1. S.Y.B.Sc. /{B} /{262} SEMESTER-4
PRAVIN PRADHAN
}

3.  Derived from Greek words
“Palaeon” = old and “Botany” = study
of plants.
 Deals with the identification of plants remains of
geological age, and its reconstruction.
 Includes the study of terrestrial
plant fossils, as well as Marine
ones such as seaweeds.

4.  Reconstruction of ancient ecological systems
and climate, known as palaeoecology
and palaeoclimatology
respectively.
 Study of green plant development
and evolution.
 Important to the field of Archaeology.

5.  First fossil record was found in SILURIAN
period of PALAEOZOIC ERA.
 Spores and cuticles, were found in
ordovician period.
 Angiosperms (flowering plants) evolved during
the Mesozoic, and Early
Cretaceous. (approx. 130 million years ago)

6.  A plant fossil is any preserved part of
a plant that has long since died.
 Bits of charcoal that are only a few hundred
years old.
 RHYNIE CHERT found
in SCOTLAND bearing the
fossils of mosses and lycopods.
(see image beside)

7.  LEAVES
 Evolved to originate as spiny
outgrowths.
 Before the evolution of leaves,
plants had the photosynthetic
apparatus on the stems.

8. The branching pattern of
megaphyll veins may belie
their origin as webbed,
dichotomising branches.
(see image right)
Leaf lamina.
The leaf architecture
probably arose multiple
times in the plant lineage
(see image left)

9.  To protect early plants from herbivory.
 Better transpiration rates and gas
exchange.
 Helps to carry out better
Photosynthesis.
 Figure beside shows the diversity in leaves
evolved according to their suitable
environmental conditions.

10.  ROOTS
 Organs differentiated from stems – did not arrive
until later.
 Roots are rarely preserved in the fossil record.
 Their evolutionary origin is sparse.
 Rhizoids are prehistoric roots.
 Rhizoids probably evolved more than once.
The root of
Lepidodendrales
(image beside)

11.  provide anchorage to the substrate.
 provide a source of water and
nutrients from the soil.
 allow plants to grow taller and faster.
Stigmaria, a common
fossil tree root.
(image beside)

12.  Stems
 Ferns were the first to have a growth of
woody habit.
 Progymnosperms were the first
plants to develop true wood.
The trunk of early
tree fern Psaronius,
showing internal-structure.
(image beside)

13.  The most obvious advantage is the harvesting
of more sunlight for photosynthesis.
 Spores can be blown greater distances if they
start higher.
 Provided support and water transport.
External mold of
Lepidodendron trunk.
(image beside)

14.  SEEDS
 Germination of microgametophytes and
megagametophytes, paved the way for seeds.
 Seed plants from Belgium has been identified the
earliest seed plants - about 20 million years.
 The first "spermatophytes" (seed plants) i.e. the first
plants to bear true seeds
are called "pteridosperms“
(seed ferns).
The fossil seed
Trigonocarpus
(image beside)

15.  increased the success rate of fertilised
gametophytes.
 increases the biodiversity of forests.
 Helps the plant to survive for
generations.
The transitional
fossil of seed of
Runcaria.
(image beside)

16. THANK U !!!!!!!!!!!