Paleobotany

Paleobotany

Paleobotany is derived from Greek words paleon that means “old” and botany the study of plants. It is the branch of paleontology that deals with recovery and identification of plant remains of geological past.

A plant fossil is any preserved part of a plant that has died long back. Fossils may be a prehistoric impression that may be hundred to millions of years old. Majority of the plant fossils are disarticulated parts of plants, it is rare to find plants to be preserved as whole.

Importance of fossils

i. They throw light on phylogeny and evolution of plants.

ii. Fossil plants give a historical approach to plant kingdom.

iii. Fossils are useful in classification of plants.

iv. Fossil plants can be used in the field of descriptive and comparative anatomy.

Kaspar Maria Von Sternberg

He is the “Father of Paleobotany” (1761– 1838) was born in Europe. He established the Bohemian National Museum in Prague and is deemed to be the founder of Modern Paleobotany.

Birbal Sahani

He is the “Father of Indian Paleobotany” (1891–1949). He presented his research on two different areas of Paleobotany (i) The anatomy and morphology of Paleozoic Ferns (ii) The fossil plants of the Indian Gondwana Formations.

1. Fossilization

The process of formation of fossil in the rocks is called fossilization.

Common methods of fossilization includes petrifaction, molds and cast, carbonization, preservation, compression and infiltration.

Petrifaction

Minerals like silica slowly penetrate in and replace the original organic tissue and forms a rock like fossil. This method of fossilization can preserve hard and soft parts. Most bones and wood fossils are petrified.

Mold and Cast

A replica of a plant or animal is preserved in sedimentary rocks. When the organism gets buried in sediment it is dissolved by underground water leaving a hollow depression called a mold. It shows the original shape but does not reveal the internal structure. Minerals or sediment fill the hollow depression and forms a cast.

Preservation

Original remains can be preserved in ice or amber (tree sap). They protect the organisms from decay. The entire plant or animal is preserved.

Compression

When an organism dies, the hard parts of their bodies settle at the bottom of the sea bed and are covered by sediment. The process of sedimentation goes on continuously and fossils are formed.

Infiltration or Replacement

The precipitation of minerals takes place which later on infiltrate the cell wall. The process is brought about by several mineral elements such as silica, calcium carbonate and magnesium carbonate. Hard parts are dissolved and replaced by these minerals.

2. Determination of age of Fossils

The age of fossils is determined by radioactive elements present in it. They may be carbon, uranium, lead or potassium. It is used in paleobotany and anthropology for determining the age of human fossils and manuscripts.

Radioactive carbon(C14) dating method

This method was discovered by W.F. Libby (1956). Carbon consumption of animals and plants stops after death and since then, only the decaying process of C14 occurs continuously. The time passed since death of a plant or animal can be calculated by measuring the amount of C14. present in their body.