ANIMAL KINGDOM FOR GRADE XI XII BACHELOR MASTER DEGREE IN ZOOLOGY.

2. • Name derived from two Greek words: Poros- pores and Ferre- to bear
Characteristic Features:
• They are commonly known as pore bearing organisms also commonly called sponge.
• They are also aquatic , mostly marine and few are found in fresh-water.
• They may be solitary and colonial .
• They are all sessile (don’t move due to absence of locomotory organs or structures and are
permanently attached to substratum by a stalk ).
• Their body may be asymmetrical or radially symmetrical (the body which can be divided into
two equal parts from any side passing through the central axis is called radially symmetrical
body) .
• They are multicellular organisms, have cellular level of the body organization.
• Acoelomate.
• Their body is diploblastic i.e they consist of two layers of cells: outer layer is known as
ectoderm or pinacoderm and inner layer is known as endoderm or choanoderm .
• The minute pores present all over their body is called ostia and a large opening at the top of its
body is called osculum.

3. • Presence of a unique water canal system which helps them in feeding , respiration and
excretion.
• The body of poriferans consist of a large number of fine tubules or canals like structure
containing water which is called water canal system
• The centrally placed hollow body cavity in them is known as spongocoel .
• Digestion is intracellular ( within the cell ).
• Absence of circulatory and nervous system .
• They can reproduce by both sexually and asexually . Also reproduce by fragmentation
(pieces break off & form a new sponge)
• Sponges can regenerate (regrow) lost body parts through mitotic cell division (asexual)
• Sponges also reproduce asexually by budding
• Sponges are hermaphrodites (produce both eggs & sperm)
• Sponges reproduce Sexually by releasing eggs & sperm into the water from the Osculum
• Cross-fertilize each other’s eggs

5. Classification
Phylum porifera has been classified into three classes mainly on the basis of endoskeleton
(inner supporting structure ).
i)Calcerea
• They are mostly marine.
• They are solitary and colonial
• The endoskeleton is made up of calcareous (caco3) spicules (spicules are crystal like
transparent structures having painted arms and are present in mesenchyma)
• They are all marine.
• Eg: Sycon , Grantia

6. ii)Hexactinellida
• Body is vase like or cup like
• Their endoskeleton is made up of silicious
(made up of spicules).
• They are all marine .
• Eg :Euplectella (venus flower basket ) ,
Hyalonema (glass rope sponge )

7. iii)Demospongiae
• It includes the largest number of sponges that are solitary or colonial.
• Their endoskeleton is mainly made up of spongin fibres .
• Spongin fibres are fine net like structure made up of amino acid .
• They are mostly marine and few are found in fresh water .
• Eg :Spongilla , Euspongia (bath sponge)

9. • Coelenterata (Gr. Koilos = cavity or hollow; enteron= intestine)
• Also called Cnidaria (Gr. Cnidos = thread )
• Commonly called stinging animals
• Leuckart (1847) ----created phylum Coelenterata
• Cnidology: The study of coelenterates
• Simplest of all metazoans. More than 9000 species
GENERAL CHARACTERISTICS
1. Habit and habitat: Aquatic, Mostly marine and few fresh water ( eg. Hydra ). Solitary or colonial.
Sedentary (corals) or free swimming (Aurelia)
2. Body form: Hollow, Polyps ( tube like) and medusa (umbrella shaped). Devoid of head and
segmentation
3. Radially symmetrical.
4. Tissue grade of organization.
5. Polymorphism: More than one type of structurally and functionally different individuals. Two basic
zooids ; Polyps and Medusa
6. Body layer: Diploblastic. multicellular with two distinct layer. Surrounds the gastrovascular cavity/
coelentron

10. 7.Locomotion: By Smooth muscles fibers and tentacles. Corals and sea anemones remains attached to
the substratum. Simple contraction and expansion, Bending and swaying movement, Looping,
somersult, swimming, gliding, floating, etc
8Skeleton: Usually present. May be external or Internal. Limy or horny and in the form of sclerite or
as continuous mass (coral)
9.Appendages: Hypostome/ mouth is encircled by short, slender and extensible projection , tentacles.
Serve for food capture, ingestion and also for defense. Nematocyst are present.
10.Acoelomate
11.Nutrition is holozoic. Digestion extracellular as well as intracellular.
12.Respiratory system: Absent. Occurs by Diffusion
13.Nervous system: Not well defined. It is in the form of network. Maximum concentration of nerve
cells occurs around hypostome. It does not has a ring or brain
14.Sensory structure: Sensory structure may be simple or complicated eg. Eye spot or statocyst. First
invertebrates to develop sense
15. Excretory system: Absent. Ammonotelic. Occurs by diffusion.
16. Reproduction: Asexual (budding and fission) and sexual (syngamy i.e by fusion of gametes (ova
and sperm). Fertilization: internally or externally.

11. CLASSIFICATION
The classification of phylum coelenterata is based on presence and absence of reproductive
form (polyp and medusa)
COELENTERATA
HYDROZOA SCYPHOZOA ANTHOZOA

12. Class 1. HYDROZOA ( Gr. hydros- water; zoon= animal)
• Marine and fresh water, solitary or colonial
• Sessile or free swimming
• Mesogloea is simple and non cellular
• Exhibit polymorphism. Mainly two types polyp and medusa
• Medusa is provided with true velum
• Many hydrozoa has alternation of generation
• Sex cells usually ectodermal origin and discharged externally
• Cleavage is holoblastic
• Planula larva
• Eg. Hydra, Obelia, Physalia

13. Class 2. SCYPHOZOA (Gr. skyphos= cup;zoon= animal)
• Exclusively marine
• Solitary and free swimming, Include large jelly fish
• Medusa form dominant
• Polyps stage may be reduced or absent
• Medusa without true vellum
• Marginal sense organs are tentaculocytes having
endodermal statolith
• Mesogloea is usually cellular
• Gonads are endodermal and the sex cells are discharged
• Eg. Aurelia, Rhizostoma
Aurelia
Rhizostoma

14. Class 3: ANTHOZOA ( Gr. anthos= flower; zoon= animal)
• Exclusively marin, solitary or colonial
• Attached to substratum
• Mesogloea has fibrous connective and amoeboid cell
• Polyp stage dominant
• Medusa stage is absent
• No alternation of generation
• Skeleton either external or internal
• Exoskeleton is formed from calcium carbonate which often form massive corals
• Gonads are endodermal and the sex cell are discharged into
coelenteron.
• Planula larva
• Eg. Metridium, Pennatula , coral

16. • Gr word. Platy-flat, Helminthes –worm
General characteristics
1. Body is dorsoventrally flattened so they are called flatworms .
2. They are mostly parasitic . Some are free living.
3. They are bilaterally symmetrical and triploblastic .
4. They are acoelomate animals i.e absence of coelom.
5. Parasitic animals develop adhesive structure like hooks , spines and suckers .
6. Digestive system is incomplete or absent
7. Excretory system consists of excretory organs (flame cells or photonephridia).
8. Reproductive system is well developed and complex . They are hermaphrodite or bisexual or
monoecious.
9. Lifecycle is simple or complex . It may require one host (monogenetic) or two hosts (digenetic)
10. Development is usually indirect , involving one or more larval stages .
11. Fertilization is internal maybe cross or self .

17. • This phylum is divided into 3 classes :
Class1:Turbellaria
Class2:Trematoda
Class3:Cestoda
Class1:Turbellaria
• They are free living aquatic forms
• They are unsegmented animals
• Hooks or suckers absence
• Life cycle is simple
• Eg:- Planaria

18. Class 2: Trematoda
• They are mostly endoparasites
• They are unsegmented and leaflike .
• Lifecycle is complex(digenetic)
• Suckers are absent
• Eg:-Fasciola hepatica
Class 3: Cestoda
• They are mostly endoparasites .
• They are segmented and ribbon (tape)like
• Hooks and suckers are present.
• Lifecycle is complex
• Eg. Taenia solium

19. NEMATHELMINTHES

20. Gk word: Nematos-thread, Helminthes – worm
General characteristics
1. They are cylindrical, elongated, unsegmented and wormlike.
2. They are mostly parasitic, some are free living.
3. They are triploblastic i.e. body wall consists of three layers .
4. They are bilaterally symmetrical .
5. They are pseudocoelomate type i.e. presence of false coelom
6. These are unisexual or diocious. Females are comparatively larger and thicker than males .
7. Nervous system consists of nerve rings and a longitudinal nerve cord
8. Fertilization is internal , maybe cross or self.
9. Development maybe direct or indirect with some larval stages .
10. Digestive system is complete.
11. Lateral external ducts collects excretory substances and expel out through anus
12. Two types of sensory organs
A. Amplid –sensory , chemoreceptor at mouth
B. Phasmid –are sensory, chemoreceptor in tail

21. • Phylum nemathelminthes is divided into two classes :
class 1 : Phasmidia
class 2: Aphasmidia
Class 1 : Plasmidia
1. Caudal sense organs (phasmid) is present .
2. Most of them are parasitic forms.
E.g. Ascaris lumbricoides, pinworm.
Class 2 : Aphasmidia
1. Caudal sense organ phasmid is absent .
2. Most of them are free living form .
3. Anterior sense organ (amphid) is present .
Eg: Rotifers

23. Introduction
• Lamarck coined the term Annelida due to the metamerically segmented rings that these organism
possess called “Annuli”. Annelida (Gr. Annulus: ring; eidos: form)
• Annelids are diverse numbering about 15,000 species.
• The most familiar are earthworms and freshwater worms (Class Oligochaeta) and leeches (Class
Hirudinea). Approximately 2/3rd of Annelids are marine worms.
General characteristics
• Habit and Habitat: Body is soft and cylindrical. They are elongated and metamerically segmented.
Mostly aquatic, free living annelids. Some are terrestrial and burrowing ( Eg. Pheretima).
Few are ectoparasites( Eg. Hirudinea).
• These organism have organ system grade level of organization.
• They have tube within tube plan.
• They feed on organic matter in the mud or soil by filtering suspended particles from the water,
act as predators or suck blood.
• Bilaterally symmetrical.
• Triploblastic.

24. • True coelom type formed by mesoderm: Schizocoel
• Locomotion: It takes place by Setae (in Pheretima) or parapodia (in Neries) or suckers (in
Hirudinaria). In the earthworms, setae are very short and can be best seen under the microscope.
• Complete digestive system with a mouth and anus.
• Digestion is entirely extracellular.
• Digestive glands are developed for the first time in annelid.
• Respiration: It takes place through moist body surface by diffusion.
• Blood vascular system is Closed type consisting of hearts and blood vessels. Heart appeared for the
first time in annelida. Blood is red in color but the haemoglobin is dissolved in blood plasma
(Erythrocruorin).
• The basic annelid nervous system consists of a single or double nerve cord running along the
ventral side of the body with an enlarged region(ganglion) in each segment.
• The annelid excretory system is made up of long tubular organs called Nephridia.
• Reproduction: usually hermaphrodite, some unisexual (Neries). Fertilization is cross and internal. It
may be direct or indirect with larval stage as trochophore.

25. About 8,700 known species of Annelida are divided into four main classes, primarily on the
basis of presence and absence of parapodia, setae, metameres, and other morphological
features.

26. Class 1- Polychaeta (Gr., poly=many, chaeta=bristles/hair)
 Mostly marine, some freshwater.
 Locomotary organs are parapodia.
 Well developed head bearing appendages.
 Cephalisation present.
 Clitellum is absent.
 Sexes are separate with a free swimming trochophore larva.
 Fertilization is external.
 Development is indirect.
 E.g. Nereis, Chaetopterus, etc.

27. Class 2- Oligochaeta (Gr., oligos=few+ chaete=hair)
 Mostly terrestrial, some freshwater.
 Locomotary organs are setae found in each segment.
 No distinct head appendages.
 Clitellum is present.
 They are hermaphrodite.
 Fertilization is external, occurs in cocoon.
 Development is direct.
 Eg: Pheretima, Megascolex dravida (largest earthworm)

28. Class 3- Hirudinea (L., hirudo= a leech)
 They are mostly ectoparasites having suckers (Sanguivorous).
 Mostly freshwater and terrestrial, some marine.
 Locomotary organs are suckers (anterior and posterior).
 No setae or parapodia.
 Clitellum is only seen in breeding season (9 to 11 segments).
 Salivary secretions substances that promote blood flow like hirudin (powerful anticoagulant) and
anesthetic.
 can be small enough to enter human body or as big as adult human forearm.
 do not feed very often
 No of segments are fixed – 33 segments
 They are Hermaphrodite.
 Fertilization is external, occurs in cocoon.
 Eg: Hirudinaria, Hirudo medicinalis

29. Class 4- Archiannellida (Gr., arch=first)
 Exclusively marine.
 Cephalisation is absent.
 External segmentation is not very distinct.
 No parapodia and setae.
 Clitellum absent.
 Tentacles present.
 Sexes are separate.
 Development is indirect. Larva is known as Lovens Larva.
 Eg.Polygordius- connecting link between Annelida and
Mollusca (living fossil), Dinophilus, Protodrilus
Dinophilus

42. Mollusca

43. Lamarck coined the term “Mollusca”.
Study of Mollusca is called Malacology.
Study of shells is called Conchology.
Diverse, successful and second largest group of animals.
Advanced than annelids due to presence of distinct head and foot, well developed gills for
respiration.
Bilaterally symmetrical, soft bodied unsegmented animals.
Body divided into head, foot, visceral mass and mantle.
Mantle secretes shell and space between mantle and body wall called mantle cavity.
Consists of gills or ctenidia for respiration located in the mantle cavity.
Alimentary canal well developed and coiled.
Most molluscs contain tongue-like radula used for feeding.
Have lacunar type of circulatory system in which there is dorsal heart and few blood vessels.
Excretion through one or two pairs of kidneys.
Sexes separate. Fertilization external or internal.
Nervous system consists of paired cephalic, pleural, pedal and visceral organs

44. Mollusca
Monoplac
ophora
Polyplaco
phora
Scaphopo
da
Gastropod
a
Bivalvia/
Pelecypoda
Cephalopo
da
Symmetry

45. 1. Monoplacophora
Molluscus with one shell, ancient
Single shelled
Foot flat and ventral
Bilaterally symmetrical
Exclusively marine
In head, eyes and sensory tentacles present
Example: Neopilina

46. 2. Polyplacophora / Amphineura
Bear many plates
About 800 species, all marine, many intertidal
Shell distinctive- 8 overlapping plates embedded partly or entirely in tough girdle
Head without eyes and tentacle
Ctenidia lateral and multiple
Foot ventral, large and flat like sole, used for creeping
Bilaterally symmetrical
Examples: Chiton.

47. 3. Scaphopoda
Tubular shell
Boat footed
Pointed foot, used in burrowing
Body covered by hard shell
Bilaterally symmetrical
Exclusively marine
Head, eyes and sensory tentacles absent
Examples: Dentalium

48. 4. Gastropoda
Belly footed or stomach footed
By far largest and most diverse mollucan class
Over 80% of molluscs are gastropods
Marine and fresh water
Grazers or predators
Prominent head with well developed sensory structures.
Examples: Snails, slugs, limpets, nudibranch, etc.

49. 5. Bivalvia/ pelecypoda
Two shells
Hatchet footed
Marine or freshwater
Head, eyes and sensory tentacles absent
Most are filter feeders
No head or radula
Burrow living
Examples: Clams, oysters, shipworms, etc.

50. 6. Cephalopoda
Head-footed
Foot modified into arms with suckers
Bilaterally symmetrical
Marine or freshwater
Head with sensory eyes and sensory tentacles present
Rapid movement: well developed nervous system
Examples: Octopus, Squid, Nautilus, etc.
Octopus

51. ECHINODERMATA

52. Echinodermata (The spiny skinned invertebrates)
(Gr. Echinos = spines; derma = skin/covering)
Jacob Klein (1738A.D.) coined the term “Echinodermata”
GENERAL CHARACTERISTICS
• Commonly known as spiny skinned organisms.
• They are exclusively marine organisms which usually inhabit in the bottom of the sea and move
slowly. But a few species are free-swimming and some are affixed to the substratum.
• They have a uniquely spherical, elongated or star-shaped body with organ level of organization.
• Echinoderms are triploblastic organisms with a true coelom.
• The body does not have a segment and lacks the head.
• They have calcareous endoskeleton and the surface of the body is covered with calcareous spicules.
• The mouth is located on the ventral side (oral side) while the anus is located on the dorsal side
(aboral side).
• The body contains water vascular system (ambulacral system) through which circulation of
nutrients, gaseous exchange, and waste elimination takes place.

53. • In the water vascular system, madreporite is present as an inlet canal while tube feet are situated on
the radial canal which assists in respiration, locomotion, and food capture.
• They have an open type blood circulatory system with five radiating vessels. In this case, the heart is
absent and blood does not contain any respiratory pigment.
• They respire through gills or cloacal respiratory tree..
• They have complete digestive tract but in some species such as a brittle star, it is incomplete.
• Poorly developed sense organs are found.
• They have no brain and nerve ring and radial nerve cords collectively make the nervous system.
• Sexes are separate and sexual reproduction takes place. In most of the species, external fertilization
occurs but in few forms, fertilization is internal.
• The larval forms are ciliated and bilaterally symmetrical and in echinoderms, various larval forms
are found such as Bipinnaria, Brachiolaria (starfish), Pluteus (sea urchin), Auricularia (sea
cucumber), Ophioputeus (brittle star), and Doliolaria (feather star).

54. Classification of Echinodermata
1. Asteroidea
• They have a flattened, star-shaped body with five arms.
• They have tube feet with suckers.
• They respire through papulae.
• The body comprises of calcareous plates and movable spines.
• Pedicellaria is present.
• Eg., Asterias, Zoroaster

55. 2. Ophiuroidea
• Commonly known as Brittle stars or ophiuroids or serpent stars.
• They have pentamerous disc-shaped flat body with five slender, long, and whip-like arms
• The water vascular system contains one madreporite.
• The tube feet do not contain suckers and ampullae.
• Respiration and excretion take place through cilia-lined sacs or bursae.
• The body does not have an anus, ambulacral groove, and intestine. In this case, egestion and
ingestion occur through the mouth.
• Indirect development occurs with the distinct larval stage (Pluteus larva).
• Example: Ophioderma longicauda(smooth brittle star)

56. 3: Echinoidea
• Also known as sea urchins and sand dollars which inhabit all oceans within 5000 meters depth
ranges.
• They have a round (sea urchin), oval or heart-shaped (heart urchin), or flattened (sand dollar) body.
• The mouth is located on the ventral side while the anus is on the dorsal surface of the body.
• The body is covered with spines and the body color may be purple, brown or tan.
• They have water-filled tube feet with suckers which aid in locomotion.
• Indirect development occurs with the distinct larval stage (Echinopliteus larva).
• Examples: Common sea urchin, Echinarachnius parma (the Common Sand Dollar)

57. 4: Holothuroidea
• Holothurians are also known as sea cucumbers
• The mouth and anus are situated on the opposite
side of the body.
• They have five rows of sucking type tube feet
which run from the mouth to the anus along the
cylindrical body.
• The body does not contain arms, spines, and
pedicellariae.
• Respiration occurs through the cloacal
respiratory trees which branch out near the
rectum for gas exchange.
• Development is indirect with different types of
planktotrophic or lecithotrophic larval stages
(Auricularia, doliolaria, pentactula larva).
• Examples: Orange sea cucumber, Holothuria
leucospilota (the black sea cucumber)

58. • Class-5: Crinoidea
• They are commonly known as sea lilies and
feather stars.
• They have a cup-shaped body with five or more
flexible and active arms.
• On the dorsal (oral) surface mouth and anus are
present.
• They do not contain madreporite but spines and
pedicellariae are present.
• They bear water vascular system which controls
hydraulic pressure in the tube feet.
• They are dioecious and development is indirect
with the distinct larval stage (Vitellaria larva).
• Examples: Antedon
mediterranea (Mediterranean feather
star), Rhizocrinus lofotensis

59. SUDHIR SINGH
MSc ZOOLOGY
• +9779845786252
• sudhirsingh9845786252@gmail.com