How many vessels do humans hasLECTURE 1 (Week 1)1. History of classification2. Contributors to the subject of classification1. The greek

LECTURE 1 (Week 1)

1. History of classification

2. Contributors to the subject of classification

1. The greek thinker Aristotle classified animals according to whether they lived on
land, in water or in the air.

2. Ernst Haeckel 1894

3. Carl Woese (1977) classified all living organisms into broad categories, called
kingdoms and introduced and divided the Monera into Archaebacteria (or Archaea)
and Eubacteria (or Bacteria)

4. Robert Whittaker (1959) proposed the five kingdoms: Monera, Protista, Fungi,
Plantae and Animalia, and is widely used. These groups are formed on the basis of
their cell structure, mode and source of nutrition and body organisation. The
modification Woese is also in use.

5. Carolus Linnaeus introduced the binomial nomenclature, Generic name and species
name. Musca domestica. Generic name begins with a capital letter and species name
with a small letter. Both type written in italics but when hand writeen underline
seperately

3. Classification of Kingdom Plantae

Refer to lecture notes in class

LECTURE 2 (Week 2)

KINDOM : ANIMALIA

Kingdom Animalia or Animal kingdom. The members of kingdom Animalia
are further classified into different

Phyla,

Class, Order, Family, and Genus based on certain identifiable characteristic features.

Criteria for classification of Animals

Levels of Organisation

Cellular level
e.g Amoeba, Paramecium, Plasmodium, Trypanosoma

Colonial/Syncytial
Animals with loose mass of cells and showing cellular level of organization. Such
animals have been categorized into the phylum Porifera.
Multicellular animals evolved from a unicellular or colonial organism

Multicellular level
a) Tissue level
At the tissue level of organisation: Body design grows more complex and the division
of labour occurs among the tissues. Phylum coelenterate/cnidaria is in this group e.g
Hydra, Corals, True jellies, Sea pens and Anemones
b) Organ level
organ level of organization have tissues performing related functions coming to form
the organism body complex.Phylum Platyhelminthes and Aschelminthes
c) System level
They have specialised organ system. Nor-chordates such as Annelids, Arthropods,
Molluscs, Echinoderms, and Chordates

Body symmetry
Body Symmetry is the line of division of the body into parts that are mirror images of
one another.
Non symmetrical orAsymmetria e.g Amoeba
Bilateral symmetrical e.gMan, Lizards, Fish, Cockroach

Radially symmetrical e.g Sea stars, Sea jellies, Britle stars

Germ layer

Tissues, organs and organ system are formed from the cells that form the embryonic
layers. The number of embryonic layers are classified into two- diploblastic and
three-triploblastic animals.

Diploblastic animals: In diploblastic animals, two embryonic layers, i.e., an outer
layer- ectoderm and an inner layer – endoderm, e.g. Phylum Coelenterata.

Triploblastic animals: In triploblastic animals, cells are arranged in three embryonic
layers- ectoderm, endoderm and a middle layer – mesoderm. Animals belonging to
Phyla Platyhelminthes Annelids, Arthropods, Molluscs, Echinoderms, and Chordates

Coelom

The coelom is a key feature for classification. The coelom is a body fluid filled cavity
between the body wall and gut wall, lined by mesoderm.
Acoelomate/Non coelomate: Coelom is absent in an acoelomate, e.g Platyhelminthes.
Pseudocoelomate: In pseudocoelomates, mesoderm appears as pouches between the
endoderm and ectoderm. But the cavity formed is not lined by mesoderm instead a
mucus lining called mesoglea, e.g. Aschelminthes.
Coelomate: Coelom of three layers ectoderm, mesoderm, and endoderm are present
in a coelomate. Animals belonging to phyla Annelida, Mollusca, Arthropoda,
Echinodermata, Hemichordata and Chordata are examples of coelomates.

Notochord

The notochord is a longitudinal, cartilaginous supporting rod running beneath the
nerve cord. The animals that lack notochord Non-Chordata and Animals with
notochord are Chordata. Animals belonging to the Members of phylum Porifera,
Coelenterata, Ctenophora, Platyhelminthes, Aschelminthes, Annelida, Arthropoda,

Mollusca, Echinodermata and Hemichordata fall under non-chordates.while Chordata
are divided into three subphyla: Urochordata, Cephalochordata, and Vertebrata.

General characteristic features of Non-Chordates

 They are cylindrical, triploblastic, coelomate, or pseudocoelomate animals.
 Respiration in these animals takes place through gills, trachea or body surface.
 Most of the times, sexes cannot be distinguished among the members.
 Modes of reproduction involve sexual and asexual
 Fertilization is external, though internal fertilization also occurs in some

species.
 The body of non-chordates generally includes an open type of circulatory

system.

Ggeneral characteristic features of Chordates

 They are bilaterally symmetrical, triploblastic, and coelomate with the organ-
system level of organization.

 They hold a post-anal tail
 The body includes a closed circulatory system.
 In some members of Phylum Chordata, the notochord is present only in the

larval tail, and in some, it is present throughout their life from head to tail
region.

 Chordates have many sub-divisions and Protochordates are one of the earliest
to evolve.

Classification of Kingdom Animalia

Phylum: Porifera/Sponges

Animals with body differentiation and division into tissues. Porifera means
organisms with holes and body covered with a hard outside layer or skeleton. They
are non-motile animals attached to some solid support. Presence of holes or ‘pores’,
called ossicles all over the body leading to a canal system that helps in circulating
water with food and oxygen. They are marine habitats. Some examples are Sycon,
Euplectelea, Spongilla

Phylum: Coelenterata (Cnidaria)

They live in water. The body is made of two layers of cells: the outer ectoderm and
the inner lining of endoderm surrounding the gastrovascular cavity Some of these
species live in colonies (corals), while others are solitary like Hydra Jellyfish and sea
anemones/

Phylum : Platyhelminthes

The body of the animals is bilaterally symmetrical, ]triploblastic, there is some degree
of tissue formation and no true internal body cavity or coelom, in which
welldeveloped organs can be accommodated. Body is dorsiventrally flattened,
meaning from top to bottom, which is why these animals are called flatworms. They
are either freeliving or parasitic. The freeliving one is Planarians, the parasitic one
include liverflukes.

Phylum: Nematoda// Aschelminthes

The nematode body is bilaterally symmetrical, triploblastic, round cylindrical rather
than flattened, pseucoelomate and tissues present no real organs, Mostly parasitic
worms causing diseases, such as Filaria worms causing elephantiasis or the intestines
roundworm Ascaris and Pinworms – Wuchereria.

Phylum : Annelida

Annelid animals are bilaterally symmetrical, triploblastic and coelomate (true body
cavity) which allows true organs to be packaged in the body structure. They have
extensive organ differentiation in a segmental fashion, with the segments lined up one
after the other from head to tail. They could be fresh water, marine and terrestrial.
Earthworms, Nereis diversicolor and the only parasitic Leeches are examples

Phylum : Arthropoda

Largest, widely distributed and most successful group of animals. These are
bilaterally symmetrical, segmented., open circulatory system, and the coelomic cavity
is blood-filled. They have jointed legs Examples are llouse, ants, grasshoppers,
millipede, centipede, prawns, butterflies, houseflies, spiders, scorpions and crabs

Phylum : Mollusca

They are triploblastic and bilateral symmetry. The coelomic cavity is reduced. There
is little segmentation. Body divided into head, visceral mass, muscular foot and

mantle. The mantle covers the visceral mass. They have an open circulatory system
and kidney-like organs for excretion. The foot is used for moving around. Examples
are snails, Octopus, Sepia, Oyster, Cuttle fish, limprts, mussels and squid

Phylum : Echinodermata

Literarily echino is called hedgehog, and derma means skin. They are spiny skinned
organisms, exclusively free-living marine animals. They are triploblastic and
coelomate. They also have a peculiar water vascular tube system that they use for
moving around. They have hard calcium carbonate structures that they use as a
skeleton. Examples are starfish, sand dollars, sea urchins, sea cucumber, brittle stars,
sea liles, feather stars and crinoids

Phylum Chordata

Subphylum – Urochordata

It is also referred to as Tunicata which are marine animals. The body of these animals
is surrounded by a leathery covering (similar to a tunic, hence the name). Larvae are
free-swimming, the notochord is present only in the tail of larvae and after settling on
the seabed, they get transformed into sessile adults. They are generally
hermaphrodites.

Examples include – Ascidians, Doliolum, Oikopleura, etc.

Subphylum – Cephalochordata

It mainly consists of small, fish-like marine animals in which the notochord is
extended along the entire body. The animals also have pharynx, which is large with
numerous gill- slits. Members of this subphylum have separate sexes.

Example include – Amphioxus or lancelet.

Subphylum – Vertebrata

In this subphylum, the notochord is present in the embryonic stages and is replaced by
a vertebral column in the adult. They have 2, 3 or 4 chambered heart, paired
appendages for locomotion and kidneys for excretion or osmoregulation.

Vertebrates Classification

The subphylum Vertebrata is divided into five classes of vertebrates. These five
classes of vertebrates comprise of all the species of animals and have developed
vertebral column as well as an internal skeleton.

There are over 66,000 species of vertebrates identified under phylum Chordata till
date. The defining feature of vertebrates is that their bodies are bilaterally
symmetrical, coelomic, triploblastic, and with complex differentiation of body tissues
and organs.

Other characteristic features of vertebrates are:

 Presence of a true vertebral column and internal skeleton with muscle
attachment points for body movement.

 A front-side muscular heart with two, three or four chambers.
 Kidneys for excretion and osmoregulation
 A paired appendages which may be fins or limbs.
 Possess notochord during the embryonic stage.
 Vertebrates are the only chordates to possess a brain as a part of the central

nervous system.

Classification of Vertebrates

 Pisces
 Amphibia
 Reptilia
 Aves
 Mammalia

Class Pisces (Fishes)

They are aquatic animals, having a streamlined body and a pair of fins which are used
for propulsion and movement. Furthermore, fish are cold-blooded, but the discovery
of a new species in 2015 has changed this perception. The opah or the moon-fish is a
fully warm-blooded fish capable of regulating its body temperature.

Endoskeleton may be cartilaginous or bony and respiration occurs through gills. They
do not possess eyelids because the surface of the eye is to be kept moist all the time.

Examples of Class Pisces includes dogfish and Rohu.

Class Amphibia

They usually comprise those organisms which are cold-blooded and require an
aquatic habitat to lay eggs. These organisms are mainly characterized by the two pairs
of limbs, smooth and moist skin for respiration. They also possess protruding eyes
which are protected by usually more than one pair of eyelids. .

Examples of Class Amphibia are frog, toad, and salamander.

Class Reptilia

Class Reptilia comprises those organisms which are ectothermic in nature (cold-
blooded). They are characterized by osteoderms which form scales, bony plates or
scutes on the skin. Reptiles lack external ear and some reptiles such as snakes are
actually “deaf” and instead, pick up vibrations through the ground. Another amazing
sense that only snakes possess is Thermoreception. This means that snakes can see
infrared radiation emitted by objects or prey.

Examples of Class Reptilia are Tortoise, Wall lizard, Snake, etc.

Class Aves (Birds)

Most members have streamlined body specially designed to offer low air resistance
during flight. In such birds, the forelimbs are modified into wings, with the power
coming from breast muscles. Pneumatised bones. Feathers play important roles, from
flight, thermal insulation to water-proofing. All members of this class are warm-
blooded and are able to regulate their body temperature.

Aves have beaks, which are used for various functions such as preening and feeding.
Furthermore, birds evolutionarily are living relatives of dinosaurs called the theropods
(a meat eating dinosuars).

Examples of Class Aves are Parrot, Pigeon, Duck, etc.

Class Mammalia

These organisms are distinguished by the presence of mammary glands. They have
two pairs of limb for walking, grasping, swimming, flying, etc. Digits are provided
with claws, nails or hooves. Skin is covered by hair and they have an external ear
called pinnae. They are warm-blooded animals.

Examples of Class Mammalia include monkeys, lions, bats, squirrels and humans.