Science and Technology Part -2 Grades of organization found in Protozoa:
Mr. Shrishail Mathapati (9922242470) 1) Protoplasmic or acellular level: This type of
organization found in protozoa or acellular
protista. All the activities are performed by single
6. Animal Classification celled body.
Important terms used in the classification 2) Cellular level: Multicellular organisms such as
of animals. mesozoans and sponges, are made of loose
association of cells. All the cells are direct contact
Animal classification: Formation of group and with the environment. i.e water which facilitate
sub-groups of animals depending upon respiration, excreation and other activities etc
similarities and difference among animals is takes by general body surface.
called animal classification
3) Cell tissue level : Celentrates are supposed to
Notochord: A cartilaginous skeletal rod make the beginning of the tissue plan of the body.
supporting the body in all embryonic and some They possess interconnected nerve net of nerve
adult chordate animals. cells with the function of transmission of the
impulse and coordination.
Depending upon presence and absence of the
notochord, the animal kingdom has been divided 4) Tissue-organ level: Platyhelminthis are the
into two groups – Chordate and Non-chordate. first bilaterally symmetrical acoelomate
metazoans to have reached the tissue-organ level
Notochord Nerve chord
of organization. They have number of well
Belongs to skeleton of Belongs to the central
defined organs such as eyespot, proboscis,
chordates. nervous system of
chordate gonads etc. they are also triploblastic because
Occurs between the Occurs below the they have a third or middle cellular germ layer
notochord and the notochord. called mesoderm. Which lies between ectoderm
central nervous system. and inner endoderm.
Provides sites for Coordinates the
attachment of the function of the body. 5) Organ-system level: In higher animals several
skeletal muscles. organs are associated to form a distinct system
concerned with a specific function like digestion,
respiration, circulation excretion and reproduction.
Pharyngeal gill-slit: pharyngeal means
This is the highest level of organization. This is
situated near the pharynx. Pharyngeal slits are
first seen in a group of marine worms known as
openings between the pharynx or throat. In
Nemerteans, Aschelminthes, Annelids and all
primitive chordates, these slits are used to filter
other higher phyla show this kind of organization.
food particles from the water. In fishes and some
amphibians, the slits bear gills and are used for Main types of symmetry seen in animals:
gas exchange.
1) Asymmetrical Symmetry: In some animals
Paired: meaning: A pair of things or two things there are no body axis and no plane of symmetry,
of the same size and shape that are used hence the animals are called asymmetrical. Ex.
together or both part of something. Ex. shoes, Amoeba, Paramecium and many sponges have
earrings or parts of the body. irregular growth pattern of the body and cannot
be divided into two equal halves.
Dorsal and Ventral side
2) Radial Symmetry: The body can be divided
Dorsal side Ventral side
into two rough equal halves by any one of many
Meaning ‘back’ side. Means ‘belly’. Opposite
of backside. vertical planes passing through the central axis
Surface of an organism Surface of organism like the spoke of wheel.
refers to the back, or refers front, or lower
upper side of an side of an organism. 3) Bilateral Symmetry: IN bilateral symmetry the
organism. body parts are arranged in such a way that the
animal is divisible into roughly mirror image nutrients flows interior the current of water
halves through one plane only. This plane passes of the sponges. exits after passing
through the axis of the body to separate the two through the
halves which are referred to as the right and left spongocoel.
halve.
Collar cells: Found in sponges and have a sticky,
What is the meaning of germinal layers in
funnel shaped collar and a hair like whip, called a
animals?
flagellum. Function of collar cells is to assists with
A germ layer is a group of cells in an embryo that water circulation in the body of sponge.
interact with each other as the embryo develops
Locomotion: Movement or ability to move from
and contributes to the formation of all organs and
one place to another
tissues.
Sedentary animals: animals have a little
Types of germinal layers:
movement or are permanently attached to
1) Diploblastic: An animal possessing 2 major something. Hence they not show locomotion.
tissue layers. These includes the outer layer (the
Spicules or spongin fibres: Skeletal structure of
ectoderm) and the inner layer (the endoderm).
sponges are Spicules or spongin fibres. Spicules
2) Triploblastic: An animal possessing 3 major are formed by carbonates of lime ar silica in the
tissue layers. It has a middle layer (the form of needle like pieces. Songin fibres are
mesoderm), between the endoderm and the composed of a silk like scleroprotein.
ectoderm.
Regeneration capacity: Regeneration is the
Body cavity or coelom: process of renewal, restoration and growth. Ex.
hydra. Hydra performs regeneration but
body cavity or coelom can be defined as a large reproduce by the method of budding.
fluid filled space lying between the body wall and
the gut wall. Coelom acts as a shock obsorber Polyp: If body of animal is cylindrical then it is
and hydrostatic skeleton. called as ‘polyp’.
a) Acoelomate: Do not have a body cavity. Ex, Medusa: If the body of animal is like umbrella
phyla Porifera, Cnidaria and Platihelmintis. then it is called as ‘Medusa’.
b) Coelomate or true coelom: which is a coelom Cnidoblast: is an explosive cell containing one
taken from the mesoderm tissue. Ex. Phylum giant secretory organelle. Cnidoblast are used for
Annelida. a prey capture. And defense from predator.
c) Pseudo coelomate or false coelom: which Endo parasite Ecto parasite
have a coelom formed in the blastocoel. Ex. Are parasites that live Are the parasites that
round worms inside the body of the live on the outer
host. surface of the host.
Body segmentation: Ex. hook worm Ex. female mosquito
If the body of animal is divided into small similar
units, then such body is called as segmented Hermaphrodite or Unisexual organisms
Bisexual
body and such small unit is called segment. Ex.
The organisms in which The organisms in which
Earth worm. both the male and male and female
female reproductive reproductive system
system are present in are present in different
the same individual are individual are called as
Ostia Osculum
called bisexual unisexual organisms.
Are tiny pores all over Is a excretory structure organisms.
the body of sponges. opening to the outside.
Ex. Planaria, Liverfluke, Ex. Ascaris, Filarial
Its function is to let the A large opening to the earth worm, Leech. worm.
water, along with desire outside through which
Metameric Non metameric
segmentation segmentation
The repetition of organsEndoderm is not
and tissues at intervalsinvolved metamery
along the body of an segmentation is not the
animal, thus thesame concept as
deviding the body into ametamerism.
linier series of similarSegmentation can be
parts or segments. confined only to
(metamers) ectodermally derived
tissue.
Ex. Annelida (Earth Ex. tape worm
worm)
