four major orders. These included the large arborescent forms Lepidodendrales e.g., Diaphorodendron, Lepidodendron, and Lepidophloios with stigmarian rooting structures the smaller woody types Isoetales e.g., Chaloneria with cor-mose rooting organs and the...

Rhynie Chert Plants

There can be little doubt that the Rhynie chert organisms have had a profound influence on many of our hypotheses figure 8.10 Section of Rhyme chert showing closely spaced upright axes and matrix Devonian . Bar 600 pm. figure 8.10 Section of Rhyme chert showing closely spaced upright axes and matrix Devonian . Bar 600 pm. figure 8.11 Harlan P. Banks. Courtesy H. N. Andrews. figure 8.11 Harlan P. Banks. Courtesy H. N. Andrews. about the early evolution of land plants. In recent years, however,...

Mor

Dawsonites

Figure 8.84 Branch of Pertica quadrifaria Devonian . Bar 2.0 cm. Yunia is a Siegenian Pragian, Lower Devonian plant with spiny axes that shares some features with Pertica Hao and Beck, 1991 . The axes dichotomize in a cruciate arrangement and each contains a conducting strand with one or two protoxylem strands, depending on the level of the axis. Conducting elements have annual scalariform sculpture patterns. Closely associated sporangia are elongate and bear tri-lete spores with a relatively...

Jlc

Phylum Anthocerotophyta hornworts Dendrocerotaceae Phylum Bryophyta bryophytes Marchantiophytina liverworts or hepatophytes Treubiopsida Marchantiopsida thalloid liverworts Marchantiales Sphaerocarpales Calobryales Ricciales Marchantiaceae, Ricciaceae Jungermanniopsida leafy liverworts Jungermanniales Lophoziaceae, Scapaniaceae, Frullaniaceae, Porellaceae, Lejeuneaceae Bryophytina Mosses sensu lato Sphagnopsida Sphagnum mosses Bryopsida Mosses sensu stricto true mosses Bryales Dicranales...

Plant Organography

The vascular plant sporophyte consists of a shoot axis stem, roots, and laterals. The primary shoot stem and leaves and the root arise in the embryo and are responsible for elongation figure 7.2 Longitudinal section of Coleus stem showing apex and axillary buds arrows Extant . Bar 600 pm. figure 7.2 Longitudinal section of Coleus stem showing apex and axillary buds arrows Extant . Bar 600 pm. growth, that is, vertical growth, in the plant. Laterals leaves and branches are borne at nodes on the...

Pseudoborniales

Pseudo Bornia Ursina

The Pseudoborniales represents a unique order that is known from relatively few localities and, to date, is represented by a single species, Pseudobornia ursina. In 1894, the noted paleobotanist A. G. Nathorst FIG. 10.3 collected a number of Late Devonian fossils from Bear Island Bj0rn0ya , south of Spitsbergen. Included in the collection were a number of interesting compression and impression specimens consisting of axes bearing whorled, lateral appendages. The only other fossils that have...

Land Plant Ancestors

For many years the green algae Chlorophyta were the group thought to be most likely to have given rise to the land plants. Today most regard the green algae and embryophytes together as a monophyletic group, the Viridiplantae, which consists of two monophyletic lineages, the Chlorophyta and the Streptophyta. Included in the Streptophyta are all embryophytes, that is bryophytes and vascular plants, and a distinct group of green algae traditionally known as the Charophyceae, which includes the...

Other Enigmatic Organisms

Although a great deal of information is known about Protosalvinia initially named Foerstia , the biological affinities of this Devonian organism remain problematic Niklas and Phillips, 1976 Niklas et al., 1976 Schopf, 1978b Gray and Boucot, 1979 . Like Spongiophyton, it has been interpreted as a fern, alga, bryophyte, or some form of semiaquatic organism. It is typically found compressed FIG. 6.15 , but may assume a variety of morphologic shapes, ranging from nearly circular to clavate. Some of...

Palynology

Images Origen Palynology

The science of palynology or, perhaps in a geologic context, paleopalynology is devoted to the study of pollen grains and spores, and also encompasses the investigation of other organic microfossils, such as chitinozoans, acritarchs Javaux and Marshall, 2006 , scolecodonts, dinoflagellates, certain types of microscopic algae, microforaminifera, rotifers, testate amoebae, chitinous fungal remains, and other forms of organic debris sometimes termed varia. Characteristic features such as grain...

Gametophyte Generation

Saprophyte Microscopy

I n this chapter, in fact throughout this book, the primary focus is on the sporophyte generation of vascular plants. This is not by choice, but rather reflects the general paucity of information about the gametophyte phase in most fossil plants. Although there is some information about the game-tophytes in certain seed plants Millay and Eggert, 1974 Chapter 14 , information about fossil vascular plant game-tophytes is generally rare. Until recently this has been especially true in discussions...

Conclusion

Prototaxites

Although land surfaces must have been available for colonization soon after life evolved in the Precambrian, the earliest record of terrestrial animals begins around 425 Ma Ward et al., 2006 and that of plants somewhat earlier, with microfossil evidence from the Ordovician discussed below . This delay in colonization of terrestrial habitats has been related to oxygen levels in the paleoatmosphere Berner et al., 2007 and specifically to the lack of a sufficient ozone shield to protect...

Geochronology And Biostratigraphy

Perhaps the most widespread application of palynology is in geochronology, the dating of events in the history of the Earth. Palynomorphs and certain microfossils can be used in geochronology, that is, dating rock units. Fossils can only provide a relative date for strata, that is in relation to other units. Absolute dating relies on other methods to give a specific date see radiometric . Dating with paly-nomorphs is possible because many change through time or possess unique features that...

Zosterophyllophytes

Stem Anatomy Psilophyton

The zosterophyllophytes or zosterophylls are the second major group of vascular plants established by Banks 1975 , as the Zosterophyllophytina. They range from Late Silurian to Late Devonian and represent some of the most interesting early vascular plants, in part because there is a considerable amount of anatomical and morphological detail known about them. They demonstrate diversity as early at the Ludlovian Late Silurian Kotyk et al., 2002 and were widespread geographically by the Early...

Trimerophytes

Pertica Quadrifaria

The third major group that was culled from the original Psilophytales by Banks is the Trimerophytophyta. Trimerophytes1 were generally more complex than either the rhyniophytes from which they are thought to have descended or the zosterophyllophytes. Trimerophytes demonstrate monopodial branching of the main axes, with lateral axes showing either dichotomous or trifurcate branching. As with rhyniophytes, the sporangia are terminal, although typically they are fusiform to elongate and aggregated...

Form And Function In Fossil Plants

From many plant fossils, it is possible to understand the relationship between form and function in ancient plants, that is, what advantages or limitations are imposed on the growth and development of a plant based on certain biomechanical properties For example, are all arborescent treelike plants constructed of cells and tissue systems of the same type If not, in what other ways can plants grow to tower over their neighbors Studies of this type examine the anatomical and morphological...

Reproduction On Land

A primitive land plant requires several adaptations in order to reproduce on land. One of these is a method to move gametes from one gametophyte to another in order to effect fertilization, and the other is some method of spore dispersal in which the dispersal units are protected from the desiccating environment. In addition, it is important to move the sporo-phytic reproductive units up off the substrate, both to prevent infection by microbes and presumably to disperse spores further, in order...

Unaltered Plant Material

Some plant parts are found as fossils in an unaltered form, either as body fossils or as chemical fossils. Pollen grains and spores FIG. 1.58 I , diatom frustules, cuticle envelopes, various types of resins, such as amber FIG. 1.59 and calcium carbonate remains of certain types of algae are all examples of unaltered plant fossils. In some instances even the soft parts are sufficiently preserved so that comparisons can be made at the cytoplasmic and ultrastructural level Wolfe et al., 2006 ....

Heterokontophyta

Bacillariophyceae ACRITARCHA We have lingered in the chambers of the sea By sea-girls wreathed with seaweed red and brown Till human voices wake us, and we drown. T.S. Eliot, The Love Song of J. Alfred Prufrock The algae are a large informal grouping of heterogeneous, polyphyletic or paraphyletic groups of primarily aquatic organisms ranging from tiny, flagellated unicells only a few microns in diameter to multicellular organisms up to 80m long, such as the giant kelps Graham and Wilcox, 2000 ....

Life History Biology

Alternation Generation Gametophyte

There remain a number of significant gaps in our understanding of the transitional steps required to move from a charophycean algal ancestor to a land plant. One of these involves significant differences in the life histories of these two groups of organisms Nishiyama, 2007 . In the haplobi-ontic life cycle of a charophycean alga, zygotic meiosis leads to the formation of haploid zoospores, each of which develops into a mature haploid organism. In this life history the only cell that is diploid...

Acritarcha Acritarchs

At one time, spiny vesicular microfossils were often termed hystrichosphaerids a designation that alludes to their morphology regardless of their biological affinities. In 1961, Evitt conclusively demonstrated that many hystrichosphaerids were the cysts of dinoflagellates. Consequently, the remaining hystrichosphaerids whose affinities remain uncertain or unknown are placed in the artificial group Acritarcha Evitt, 1963 b,c . As a result the acritarchs represent a highly heterogeneous group of...

Bryqphyta Bryqphytes

Living bryophytes are represented by 900 genera and nearly 24,000 species. They are not a conspicuous portion of the Earth's flora, although they may dominate the vegetation in certain special environments, for example Sphagnum in certain types of bogs. Most bryophytes are small plants, many lt 2 cm long. The largest forms rarely exceed 60 cm in length e.g., species in the genus Dawsonia . In general, bryophytes are most abundant in relatively moist areas. They range throughout the world and...

Fungianimal Interactions

Freshwater Obligate Plant Pictures

Despite the obvious role fungi play in modern ecosystems as decomposers, parasites, and mutualists, the interactions between fungi and animals are not extensively documented in the fossil record. A common fungus-animal interaction known from the Paleozoic to the recent is evidence of borings made by endolithic fungi also algae and bacteria in calcium carbonate skeletons of marine invertebrates Gatrall and Golubic, 1970 Grahn, 1981 . This represents a trace fossil or ichnofossil , in that no...

Impressions

When a paleobotanist splits a rock that contains fossil plant fragments along a bedding plane, it is sometimes possible to see the carbonaceous film of a compression along one face, and a negative imprint of the plant part, with little or no carbon adhering, on the other face FIG. 1.32 these two faces are called part and counterpart in paleobotany. The fossil with little or no carbonaceous material is called an impression FIGURE 1.34 Impression of Sigillaria leaf bases showing parichnos scars...

Other Rhyniophytes

Yarravia Plants

As mentioned earlier, Cooksonia, a plant that has been historically regarded as the oldest vascular plant, is included in this group. Compressed specimens have been described from localities all over the world, including North America, Great Britain, North Africa, Europe, Siberia, and South America e.g., Fig. 8.59 . Some Cooksonia specimens discovered in Wales are known from deposits as old as the Ludlovian other specimens suggest that the taxon extended into the Early Devonian Emsian ....

Aglaophyton With Cyanobacteria

FIGURE 3.45 Intercalary glomalean chlamydospore Devonian . Bar 70 im. The fossil record of Glomeromycota is believed to be ancient, extending well back into the Paleozoic. Spores and hyphae of a glomeromycotan type have been reported from rocks as old as the Cambrian Pirozynski and Daple, 1989 , and from 460-455 Ma Upper Ordovician rocks Redecker et al., 2000 . Palaeoglomus grayi has aseptate coenocytic hyphae and spores that resemble living Glomus spores Redecker et al., 2002 . In these...

Spongiophytaceae

The Spongiophytaceae an artificial taxon used to include a variety of enigmatic early organisms, some of which may represent or be related to vascular land plants Krausel, 1954 Krausel and Venkatachala, 1966 . Some organisms included in this family show features of vascular plants, but not all as a result, they are sometimes interpreted as depicting transitional stages in the evolution of true vascular land plants. Spongiophyton is a thalloid fossil that has been reported from numerous Devonian...

Lichens

Winfrenatia

Lichens are unique, double organisms that consist of two unrelated components, an alga and or cyanobacterium pho-tobiont and a fungus mycobiont . The organisms that make up the lichen live in a close symbiotic relationship in which the photobiont gains mechanical protection, increased water availability, reduced desiccation, and an improved ability to obtain nutrients from the mycelium of the fungus. The fungus, in turn, gains organic nutrients synthesized by the photobiont s that is, a source...

Further Reading

After all, I guess it doesn't matter whether you look down through a microscope or up through a telescope as long as you look. it is the presence of green vegetation on the surface of the Earth that makes it a pleasant and interesting place to live. Frequently, we take this green mantle for granted, forgetting that for most of earth history the landscape was barren. Cyanobacteria, algae, and algal-like organisms must have lived in terrestrial habitats before true land plants evolved, but surely...

Paleoecology

Palynology has also been extensively used as a method of characterizing past depositional systems paleoenvironments Farley and Traverse, 1990 . Here palynomorphs play an important role in defining, for example, the extent of a marine or terrestrial environment. In other instances, certain types of palynomorphs may provide valuable information about water depth, temperature, salinity, and nutrient levels where the organisms once lived. In a few cases where vertebrates and invertebrates are found...

About the authors

Michael Krings Geology

Taylor is a distinguished Professor in the Department of Ecology and Evolutionary Biology, and Curator of Paleobotany in the Natural History Museum and Biodiversity Research Center at the University of Kansas. He also holds a courtesy appointment in the Department of Geology. He received his Ph.D. in botany from the University of Illinois, and was a National Science Foundation Postdoctoral Fellow at Yale University. He is a member of the National Academy of Sciences. His research...

Compressions

Osmunda Claytoniites

As sediments accumulate, such as in an oxbow lake, water is squeezed out, so the sediments become much more compact, and plant fragments contained within them become flattened Rex and Chaloner, 1983 Chaloner, 1999a . Internal structure is usually obliterated as the cells become flattened, and frequently all that is left is a delicate carbonaceous film that conforms to the original outline of the plant part. This type of fossil is called a compression FIG. 1.13 , and it is one of the most common...

Grh

Fossil Bark Cross Section

When the tree goes dormant in the fall, either due to seasonal deciduousness leaf drop or to cold temperatures if it is evergreen, the cambial cells cease to divide. The following spring, the cambium begins producing earlywood again. The contrast between the late-wood of the previous growing season and the earlywood of the present season is the ring boundary, which can be very sharp and visible to the naked eye. Secondary phloem, the tissue produced to the outside...

Preservation How Plant Fossils Are Formed And Preserved

A relatively small fraction of the plants and other organisms that live on the Earth at any particular time will ever become fossils. Most dead plant material is decayed by aerobic oxygen-loving fungi and bacteria. So, the first requirement for fossilization is that dead plants must be deposited in an environment where air is excluded, that is an anaerobic environment. This usually involves deposition in a body of water discussed below , but not always. Once deposited, the plants must be buried...

Plant Tissues And Primary Growth

Lepidodendron Stem Anatomy

A plant tissue is a group of cells having a similar origin, structure, or major function. Plant tissues contain a characteristic complement of one or more types of cells simple tissues figure 7.13 Transverse section of Lepidodendron stem showing extensive periderm P Pennsylvanian . Bar 1 mm. figure 7.13 Transverse section of Lepidodendron stem showing extensive periderm P Pennsylvanian . Bar 1 mm. contain one cell type and complex tissues, more than one type. Under the system of Sachs 1875 ,...

Systematics And Classification

This book emphasizes the origin, evolution, and diversity of the major groups of plants based on the fossil record, and their relationships through geologic time floristic changes through time are discussed to a lesser extent. To do this, we need to address the systematics of plants. The field of system-atics is concerned with classifying, naming, and determining the evolutionary relationships of taxa. Taxon pl. taxa is a general name to indicate any level of organization i.e., a species, a...

Cellulose Acetate Peel Technique

Bottle Contain Acetone

FIGURE 1.42 Diagrammatic representations of the steps involved in the preparation of the coal ball peel technique. A. Section of coal ball slab calcium carbonate matrix containing plant material crosshatched B. coal ball slab after acid etching to partially expose plant material C. etched coal ball slab surface with cellulose acetate sheet in place D. cellulose acetate sheet peel being pulled from the surface with adhering plant material and E. coal ball peel containing embedded plant material....

Depositional Environments Of Fossil Plants

Uniseriate Trichomes

Fossil plants are found in almost all regions of the Earth, the most notable exceptions being recent volcanic islands or in rocks that have been extensively metamorphosed FIG. 1.9 . Marine plants, such as various forms of algae Chapter 4 , are generally found in rocks deposited in marine environments e.g., nearshore deposits, carbonate shelves, etc. . Although land plants are occasionally found in marine rocks, generally, wherever terrestrial sedimentary rocks occur, there is a good chance that...

Determining Paleoclimate From Fossil Plants

Understanding climates of the past has become more and more crucial to appreciating the changes occurring on our warming planet today, and paleobotany is very important in providing baseline data to reconstruct past climates and in calibrating paleoclimate models based on physical parameters Steppuhn et al., 2007 . This area is rapidly expanding, so we will only cover a few of the many ways in which plant fossils can be used to reconstruct paleoclimate Data from fossil tree rings...

Leaf Anatomy

Chlorenchyma Cells

Leaves are composed of three principal tissue systems epidermis, mesophyll, and vascular tissue, but the organization and extent of each of these systems are almost as variable as leaf morphology. Because a leaf is typically a dorsiventral structure, the epidermis of the abaxial surface is often different from that on the adaxial side. When stomata occur on both the adaxial upper and abaxial lower surface, the leaf is amphistomatic, on only the upper surface, epistomatic, and on only the lower...

What Is Fossil

FIGURE 2.13 Generalized stratigraphie column of the Pilbara Supergroup showing position of various putative fossil-bearing chert formations. From Allwood et al., 2007. MESOARCHEAN-NEOARCHEAN LIFE Neoarchean 2.8-2.5 Ga . Filamentous microorganisms have been described from rocks of the Fortescue Group in The record of life on Earth becomes more widespread and Western Australia 2.768 Ga Schopf and Walter, 1982 . more diverse during the Mesoarchean 3.2-2.8 Ga and Although poorly preserved, these...

Chlorophyceae

Fossil Pediastrum

The Chlorophyceae encompass the widest range of morphologies in the green algae. The colonial Volvocaceae Volvocales and their unicellular relative Chlamydomonas reinhardtii Chlamydomonaceae have frequently been used as a model in studies addressing the evolutionary pathways leading from unicellularity to multicellularity, including a division of labor within the algal thallus Kirk, 1998, 1999 . Molecular evidence suggests a minimum age of 400-500 Ma for a few Chlamydomonas species Van den Hoek...

Sclereids In Podocarpus

Figure Sclereids

Figure 7.16 Section of Podocarpus urbanii stem showing thick cuticle arrows , hypodermal sclereids S , and stomatal chamber C Extant . Bar 50pm. figure 7.16 Section of Podocarpus urbanii stem showing thick cuticle arrows , hypodermal sclereids S , and stomatal chamber C Extant . Bar 50pm. figure 7.17 Section of Yucca sp. leaf showing thick cuticle arrow Extant . Bar 50pm. figure 7.17 Section of Yucca sp. leaf showing thick cuticle arrow Extant . Bar 50pm. atmosphere, and sometimes...

Tetrahedraletes Medinensis

Naked monads with pseudo-trilete mark naked fused dyads i.e., Pseudodyadospora naked unfused dyads i.e., Dyadospora naked fused tetrads i.e., Tetrahedraletes naked unfused tetrads i.e., Stegambiquadrella smooth envelope enclosed dyads i.e., Segestrespora envelope enclosed ornamented tetrads ornamented envelope enclosed tetrads figure 6.23 Stratigraphic ranges of numerous miospore morphologies showing evolution of biodiversity from the Ordovician into the Silurian. From Steemans and Wellman,...

Introduction to Paleobotany

The Objectives of Paleobotany 2 Form and Function in Fossil Plants 4 Biostratigraphy and Correlation 4 Paleoecology Plants in Their Environment 5 Determining Paleoclimate from Fossil Plants 6 Summary 7 Preservation How Plant Fossils are Formed and Depositional Environments of Fossil Plants 8 Biofilms and Plant Fossil Preservation 16 Geochronology and Biostratigraphy 36 Systematics and Classification 40 Nomenclature of Fossil Plants 41

Conclusions Archean Life

Despite the fact that there are doubters for almost all of the evidence for life in the Archean, evidence for early life has expanded tremendously in the past 20 years, from body fossils to isotopic and geochemical studies. These data are supported in most cases by detailed stratigraphic and sedi-mentologic evidence of the environments of early life, and by knowledge of the depositional and metamorphic history of the rocks that contain ancient carbonaceous matter. Nisbet 2000 provided an...

Arrangement Of Primary Tissues

Crosssection Elodea Stem

The arrangement of tissues in stems and roots is similar, although there are differences between monocots and dicots, as well as between seed plants and non-seed plants. These will be discussed later under section Stele Types. In gymnosperm and dicot stems, the center of the axis is occupied by parenchymatous pith tissue, which functions as a storage tissue and sometimes a water source. Surrounding the pith is a ring of vascular bundles, each containing xylem and phloem. The most common type of...

Other Sphenophyllales

Sphenophyllales

There are several other types of articulated axes bearing leaves arranged in nodal whorls for which affinities with the Sphenophyllales have been suggested. One is Gondwanophyton from the Early Permian of India and Australia Maithy, 1974 Srivastava and Rigby, 1983 McLoughlin, 1992 , a plant characterized by slender, articulated striate stems and narrow cuneate, semicircular to reniform leaves arranged in nodal whorls or pairs FIG. 10.18 . Leaf venation is dichotomous and similar to...

Ulvophyceae

Plant Classification

Among the most commonly encountered members of fossil green macroalgae are those forms assignable or structurally similar to the Dasycladales FIG. 4.7 . There are 180 genera currently recognized within this order, of which only 11 still exist today. Berger and Kaever 1992 classified the 180 genera into five families, that is, the Seletonellaceae Cambrian-Cretaceous , the Diploporaceae Devonian-Triassic , the FIGURE 4.8 Suggested reconstruction of Triploporella remesii. From Pia in Hirmer, 1927....

Conducting Elements In Early Land Plants

Early Land Plants

Kidston and Lang 1920a , in their detailed descriptions of plants from the Rhynie chert see below , noted that they were unable to resolve secondary wall thickenings in the central strand of Rhynia major now Aglaophyton FIG. 7.1 . When David S. Edwards 1986 demonstrated that these conducting elements were structurally different from tracheids, he provided the first evidence that Aglaophyton was not a true vascular plant. Additional detailed studies of water-conducting elements in other early...

Other Lepidodendrid Genera

Bothrodendron Bilder

Some lycopsid stems have leaf bases that are inconspicuous or lacking, and these are sometimes difficult to distinguish from decortication stages. For example, in Bothrodendron FIG. 9.92 , an arborescent lycopsid that was 10m tall, the leaf scars are not on raised cushions, but are flush with the surface of the stem Wnuk, 1989 . In some specimens, figure 9.92 Bothrodendron minutifolium, branched twigs partially foliated and a cone arrow Pennsylvanian . Bar 2 cm. Courtesy BSPG. figure 9.92...

Marchantiophy TinA liverworts or hepAtoph Yres

Calymperes Maranhao

Recent divergence-time estimates of the origin of the liverworts obtained using penalized likelihood suggest a Late Ordovician divergence of the liverworts Heinrichs et al., 2007 , based on a maximum age from Wellman et al. 2003 for the oldest fossils generally accepted as land plants, and Kenrick and Crane 1997a for the oldest split of vascular plants. The earliest liverwort in the fossil record is table 5.1 Bryophyte genera known from amber. Baltic Eocene and Bitterfeld Eocene or...

Oxygenation Of The Earth Ga

Around the Archean-Proterozoic boundary, Earth began a transition phase in a number of different areas. The two supercontinents that came together in the Neoarchean began to break apart in the Paleoproterozoic, and a major glaciation the Huronian occurred from 2.45 to 2.22 Ga. There were large eruptions of flood basalts and an increase in atmospheric oxygen, eventually leading to the oxygen-rich environment we live in today Melezhik et al., 2005 . Some researchers have suggested that the rise...

Early Fossil Evidence

Picture Sporogonites Exuberans

The origin and early evolution of the bryophytes is a complex and perplexing problem Goffinet, 2000 . Phylogenetic evidence suggests that bryophytes in general, and liverwort-like plants in particular, should have been important components of early terrestrial floras Bateman et al., 1998 Renzaglia et al., 2007 . The fossil record of bryophytes, however, especially of early bryophytes, is meager and those known from fossils appear comparable in many ways to extant taxa. Even the earliest...

Pirozynski Fossil 2016

Araucarioxylon

FIGURE 3.65 Aspergillus collembolorum, conidial head with radial chains of conidia see FIG. 3.64 Eocene . Bar 25 pm. Courtesy A. Schmidt. FIGURE 3.64 Aspergillus collembolorum, sporulating conidio-phores see FIG. 3.63 Eocene . Bar 50pm. Courtesy A. Schmidt. Stigmatomyces succini is a parasitic ascomycete that has been found attached to the thorax of a stalk-eyed fly preserved in Baltic amber Rossi et al., 2005 . It represents the earliest fossil account for the ascomycete order Laboulbeniales,...

Anthocerotophyta Hornworts

Anthocerotophyta Fossil

The hornworts include 300 living species e.g., Duff et al., 2007 and differ from mosses and liverworts in the nature of their spore dispersal, which is accomplished by a longitudinal splitting of the capsule into several valves along with the action of pseudoelaters. The capsules sporangia characteristically have a central column of sterile tissue, called a columella. Hornworts produce symmetrical spermatozo-ids, and on the ventral surface of the gametophytic thallus are specialized, apically...

Higher taxa of gReen algae in this chApter based LArgeLy on the cLAssi FicAnou system of

Ulvophyceae

Class Prasinophyceae Pyramimonadales Cymatiosphaeraceae, Tasmanaceae Class Chlorophyceae Chlorococcales Hydrodictyaceae, Scenedesmaceae, Chlorococcaceae Tetrasporales Botryococcaceae, Palmellaceae Chaetophorales Volvocales Lageniastraceae Class Ulvophyceae Cladophorales Families See Table 4.1 Receptaculitida artificial group, may not be algae Cyclocrinales Cambrian-Devonian Caulerpales Codiaceae, Caulerpaceae Ulvales Class Charophyceae Charales Eocharaceae, Calvatoraceae Moellerinales...

Historical Background

Warrawoona Chert

Before discussing current evidence, it is important to mention historical work on Precambrian life. Although there were some earlier reports of Precambrian life, the work of Stanley Tyler and Elso Barghoorn FIG. 2.3 on the Gunflint Iron Formation Gunflint chert of the Canadian Shield provided the first detailed, irrefutable evidence for life in the Precambrian. These researchers began with a preliminary report on the organisms Tyler and Barghoorn, 1954 and the description of coal from the same...

Cellular Preservation

With few exceptions, none of the preceding types of fossil preservation provide the opportunity to examine the internal structure of a plant or plant part. In the case of perminerali-zations and petrifactions, however, it is possible to study the internal anatomy of ancient plants Schopf, 1975 . In these fossils, one can examine cells and tissue systems within a plant, as well as produce a series of serial sections that can be used to reconstruct the three-dimensional organization of a...

Chlorophyta Green Algae

Gametangia

The Chlorophyta FIG. 4.2 , or green algae, are the most diverse group of algae in the world today in terms of number of species at least 7000 species , organization of the plant body unicellular to multicellular , and habitat from the surface of snow to a variety of symbiotic relationships Graham and Wilcox, 2000 . The green algae are generally assumed to include the ancestral group that has given rise FIGURE 4.2 Life history of the green alga Ulva showing an isomorphic alternation of...

Evolution of the Microphyll

Enation Theory Images

One of the synapomorphies of the lycophytes is the presence of microphylls. Microphylls are true leaves, and as such, are borne in a definite pattern phyllotaxy on the stem, but they have an evolutionary history separate from the leaves of other vascular plants megaphylls, see discussion in Chapter 11 . Extant microphylls are small, although not all fossil microphylls are small. They usually contain a single vascular bundle vein and there is no leaf gap formed in the stele during the production...

Rhyniophytes

Rhynie Chert

Some of the plants included in this group were previously included in the Rhyniophyta Rhyniophytina of Banks, 1975 . They can be characterized by dichotomously branched, naked aerial axes with terminal sporangia. The aerial axes arise from horizontal, dichotomizing rhizomes that bear rhizoids no true roots are known. Sporangial shape figure 8.7 Suggested reconstruction of Psilophyton princeps. From Taylor and Taylor, 1993. figure 8.7 Suggested reconstruction of Psilophyton princeps. From Taylor...