Paleobotany for B.Sc III(Botany-Semester III) As per the syllabus of S.P.P.U. PUNE

This topic includes fossils,process and conditions for fossilization. types of fossils and study of some fossils.

1. T.Y.B.Sc . (Botany IV) Paleobotany As per Syllabus Of S.P.P.U. Pune Topics include 1.Paleobotany and Geological timescale 2.Fosssils,Process and Types Of Fossils 3.Study of some Fossils By- Mohanish Wankhade Assistant professor Department of Botany Annasaheb Awate college , Manchar (Pune)

2. Paleobotany is The study of fossil plants. Fossils are the remain or imprints of organisms Prof. Birbal Sahni is the father of indian Paleobotany . 1.1.Paleobotany

3. It is a table showing the sequence of geological period in the history of earth. Shows the length of time of different geological period. Measure in Million year ago GTS has divided into Era .each era sub-divided into period and period into Epoch. The earliest era is Precambrian which began about 4600 million year ago 1.2.Geological Time Scale

4. Geological history divided into five era 1.Archaeozoic era(Era of Primitive life) 2.Proterozoic era(Era of early life) 3.Paleozoic era(Era of ancient life) 4.Mesozoic era(Era of Medieval life) 5.Coenozoic Era(Era of modern life) Archaeozoic and Proterozoic are together kn /as Precambrian Era Geological era

5. Era Period Epoch Began in million years Major Events Coenozoic 65-2.5     Quaternary Recent Pleistocene 2.5- Herbaceous plant Dominant     Tertiary Pliocene 7-2.5 Rise of herbaceous dicotyledon Oligocene 38-7 Rise of herbaceous angiosperm Eocene 54-38 Dispersal Of woody angiosperm Paleocene 65-54 Rise of woody angiosperm Mesozoic 280-65 Cretaceous   136-65 Angiosperm Dominnat Jurasic   190-136 Formation of Pangea.Angiosperm evolved Triassic   280-190 Conifers,Ferns Cycads,Ginkgoas were dominant Paleozoic 570-280 Permian   325-280 Primitive gymnosperm evolved & extinct Carboniferous   345-325 Many Pteridophytes evolved Devonian   395-345 Fossils of land plant dominant.Terrestrial Life become Abundant Silurian   430-395 Land Plant Evolved Ordovician   500-430 Green and Red algae were dominant Cambrian   570-500 Algae were dominant Precambrian 4600-570 late     Eukaryotic Oraganism Evolved middle Origin Of Blue green algea Early Prokaryotic organism Evolved Table Showing major events

6. Fossils are the remains or traces of plants and animals.. They furnish evidence of the prehistoric life. They also provide missing link in the evolutionary chain. 2.Fossils

7. Formation of Fossils is called fossilization . The physical part of any plants must be Buried within well protective matrix in the earth crust. Process according to tissue type and condition. Theories Replacement theory- Replacement of molecules of the original material of the one by one by the molecules of the mineral solution. Infiltration Theory- By means of Infiltration and precipitation of mineral through cell wall. The plant body undergoes partial decomposition releasing carbon that converted into carbonat e b y reacting with Ca &Mg . 2.2.Process of Fossilization

8. Living organism must be buried alive or soon after death The cold and acidic water favours Valley ,lake basin,esturies are best place Steps Whole organism or part buried alive or soon after death Fine sand or clay mud is deposited on organism With passing time this sediment is compressed under weight of some sediments Through ecological changes it is converted into rock. Conditions For fossilization

9. 1) Impression Plant part is clearly visible on rock Commonly found in slits or clay t he entire shape is clearly visible but cellular details not No involvement of organic matter It is negative print made by the plant If layer of rock split apart .the organic material adhere to only one side of the rock kn /as Part and other side is known as Counterpart . 2.3.Type of fossils

10. By layering sediments from above, water squeezes out of the part of the plant and make them more compact and flattened Ultimately a thin carbanaceous film remain which correspond to original outline Some cellular details such as cuticle,epidermal hairs, spore are seen Most common fossil 2.Compression When the bulk of the plant compressed in layers of sediments –compression

11. After an organism become deposited in a body of water it may be infiltrated by mineralized solution that precipitates and harden within the cell These fossils preserve both internal and external features The organic material making up the plant part becomes completely replaced by silica and their compounds like Ca,Mg,Fe , and Phosphate and Ca and Mg. It involves molecule to molecule replacement 3.Petrification

12. The plant is decomposed and its body is replaced by hollow cavity Hollow cavity filled with mineral Matter –cast No involvement of actual part of plants Fruits ,hard seeds, tree trunk are commonly fossilized as cast 4)Cast

13. Mold are formed by 3-D structure dissolve by seepage of ground water leaving the hollow cavity in the rock Such Hollow cavity resembles with original organ in size & Shape. Molds are formed before the crushing plant body. The sediments surrounding it hardens . During the course of time ,the internal plant material dissolve and result in the formation of hollow fossils-mold 5.Mold

14. Coal balls represents the kind of petrification fossils in which isolated plants parts are preserved as masses of calcium carbonate. Best known example of sedimentary Rocks Pollen grains are best preserved 6.Coal Balls

15. 1.Psilopsida Psilopsida is the subdivision of tracheophyta (Vascular palnt ) that reproduce by means of spores. .The class was established in 1917, under the name  Psilophyta , with only three genera ( Rhynia ,  Horneophyton  and  Psilophyton ) [ for a group of   fossils  plants from the Upper  Silurian and Devonian  periods . Salient features of Psilopsida Psilopsida lack true roots and leaves, but have a vascular system within a branching cylindrical stem. Plant body is simple and does not shows much differentiation. Dichotomously branched rhizome in place of roots. Stem bears small spirally arrange leaves Sporangia are born directly on the stem( cauline ),or either terminal. Study of fossils

16. Rhynia genus with its two species was discovered in middle Devonian in 1913 by kindstom and Lang External Morphology Plant body Consisting cylindrical subterranian rhizome that are upright. Shoot s aerial branched ,leafless. Instead of root ,rhizome is present which bear rhizoid and functioned to absorb water and minerals. The smooth aerial stem tapers gradually from the base to the tip. Tip is either pointed or terminate in upright oval sporangia. Rhynia

17. The stem shows cuticle ,epidermis and hypodermis The vascular system consist of slender cylindrical column of xylem tracheid surrounded by phloem. The phloem is a simple tissue which function as sieve tube Phloem surrounded by pericycle and endodermis. Epidermis shows stomata. Internal structure of stem of Rhynia

18. The sporangia are oval or cylindrical structure with pointed end. The sporangium wall thick and multilayered with outer thick & inner thin walled. The whole interior is filled with spore tetrad or free spore. L.S . Of sporangia of Rhynia

19. Lycopsida are spore bearing vascular plants represent in the recent flora by the four genera Lycodium , Selaginela , Pylloglossuman , Isoetus Lycopsida evolved during paleozoic and diminished in mesozoic era. Principally in lepidodendrales , the important genera lepidodendron is mostly studied. Salient Features of lepidodendrales The sporophytic body is differentiate into root stem and leaf. Leaves are microphyllous and spirally arranged. The sporangia are born singly on the adaxial surface of the sporophyll and contain either homosporous . Sperms usually biflagellated . 2.Lycopsida

20. Lepidodendron is one of the largest and most abundant fossil of paleozoic era found in the shales and sandstone of the carboniferous coal bearing formation. External features of Lepidodendron .The trunk was reported to 114 ft long. . The upper part of the trunk is branched by an unequal dichotomy to produce lagge crown leafy twig. .The ultimate branches borne simple linear leaves which are 1 to 50 cm in length taper gradually. .The base of the trunk splits into two large root like organ that immediately divided again forming four arms. .The cone is elongated organ produced at tip of the slender twig laterally on the larger one. Lepidodendron

21. T.S. Of Stem of Lepidodendron shows Outermost surface covered by the persistent leaf base There is a massive z one beneath the leaf base Periderm layer differentiated into outer, middle and inner cortex Outer cortex is parenchymatous , middle cortex is ruptured parenchymatous cell and inner cortex is surrounded by secretary zone. There are leaf traces in middle and inner cortex. The stele is protostele with exarch and polyarch xylem i.e. Metaxylem at the centre and protoxylem on the periphery Internal structure of Lepidodendron

22. It is a class of vascular plants appeared in devonian . They are commonly called horsetail. Living horxtails are represented by about 20 species of single genus of Equisetum. Sphenopsida consist of five orders Hyeniales , Psuedoborniales,Sphenophyllales,Equisetales and Calamitales Among these calamitales is mostly studied extinct group , consisting genera Calamites. 3.Sphenopsida

23. It is characterized by horizontal rhizome ,tall upright groove and articulated stem. Some members reached a height of 8-12 m and diameter of 0.5-1 m Stem is differentiated into root ,stem and leaves. Leaves are microphyllous in whorl at each node. Sporangia are borne in group on sporangiophore . Salient Features of Calamitales

24. External Features The stem is known as calamites ,leafy twig are called Nularia and fructification is known as Calanostachys . The plant body of Calamites was tall tree growing to height of 20-30 meter. The plant had underground prostrate rhizome . The rhizome was differentiated into nodes and internodes and had a whorl of adventitious root at each node. From the upper surface of the rhizome arose number of aerial shoots. Some of these aerial shoots produces roots at some of the lower nodes. Calamites

25. Calamites

26. Internal structure of Calamites It shows periderm layer at the outermost surface of the stem Periderm followed by cortex which is differentiated into outer thick and inner thin walled. Innermost zone is broken down to form pith cavity The pith cavity is surrounded by endarch siphonostele . Protoxylem strands have disintegrates to form cornical canal. There is a massive secondary xylem lies in between cortex and primary V.B. Calamites

27. Calamites