ANIMAL KINGDOM:-
Circulatory System : Open type : Blood pumped out through heart. Cells and
tissues are directly bathed in it.
Closed type : Blood is circulated through vessels
Symmetry : • Asymmetrical : Cannot be divided into equal halves through
median plane. e.g., Sponges.
• Radial symmetry : Any plane passing through cental axis can divide organism
into equal halves. e.g., Hydra.
• Bilateral symmetry : Only one plane can divide the organism into equal
halves. e.g., Annelids and Arthropods.
CLASSIFICATION ON BASIS OF GERMINAL LAYERS :-
Diploblastic : Cells arranged in two embryonic layers i.e. external ectoderm
and internal endoderm. (Mesoglea may be present in between ectoderm
and endoderm) e.g., Coelentrates. (Cnidarians)
Triploblastic : Three layers present in developing embryo i.e., ectoderm,
endoderm and mesoderm. e.g., Chordates.
Coelom (Body cavity which is lined by mesoderm)
Coelomates : Have coelom e.g., Annelids, Chordates etc.
Pseudocoelomates : No true coelem as mesoderm is present in scattered
pouches between ectoderm and endoderm. e.g., Aschelminthes.
Acoelomates : Body cavity is absent. e.g. Platyhelminthes.
Metamerism : If body is externally and internally divided into segments with
serial repetition of atleast some organs then phenomenon is called metamerism.
e.g., Earthworm.
Notochord : Rod-like structure formed during embryonic development on the
dorsal side. It is mesodermally derived. e.g., Chordates.
PHYLUM:-
PORIFERA :
• Also called sponges.
• Are usually marine and asymmetrical.
• Have cellular level of organisation.
• Food gathering, respiratory exchange and removal of wastes occurs through
water canal system. Digestion intracellular.
• Ostia (minute pores on body), spongocoel (body cavity) and osculum help
in water transport. They are lined by choanocytes (collar cells).
•Body wall has spicules and spongin fibres.
Animals are hermaphrodite. Fertilisation internal. Development is indirect
They are pore bearing animals
They are Diploblastic animals,ectoderm and endoderm are known as pinacoderm and choanoderm respectively.they are separated by mesenchyme which is non cellular.
They are sessile i.e. they are attached to base by the help of substratum.
(i.e., has a larval stage distinct from adult stage) e.g., Sycon, Euspongia.
#clases of porifera:-
Calceria:-
Spicules are made up of calcium.
They are mostly marime
Eg. sycon
Hexactinellida:-
Spicules are made up of silica
They are marine
Eg.Hyalonema.
Demospongia:-
Spicules are made up of sponginfibres.
They are both marine and freshwater.
Eg. Spongilla.
PHYLUM
COELENTERATA :
• Also called Cnidarians.
• Are usually marine and radially symmetrical.
• Have tissue level of organization
• Are Diploblastic
• Food gathering, anchorage and defends occurs through cnidoblasts present
On tentacles.
• Digestion extracellular and intracellular.
• Have gastro-vascular cavity and an opening, hypostome.
• Body wall composed of calcium carbonate.
• Exhibit two body forms: polyp and medusa e.g., Hydra, Aurelia.
• Alternation of generation between body forms called Metagenesis occurs
in Obelia where Medusa sexually Polyp.
Asexually
• e.g., Physalia, Adamsia.
#classes of coelenterate:-
Hydrozoa:-
Dominance of polyp is seen and medusa is reduced
Both marine and fresh water.
E.g. hydra.
Scyphozoa:-
Dominance of medusa is seen and polyp is reduced
Marine animals
E.g. Aurelia
Anthozoa:-
Medusa absence and polyp present
They are marine
E.g. metridium.
PHYLUM PLATYHELMINTHES:
• Also called as ‘flat worms’.
• Have dorsoventrally flattened body. Are endoparasites in animals.
• Are bilaterally symmetrical, triploblastic, acoelomate.
• Absorb nutrients through body surface.
• Parasite forms have hooks and suckers.
• ‘Flame cells’ help in osmoregulation and excretion.
• Fertilization internal. Many larval stages. Planaria has high regeneration
capacity.
Digestion is extra cellular.
They are acoelomate.
They are hermaphrodite animals.
They possess ladder like nervous system.
e.g., Taenia, Fasciola.
PHYLUM ASCHELMINTHES:
• Also called ‘round worms’.
• May be free living, parasitic, aquatic or terrestrial.
• Are bilaterally symmetrical, triploblastic, Pseudocoelomates.
• Alimentary canal complete (has muscular pharynx), wastes removed through
Excretory pore.
• Sexes separate. Shows dimorphism.
• Females longer than males.
• Fertilization internal. Development direct or indirect.
Absence of respiratory system ant takes place through general body surface.
Sensory organs are less developed
Body is covered with cuticle.
Circulatory and skeletal system is absent.
e.g., Ascaris, Wuchereria.
PHYLUM ANNELIDA:
• Are aquatic or terrestrial, free-living or parasitic.
• Are bilaterally symmetrical, triploblastic, organ-system level of organization
And metamerically segmented body.
• Have longitudinal and circular muscles for locomotion.
• Nereis (dioecious and aquatic annelid) has lateral appendages called parapodia
for swimming.
• Have nephridia for osmoregulation and excretion.
They are Coelomates animals.
Alimentary anal is complete
Nervous system is well developed
Circulatory system is present and is closed type.
Blood is red due to the presence of haemoglobin
Sexual reproduction takes place and fertilization is external.
• e.g., Earthworm (Pheretima) and Leech (Hirudinaria) which are hermaphrodites
(i.e., monoecious).
PHYLUM ARTHROPODA:
• Largest phylum of Animalia.
• Are bilaterally symmetrical, triploblastic and organ system level of
Organization, Coelomates.
• Body divisible into head, thorax, abdomen and has a chitinous exoskeleton.
Jointed appendages are present.
• Respiration by gills, book gills, lungs or trached system. Excretion through
malpighian tubules.
• Sensory organs: Antennae, eyes; Organs of balance: Statocysts.
• Fertilization internal. Development is indirect or direct. Are mostly oviparous.
e.g., Apis, Bombyx, Anopheles, Locusta, Limulus.
#classes of arthropoda:
Arachnida:-
Crustacea:-
Chilopoda:-
Diplopoda:-
Insecta:-
Arachnida:-
Body is divisible into prosoma and ophisthosoma.
Presence of four pairs of leg
Antennae are absent.
Respiration takes place through book lungs. Gills absent.
The glands called spinnerets are present in spider to secrete thread.
Scorpions are neuro toxic animals.
Black widow spider eats its own partner after copulation.
E.g. Spider, scorpion, mites, ticks etc
Crustacea:-
Body is divided into cephalo thorax and abdomen.
Presence of hard shield on the dorsal surface.
Presence of 5-6 pairs of legs.
Presence of 2 pairs of antennae.
Excretion through coxal green gland.
Respiration through gills.
In prawn only oxygenated blood flows.
E.g. prawn, ray fish, cancer, daphnia etc.
Chilopoda:-
Body is long and divided into head and trunk.
Each segment has a pair of leg.
1st pair of leg is modified into poison claws.
There is a pair of antennae.
E.g. centipede.
Diplopoda:-
Body is long and divided into head thorax and abdomen.
Each thoracic segment except 1st has a pair of leg.
Each abdominal segment has 2 pair of leg.
E.g. Julus (millipede).
Insecta:-
BODY IS DIVIDED INTO HEAD THORAX AND ABDOMIN.
PRESENCE OF A PAIR OF ANTENNAE.
PRESENCE OF THREE PAIR OF LEG ANGD USUALLY 2 PAIR OF WINGS.
RESPIRATION TAKES PLACE THROUGH TRACHEAE.
EXCRETION TAKES PLACE BY MALPIGHIAN TUBULES.
EXCRETORY PRODUCT IS USUALLY URIC ACID.
E.G. COCKROACH.FLEA,LICE,ANT ETC.
PHYLUM MOLLUSCA:
• Second largest phylum of Animalia.
• Are bilaterally symmetrical, triploblastic and organ system level of
Organization, Coelomates.
• Body divisible into head, muscular foot and visceral hump and is covered
by calcareous shell. It is unsegmented over visceral hump.
• Mantle: Soft and spony layer of skin; Mantle cavity: Space between visceral
Hump and mantle.
• Respiration and excretion by feather like gills in mantle cavity.
• Head has sensory tentacles. Radula-file like rasping organ for feeding.
• Are oviparous, dioecious, have indirect development.
e.g., Pila, Pinctada, Octopus.
PHYLUM ECHINODERMATA:
• Are spiny bodied organisms.
• Are exclusively marine, radially symmetrical in adult but bilaterally symmetrical
in larval stage. Organ system level of organization.
• Digestive system complete. Mouth ventral, Anus on dorsal side.
• Food gathering, respiration, locomotion carried out by water vascular system.
• Excretory system is absent.
• Fertilization external. Development indirect (free swimming larva).
Locomotion takes place by the help of tube feet.
e.g., Asterias, Cucumaria.
PHYLUM HEMICHORDATA: • Has small worm-like organisms.
• Was earlier placed as sub-phylum of Phylum Chordata.
• Bilaterally symmetrical, triploblastic and Coelomates.
• Body cylindrical, has proboscis, collar and trunk.
• Respiration by gills, excretion by proboscis gland.
• Sexes separate, external fertilization, indirect development.
e.g., Balanoglossus
PHYLUM CHORDATA • Presence of Notochord
• Have dorsal hollow nerve chord.
• Have paired pharyngeal gill slits.
• Heart is ventral.
• Post anal tail present.
(i) SUB-PHYLA UROCHORDATA
• Notochord present only in larval tail.
e.g., Ascidia, Sepia.
(ii) SUB-PHYLA CEPHALOCHORDATA
• Notochord extends from head to tail.
e.g., Amphioxus.
(iii) SUB-PHYLA VERTEBRATA
• Have notochord only during embryonic period.
• Notochord gets replaced by bony or cartilaginous vertebral column.
• Have ventral muscular heart, paired appendages and kidneys for excretion
and osmoregulation.
SUB-PHYLUM VERTEBRATA
(a) AGNATHA (Lock Jaw) : Class : Cyclostomata
• Have sucking and circular mouth without jaws.
• Live as ectoparasites on some fishes.
• No scales, no paired fins.
• Cranium and vertebral column is cartilaginous.
• Migrate to fresh water for spawning and die after spawning.
• Larva returns to ocean after metamorphosis.
e.g., Petromyzon.
(b) GNATHOSTOMATA (Bear Jaws)
SUPER-CLASS: PISCES
1. Class: Chondrichthyes
• Have cartilagenous endoskeleton.
• Mouth ventral.
• Gill slits without operculum
• Skin has placoid scales.
• Usually oviparous, fertilization internal.
• No air bladder, so swim constantly to avoid sinking.
• Teeth are backwardly directed, modified placoid scales.
• Notochord is persistent throughout life. Males have claspers on
pelvicfins.
• e.g., Torpedo, Trygon, Scoliodon.
2. Class: Osteichthyes
• Have bony endoskeleton.
• Mouth is usually terminal.
• Four pairs of gill slits covered by operculum.
• Skin has cycloid/ctenoid scales.
• Usually viviparous, fertilization external.
• Have air bladder which regulates buoyancy.
• e.g., Hippocampus, Labeo, Catla, Betta.
SUB-PHYLUM VERTEBRATA: GNATHOSTOMATA
SUPER CLASS: TETRAPODA
Class: Amphibia
* This class includes the animals that came out of the water and established a successful life on land.
* They took advantages of the improved possibilities by remaining close to water, by keeping a soft and moist skin, by developing lungs and by evolving a bony skeleton with a strong vertebral column and four legs.
* They cope with seasonal changes by burrowing during extreme cold and save water by sealing themselves in a mucous envelop on dry land.
* The bony endoskeleton is the main body support.
* The notochord is absorbed during development
* Breathing is mostly by means of skin and also lung, and also by lining of buccal cavity.
* In larva the breathing is mostly by means of external or internal gills.
* The circulatory system shows a three chambered heart, with two atria and one ventricle.
* The amphibians are “Cold Blooded” (Poikilothermic) that is having internal temperature that very with the environment.
* Eggs and sperms are laid in water and fertilization is external.
E.g.: Frog and Toads, Salamanders, Newts, Mud puppies etc.
CLASS: REPTILIA
* All reptiles lay their eggs on land.
* They are cold-blooded animals and are less active during low temperature.
* They possess dry skin covered with epidermal scales.
* In some lizards and crocodiles, small bony plates develop below the epidermal scales.
* The skeleton is built on the same plane as that of amphibians, but is much stronger to support their body weight.
* Respiration takes place exclusively through lungs.
* Heart is three chambered two auricles and one incompletely divided ventricle. (In Crocodiles, the ventricle is completely divided into two chambers.)
* The excretion takes place through kidneys. The reptiles secrete much of their waste products in form of non-toxic “Uric-Acid.”
* In most reptiles fertilization is internal.
* Eggs are provided with a shell and are laid on land.
* The early development of embryo takes place on the large quantities of yolk and albumin present in the egg.
egAlligators, Crocodile, Snake, Turtle and Gecko etc.
Class:aves
* The great mobility of neck is helpful in feeding, nest building, preening and defence.
* There are developed a number of types of bills according to their feeding habits.
* The digestive system of birds is compact and can accommodate large quantity of food.
* The food is stored for a short period in the crop.
* “Gizzard” possess thick muscular wall with horny lining, small stones swallowed by birds are passed on the gizzard for grinding the food.
* The “Syrinx” or sound-producing organ is found in no other vertebrate except the birds. It is located at the junction between the trachea and the paired bronchi.
* The lungs of birds are small, solid, spongy and slightly distensible. They are in contact with a number of air sacs.
E.g. Sparrow, crow, pegion.
Class: mammalia
Mostly terrestrial, a few aquatic animals.
* They are warm-blooded animals.
* They can maintain a fairly high body temperature and so can successfully survive in colder areas of the world.
* Heat is generated by high metabolic rate of their body and is lost by increasing blood circulation in the skin and evaporation of sweat.
* All mammals possess hair on skin.
* Sweat glands and sebaccous glands are present on skin.
* Mammary glands secrete milk in females.
* External ears (Pinna) are present.
* Vertebrae are “Gastrocentrous,” composed of three pieces i.e. the centrum and two epiphyses.
* Heart is four-chambered.
* R.B.Cs are non-nucleated.
* Brain with four optic lobes.
* Kidney is metanephrous.
* The stomach is simple sac but rarely complicated.
* Fertilization is internal.
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Circulatory System : Open type : Blood pumped out through heart. Cells and
tissues are directly bathed in it.
Closed type : Blood is circulated through vessels
Symmetry : • Asymmetrical : Cannot be divided into equal halves through
median plane. e.g., Sponges.
• Radial symmetry : Any plane passing through cental axis can divide organism
into equal halves. e.g., Hydra.
• Bilateral symmetry : Only one plane can divide the organism into equal
halves. e.g., Annelids and Arthropods.
CLASSIFICATION ON BASIS OF GERMINAL LAYERS :-
Diploblastic : Cells arranged in two embryonic layers i.e. external ectoderm
and internal endoderm. (Mesoglea may be present in between ectoderm
and endoderm) e.g., Coelentrates. (Cnidarians)
Triploblastic : Three layers present in developing embryo i.e., ectoderm,
endoderm and mesoderm. e.g., Chordates.
Coelom (Body cavity which is lined by mesoderm)
Coelomates : Have coelom e.g., Annelids, Chordates etc.
Pseudocoelomates : No true coelem as mesoderm is present in scattered
pouches between ectoderm and endoderm. e.g., Aschelminthes.
Acoelomates : Body cavity is absent. e.g. Platyhelminthes.
Metamerism : If body is externally and internally divided into segments with
serial repetition of atleast some organs then phenomenon is called metamerism.
e.g., Earthworm.
Notochord : Rod-like structure formed during embryonic development on the
dorsal side. It is mesodermally derived. e.g., Chordates.
PHYLUM:-
PORIFERA :
• Also called sponges.
• Are usually marine and asymmetrical.
• Have cellular level of organisation.
• Food gathering, respiratory exchange and removal of wastes occurs through
water canal system. Digestion intracellular.
• Ostia (minute pores on body), spongocoel (body cavity) and osculum help
in water transport. They are lined by choanocytes (collar cells).
•Body wall has spicules and spongin fibres.
Animals are hermaphrodite. Fertilisation internal. Development is indirect
They are pore bearing animals
They are Diploblastic animals,ectoderm and endoderm are known as pinacoderm and choanoderm respectively.they are separated by mesenchyme which is non cellular.
They are sessile i.e. they are attached to base by the help of substratum.
(i.e., has a larval stage distinct from adult stage) e.g., Sycon, Euspongia.
#clases of porifera:-
Calceria:-
Spicules are made up of calcium.
They are mostly marime
Eg. sycon
Hexactinellida:-
Spicules are made up of silica
They are marine
Eg.Hyalonema.
Demospongia:-
Spicules are made up of sponginfibres.
They are both marine and freshwater.
Eg. Spongilla.
PHYLUM
COELENTERATA :
• Also called Cnidarians.
• Are usually marine and radially symmetrical.
• Have tissue level of organization
• Are Diploblastic
• Food gathering, anchorage and defends occurs through cnidoblasts present
On tentacles.
• Digestion extracellular and intracellular.
• Have gastro-vascular cavity and an opening, hypostome.
• Body wall composed of calcium carbonate.
• Exhibit two body forms: polyp and medusa e.g., Hydra, Aurelia.
• Alternation of generation between body forms called Metagenesis occurs
in Obelia where Medusa sexually Polyp.
Asexually
• e.g., Physalia, Adamsia.
#classes of coelenterate:-
Hydrozoa:-
Dominance of polyp is seen and medusa is reduced
Both marine and fresh water.
E.g. hydra.
Scyphozoa:-
Dominance of medusa is seen and polyp is reduced
Marine animals
E.g. Aurelia
Anthozoa:-
Medusa absence and polyp present
They are marine
E.g. metridium.
PHYLUM PLATYHELMINTHES:
• Also called as ‘flat worms’.
• Have dorsoventrally flattened body. Are endoparasites in animals.
• Are bilaterally symmetrical, triploblastic, acoelomate.
• Absorb nutrients through body surface.
• Parasite forms have hooks and suckers.
• ‘Flame cells’ help in osmoregulation and excretion.
• Fertilization internal. Many larval stages. Planaria has high regeneration
capacity.
Digestion is extra cellular.
They are acoelomate.
They are hermaphrodite animals.
They possess ladder like nervous system.
e.g., Taenia, Fasciola.
PHYLUM ASCHELMINTHES:
• Also called ‘round worms’.
• May be free living, parasitic, aquatic or terrestrial.
• Are bilaterally symmetrical, triploblastic, Pseudocoelomates.
• Alimentary canal complete (has muscular pharynx), wastes removed through
Excretory pore.
• Sexes separate. Shows dimorphism.
• Females longer than males.
• Fertilization internal. Development direct or indirect.
Absence of respiratory system ant takes place through general body surface.
Sensory organs are less developed
Body is covered with cuticle.
Circulatory and skeletal system is absent.
e.g., Ascaris, Wuchereria.
PHYLUM ANNELIDA:
• Are aquatic or terrestrial, free-living or parasitic.
• Are bilaterally symmetrical, triploblastic, organ-system level of organization
And metamerically segmented body.
• Have longitudinal and circular muscles for locomotion.
• Nereis (dioecious and aquatic annelid) has lateral appendages called parapodia
for swimming.
• Have nephridia for osmoregulation and excretion.
They are Coelomates animals.
Alimentary anal is complete
Nervous system is well developed
Circulatory system is present and is closed type.
Blood is red due to the presence of haemoglobin
Sexual reproduction takes place and fertilization is external.
• e.g., Earthworm (Pheretima) and Leech (Hirudinaria) which are hermaphrodites
(i.e., monoecious).
PHYLUM ARTHROPODA:
• Largest phylum of Animalia.
• Are bilaterally symmetrical, triploblastic and organ system level of
Organization, Coelomates.
• Body divisible into head, thorax, abdomen and has a chitinous exoskeleton.
Jointed appendages are present.
• Respiration by gills, book gills, lungs or trached system. Excretion through
malpighian tubules.
• Sensory organs: Antennae, eyes; Organs of balance: Statocysts.
• Fertilization internal. Development is indirect or direct. Are mostly oviparous.
e.g., Apis, Bombyx, Anopheles, Locusta, Limulus.
#classes of arthropoda:
Arachnida:-
Crustacea:-
Chilopoda:-
Diplopoda:-
Insecta:-
Arachnida:-
Body is divisible into prosoma and ophisthosoma.
Presence of four pairs of leg
Antennae are absent.
Respiration takes place through book lungs. Gills absent.
The glands called spinnerets are present in spider to secrete thread.
Scorpions are neuro toxic animals.
Black widow spider eats its own partner after copulation.
E.g. Spider, scorpion, mites, ticks etc
Crustacea:-
Body is divided into cephalo thorax and abdomen.
Presence of hard shield on the dorsal surface.
Presence of 5-6 pairs of legs.
Presence of 2 pairs of antennae.
Excretion through coxal green gland.
Respiration through gills.
In prawn only oxygenated blood flows.
E.g. prawn, ray fish, cancer, daphnia etc.
Chilopoda:-
Body is long and divided into head and trunk.
Each segment has a pair of leg.
1st pair of leg is modified into poison claws.
There is a pair of antennae.
E.g. centipede.
Diplopoda:-
Body is long and divided into head thorax and abdomen.
Each thoracic segment except 1st has a pair of leg.
Each abdominal segment has 2 pair of leg.
E.g. Julus (millipede).
Insecta:-
BODY IS DIVIDED INTO HEAD THORAX AND ABDOMIN.
PRESENCE OF A PAIR OF ANTENNAE.
PRESENCE OF THREE PAIR OF LEG ANGD USUALLY 2 PAIR OF WINGS.
RESPIRATION TAKES PLACE THROUGH TRACHEAE.
EXCRETION TAKES PLACE BY MALPIGHIAN TUBULES.
EXCRETORY PRODUCT IS USUALLY URIC ACID.
E.G. COCKROACH.FLEA,LICE,ANT ETC.
PHYLUM MOLLUSCA:
• Second largest phylum of Animalia.
• Are bilaterally symmetrical, triploblastic and organ system level of
Organization, Coelomates.
• Body divisible into head, muscular foot and visceral hump and is covered
by calcareous shell. It is unsegmented over visceral hump.
• Mantle: Soft and spony layer of skin; Mantle cavity: Space between visceral
Hump and mantle.
• Respiration and excretion by feather like gills in mantle cavity.
• Head has sensory tentacles. Radula-file like rasping organ for feeding.
• Are oviparous, dioecious, have indirect development.
e.g., Pila, Pinctada, Octopus.
PHYLUM ECHINODERMATA:
• Are spiny bodied organisms.
• Are exclusively marine, radially symmetrical in adult but bilaterally symmetrical
in larval stage. Organ system level of organization.
• Digestive system complete. Mouth ventral, Anus on dorsal side.
• Food gathering, respiration, locomotion carried out by water vascular system.
• Excretory system is absent.
• Fertilization external. Development indirect (free swimming larva).
Locomotion takes place by the help of tube feet.
e.g., Asterias, Cucumaria.
PHYLUM HEMICHORDATA: • Has small worm-like organisms.
• Was earlier placed as sub-phylum of Phylum Chordata.
• Bilaterally symmetrical, triploblastic and Coelomates.
• Body cylindrical, has proboscis, collar and trunk.
• Respiration by gills, excretion by proboscis gland.
• Sexes separate, external fertilization, indirect development.
e.g., Balanoglossus
PHYLUM CHORDATA • Presence of Notochord
• Have dorsal hollow nerve chord.
• Have paired pharyngeal gill slits.
• Heart is ventral.
• Post anal tail present.
(i) SUB-PHYLA UROCHORDATA
• Notochord present only in larval tail.
e.g., Ascidia, Sepia.
(ii) SUB-PHYLA CEPHALOCHORDATA
• Notochord extends from head to tail.
e.g., Amphioxus.
(iii) SUB-PHYLA VERTEBRATA
• Have notochord only during embryonic period.
• Notochord gets replaced by bony or cartilaginous vertebral column.
• Have ventral muscular heart, paired appendages and kidneys for excretion
and osmoregulation.
SUB-PHYLUM VERTEBRATA
(a) AGNATHA (Lock Jaw) : Class : Cyclostomata
• Have sucking and circular mouth without jaws.
• Live as ectoparasites on some fishes.
• No scales, no paired fins.
• Cranium and vertebral column is cartilaginous.
• Migrate to fresh water for spawning and die after spawning.
• Larva returns to ocean after metamorphosis.
e.g., Petromyzon.
(b) GNATHOSTOMATA (Bear Jaws)
SUPER-CLASS: PISCES
1. Class: Chondrichthyes
• Have cartilagenous endoskeleton.
• Mouth ventral.
• Gill slits without operculum
• Skin has placoid scales.
• Usually oviparous, fertilization internal.
• No air bladder, so swim constantly to avoid sinking.
• Teeth are backwardly directed, modified placoid scales.
• Notochord is persistent throughout life. Males have claspers on
pelvicfins.
• e.g., Torpedo, Trygon, Scoliodon.
2. Class: Osteichthyes
• Have bony endoskeleton.
• Mouth is usually terminal.
• Four pairs of gill slits covered by operculum.
• Skin has cycloid/ctenoid scales.
• Usually viviparous, fertilization external.
• Have air bladder which regulates buoyancy.
• e.g., Hippocampus, Labeo, Catla, Betta.
SUB-PHYLUM VERTEBRATA: GNATHOSTOMATA
SUPER CLASS: TETRAPODA
Class: Amphibia
* This class includes the animals that came out of the water and established a successful life on land.
* They took advantages of the improved possibilities by remaining close to water, by keeping a soft and moist skin, by developing lungs and by evolving a bony skeleton with a strong vertebral column and four legs.
* They cope with seasonal changes by burrowing during extreme cold and save water by sealing themselves in a mucous envelop on dry land.
* The bony endoskeleton is the main body support.
* The notochord is absorbed during development
* Breathing is mostly by means of skin and also lung, and also by lining of buccal cavity.
* In larva the breathing is mostly by means of external or internal gills.
* The circulatory system shows a three chambered heart, with two atria and one ventricle.
* The amphibians are “Cold Blooded” (Poikilothermic) that is having internal temperature that very with the environment.
* Eggs and sperms are laid in water and fertilization is external.
E.g.: Frog and Toads, Salamanders, Newts, Mud puppies etc.
CLASS: REPTILIA
* All reptiles lay their eggs on land.
* They are cold-blooded animals and are less active during low temperature.
* They possess dry skin covered with epidermal scales.
* In some lizards and crocodiles, small bony plates develop below the epidermal scales.
* The skeleton is built on the same plane as that of amphibians, but is much stronger to support their body weight.
* Respiration takes place exclusively through lungs.
* Heart is three chambered two auricles and one incompletely divided ventricle. (In Crocodiles, the ventricle is completely divided into two chambers.)
* The excretion takes place through kidneys. The reptiles secrete much of their waste products in form of non-toxic “Uric-Acid.”
* In most reptiles fertilization is internal.
* Eggs are provided with a shell and are laid on land.
* The early development of embryo takes place on the large quantities of yolk and albumin present in the egg.
egAlligators, Crocodile, Snake, Turtle and Gecko etc.
Class:aves
* The great mobility of neck is helpful in feeding, nest building, preening and defence.
* There are developed a number of types of bills according to their feeding habits.
* The digestive system of birds is compact and can accommodate large quantity of food.
* The food is stored for a short period in the crop.
* “Gizzard” possess thick muscular wall with horny lining, small stones swallowed by birds are passed on the gizzard for grinding the food.
* The “Syrinx” or sound-producing organ is found in no other vertebrate except the birds. It is located at the junction between the trachea and the paired bronchi.
* The lungs of birds are small, solid, spongy and slightly distensible. They are in contact with a number of air sacs.
E.g. Sparrow, crow, pegion.
Class: mammalia
Mostly terrestrial, a few aquatic animals.
* They are warm-blooded animals.
* They can maintain a fairly high body temperature and so can successfully survive in colder areas of the world.
* Heat is generated by high metabolic rate of their body and is lost by increasing blood circulation in the skin and evaporation of sweat.
* All mammals possess hair on skin.
* Sweat glands and sebaccous glands are present on skin.
* Mammary glands secrete milk in females.
* External ears (Pinna) are present.
* Vertebrae are “Gastrocentrous,” composed of three pieces i.e. the centrum and two epiphyses.
* Heart is four-chambered.
* R.B.Cs are non-nucleated.
* Brain with four optic lobes.
* Kidney is metanephrous.
* The stomach is simple sac but rarely complicated.
* Fertilization is internal.
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Great read thank yoou
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