What is the diversity of organisms?
Biological diversity is the variety of life on earth. This includes
all the different plants, animals, and microorganisms; the
genes they contain; and the ecosystems they form on land and
in water. Biological diversity is constantly changing.
external form, internal structure, mode of nutrition, habitat, etc.
Our earth has high bio-diversity as it has about 1.7-1.8 million species.
GLOBAL DIVERSITY
Diversity on the Basis of Habitat
Hydrophytes – Plants growing near water or submerged
under water.
i. Poor Root System, Soft Stem & poor vascular tissue.
ii. Spongy Tissue with air spaces.
(a) Submerged – Hydrilla , (b) Free Floating &
Fixed Floating –Utricularia,Pistia,Lemna,Eichornia
(c) Amphibious(only partly submerged)Rannaculus, Sagittaria, Limnophylla
HYDRILLA
UTRICULARIA
(Bladder warts)
MANGROOVE VEGETATION
SAGITTARIA
EICHHORNIA
LEMNA – DUCKWEED
Mesophytes- Plants grow in places of moderate water supply.
(i) Large & fast growing
(ii) Well developed roots, leaves & stems
(iii) Stem may be herbaceous or woody
Examples:- Mango Tree, Rose plant, Apple Tree etc.
( There are certain mesophytes which are shedding leaves at
a particular season- deciduous tree)
Hygrophytes – Plants grow in moist & shaddy habitats.
Stem & roots are soft and spongy and show stunted growth.
The leaves are well developed with stomata( Ferns ,Begonia)
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3
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Xerophytes- Plants grow in xeric or dry conditions (negligible
water availability
Ex- Argemone, Calotropis, Amaranthus, Zizyphus etc
(i) Some store water in their stem – Opuntia,
(ii) Some store water in their Leaves – Aloe, Agave,
Bryophyllum
(iii) Some store water in their Roots – Asparagus (succulents)
Halophytes – Plants grow in Saline soil or saline water.
They have negatively geotropic breathing roots called
Pneumatophores. (Mangroove Vegetations- Rhizophora,
Sonneratia)
Epiphytes
An epiphyte is an organism that grows on the
surface of a plant and derives its moisture and nutrients from the
air, rain, water (in marine environments) or from debris
accumulating around it.
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The majority of epiphytic plants are angiosperms (flowering
plants); they include many species of orchids, tillandsias, and
other members of the pineapple family (Bromeliaceae).
Mosses, ferns, and liverworts
Parasitic Plant
A parasitic plant is a plant that derives some or all of its
nutritional requirement from another living plant. They make up
about 1% of angiosperms and are found in almost every biome.
Ex- Rafflesia , Cuscuta
BRANCHES OF BOTANY
1)MORPHOLOGY
11.EMBRYOLOGY
2)ANATOMY
12.EVOLUTION
3)TAXONOMY
13.VIROLOGY
4)PLANT PHYSIOLOGY
5)CYTOLOGY
6)GENETICS
7)ECOLOGY
8)PALEOBOTANY
9)MOLECULAR BIOLOGY
10)PLANT BREEDING
1.Taxonomy: It is the science of identification, nomenclature and
classification of organisms.
2.Morphology: It is the study of external form, size, shape, colour,
structure and relative position of various living organ of living beings.
3. Anatomy: It is the study of internal structure which can be
observed with unaided eye after dissection.
4.Histology: It is the study of tissue organization and structure as
observed through light microscope.
5.Cytology: It is the study of form and structure of cells including the
behavior of nucleus and other organelles
6.Cell Biology: It is the study of morphological, organizational,
biochemical, physiological, genetic, developmental, pathological
and evolutionary aspects of cell and its components.
7.Molecular Biology: It is the study of the nature, physicochemical
organization, synthesis working and interaction of bio-molecules
that bring about and control various activities of the protoplasm.
8. Physiology: It is the study of different types of body functions and
processes.
9.Embryology: It is the study of fertilization, growth, division and
differentiation of the zygote into embryo or early development of
living beings before the attainment of structure and size of the
offspring.
10.Ecology: It is the study of living organisms is relation to other
organism and their environment.
11.Genetics: It is the study of inheritance of characters or heredity
and variations. Heredity is the study of expression and transmission
of traits from parents to offspring.
12.Evolution: It studies the origin of life as well as new
types of organism from the previous ones by
modifications involving genetic changes and
adaptations.
13.Palaeontology: It deals with the study of fossils or
remains and impressions of past organisms present in the
rocks of different ages.
14.Virology: It is the study of viruses in all their aspects.
Submerged Floating Hydrophytes
Rooted Submerged Hydrophytes
Free Floating
Hydrophytes
Rooted
Emergent
Hydrophytes
with
Heterophylly
MARSH
PLANTS
Rooted
Hydrophytes
with Floating
Leaves