Introduction to Paleobotany

1. PBB418/323
PALEOBOTANY

2. What is Paleontology?

3. Origin Of The Word -Paleontology
The term itself originates from Greek,
palaios, i.e. "old, ancient",
ὄν, on (gen. ontos), i.e. "being, creature“
and logos, i.e. "speech, thought, study"

4. What is Paleontology? Contd.
• I t is simply defined as the study of ancient life and its preservation.
• It is the study of plant and animal fossils, giving us a glimpse of the occurrence and nature
of ancient life-flora and fauna in past geological ages.
• Paleontology can also be the study of what fossils tell us about the ecologies of the past,
about evolution, and about our place, as humans, in the world.
• Palaeontology is the study of prehistoric life forms on Earth through the examination of
plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows,
cast-off parts, fossilised faeces (coprolites), palynomorphs and chemical residues.
• It gives us precise information about the period of the earth’s history when particular types
of plants and animals came into existence, flourished and became extinct and also their
geographical extent.
• Paleontology incorporates knowledge from biology, geology, ecology, anthropology,
archaeology, and even computer science to understand the processes that have led to the
origination and eventual destruction of the different types of organisms since life arose.

5. Branches of Paleontology
• Micropaleontology: Study of generally microscopic fossils, regardless of the
group to which they belong.
• Paleobotany: Study of fossil plants; traditionally includes the study of fossil
algae and fungi in addition to land plants.
• Palynology: Study of pollen and spores, both living and fossil, produced by land
plants and protists. Palynology, which is the study
of fossilized and extant spores and pollen.
• Paleoanthropology can be described as the study of fossils of humans of early
time period and their ancestors
• Paleoethnobotany- study of past human-plant interactions through the
recovery and analysis of ancient plant remains.
• Paleoclimatology- study of ancient climate.

6. Branches of Paleontology Contd.
• Invertebrate Paleontology: Study of invertebrate animal fossils, such as
mollusks, echinoderms, and others.
• Vertebrate Paleontology: Study of vertebrate fossils, from primitive fishes to
mammals.
• Taphonomy: Study of the processes of decay, preservation, and the formation
of fossils in general.
• Ichnology: Study of fossil tracks, trails, and footprints.
• Paleoecology: Study of the ecology of the past, as revealed both by fossils and
by other methods.

7. What are Fossils?
• A fossil is any evidence of an ancient organism. It can also be described as evidence of life life. The
study of fossils is useful academically as well as economically. Academically, their study clears up to a
great extent the inter-relationships and evolution of the ancient groups of the plants and the
determination of the climate of ancient time in different regions. Economiccally, some fossils are
confined to definite strata of earth crust and they are associated with petroleum, coal and similar
other things of economic value. E.g., some coal fields were discovered only on account of the
presence of certain fossils just above the coal mines.
• Fossils, like herbarium specimens and leaf fragments kept in silica gel for DNA analysis, are the
remains of once-living organisms gathered at a particular time and from a particular place. There is
no essential difference between a dried specimen collected a decade ago and a fossil specimen
entombed within rocks for millions of years.
• Fossils are the remains of once living organisms. The vast majority of fossils are the remains of the
hardparts of extinct organisms. They belong to species no longer living anywhere on Earth. The kinds
of fossils found in rocks of different ages differ because life on Earth has changed through time.
• Fossil record, though incomplete, is a rich history of life on earth.

8. What are Fossils? Contd.
• A plant fossil is any preserved part of a plant that has long since died. Such fossils may be
prehistoric impressions that are many millions of years old, or bits of charcoal that are only a
few hundred years old. Prehistoric plants are various groups of plants that lived before
recorded history (before about 3500 BC).
• A fossil plant is the remains or traces of a once living plant. Fossil plants are generally found
buried below ground.
• Fossil plants are generally more poorly known than their living counterparts. However,
perhaps surprisingly, they are sometimes exquisitely well preserved. In many cases, they
provide a level of structural detail that cannot be retrieved from living plants without
significant investment of time and effort. For example, permineralized plant fossils from
classic localities such as the Eocene Princeton Chert preserve near perfect anatomical details
of stems, fruits, and seeds.

9. Types of Fossils
• Body fossils - elements of original body of ancient organisms (e.g., bones, shells, teeth). The remains
of the body, such as bones,shells, leaf impressions, etc. are called body fossils. They are direct
evidence of prehistoric life.
• Trace fossils - traces and structures recording activity of ancient organisms (e.g., footprints, burrows,
tooth marks, root marks, coprolites, egg shells). The evidence of animal activity, such as tracks, trails,
and burrows, are called trace fossils. Tracks and traces are unique because they provide direct
evidence of behavior in extinct animals. Tracks can tell us how fast animals ran, or whether they
traveled in herds.
• Chemical fossils - relics of biogenic organic compounds that may be detected geochemically in rocks
(isotopically enriched carbon, sponge compounds)
• Psuedofossils are mineral structures that bear a superficial resemblance to a plant. E.g dendrites
found in rock crevices bear a resemblance to fern leaves. They are considered as neither plants nor
animals as these are the watery solutions of various minerals that take the shape of a plant part or
animal
• Molecular Fossils are considered as biomarkers or biosignatures.Biomarkers found in crude oils, rocks
and sediments, are also referenced as “molecular fossils”.The products of cellular biosynthesis get
incorporated into sediments and then finally into a rock and these are described as molecular fossils.
Few of them can be observed to be stable for billions of years.
• Carbon fossil- These are carbon remains of organisms such as plants useful in in observing an organism’s
delicate parts like leaves.

10. Taxonomy of Plant Fossils
• Paleontologists have identified and named only about 150,000 fossil species, or about
0.00008% of these species calculated to have lived on Earth in all of history. Thus, if only 1 in
12,000 extinct species has been found in fossil form, it follows that few species have
fossilized. Or, does it instead mean that few of the fossils have been found?
• In order to prevent confusion, fossils, like living species, need to be named and classified in a
consistent, systematic fashion recognized by paleobiologists throughout the world. The
branch of biology devoted to the naming and classification of organisms is called taxonomy.
• The same taxonomic system apply to both living and fossilized plants. According to the
system of binomial nomenclature, each species is given a scientific name consisting of two
parts: the genus name followed by the species name.
• The former is capitalized, whereas the latter is written in lower case; both are italicized.
Often a name follows that belongs to the person who assigned that name. As example, the
scientific name of an extinct redwood tree is Sequoia dakotensis Brown, while that of a
stemless palm is Nipa burtinii Brongniart.

11. Taxonomy of Plant Fossils Contd.
• The ginkgo tree, Ginkgo biloba L., is considered a "living fossil". Known from the fossil record,
it persists as a commonly planted shade tree. The initial following its scientific name is that of
Carolus Linnaeus, the Swedish botanist who established this binomial system of nomenclature
in 1753.
• Species, living or dead, are classified using a hierarchical system(also by Linnaeus), which
reflects degrees of similarity or dissimilarity to other species. All three trees already
mentioned, because they are (or were) vascular plants, are assigned to the division
Tracheophyta.
• Within that division the redwood and ginkgo, because they produce uncovered seeds, are
placed into the class Gymnospermopsida (naked seeded plants), whereas the palm, a
flowering plant, is assigned to the class Angiospermophytina.
• The plant fossil record is often used to establish natural relationships among various extant
plant species and other taxa at higher levels. This is especially true of the vascular plants. In
fact, the division Tracheophyta was established by A. J. Eames in 1936 to show the natural
relationship between seed plants and ferns.

12. Taxonomy of Plant Fossils Contd.
• The basis for this new category was the discovery, earlier in the twentieth century, of Devonian
fossils of a group of primitive vascular plants known as psilotophytes. They were recognized as
ancestral to both ferns and seed plants. Previously, ferns and seed plants had been assigned to
a separate division of the plant kingdom.
• The fossils naturally would be pieces of plants. It is very rare that the entire plant could have
been preserved. This way, only pieces can be studied. In such type of study the individual
pieces are given botanical names, just as in living plants. The botanical names of the fossil
plants are not so significant as those of living ones.
• As they are represented by the pieces of the plants and, therefore, their generic names would
be according to stem, leaf and root or any reproductive structure. The stems are usually given
the generic names which end with ‘dendron’ (tree) or ‘xylon’ such as, Lygenodendron or
Cladoxylon. The leaves end with ‘pteris’ or ‘phyllum’ and reproductive parts end with strobilus.
• As the plant fossil record becomes more complete, further revision of the classification system
becomes necessary to allow the system to more nearly reflect the true or natural relationships
among the various categories. This is, at least, the goal of both paleobotanists and those who
study modern plants.

13. A Brief on the Term -Paleobotany
• It is one half of a larger branch of science called paleontology .
• Pleobotany (Palaeobotany) is a term derived from the Greek word-’’Palaeon’’- Old ; and
Botany”-study of plants.
• It deals with the identification of the remains of plant of geological age, and its reconstruction. It
includes the study of terrestrial plant fossils as well as marine ones such as seaweeds.
• Paleobotany is the study of plant fossils including algae, fungi, and related organisms, as well as
mosses, ferns, and seed plants
• It can also be described as plant life and the ecology of ancient eras.
• Paleobotany is the scientific study of ancient plants, using plant fossils found in sedimentary
rocks. These fossils can be impressions or compressions of the plants left on the rock's surface,
or "petrified" objects, such as wood, which preserve the original plant material in rocklike form.
• A lot can be learnt about the environment during prehistoric times by studying the types of
plants that grew then. Fossilized plant life tells a story of how the Earth has changed over time.
Studying plants can even tell us important information about the animals that lived long ago.
Many animals, both today and in the past, eat a variety of plants, so learning about plants also
gives new insights into the animals that ate them.

14. A Brief on the Term -Paleobotany Contd.
• Paleobotanists study fossilized plant life to get information about the types of plants that
lived during different time periods. Studying these plant fossils can give us information
about the climate in the past, and can help us to better understand the animals that lived
during prehistoric times as well. French botanist Adolphe-Théodore Brongniart is known
as the Father of Paleobotany.
• Paleobotany, also spelled as palaeobotany, is the branch of botany dealing with the
recovery and identification of plant remains from geological contexts, and their use for
the biological reconstruction of past environments (paleogeography), and
the evolutionary history of plants, with a bearing upon the evolution of life in general.
• Paleobotany also refers to plant life and the ecology of ancient eras. Only a small
percentage of the plants that ever lived left a record of their existence, surviving as fossils:
mineralized wood, flowers in amber, leaf imprints in coal, or other indicators of life in an
earlier era. Paleobotanists document this fossil record and use it to interpret the past
evolution of plants.

15. Applications/Importance of Paleobotany
• Paleobotany is of importance primarily because the record of fossil plants helps scientists understand
the long process of plant evolution. Especially since the 1940’s, fossil evidence has helped to explain
the origin of major classes of organisms, such as algae and fungi.
• The location of fossils, including both their temporal (age) and their spatial (geographical)
arrangement, is used to determine past climates. For example, the location of coal deposits (which
are the remains of giant tree ferns) in what is now Pennsylvania indicates the warmer climate that
must have existed then.
• 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 have been
extensively used as index fossils in biostratigraphy and in the correlation of rock units. megafossils,
such as leaves and seeds, have also provided a method of correlating rock units which are widely
separated geographically.
• Paleobotany has also become important to the field of archaeology, primarily for the use of
phytoliths in relative dating and in paleoethnobotany.

16. Fossilization: How Fossils are Formed
• Taphonomy is the science that tries to explain how living organisms, their parts, tracks, and traces become fossils in
the rock of Earth. Taphonomy addresses all the biological and physical processes that transform an organism as it
leaves the biosphere and becomes established in the lithosphere.
• The fates of organisms after death depend on many variables: where they die, how they die, the altitude of the land,
the turbulence of the seawater, the fallout of a volcano, how palatable they are to other organisms, how quickly
they become buried in sediments, and how mineralized is their skeletal structure. The list of conditions that favor
fossilization is extensive.
• In an unaltered state where the hard parts such as shell or bone are relatively unchanged. In exceptional cases the
organism may be mummified, frozen, or preserved in amber.
• By carbonization. This is indicated by a black film on an impression of the organism such as a leaf. This black film is
the organic residue of the organism after its other material is removed or replaced by the fossilization process.
• By permineralization. In this case, pores of the skeleton of the organism (such as bone or wood) are replaced with
mineral. Most petrified wood is preserved in this manner.
• By replacement. Original shell or bone undergoes an atom-by-atom substitution with another mineral. Pyrite (fool’s
gold) is a common replacement mineral. The replaced fossil is usually a faithful replica of the original.
• By molds and casts. Here the original material dissolves leaving only impressions or infillings. Impressions of the
interior or exterior of a fossil are molds. An infilling of the mold, so that an exact likeness of the organism is
reproduced, is a cast. A mold is the external impression or cavity left by the fossil, while a cast is the filling of the
mold).

17. Defining Microfossils
• Microfossils are the tiny remains of bacteria, protists, fungi, animals, and plants. They are small
or microscopic fossils that cannot be seen with the unaided eye. Collectively they range in size
from 0.05mm to 1mm. They are generally not larger than 4mm.
• The term microfossil also means “small fossil” which is usually defined as smaller than 1
millimeter in diameter. Some can be seen with a magnifying glass; others require microscopes
to view them. Microfossils are very important in paleontology because they can be abundantly
preserved in small samples such as ocean cores where larger fossils may be rare.
• Microfossils are often very widespread because ocean currents can carry them around the
world. This wide distribution makes them excellent for correlating rocks on different
continents. The organisms that comprise microfossils can be very simple or complex. Some are
simple single celled organisms such as diatoms, radiolaria, and foraminifera. Others, such as
ostracods, are complex multicelled animals. And still others, such as mollusks, are the larval or
juvenile stages of organisms that are much larger as adults.

18. Preparation of Microfossil
• Microfossils are usually present in fine-grained sedimentary rocks, such as shales, siltstones,
and clays that also contain macrofossils. They may also be present in sands, but since they are
the same size as sand granules, they are usually outnumbered by the much more numerous
mineral grains and difficult to find.
• If one is lucky enough to have unconsolidated (not yet turned to rock) fossil-bearing sediments
nearby, you can easily look for microfossils yourself.
• Excavate a small piece of the sediment and let it dry completely.
• Then put it in a jar with hot water and a tablespoon of baking soda. If the sediment has clay in
it, the baking soda and hot water will help separate the clay grains. Let the mixture sit for
about 30 minutes.
• When the sample is completely liquefied, wash it through two sieves, one made out of
window screen (which has openings of about 1 mm) on top and one make out of cheesecloth
or panty hose underneath. The top screen will remove the coarser particles, making it easier
to see the microfossils, and the bottom screen will let the clay and finer material pass through.
• The microfossils will be concentrated on the cheesecloth or pantyhose. Let the material dry
and then examine it under a 10–30 power binocular microscope.

19. Collection of Microfossil
• Following their small size, microfossils are difficult to handle. One good way to pick them up
is to use a fine tip camel hair paintbrush (a 00000 or “5 zero” size works well).
• Moisten the tip with water and touch it to the fossil. The water in the brush will pick up the
fossil by surface tension and you can then transfer it to a small petri dish.
• A permanent mounting on cardboard or paper can also be made. Take an index card or piece
of stiff paper (black or another dark color is best for highlighting the fossils) and rub it with a
water-soluble glue stick (e.g. Pritt or UHU brands).
• After the glue has dried, pick up the microfossil with a moistened brush as described above.
Gently place the fossil onto the glued surface while at the same time working the wet brush
tip into the glue to soften it and hold the fossil.
• Arrange the fossils according to species and group them in lines across the card.

20. Index Fossils
• Index fossils (also known as type or key fossils) are fossils used to define and identify geologic
periods.
• They are used to study the rocks and species of the past. They help give a relative age for the
rock layers and other fossils found in .
• They are guide or indicator fossils. They can be categorized into microfossils or macrofossils.
• Characteristics of a Good Index fossils include-
Abundant
Geographically widespread
Easily preservable
Diagnosable
Found in multiple environments (when dead)
Short species duration
Easily recognizable
Examples- Ammonites, Trilobites, Forams and Conodonts.

21. IMPORTANT INDEX FOSSILS IN
DIFFERENT TIME PERIODS
• Cenozoic: planktonic microorganisms, especially forams
• Mesozoic: Ammonoids predominate
• Late Paleozoic: Ammonoids and conodonts
• Ordovician - Devonian: Conodonts and graptolites
• Cambrian - Ordovician: Trilobites