IGCSE
UNIT-1
CHARACTERISTICS &
CLASSIFICATION
of
LIVING ORGANISMS
After completion of chapter:
Characteristics of Living organism
Naming-Binomial System
Classification of living organisms
Identification of living organisms
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Characteristic
of
Living organisms
MRS GREN
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Characteristic
of
Living organisms
Nutrition
Respiration
Excretion
Movement
MRS GREN
Growth
Sensitivity
Reproduction
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Growth as a permanent increase in size and dry mass
Sensitivity as the ability to detect and respond to
changes in the internal or external environment.
Movement as an action by an organism or part of
an organism causing a change of position or place.
Nutrition as the taking in of materials for energy, growth and development.
Respiration as the chemical reactions in cells that break
down nutrient molecules and release energy for metabolism.
Excretion as the removal of the waste products of
metabolism and substances in excess of requirements.
Reproduction as the processes that make more of the
same kind of organism
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HIERARCHY OF
BIOLOGICAL
CLASSIFICATION
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Linnaeus gave every species of living organism two names, written in Latin.
This two-word name is called a binomial.
Each name has two components – the Generic name and the specific epithet
Binomial system is an internationally agreed system in which the scientific name of an organism
Genus
Panthera leo
Species
Species are group of similar organisms that can reproduce and produce fertile off
spring.
Species are grouped into larger groups called genera (singular: genus).
Each genus contains several species with similar characteristics.
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ASSIGNMENT
Find out the scientific names of the following:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Wheat Rice Dog Hibiscus Cat Tiger Mango Potato –
Wolf Human –
Triticum aestivum
Oryza sativa
Canis lupus familiaris
Rosa sinensis
Felis catus
Panthera tigris
Mangifera indica
Solanum tuberosum
Canis lupus
Homo sapiens
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DIFFERENCE IN PROKARYOTIC & EUKARYOTIC CELL
CHARACTERISTICS
PROKARYOTES
EUKARYOTES
Cellular organization
Single celled
Single or multiple celled
Nucleus
No nucleus
True nucleus
Cell Wall
Present in most cells (Peptidoglycan)
Present in Plants (cellulose) & Fungi (chitin)
Ribosome
Ribosomes: 70S
Ribosomes: Cytoplasmic (80S); Organelles (70S)
Respiratory Enzymes
Cell Membrane
Mitochondria
External Layer
Capsule or Slime Layer
Pellide/Test/Shell
Genetic Material
DNA is naked & circular
DNA is linear & bound to proteins
Location of Genetic material
Nucleoid (Nuclear Region)
Nucleus
Haploid chromosome (single)
Diploid chromosomes (paired)
Binary Fission / Budding
Mitosis & Meiosis
Asexual
Asexual or Sexual
Chromosome
Mode of Cell Division
Reproduction
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KINGDOMS
PROKARYOTES
EUKARYOTES
PROTISTA
FUNGI
PLANTAE
ANIMALIA
MONERA
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www.youtube.com/watch?v=FGnS-Xk0ZqU&t=183s
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MONERA
PROKARYOTES
BACTERIA
ARCHAEA
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A General Overview
Prokaryotes = Pro (before) + Karyon (nucleus)
 Prokaryotes are simple unicellular organisms that lack nucleus & membrane bound structures.
 The prokaryotic cell division takes place by binary fission.
 Prokaryotes are distinguished from eukaryotes on the basis of cell structure & molecular makeup.
 Prokaryotes are very small most being approximately 0.5 to 1.0 μm in diameter.
 Due to the small size the surface area/volume ration is extensively high for the prokaryotes.
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A
B
C
D
E
J
H
F
I
G
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PROTISTA
Characteristics:
 Unicellular or Multicellular
 Cells have a nucleus.
 Cells may or may not have a cell wall and
chloroplast.
 Autotrophic or Heterotrophic.
 Uninucleate, binucleate or multinucleate.
 Asexual reproduction by binary fission,
multiple fission, and sexual reproduction by
conjugation.
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FUNGI
Characteristics:
 They may be unicellular (yeast).
 They may be multicellular & filamentous (Mycelium).
 Cells have a nucleus.
 Cells have a cell wall (chitin).
 Don not have chlorophyll.
 Saprophytic or parasitic.
 Some fungi are decomposers.
 Fungi carry thread like structures called Hyphae.
 Fungi can live in symbiosis (Lichens).
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ASSIGNMENT
1. Give different examples of Kingdom Protista & Fungi
(5 examples each).
2. Describe about symbiosis existence of FUNGI.
3. Write a note on Amoeba.
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PLANTAE
Characteristics:
1. Plantae includes multicellular organisms except for some primitive relatives of algae.
2. They are eukaryotes, that is, their each cell has a nucleus and membrane bound cellular
organelles.
3. Cellulose – containing cell wall occurs around the cell.
4. A mature plant commonly possesses a single large central vacuole bound by tonoplast
(membrane).
5. Reserve food of plants is starch and lipids (oil/fat).
6. In all plant cells occur double membrane covered cell organelles, called plastids. Some
plastids possess photosynthetic pigments (chlorophylls). They are called chloroplasts.
7. Nutrition of plants is autotrophic type with the help of chlorophyll present in
chloroplasts, plants are able to perform photosynthesis.
8. Growth in plants is generally indefinite due to presence of growing points.
9. Body form of the plants is irregular due to presence of branches.
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plantae
(Do not have differentiated plant body)
(Have differentiated plant body)
1. THALLOPHYTA
Without specialized tissues
With specialized tissues
2. BRYOPHYTA
Produce seeds
Do not produce seeds
3. PTERIDOPHYTA
Bear naked seeds
4. GYMNOSPERMS
Bear seeds in fruits
5. ANGIOSPERMS
1. Monocots
2. Dicots
1. THALLOPHYTA (ALGAE)
1.
2.
3.
Most primitive & simple plants.
The plant body is not differentiated into roots, stem & leaves.
It is in the form of undivided thallus.
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2. BRYOPHYTA
1.
2.
3.
4.
5.
Small multicellular green land plants.
Habitat: shady & damp areas.
Amphibians of plant kingdom.
They lack real root, stem or leaves and have no flowers.
Fixation of plant body is carried out by rhizoids.
Liverworts
Mosses
Flat, green thallus structures
Leafy, erect structures
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3. PTERIDOPHYTA
1.
2.
3.
4.
Small multicellular green land plants.
Habitat: shady & damp areas.
Well differentiated plant structure (root, stem, leaves)
They lack fruits & flowers.
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4. GYMNOSPERM
1.
2.
3.
4.
Simple seed bearing plants
The seeds produces by these plants are naked & are not
enclosed inside fruits
Usually evergreen woody plants.
Examples: Pinus (pines), Cedrus (Deodar)
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5. ANGIOSPERM
1.
These are highly evolved plants and they
produce seeds that are enclosed within the
fruit.
2.
Plant seeds (embryo) are covered by structure
called cotyledons (seed leaves).
3.
On the basis of number of cotyledons the
angiosperms are divided into two groups:
 Monocotyledons
(Monocots);
Examples:
Maize, Wheat, rice, sugarcane, coconut.
 Dicotyledons (Diocots); Examples: Pea, Apple
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MONOCOTS
DICOTS
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ANIMALIA
Characteristics:
1.
Animals have wall-less eukaryotic cells.
2.
Animals have organisation of cellular, tissue, organs and organ system level.
3.
Animal’s heterotrophic nutrition is of holozoic (ingestive) type. An internal alimentary canal is
present for extra-cellular or intracellular digestion and absorption of food in most animals.
Digestion is intracellular in primitive animals. The undigested matter is thrown out.
4.
Growth of animals is limited and stops after reaching maturity.
5.
Animals generally possess a definite shape, size and symmetry. Exceptions occur in some lower
forms.
6.
Most animals are mobile (locomotary). Locomotion is required for obtaining food and other
necessities (e.g., dwelling, mate). Sponges and cnidarians (e.g., Hydra, Obelia, corals), however, are
mobile (e.g., tentacles in Hydra and flagella of choanocytes in sponges).
7.
Movements occur in animals with the help of a muscular system. Information is conveyed to
different parts of the body by nervous system which also provides stimulus to muscles for
contraction.
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Phylum ARTHOPODA
Invertebrate
Triploblastic
Bilaterally symmetrical
Body is segmented into head thorax and abdomen.
Possess exoskeleton
Joint legs.
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Phylum ARTHOPODA
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Phylum ARTHOPODA
Insecta
Myriapoda
Crustacea
Arachnids
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