Download DIVERSITY IN LIVING ORGANISMS Till page 88(till PLANTAE

DIVERSITY IN LIVING ORGANISMS
Till page 88(till PLANTAE kingdom)
By making a comparative study and assorting the similarities and differences amongst the various
varieties of species, organisms can be classified into groups or sets.
1. Importance of Classification
a. It makes the study of such a wide variety of organisms easy.
b. It projects before us a good picture of all life forms at a glance.
c. It helps us understand the interrelationship among different groups of organisms.
d. It serves as a base for the development of other biological sciences such as
biogeography etc.
2. Basis of classification
Cell structure
Mode and source of nutrition
a. Whether the organism is prokaryotic or eukaryotic.
Body organisation
b. Whether the organism is unicellular or multicellular.
c. The mode of nutrition of the organism. Whether it is autotrophic, heterotrophic
d. Its way of evolution.
i. A process of changes in body design that allow the organism possessing them to
survive better. OR
ii. A process of change in an organism which increases its survival chances.
3. Relation between classification and evolution
a. All living things are identified and categorized on body design in form and function.
b. Some changes impact body design more than other changes.
c. As evolution occurs, classification may change with characteristics.
4. Hierarchy of Classification – Groups
a. Formation of the Hierarchal Classification
i. Biologists such as Ernest Haeckel (1894), Robert Whittaker (1959) and Carl Woese
(1977) tried classification by broad categories
ii. Robert Whittaker’s classication scheme is today accepted worldwide
1. According to him, this classification composed of 5 kingdoms
a. Monera
b. Protista
c. Fungi
d. Plantae
e. Animilia
iii. Carl Woese suggested the division of Monera into the following groups and is still
in use.
1. Archaebacteria ( or Archea)
2. Eubacteria (or bacteria)
b. The Hierarchal Classification
i. Kingdom
1. Class
a. Order
i. Family
1. Genus
A group of organisms of the same kind
a. Species
which can inter breed and perpetuate.
c. The Five Kingdom Classification
i. Monera
1. Characteristics
a. They are unicellular and prokaryotic.
b. Cell wall is mostly present. May be absent in some organisms
c. Mode of nutrition is autotrophic or heterotrophic.
2. Examples
a. Bacteria
b. Blue green algae or cyanobacteria
c. Mycoplasma
ii. Protista
1. Characteristics
a. They are eukaryotic and unicellular.
b. They have appendages( cilia or flagella) which aid in movement.
c. They are mostly autotrophic while some are heterotrophic.
2. Examples
a. Diatoms
b. Protozoans
c. Unicellular algae
iii. Fungi
1. Characteristics
a. They are unicellular primarily and can become multicellular at later
stages in their life.
b. They are eukaryotic.
c. They are heterotrophic.
d. Cell walls made of a tough sugar complex called chitin.
2. Examples
a. Yeast
b. Mushrooms
3. Symbiotic Associations
a. Some species live in permanent mutually dependent relationships
with blue-green algae or cyanobacteria
i. Such an association is called symbiotic
b. Symbiotic life forms are called lichens.
i. They are slow – growing large, coloured, patches on the bark
of trees.
iv. Plantae
1. Characteristics
a. They are multicellular and eukaryotic.
b. They are autotrophs and use chlorophyll for photosynthesis.
c. All plants are included in this group.
2. Criteria of levels of classification
a. The first level of classification depends on whether the plant body
has well differentiated and distinct features.
b. The second level of classification is based on the specialization of
tissues for transportation of water and other substances.
c. Further classification is based on the ability to bear seeds and the
seeds being or not being enclosed within fruits.
3. Types
a. Cryptogamae [meaning – those with hidden reproductive organs]
i. Characteristics
1. Have naked embryos called spores.
2. Inconspicuous reproductive organs
ii. Types
1. Thallophyta
a. Characteristics
i. Don’t have well differentiated body design
ii. Commonly called algae
iii. Predominantly aquatic
b. Examples
i. Spirogyra
ii. Ulothrix
iii. Cladophora
iv. Chara
2. Bryophyta
a. Characteristics
i. Amphibians of the plant kingdom
ii. Plant body is commonly differentiated
iii. Forms stem and leaf like structures
iv. No specialized tissue for conduction of
water and other substances and their
transportation to other plant parts
b. Examples
i. Moss – Funaria
ii. Riccia
iii. Marchantia
iv.
3. Pteridophyta
a. Characteristics
i. Differentiated plant body
ii. Has roots, stems and leaves
iii. Has Specialized tissue for for conduction of
water and other substances and their
transportation to other plant parts
b. Examples
i. Marseila
ii. Ferns
iii. Horse – tails
b. Phanerogams
i. Characteristics
1. Well differentiated reproductive tissues
a. Make seeds which are a result of the reproductive
process
b. Components
i. Embryo
ii. The stored food which serves for the initial
growth during germination
ii. Types
1. Gymnosperms [Greek: gymno(naked) + sperma(seed)]
a. Characteristics
i. Bear naked seeds
ii. They are perennial, evergreen and woody.
b. Examples
i. Pines
ii. Deodar
iii. Pinus
iv. Cyas
2. Angiosperms [Greek: angio(covered) + sperma(seed)]
a. Seeds develop an organ which later becomes fruit
b. Also called flowering plants
c. Have structures called cotelydons
i. Called seed leaves because they often
become green upon germination
ii. Present a bit of pre-designed plant in the
seed
d. Types: based on the number of cotelydons
present
i. Monocotyledonous/Monocots
ii. Dicots
e. Monocotyledonous/Monocots
i. Have a single cotyledon
ii. Paphlopedilum is an example.
f. Dicots
i. Have two cotyledons
ii. Ipomea is an example.
v. Animalia
1. Characteristics
a. They are multicellular and eukaryotic.
b. They don’t have cell walls.
c. They are heterotrophic.
5. A Flow Chart for the Plant Kingdom Classification