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Chapter-4
ANIMAL KINGDOM
Presented by
B.Prabhakar
Principal
JNV. Panchmahal (Guj)
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
Characters of porifera
• Members of this phylum are commonly known as sponges.
• They are generally marine and mostly asymmetrical animals are
primitive multicellular animals and have cellular level of organisation.
• Sponges have a water transport or canal system. Water enters through
minute pores (ostia) in the body wall into a central cavity, spongocoel,
from where it goes out through the osculum. This pathway of water
transport is helpful in food gathering, respiratory exchange and
removal of waste.
• Choanocytes or collar cells line the spongocoel and the canals.
Digestion is intracellular.
• The body is supported by a skeleton made up of spicules or spongin
fibres.
• Sexes are not separate (hermaphrodite), i.E., Eggs and sperms are
produced by the same individual.
• Sponges reproduce asexually by fragmentation and sexually by
formation of gametes.
• Fertilisation is internal and development is indirect having a larval
stage which is morphologically distinct from the adult. Examples:
sycon (scypha), spongilla (fresh water sponge) and euspongia (bath
sponge).
4. Animal Kingdom
4. Animal Kingdom
Jelly fish
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
Characters of coelenterata
• They are aquatic, mostly marine, sessile or free-swimming, radially
symmetrical animals
• The name cnidaria is derived from the cnidoblasts or cnidocytes
(which contain the stinging capsules or nematocytes) present on the
tentacles and the body. Cnidoblasts are used for anchorage, defense
and for the capture of prey
• Cnidarians exhibit tissue level of organisation and are diploblastic.
They have a central gastro-vascular cavity with a single opening,
mouth on hypostome.
• Digestion is extracellular and intracellular.
• Some of the cnidarians, e.G., Corals have a skeleton composed of
calcium carbonate. Cnidarians exhibit two basic body forms called
polyp and medusa
• The former is a sessile and cylindrical form like hydra, adamsia, etc.
Whereas, the latter is umbrella-shaped and free-swimming like aurelia
or jelly fish. Those cnidarians which exist in both forms exhibit
alternation of generation (metagenesis), i.E., Polyps produce medusae
asexually and medusae form the polyps sexually (e.G., Obelia).
Cnidoblast
Charecters of Ctenophora
• Ctenophores, commonly known as sea walnuts or comb
jellies are exclusively marine, radially symmetrical,
diploblastic organisms with tissue level of organisation.
• The body bears eight external rows of ciliated comb
plates, which help in locomotion
• Digestion is both extracellular and intracellular.
• Bioluminescence (the property of a living organism to
emit light) is well-marked in ctenophores.
• Sexes are not separate. Reproduction takes place only
by sexual means. Fertilisation is external with indirect
development.
• Examples: pleurobrachia and ctenoplana.
4. Animal Kingdom
4. Animal Kingdom
• Examples: physalia (portuguese man-of-
war), adamsia (sea anemone), pennatula
(sea-pen), gorgonia (sea-fan) and
meandrina (brain coral).
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
Characters of platyhelmenthes
• They have dorso-ventrally flattened body, hence are called
flatworms
• These are mostly endoparasites found in animals including human
beings.
• Flatworms are bilaterally symmetrical, triploblastic and acoelomate
animals with organ level of organisation.
• Hooks and suckers are present in the parasitic forms. Some of them
absorb nutrients from the host directly through their body surface.
• Specialised cells called flame cells help in osmoregulation and
excretion.
• Sexes are not separate. Fertilisation is internal and development is
through many larval stages.
• Some members like planaria possess high regeneration capacity.
Examples: taenia (tapeworm), fasciola (liver fluke).
4. Animal Kingdom
Characters of Nematoda
• The body of the aschelminthes is circular in cross-section, hence, the
name roundworms
• They may be freeliving, aquatic and terrestrial or parasitic in plants
and animals.
• Roundworms have organ-system level of body organisation. They are
bilaterally symmetrical, triploblastic and pseudocoelomate animals.
• Alimentary canal is complete with a well- developed muscular
pharynx.
• An excretory tube removes body wastes from the body cavity through
the excretory pore.
• Sexes are separate (dioecious), i.E., Males and females are distinct.
Often females are longer than males. Fertilisation is internal and
development may be direct (the young ones resemble the adult) or
indirect.
• Examples : ascaris (round worm), wuchereria (filaria worm),
ancylostoma (hookworm).
4. Animal Kingdom
Characters of Annelida
• They may be aquatic (marine and fresh water) or terrestrial; free-living,
and sometimes parasitic.
• They exhibit organ-system level of body organisation and bilateral
symmetry.
• They are triploblastic, metamerically segmented and coelomate
animals. Their body surface is distinctly marked out into segments or
metameres and, hence, the phylum name annelida (latin, annulus : little
ring)
• They possess longitudinal and circular muscles which help in
locomotion. Aquatic annelids like nereis possess lateral appendages,
parapodia, which help in swimming.
• A closed circulatory system is present.
• Nephridia (sing. Nephridium) help in osmoregulation and excretion.
• Neural system consists of paired ganglia (sing. Ganglion) connected by
lateral nerves to a double ventral nerve cord.
• Nereis, an aquatic form, is dioecious, but earthworms and leeches are
monoecious. Reproduction is sexual.
• Examples : nereis, pheretima (earthworm) and hirudinaria (blood
sucking leech).
4. Animal Kingdom
(A) NEREIS (B) HIRUDINARIA
Characters of Arthropoda
• This is the largest phylum of animalia which includes insects. Over
two-thirds of all named species on earth are arthropods.
• They have organ-system level of organisation. They are bilaterally
symmetrical, triploblastic, segmented and coelomate animals.
• The body of arthropods is covered by chitinous exoskeleton. The body
consists of head, thorax and abdomen.
• They have jointed appendages (arthros-joint, poda-appendages).
• Respiratory organs are gills, book gills, book lungs or tracheal
system.
• Circulatory system is of open type.
• Sensory organs like antennae, eyes (compound and simple),
statocysts or balance organs are present.
• Excretion takes place through malpighian tubules.
• They are mostly dioecious. Fertilisation is usually internal. They are
mostly oviparous. Development may be direct or indirect.
• Examples: economically important insects – apis (honey bee), bombyx
(silkworm), laccifer (lac insect)
• Vectors – anopheles, culex and aedes (mosquitoes)
4. Animal Kingdom
4. Animal Kingdom
Cockroach
Book lungs
Horse shoe crab – Book gills
4. Animal Kingdom
4. Animal Kingdom
Characters of Mollusca
• This is the second largest animal phylum
• Molluscs are terrestrial or aquatic (marine or fresh water) having an
organ-system level of organisation.
• They are bilaterally symmetrical, triploblastic and coelomate
animals.
• Body is covered by a calcareous shell and is unsegmented with a
distinct head, muscular foot and visceral hump.
• A soft and spongy layer of skin forms a mantle over the visceral
hump.
• The space between the hump and the mantle is called the mantle
cavity in which feather like gills are present.
• They have respiratory and excretory functions.
• The anterior head region has sensory tentacles.
• The mouth contains a file-like rasping organ for feeding, called
radula.
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
Characters of Echinodermata
• These animals have an endoskeleton of calcareous ossicles
and, hence, the name echinodermata (spiny bodied,
• All are marine with organ-system level of organisation. The
adult echinoderms are radially symmetrical but larvae are
bilaterally symmetrical.
• They are triploblastic and coelomate animals. Digestive system
is complete with mouth on the lower (ventral) side and anus on
the upper (dorsal) side.
• The most distinctive feature of echinoderms is the
presence of water vascular system which helps in locomotion,
capture and transport of food and respiration.
• An excretory system is absent.
• Sexes are separate. Reproduction is sexual. Fertilisation is
usually external.
• Development is indirect with free-swimming larva. Examples:
asterias (star fish), echinus (sea urchin), antedon (sea lily),
cucumaria (sea cucumber) and ophiura (brittle star).
4. Animal Kingdom
Hemichordata
• Hemichordata was earlier considered as a sub-phylum under
phylum chordata. But now it is placed as a separate phylum under
non-chordata.
• This phylum consists of a small group of worm-like marine animals
with organ-system level of organisation.
• They are bilaterally symmetrical, triploblastic and coelomate
animals.
• The body is cylindrical and is composed of an anterior proboscis, a
collar and a long trunk
• Circulatory system is of open type.
• Respiration takes place through gills.
• Excretory organ is proboscis gland.
• Sexes are separate. Fertilisation is external. Development is
indirect.
• Examples: balanoglossus and saccoglossus.
4. Animal Kingdom
Chordata
• Animals belonging to phylum
Chordata are fundamentally
characterised by the presence
of a notochord, a
dorsal hollow nerve cord and
paired pharyngeal gill slits.
These are bilaterally
symmetrical, triploblastic,
coelomate with organ-system
level of organisation.
• They possess a post anal tail
and a closed circulatory
system.
S
.
N
o
Chordates Non-chordates
1 Notochord present Notochord absent
2
Central nervous system is
dorsal, hollow and single
Central nervous system is
ventral, solid and double.
3
Pharynx perforated by
gill slits.
Gill slits are absent.
4 Heart is ventral.
Heart is dorsal (if
present).
5
A post-anal part (tail) is
present.
Post-anal tail is absent.
• Phylum chordata is divided into
three subphyla: urochordata or
tunicata , cephalochordata and
vertebrata.
• Subphyla urochordata and
cephalochordata are often
referred to as protochordates
and are exclusively marine.
• In urochordata, notochord is
present only in larval tail, while
in cephalochordata, it extends
from head to tail region and is
persistent throughout their life.
• Examples: urochordata –
ascidia, salpa, doliolum;
cephalochordata –
branchiostoma (amphioxus or
lancelet).
Ascidia
4. Animal Kingdom
4. Animal Kingdom
Vertebrata
• The members of subphylum vertebrata possess
notochord during the embryonic period. The
notochord is replaced by a cartilaginous or bony
vertebral column in the adult. Thus all
vertebrates are chordates but all chordates are
not vertebrates.
• Besides the basic chordate characters,
vertebrates have a ventral muscular heart with
two, three or four chambers, kidneys for
excretion and osmoregulation and paired
appendages which may be fins or limbs.
4. Animal Kingdom
4. Animal Kingdom
Class – Cyclostomata
• All living members of the class
Cyclostomata are ectoparasites on
some fishes.
• They have an elongated body
bearing 6-15 pairs of gill slits for
respiration.
• Cyclostomes have a sucking and
circular mouth without jaws. Their
body is devoid of scales and
paired fins.
• Cranium and vertebral column are
cartilaginous.
• Circulation is of closed type.
Cyclostomes are marine but
migrate for spawning to fresh
water. After spawning, within a
few days, they die. Their larvae,
after metamorphosis, return to the
ocean. Examples: Petromyzon
(Lamprey) and Myxine (Hagfish).
Class – Chondrichthyes
• They are marine animals with streamlined body and have cartilaginous
endoskeleton.
• Mouth is located ventrally. Notochord is persistent throughout life.
• Gill slits are separate and without operculum (gill cover).
• The skin is tough, containing minute placoid scales. Teeth are
modified placoid scales which are backwardly directed.
• Their jaws are very powerful. These animals are predaceous.
• Due to the absence of air bladder, they have to swim constantly to
avoid sinking.
• Heart is two-chambered (one auricle and one ventricle).
• Some of them have electric organs (e.g., Torpedo) and some possess
poison sting (e.g., Trygon).
• They are cold-blooded (poikilothermous) animals, i.e., they lack the
capacity to regulate their body temperature.
• Sexes are separate. In males pelvic fins bear claspers. They have
internal fertilisation and many of them are viviparous.
• Examples: Scoliodon (Dog fish), Pristis (Saw fish), Carcharodon
(Great white shark), Trygon (Sting ray).
(A) SCOLIODON (B) PRISTIS
(A) HIPPOCAMPUS (B) CATLA
Class – Osteichthyes
• It includes both marine and fresh water fishes with bony
endoskeleton. Their body is streamlined.
• Mouth is mostly terminal.
• They have four pairs of gills which are covered by an operculum on
each side.
• Skin is covered with cycloid/ctenoid scales.
• Air bladder is present which regulates buoyancy.
• Heart is two-chambered (one auricle and one ventricle).
• They are cold-blooded animals.
• Sexes are separate. Fertilisation is usually external. They are mostly
oviparous and development is direct.
• Examples: Marine – Exocoetus (Flying fish), Hippocampus (Sea
horse); Freshwater – Labeo (Rohu), Catla (Katla), Clarias (Magur);
Aquarium – Betta (Fighting fish), Pterophyllum (Angel fish).
Class – Amphibia
• As the name indicates (Gr., Amphi : dual, bios, life), amphibians can
live in aquatic as well as terrestrial habitats.
• Most of them have two pairs of limbs. Body is divisible into head and
trunk. Tail may be present in some.
• The amphibian skin is moist (without scales).
• The eyes have eyelids.
• A tympanum represents the ear.
• Alimentary canal, urinary and reproductive tracts open into a common
chamber called cloaca which opens to the exterior. Respiration is by
gills, lungs and through skin.
• The heart is threechambered (two auricles and one ventricle). T
• hese are cold-blooded animals.
• Sexes are separate. Fertilisation is external. They are oviparous and
development is direct or indirect.
• Examples: Bufo (Toad), Rana (Frog), Hyla (Tree frog), Salamandra
(Salamander), Ichthyophis (Limbless amphibia
Class – Reptilia
• The class name refers to their creeping or crawling mode of
locomotion (Latin, repere or reptum, to creep or crawl). They are
mostly terrestrial animals and their body is covered by dry and
cornified skin, epidermal scales or scutes. They do not have
external ear openings. Tympanum represents ear. Limbs, when
present, are two pairs.
• Heart is usually three-chambered, but four-chambered in crocodiles.
Reptiles are poikilotherms (A poikilotherm is an animal whose
internal temperature varies along with that of the ambient
environmental temperature.). Snakes and lizards shed their scales
as skin cast. Sexes are separate. Fertilisation is internal. They are
oviparous and development is direct.
• Examples: Chelone (Turtle), Testudo (Tortoise), Chameleon (Tree
lizard), Calotes (Garden lizard), Crocodilus (Crocodile), Alligator
(Alligator). Hemidactylus (Wall lizard), Poisonous snakes – Naja
(Cobra), Bangarus (Krait), Vipera (Viper).
Class – Aves
• The characteristic features of Aves (birds) are the presence of
feathers and most of them can fly except flightless birds (e.g.,
Ostrich). They possess beak. The forelimbs are modified into wings.
The hind limbs generally have scales and are modified for walking,
swimming or clasping the tree branches. Skin is dry without glands
except the oil gland at the base of the tail.
• Endoskeleton is fully ossified (bony) and the long bones are hollow
with air cavities (pneumatic). The digestive tract of birds has
additional chambers, the crop and gizard.
• Endoskeleton is fully ossified (bony) and the long bones are hollow
with air cavities (pneumatic). The digestive tract of birds has
additional chambers, the crop and gizard.
• Heart is completely fourchambered. They are warm-blooded
(homoiothermous) animals, i.e., they are able to maintain a constant
body temperature. Respiration is by lungs. Air sacs connected to
lungs supplement respiration. Sexes are separate. Fertilisation is
internal. They are oviparous and development is direct.
• Examples: Corvus (Crow), Columba (Pigeon), Psittacula (Parrot),
Struthio (Ostrich), Pavo (Peacock), Aptenodytes (Penguin), Neophron
(Vulture).
Class – Mammalia
• The most unique mammalian characteristic is the presence of milk
producing glands (mammary glands) by which the young ones are
nourished. They have two pairs of limbs, adapted for walking,
running, climbing, burrowing, swimming or flying. The skin of
mammals is unique in possessing hair. External ears or pinnae are
present. Different types of teeth are present in the jaw.
• Heart is four-chambered. They are homoiothermous. Respiration is
by lungs. Sexes are separate and fertilisation is internal. They are
viviparous with few exceptions and development is direct.
• Examples: Oviparous-Ornithorhynchus (Platypus);
• Viviparous - Macropus (Kangaroo), Pteropus (Flying fox), Camelus
(Camel), Macaca(Monkey), Rattus (Rat), Canis (Dog), Felis (Cat),
Elephas (Elephant), Equus (Horse), Delphinus (Common dolphin),
Balaenoptera (Blue whale), Panthera tigris (Tiger), Panthera leo
(Lion).
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
4. Animal Kingdom
• Marginal placentation: The placenta forms a ridge along the
ventral suture of the ovary and the ovules are borne on the ridge.
Example: Peas
• Axile placentation: The placenta is axial and the ovules are
attached to the multilocular ovary. Example: China rose, lemon and
orange.
• Parietal placentation: In this type of placentation, the ovules
develop on the inner wall of the ovary. Ovary has a single chamber
but appears to be double-chambered because of the formation of a
false septum. Example: Mustard and argemone.
• Free central placentation: The ovules are borne on the central
axis. The septum is absent in this type of placentation. Example:
Dianthus and primrose.
• Basal placentation: In this type of placentation, the placenta is
situated at the base of the ovary and a single ovule is attached to it.
Example: Sunflower.
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4. Animal Kingdom
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4. Animal Kingdom
4. Animal Kingdom

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4. Animal Kingdom

  • 12. Characters of porifera • Members of this phylum are commonly known as sponges. • They are generally marine and mostly asymmetrical animals are primitive multicellular animals and have cellular level of organisation. • Sponges have a water transport or canal system. Water enters through minute pores (ostia) in the body wall into a central cavity, spongocoel, from where it goes out through the osculum. This pathway of water transport is helpful in food gathering, respiratory exchange and removal of waste. • Choanocytes or collar cells line the spongocoel and the canals. Digestion is intracellular. • The body is supported by a skeleton made up of spicules or spongin fibres. • Sexes are not separate (hermaphrodite), i.E., Eggs and sperms are produced by the same individual. • Sponges reproduce asexually by fragmentation and sexually by formation of gametes. • Fertilisation is internal and development is indirect having a larval stage which is morphologically distinct from the adult. Examples: sycon (scypha), spongilla (fresh water sponge) and euspongia (bath sponge).
  • 24. Characters of coelenterata • They are aquatic, mostly marine, sessile or free-swimming, radially symmetrical animals • The name cnidaria is derived from the cnidoblasts or cnidocytes (which contain the stinging capsules or nematocytes) present on the tentacles and the body. Cnidoblasts are used for anchorage, defense and for the capture of prey • Cnidarians exhibit tissue level of organisation and are diploblastic. They have a central gastro-vascular cavity with a single opening, mouth on hypostome. • Digestion is extracellular and intracellular. • Some of the cnidarians, e.G., Corals have a skeleton composed of calcium carbonate. Cnidarians exhibit two basic body forms called polyp and medusa • The former is a sessile and cylindrical form like hydra, adamsia, etc. Whereas, the latter is umbrella-shaped and free-swimming like aurelia or jelly fish. Those cnidarians which exist in both forms exhibit alternation of generation (metagenesis), i.E., Polyps produce medusae asexually and medusae form the polyps sexually (e.G., Obelia).
  • 26. Charecters of Ctenophora • Ctenophores, commonly known as sea walnuts or comb jellies are exclusively marine, radially symmetrical, diploblastic organisms with tissue level of organisation. • The body bears eight external rows of ciliated comb plates, which help in locomotion • Digestion is both extracellular and intracellular. • Bioluminescence (the property of a living organism to emit light) is well-marked in ctenophores. • Sexes are not separate. Reproduction takes place only by sexual means. Fertilisation is external with indirect development. • Examples: pleurobrachia and ctenoplana.
  • 29. • Examples: physalia (portuguese man-of- war), adamsia (sea anemone), pennatula (sea-pen), gorgonia (sea-fan) and meandrina (brain coral).
  • 38. Characters of platyhelmenthes • They have dorso-ventrally flattened body, hence are called flatworms • These are mostly endoparasites found in animals including human beings. • Flatworms are bilaterally symmetrical, triploblastic and acoelomate animals with organ level of organisation. • Hooks and suckers are present in the parasitic forms. Some of them absorb nutrients from the host directly through their body surface. • Specialised cells called flame cells help in osmoregulation and excretion. • Sexes are not separate. Fertilisation is internal and development is through many larval stages. • Some members like planaria possess high regeneration capacity. Examples: taenia (tapeworm), fasciola (liver fluke).
  • 40. Characters of Nematoda • The body of the aschelminthes is circular in cross-section, hence, the name roundworms • They may be freeliving, aquatic and terrestrial or parasitic in plants and animals. • Roundworms have organ-system level of body organisation. They are bilaterally symmetrical, triploblastic and pseudocoelomate animals. • Alimentary canal is complete with a well- developed muscular pharynx. • An excretory tube removes body wastes from the body cavity through the excretory pore. • Sexes are separate (dioecious), i.E., Males and females are distinct. Often females are longer than males. Fertilisation is internal and development may be direct (the young ones resemble the adult) or indirect. • Examples : ascaris (round worm), wuchereria (filaria worm), ancylostoma (hookworm).
  • 42. Characters of Annelida • They may be aquatic (marine and fresh water) or terrestrial; free-living, and sometimes parasitic. • They exhibit organ-system level of body organisation and bilateral symmetry. • They are triploblastic, metamerically segmented and coelomate animals. Their body surface is distinctly marked out into segments or metameres and, hence, the phylum name annelida (latin, annulus : little ring) • They possess longitudinal and circular muscles which help in locomotion. Aquatic annelids like nereis possess lateral appendages, parapodia, which help in swimming. • A closed circulatory system is present. • Nephridia (sing. Nephridium) help in osmoregulation and excretion. • Neural system consists of paired ganglia (sing. Ganglion) connected by lateral nerves to a double ventral nerve cord. • Nereis, an aquatic form, is dioecious, but earthworms and leeches are monoecious. Reproduction is sexual. • Examples : nereis, pheretima (earthworm) and hirudinaria (blood sucking leech).
  • 44. (A) NEREIS (B) HIRUDINARIA
  • 45. Characters of Arthropoda • This is the largest phylum of animalia which includes insects. Over two-thirds of all named species on earth are arthropods. • They have organ-system level of organisation. They are bilaterally symmetrical, triploblastic, segmented and coelomate animals. • The body of arthropods is covered by chitinous exoskeleton. The body consists of head, thorax and abdomen. • They have jointed appendages (arthros-joint, poda-appendages). • Respiratory organs are gills, book gills, book lungs or tracheal system. • Circulatory system is of open type. • Sensory organs like antennae, eyes (compound and simple), statocysts or balance organs are present. • Excretion takes place through malpighian tubules. • They are mostly dioecious. Fertilisation is usually internal. They are mostly oviparous. Development may be direct or indirect. • Examples: economically important insects – apis (honey bee), bombyx (silkworm), laccifer (lac insect) • Vectors – anopheles, culex and aedes (mosquitoes)
  • 50. Horse shoe crab – Book gills
  • 53. Characters of Mollusca • This is the second largest animal phylum • Molluscs are terrestrial or aquatic (marine or fresh water) having an organ-system level of organisation. • They are bilaterally symmetrical, triploblastic and coelomate animals. • Body is covered by a calcareous shell and is unsegmented with a distinct head, muscular foot and visceral hump. • A soft and spongy layer of skin forms a mantle over the visceral hump. • The space between the hump and the mantle is called the mantle cavity in which feather like gills are present. • They have respiratory and excretory functions. • The anterior head region has sensory tentacles. • The mouth contains a file-like rasping organ for feeding, called radula.
  • 60. Characters of Echinodermata • These animals have an endoskeleton of calcareous ossicles and, hence, the name echinodermata (spiny bodied, • All are marine with organ-system level of organisation. The adult echinoderms are radially symmetrical but larvae are bilaterally symmetrical. • They are triploblastic and coelomate animals. Digestive system is complete with mouth on the lower (ventral) side and anus on the upper (dorsal) side. • The most distinctive feature of echinoderms is the presence of water vascular system which helps in locomotion, capture and transport of food and respiration. • An excretory system is absent. • Sexes are separate. Reproduction is sexual. Fertilisation is usually external. • Development is indirect with free-swimming larva. Examples: asterias (star fish), echinus (sea urchin), antedon (sea lily), cucumaria (sea cucumber) and ophiura (brittle star).
  • 62. Hemichordata • Hemichordata was earlier considered as a sub-phylum under phylum chordata. But now it is placed as a separate phylum under non-chordata. • This phylum consists of a small group of worm-like marine animals with organ-system level of organisation. • They are bilaterally symmetrical, triploblastic and coelomate animals. • The body is cylindrical and is composed of an anterior proboscis, a collar and a long trunk • Circulatory system is of open type. • Respiration takes place through gills. • Excretory organ is proboscis gland. • Sexes are separate. Fertilisation is external. Development is indirect. • Examples: balanoglossus and saccoglossus.
  • 64. Chordata • Animals belonging to phylum Chordata are fundamentally characterised by the presence of a notochord, a dorsal hollow nerve cord and paired pharyngeal gill slits. These are bilaterally symmetrical, triploblastic, coelomate with organ-system level of organisation. • They possess a post anal tail and a closed circulatory system.
  • 65. S . N o Chordates Non-chordates 1 Notochord present Notochord absent 2 Central nervous system is dorsal, hollow and single Central nervous system is ventral, solid and double. 3 Pharynx perforated by gill slits. Gill slits are absent. 4 Heart is ventral. Heart is dorsal (if present). 5 A post-anal part (tail) is present. Post-anal tail is absent.
  • 66. • Phylum chordata is divided into three subphyla: urochordata or tunicata , cephalochordata and vertebrata. • Subphyla urochordata and cephalochordata are often referred to as protochordates and are exclusively marine. • In urochordata, notochord is present only in larval tail, while in cephalochordata, it extends from head to tail region and is persistent throughout their life. • Examples: urochordata – ascidia, salpa, doliolum; cephalochordata – branchiostoma (amphioxus or lancelet). Ascidia
  • 69. Vertebrata • The members of subphylum vertebrata possess notochord during the embryonic period. The notochord is replaced by a cartilaginous or bony vertebral column in the adult. Thus all vertebrates are chordates but all chordates are not vertebrates. • Besides the basic chordate characters, vertebrates have a ventral muscular heart with two, three or four chambers, kidneys for excretion and osmoregulation and paired appendages which may be fins or limbs.
  • 72. Class – Cyclostomata • All living members of the class Cyclostomata are ectoparasites on some fishes. • They have an elongated body bearing 6-15 pairs of gill slits for respiration. • Cyclostomes have a sucking and circular mouth without jaws. Their body is devoid of scales and paired fins. • Cranium and vertebral column are cartilaginous. • Circulation is of closed type. Cyclostomes are marine but migrate for spawning to fresh water. After spawning, within a few days, they die. Their larvae, after metamorphosis, return to the ocean. Examples: Petromyzon (Lamprey) and Myxine (Hagfish).
  • 73. Class – Chondrichthyes • They are marine animals with streamlined body and have cartilaginous endoskeleton. • Mouth is located ventrally. Notochord is persistent throughout life. • Gill slits are separate and without operculum (gill cover). • The skin is tough, containing minute placoid scales. Teeth are modified placoid scales which are backwardly directed. • Their jaws are very powerful. These animals are predaceous. • Due to the absence of air bladder, they have to swim constantly to avoid sinking. • Heart is two-chambered (one auricle and one ventricle). • Some of them have electric organs (e.g., Torpedo) and some possess poison sting (e.g., Trygon). • They are cold-blooded (poikilothermous) animals, i.e., they lack the capacity to regulate their body temperature. • Sexes are separate. In males pelvic fins bear claspers. They have internal fertilisation and many of them are viviparous. • Examples: Scoliodon (Dog fish), Pristis (Saw fish), Carcharodon (Great white shark), Trygon (Sting ray).
  • 74. (A) SCOLIODON (B) PRISTIS
  • 76. Class – Osteichthyes • It includes both marine and fresh water fishes with bony endoskeleton. Their body is streamlined. • Mouth is mostly terminal. • They have four pairs of gills which are covered by an operculum on each side. • Skin is covered with cycloid/ctenoid scales. • Air bladder is present which regulates buoyancy. • Heart is two-chambered (one auricle and one ventricle). • They are cold-blooded animals. • Sexes are separate. Fertilisation is usually external. They are mostly oviparous and development is direct. • Examples: Marine – Exocoetus (Flying fish), Hippocampus (Sea horse); Freshwater – Labeo (Rohu), Catla (Katla), Clarias (Magur); Aquarium – Betta (Fighting fish), Pterophyllum (Angel fish).
  • 77. Class – Amphibia • As the name indicates (Gr., Amphi : dual, bios, life), amphibians can live in aquatic as well as terrestrial habitats. • Most of them have two pairs of limbs. Body is divisible into head and trunk. Tail may be present in some. • The amphibian skin is moist (without scales). • The eyes have eyelids. • A tympanum represents the ear. • Alimentary canal, urinary and reproductive tracts open into a common chamber called cloaca which opens to the exterior. Respiration is by gills, lungs and through skin. • The heart is threechambered (two auricles and one ventricle). T • hese are cold-blooded animals. • Sexes are separate. Fertilisation is external. They are oviparous and development is direct or indirect. • Examples: Bufo (Toad), Rana (Frog), Hyla (Tree frog), Salamandra (Salamander), Ichthyophis (Limbless amphibia
  • 78. Class – Reptilia • The class name refers to their creeping or crawling mode of locomotion (Latin, repere or reptum, to creep or crawl). They are mostly terrestrial animals and their body is covered by dry and cornified skin, epidermal scales or scutes. They do not have external ear openings. Tympanum represents ear. Limbs, when present, are two pairs. • Heart is usually three-chambered, but four-chambered in crocodiles. Reptiles are poikilotherms (A poikilotherm is an animal whose internal temperature varies along with that of the ambient environmental temperature.). Snakes and lizards shed their scales as skin cast. Sexes are separate. Fertilisation is internal. They are oviparous and development is direct. • Examples: Chelone (Turtle), Testudo (Tortoise), Chameleon (Tree lizard), Calotes (Garden lizard), Crocodilus (Crocodile), Alligator (Alligator). Hemidactylus (Wall lizard), Poisonous snakes – Naja (Cobra), Bangarus (Krait), Vipera (Viper).
  • 79. Class – Aves • The characteristic features of Aves (birds) are the presence of feathers and most of them can fly except flightless birds (e.g., Ostrich). They possess beak. The forelimbs are modified into wings. The hind limbs generally have scales and are modified for walking, swimming or clasping the tree branches. Skin is dry without glands except the oil gland at the base of the tail. • Endoskeleton is fully ossified (bony) and the long bones are hollow with air cavities (pneumatic). The digestive tract of birds has additional chambers, the crop and gizard. • Endoskeleton is fully ossified (bony) and the long bones are hollow with air cavities (pneumatic). The digestive tract of birds has additional chambers, the crop and gizard. • Heart is completely fourchambered. They are warm-blooded (homoiothermous) animals, i.e., they are able to maintain a constant body temperature. Respiration is by lungs. Air sacs connected to lungs supplement respiration. Sexes are separate. Fertilisation is internal. They are oviparous and development is direct. • Examples: Corvus (Crow), Columba (Pigeon), Psittacula (Parrot), Struthio (Ostrich), Pavo (Peacock), Aptenodytes (Penguin), Neophron (Vulture).
  • 80. Class – Mammalia • The most unique mammalian characteristic is the presence of milk producing glands (mammary glands) by which the young ones are nourished. They have two pairs of limbs, adapted for walking, running, climbing, burrowing, swimming or flying. The skin of mammals is unique in possessing hair. External ears or pinnae are present. Different types of teeth are present in the jaw. • Heart is four-chambered. They are homoiothermous. Respiration is by lungs. Sexes are separate and fertilisation is internal. They are viviparous with few exceptions and development is direct. • Examples: Oviparous-Ornithorhynchus (Platypus); • Viviparous - Macropus (Kangaroo), Pteropus (Flying fox), Camelus (Camel), Macaca(Monkey), Rattus (Rat), Canis (Dog), Felis (Cat), Elephas (Elephant), Equus (Horse), Delphinus (Common dolphin), Balaenoptera (Blue whale), Panthera tigris (Tiger), Panthera leo (Lion).
  • 89. • Marginal placentation: The placenta forms a ridge along the ventral suture of the ovary and the ovules are borne on the ridge. Example: Peas • Axile placentation: The placenta is axial and the ovules are attached to the multilocular ovary. Example: China rose, lemon and orange. • Parietal placentation: In this type of placentation, the ovules develop on the inner wall of the ovary. Ovary has a single chamber but appears to be double-chambered because of the formation of a false septum. Example: Mustard and argemone. • Free central placentation: The ovules are borne on the central axis. The septum is absent in this type of placentation. Example: Dianthus and primrose. • Basal placentation: In this type of placentation, the placenta is situated at the base of the ovary and a single ovule is attached to it. Example: Sunflower.