CLASSIFICATION OF ANIMALS – Non Chordates – Class XI Biology by TEACHING CARE online tuition and coaching classes
CLASSIFICATION OF ANIMALS – Non Chordates – Class XI Biology by TEACHING CARE online tuition and coaching classes
Classification of Animals—Non Chordates
On an estimation about 5 to 20 million kinds of organisms exist on our planet. Out of these about 1.2 million animals and 0.2 million plants species have been identified, given scientific name and classified.
FUNDAMENTALS OF ANIMAL CLASSIFICATION
Levels Of Body Organization
Following are the different levels of organization in animals from simpler to complex state:
- Protoplasmic grade – In this grade all life activities are confined within the boundaries of a single cell which is a structural and functional unit of life. e.g. Protozoa and other unicellular organism.
- Cellular grade – It is a loose association or aggregation of cells that are functionally differentiated, e.g. sponges.
- Tissue grade – An aggregation of cells which act in co-ordination. e.g. Cnidarians.
- Tissue-organ grade – When tissues aggregate to form a particular organ. First appeared in platyhelminthes.
- Organ system grade – When organs work together to perform some common function such as digestion, respiration, circulation etc. e.g., most of the higher animals.
- Cell Aggregate Body plan – The body is made up of cells (Aggregate) and each cell act almost independently. e.g. Porifera (sponges)
- Blind Sac – The body resembles a sac and contains a single cavity with one opening that serves for ingestion and egestion both e.g., Cnidaria (Hydra), Platyhelminthes (flatworms).
- Tube within a tube – The body is made up of two tubes, outer body wall and the inner digestive tract. e.g. Annelida
Tube-within-tube body plan is divided into two parts:
- Protostomes – In protostomes mouth develops from blastopore. e.g. Annelida, Arthropoda, Mollusca.
- Deuterostomes – The mouth never develops from the blastopore, although the blastopore may give rise to the anus. e.g. Echinoderms and chordata.
The arrangement of body parts in a geometrical pattern is called a symmetry.
Following types –
- Spherical symmetry – Found in spherical body. All planes that pass through the center will cut it into similar halves. e.g. Some protozans like Volvox, Heliozoa, Radiolaria.
- Radial symmetry – The body is in the form of a flat or tall cylinder. All the lines passing through longitudinal axes in a radiating manner divide the body into equal halves. e.g. Hydra.
(a) Biradial symmetry – divides the animal into two equal halves. e.g. Ctenophora and most anthozoa (e.g. Sea anemones)
(b) Pentamerous radial – divides into 5 equal parts e.g., star fish.
- Bilateral symmetry – The body is divided into two equal parts by a single median longitudinal or sagittal plane. e.g., most higher animals.
- Asymmetry – when an animal cannot be divided into equal parts by any plane e.g., Amoeba, most sponges.
When the segmentation in bilateral animal such as annelids involves a longitudinal division of the body into a linear series of similar sections or parts is termed Metamerism or metameric segmentation. e.g. Annelids, Arthropods, Chordates and Cestodes.
- Annelids show both external and internal segmentation.
- Arthropods show only external segmentation.
- The segmentation in flatworms such as tapeworm is termed as pseudometamerism.
During early stages of embryonic development the cells are arranged in groups forming germ layers. They appear in gastrula stage.
- Diploblastic animals – Having two distinct germ layers i.e. outermost ectoderm and innermost endoderm e.g. Cnidarians and porifera.
- Triploblastic animals – Having three distinct germ layers i.e. ectoderm, mesoderm and endoderm. The mesodermal layer always lies between ectoderm and endoderm e.g. Most metazoans (Bilateria).
Body cavity or Coelom
The fluid filled space between the gut and the outer body wall is a body cavity. On the basis of development, it is of following types:
- Acoelomates – The animals without coelom or body cavity are called a coelomates. e.g. Cnidarians, flatworms (platyhelminthes).
- Pseudocoelom – The body cavity between the gut and body wall is not lined by mesoderm (Peritoneum) e.g. Nemathelminthes (Ascaris).
- Eucoelom – The body cavity lined from all sides by mesodermal peritoneum.
(a) Schizocoel – formed by the splitting of mesodermal band. e.g. Annelids, Arthropods, Molluscs.
(b) Enterocoel – formed from the pouches of the archenterons or primitive gut e.g. Echinoderms and chordates.
Table: Non-chordates And Chordates
- Radially, bilaterally symmetrical Bilaterally symmetrical or symmetrical
- Diploblastic or Triploblastic Triploblastic
- Acoelomate, Pseudocoelomate or Eucoelomate Eucoelomate
- Notochord – absent Notochord – present
- Pharyngeal gill-slits – absent Pharyngeal gill-slits present at some stage of life.
- Ventral nerve cord – present Dorsal tubular nervous system present
Protozoans are small, generally microscopic organisms where single cell performs all the vital activities hence, also called as acellular organisms.
Exhibit a great variety of shape.
Cytoplasms differentiated into outer ectoplasm and inner endoplasm.
Generally uninucleate but all ciliates and many amoeboid forms are multinucleate. Nucleus is vesicular and massive.
Locomotory organs are pseudopodia in sarcodina, flagella in mastigophora, cilia in ciliata and absent in Sporozoa (parasitic forms).
Nutrition may be holophytic (plant-like), holozoic (animal-like), saprozoic or parasitic.
Contractile vacuole is found in almost all freshwater protozoans for maintenance of osmotic concentration of cell body. It also helps in excretion.
Reproduction is asexual or sexual. Most flagellates, rhizopods and ciliates show asexual reproduction by binary or multiple fission, budding or sporulation. Some ciliates e.g.;Paramecium reproduce by sexual means i.e. conjugation. In sporozoa, some stages of life cycle show formation of morphologically distinct gametes.
Cyst formation during unfavourable conditions commonly occurs among the freshwater and parasitic protozoans.
Life cycle often exhibits alternation of generation ie – includes both asexual and sexual phase.
Protozoans show mainly 2 modes of life, free-living inhabiting fresh and salt water and damp places, parasitic living as ectoparasites or endoparasites on other animals and plants.
Sponges are often placed under a separate group called “Parazoa” which means side animals.
This phylum includes lowest of multicellular cellular grade animals commonly called sponges.
They are mostly marine and asymmetrical.
They have water transport canal system in their body.
There are several minute pores on entire body surface called ostia through which water enters in body and goes to central cavity, Spongocoel. From spongocoel the water goes out through the osculum.
This pathway of water transport is helpful in food gathering, respiratory exchange and excretion.
Choanocytes or collar cells line the spongocoel and the canals.
Digestion is intracellular.
The body skeleton is made up of Spicules or sponging fibres.
All are hermaphrodite, i.e. Sexes are not separate.
Reproduction is both asexual and sexual type.
Asexual reproduction by fragmentation and sexual by formation of gametes.
Fertilization is internal and development is indirect i.e. larva is morphologically distinct from the adult.
Sponges have originated from colonial choanoflagellates (protozoans) connecting link between protozoa & porifera is Proterospongia (protozoan)
Example: Sycon, (Scypha), Spongilla (Fresh water sponge) and Euspongia (Bath sponge).
They are aquatic, mostly marine, sessile or free-swimming, radially symmetrical animals.
They are commonly known as cnidarians due to presence of the specialised cell called cnidoblast or cnidocysts, a stinging cell.
Body form is various —vase-like, umbrella-like, branched or unbranched filament.
Coelenterates are diploblastic, i.e., develop from two germ layers and the body with cell-tissue level of organization..
Most of the coelenterates are colonial (e.g., Physalia), but some are solitary also (e.g., Hydra).
Coelenterates usually are found in more than one form and exhibit the phenomenon of polymorphism (i.e., in an individual more than one type of zooids are present). The two common forms are polyps and medusae.
The animals have blind sac body plan. There is a single opening which serves both as mouth
and anus. It is commonly called oral aperture. The single aperture leads into a cavity called
gastrovascular cavity or coelenteron. The latter may have septa.
Symmetry is radial or biradial.
The oral end often bears thread like flexible tentacles.
Body wall is two layered, i.e., outer epidermis (ectoderm) and inner gastrodermis (endoderm).
In between these two layers is present a non-cellular, nonliving gelatinous matrix or layer called
mesogl Sea. Branches of nerve cells may traverse mesogloea.
A chitinous or calcareous exoskeleton may occur.
Polyp is usually fixed and sessile. . It is like a cylindrical stalk with mouth and tentacles facing upwards.
Medusa is free- living and umbrella or bell like with mouth and tentacles facing downwards. It is regarded as upside down polyp which can swim. In many forms polyps produce medusae by budding and medusae produce polyps after sexual reproduction.
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).
Examples: Physalia (Portuguese man-of-war), Adamsia (Sea anemone), Pennatula (Sea-pen), Gorgonia (Sea-fan) and Meandrina (Brain coral).
Commonly known as sea walnuts and comb jellies.
They are exclusively marine, radially symmetrical, diploblastic organisms with tissue level of organisation.
The body consists eight external rows of ciliated comb plates used form locomotion.
Digestion is both extracellular and intracellular.
They show Bioluminescence (the property of a living organism to emit light) is well-marked in ctenophores.
They hermaphrodite i.e., sexes are not separate.
Reproduction takes place only by sexual means.
Fertilization is external i.e. takes place in water.
Development is indirect i.e. Cydipid larva is present.
Examples: Pleurobrachia and Ctenoplana.
They have dorso-ventrally flattened body, hence are called flatworms.
Most of the flatworms are endoparasite found in animals including human beings.
Body of flatworms are bilaterally symmetrical, triploblastic and acoelomate with organ level of organization.
Body divided into head, neck and proglottids.
Hooks and suckers are present in head in parasitic forms.
Excretion and osmoregulation occurs through specialised cell called flame cells.
They are hermaphrodite.
Fertilization is internal.
Development is indirect through many larval stages.
Some members Planaria possess high regeneration capacity.
Example: Taenia solium (Tape worm), Fasciola hepatica (Liver fluke) etc.
Bilaterally symmetrical, triploblastic, unsegmented, pseudocoelomate and cylindrical worms.
Organ-system level of organization.
No appendages in roundworms.
The body of the aschelminthes is circular in cross-section, hence, the name roundworms.
They may be free living, aquatic and terrestrial or parasitic in plants and animals.
Alimentary canal is complete with a well development muscular pharynx.
The excretory products are removed through the excretory pore.
Sexes are separate (dioecious) and they show sexual dimorphisms. Females are longer than males.
Fertilization is internal and development may direct or indirect.
Examples : Ascaris (Round Worm), Wuchereria (Filaria worm), Ancylostoma (Hookworm).
They may be aquatic (fresh water and marine) or terrestrial; free living and sometimes parasitic.
They exhibit organ-system level of organization and bilateral symmetry.
They are triploblastic, shizocoelomate and metamerically segmented animals.
Their body surface distinctly marked out into segments or metameres and, hence, the phylum name as annelid.
They have longitudinal as well as circular muscles.
Aquatic annelids like Nereis possess lateral appendages, parapodia, which helps in swimming.
Circulatory system is closed type.
Excretory and osmoregulatory organ is Nephridia.
Neural system consists of paired ganglia connected by lateral nerves to double nerve cord.
The nerve cord is double ventral and solid.
They are both dioecious (Nereis) and monoecious (Earthworm and Leeches).
Reproduction is sexual type.
Examples : Nereis, Pheretima (Earthworm) and Hirudinaria (Blood sucking leech).
Largest Phylum of the animal kingdom including 900,000 species in which 750,000 are insects.
They are triploblastic, bilaterally symmetrical, metamerically segmented animals.
Body covered with a thick chitinous cuticle forming an exoskeleton.
Body segments usually bear paired lateral and jointed appendages.
Their body divisible into head, thorax and abdomen; head and thorax often fused to form cephalothorax.
The true coelom is reduced in adults; and is only represented by the cavities of the reproductive and excretory organs. The body cavity is a haemocoel.
Digestive system is complete; mouth parts adapted for different modes of feeding.
The alimentary canal consists of stomodaeum (fore-gut), mesenteron (mid-gut) and proctodaeum (hind-gut).
The respiratory organs are gills or book gills in aquatic forms and trachea or book lungs in terrestrial forms.
Circulatory system opens with a dorsal heart, arteries and blood sinuses.
Excretory organs are green glands, coxal glands, malpighian tubules.
Nervous system with solid double ventral nerve cord.
Sensory organs comprise simple eyes, compound eyes, chemo-receptors and tactile receptors antenna. Some forms also have statocysts (a balancing organ).
Muscles are mostly striated.
Endocrine glands are present. Insects secrete pheromones which are used for communication between two organisms of the same species.
Sexual dimorphism is exhibited. Fertilization is internal; oviparous or ovo-viviparous; development direct or indirect. Parthenogenesis occurs in some forms.
Example: Economically important insects Apis (Honey bee), Bombyx (Silkworm), Laccifer (Lac insect)
Vectors – Anopheles, Culex and Aedes (Mosquitoes)
Gregarious pest – Locusta (Locust)
Living fossil – Limulus (King crab).
Second largest phylum of kingdom animalia.
Molluscs are essentially aquatic, mostly marine, few fresh-water & some terrestrial forms.
The body is soft, unsegmented, triploblastic and bilaterally symmetrical (In some molluscs like Pila, due to torsion during growth, the adults become asymmetrical).
Body divisible into head, mantle, foot and visceral hump.
Body is commonly protected by an exoskeletal calcareous shell of one or more pieces, secreted by mantle. Shell may be external (e.g., most of molluscs), internal (e.g., slug, cuttle fish, squid) or absent (e.g., Octopus).
Body cavity is haemocoel.
Digestive tract is complete.
Buccal cavity often contains a rasping organ, the radula
Respiration usually takes place by gills, called the ctenidia.
The circulatory system is open. It includes dorsal pulsatile heart and a few arteries that open into sinuses.
Blood consists of copper containing pigment known as haemocyanin.
Excretion by paired metanephridia (kidneys). Gills are also excretory in function. The excretory matter is ammonia or uric acid.
Nervous system consists of paired cerebral, pleural, pedal and visceral ganglia joined by longitudinal and transverse connectives.
Sense organs include eyes (photoreceptors) and tentacles (tactoreceptors) on the head.
Statocysts for equilibrium and osphradia for testing chemical and physical nature of water (chemoreceptor).
Fertilization external or internal; development direct or indirect.
They are usually dioecious and oviparous with indirect development.
Examples: Pila (Apple snail), Pinctada (Pearl oyster), Sepia (Cuttlefish), Loligo (Squid), Octopus (Devil fish), Aplysia (Seahare), Dentalium (Tusk shell) and Chaetopleura (Chiton).
Triploblastic, enterocoelous coelomates with pentamerous radial symmetry having a calcareous endoskeleton of separate plates embedded in the skin.
Body unsegmented with globular, star-like, spherical, discoidal or elongated shape.
Head absent; body surface is marked by five symmetrically radiating areas (ambulacra) and five alternating inter-radii (inter-ambulacra).
Alimentary canal straight or coiled.
Respiratory organs include dermal branchiae (eg. starfish), tubefeet, respiratory tree (e.g., Holothuria), bursae (e.g., brittle star) & peristomial gills system.
Presence of ambulacral system or water vascular system is the most characteristic feature. A perforated plate called madreporite, allows water into the system.
Tube feet help in locomotion.
The circulatory system is greatly reduced & is of open type. It is called haemal system. Blood often lacks a respiratory pigment. There is no heart
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).
Body is soft and unsegmented divided into proboscis, collar and trunk.
Bilaterally symmetrical, triploblastic, eucoelomate.
Digestive tract complete, respiration occurs through gills.
Blood colourless without corpuscles.
Restriction of ‘notochord’ to the anterior part of the body draws the name Hemichordata.
Stomochord is an outgrowth from the anterior part of gut of Balanoglossus which was earlier considered as half notochord.
This phylum consists of a small group of worm-like marine animals with organ-system level of organisation.
The body is cylindrical and is composed of an anterior proboscis, a collar and a long trunk. Circulatory system is of open type. Excretory organ is proboscis gland. Sexes are separate. Fertilisation is external. Development is indirect.
Examples: Balanoglossus and Saccoglossus.
Subphylum : Urochordata
Body is unsegmented and usually lacks tail, covered by a test or tunic composed largely of tunicin, allied to cellulose. Appendages absent. (Tunicin is called animal cellulose)
The notochord is only present in the tail of the larva but disappears in the adult.
Larva undergoes retrogressive metamorphosis.
The larva is known as Ascidian tadpole e.g., Herdmania (Sea squirt), Salpa, Doliolum.
Subphylum : Cephalochordata
Notochord extends from head to tail and persistents throughout life.
A true enterocoelous coelom is present.
Sexes are separate; fertilization external; holoblastic segmentation.
Larva undergoes progressive metamorphosis. e.g. Branchiostoma (Amphioxus).
Notochord is only present in the embryonic stage; it is replaced by vertebral column in adult forms.
Division – I Agnatha (Jawless Vertebrates)
Jawless primitive fish-like vertebrates without true jaws and paired limbs.
Mouth without jaws and remains permanently open.
Mouth circular and suctorial.
Cranium and vertebral column are cartilaginous.
Their body devoid of scales and paired fins.
Gill slits 6-15 pairs. Heart 2-chambered and they are poikilothermous.
Cyclostomes are marine but migrate for spawning to fresh water.
After spawning, within a few days, they die.
Sexes separate or united; fertilization external; development direct or with prolonged larval stage (larva is ammocoete. Their larvae, after metamorphosis, return to ocean.
Example: Lamprey (Petromyzon), Hag fish (Myxine).
Division II : Gnathostomata (Mouth bears jaw) :
All the fish and fish-like aquatic gnathostomes are placed in the superclass Pisces, whereas all the four footed terrestrial gnathostomes are placed in the superclass Tetrapoda.
Super Class- Pisces
Class I- Chodrichthyes
They are cartilaginous fishes.
Most chondrichthyes are marine. All are predaceous.
They are poikilothermal animals.
The pelvic fins bear claspers in the male which are posterior in location.
There are generally two dorsal fins. The caudal fin is asymmetrical (heterocercal).
Skin has unicellular epidermal mucous glands and dermal scales (placoid scales).
Endoskeleton is entirely cartilaginous.
Mouth is ventral. Jaws well developed. The alimentary canal opens into the cloaca.
Respiration through gill. Gills are without gill cover except; Chimera.
Lungs, swim bladder and operculum are absent.
Heart is two-chambered, having one auricle and one ventricle. Sinus venosus and conus arteriosus are present. Renal portal system is well developed.
Nitrogenous waste matter is urea.
Sexes are separate. The reproductive ducts discharge into the cloaca. Male usually has claspers which are used for copulation. Fertilization is internal. Most forms are ovoviviparous or oviparous. Some are viviparous. Life history is simple.
Examples: Scoliodon (Dog fish), Sphyrna (Hammer-headed shark) Pristis (Jaw fish), Torpedo (Electric ray) Trygon (Sting ray), Chimaera (Rat or Rabbit Fish or king of herrings).
Class II- Osteichthyes (Bony Fishes)
They are cold-blooded animals.
Skin has unicellular mucous glands and dermal scales.
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).
Sexes are separate. Fertilisation is usually external.
They are mostly oviparous and development is direct.
Endoskeleton is partly or wholly bony, replaced by distinct vertebrae.
Mouth is terminal or sub-terminal.
Alimentary canal opens out by anus.
Nitrogenous waste matter is mostly ammonia.
Freshwater Species: Labeo rohita (Rohu), Labeo calbasu (Calbasu), Catla catla (Catla), Cyprinus carpio (Carp), Anabas – climbing perch, Gambusia – mosquito fish. (b) Marine Species: Harpodon (Bombay Duck), Anguilla (Eel), Sardinella (Salmon), Hilsa (Hilsa), Hippocampus – sea horse, Pterophyllum (Angel fish).
Super Class- Tetrapoda
Amphibian can live in aquatic as well as terrestrial habitat.
Most of them have two pairs of legs.
Body divided into head and trunk.
The amphibians skin is moist and highly vascularised.
The eyes with eyelids and nictitating membrane.
A tympanum represents ear.
Alimentary canal, Urinary bladder and reproductive tracts open into common chamber called cloaca which open outside.
Respiration by gills, skin and lungs.
Heart three chambered (two auricles and one ventricle)
They are cold-blooded animals.
Sexes are separate. Fertilization is external.
They are oviparous and development is indirect.
Example: Bufo (Toad), Rana (Frog), Hyla (Tree frog), Salamander (Salamander) Ichthyophis (Limbless amphibian).
Creeping or Crawling animal.
They are cold-blooded animal.
They are mostly terrestrial animal and their body is covered with dry and cornified skin, epidermal scales or scutes.
They do not have external ear openings. Tympanic membrane represents the ear.
Limbs when present are two pairs. Heart is usually three-chambered, but four chambered in crocodiles.
They are poikilothermal (cold-blooded) animals.
Their sexes are separate. They are oviparous. Fertilization is external and development is direct.
Example: Snakes, Crocodile, Chelon (Turtle), Testudo (Tortoise), Chameleon (TreeLizard), Calotes (Garden Lizard) Bangarus (Krait).
Class: Aves (Birds)
The most characteristics feature of Aves are presence of feathers on body and most of them are flightless
They have 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 devoid of 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 gizzard.
Their heart is completely four chambered.
They are warm-blooded (homoiothermal) 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 and most of them show sexual dimorphism. Fertilization is internal. They are oviparous and development is direct.
Mammals are found in any environment-polar ice caps, deserts, mountains, forest, oceans, grasslands and dark caves.
The most unique features of mammalian are presence of mammary gland by which is young is nourished.
They have two pairs of limbs adapted for walking, running, climbing, burrowing, swimming or flying.
Heart is four chambered.
They are homoiothermal. Respiration by lungs.
They are viviparous with a few exceptions. 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).
Very Short Answer question
- Write any one unique feature of the phylum Porifera.
- Species Nereis belongs to which phylum of the animal kingdom.
- What is the excretory organ of Tape worm?
- What type of fertilization found in phylum Ctenophora?
- What are the excretory organs of Molluscans?
- What is the excretory product of Chondrichthyes?
Short Answer Question
- Write two characteristic feature of the division Cyclostomata.
- What is the name of excretory organ of the phylum Hemichordata and also write the name of its larva.
- Define the following terms – (i) Poikilothermal and (ii) Homoiothermal
- What are the respiratory organs of class Amphibia? Explain them with species name.
- What is the difference between direct and indirect development?
- Distinguish between intracellular and extracellular digestion?
- What are the peculiar features that you find in parasitic platyhelminthes?
Long Answer question
- What are the difficulties that you would face in classification of animals, if common fundamental features are not taken into account?
- How useful is the study of the nature of body cavity and coelom in the classification of animals?
- What are the reasons that you can think of for the arthropods to constitute the largest group of the animal kingdom?
- “All vertebrates are chordates but all chordates are not vertebrates”. Justify the statement.
- What are the modifications that are observed in birds that help them fly?
- Could the number of eggs or young ones produced by an oviparous and viviparous mother be equal? Why?
- Prepare a list of some animals that are found parasitic on human beings.
Multiple choice questions:
- Water vascular system is the characteristic of which group of the following:
(a) Porifera (b) Ctenophora (c) Echinodermata (d) Chordata
- Segmentation in the body is first observed in which of the following:
(a) Platyhelminthes (b) Aschelminthes (c) Annelida (d) Arthropoda
- Match the following:
Column I ColumnII
(a) Operculum (i) Ctenophora
(b) Parapodia (ii) Mollusca
(c) Scales (iii) Porifera
(d) Comb plates (iv) Reptilia
(e) Radula (v) Annelida
(f ) Hairs (vi) Cyclostomata and Chondrichthyes
(g) Choanocytes (vii) Mammalia
(h) Gill slits (viii) Osteichthyes
- Tornoria is the larva of:
(a) Star fish (b) Balanoglossus (c) Bufo (d) Scoliodon
- Which of the following sets of animals belong to class cyclostomata
(1) Amphioxus and Balanoglossus
(2) Herdamania and Myxine
(3) Herdmania and Petromyzon
(4) Petromyzon and myxine
- The fish which acts as a structural bridge between fish and amphibia is
(1) Protopterus (2) Petromyzon
(3) Myxine (4) Saw fish
- Cartilaginous and bony fishs differ in
(1) Arrangement of skeleton
(2) Composition of skeleton
(3) Types of skeleton
(4) All of these
- Weberian ossicles detect the
(1) Quality of water
(2) Quantity of water
(3) Intensity of sound wave
(4) Speed of water
- The bird buries its head in sand to avoid enemy
(1) Ostrich (2) Sand piper
(3) Sand grouse (4) Pelican
- Wading feet is found in
(1) Fowls (2) Parrots
(3) Herons (4) Quails
- Tear glands make their first appearance in
(1) Fish (2) Amphibia
(3) Reptiles (4) Mammals
- Pineal eye is the characteristic feature of
(1) Amphibia (2) Birds
(3) Reptiles (4) Some fishes
- Synsacrum results by fusion of
(1) Posterior thoracic, lumbar, sacral and anterior caudal vertebrae
(2) Posterior thoracic, and lumbar vertebrae
(3) Posterior thoracic, lumbar and sacral vertebrae
(4) Posterior lumbar, sacral and anterior caudal
- Absence of tympanum, eye lids and urinary bladder are features of
(1) All lizards
(2) All snakes
(3) All reptiles
(4) All turtles
- Hairless mammals are
(1) Rodents (2) Chiropterans
(3) Primates (4) Cetaceans
- The belly of the snake is completely covered by ventrals. The snake is
(3) May be poisonous or non poisonous
(4) Such features does not occur in snake
- A pigeon, in the absence of down feathers will not be able to
(1) Fly for long distance
(2) Protect from ectoparasites
(3) Exhibit secondary sexual dimorphism
(4) Keep the body warm
- Scales are
(1) Absent in birds
(2) Distributed through out the body in birds
(3) Restricted to certain parts of birds
(4) Present only at the base of beak
- The integument of rabbit differs from that of frog in
(1) Possessing stratum corneum for protection against wear and tear
(2) Possessing mucous glands for producing mucous
(3) Possessing sebaceous glands which produce sebum for keeping skin greasy and water proof
(4) Not possessing cutaneous fat
- Retrogressive metamorphosis is shown by
(1) Nereis (2) Amphioxus
(3) Herdmania (4) None of these
- Match List I with List II and give, the correct answer from the code given below the lists
List I List II
Common Name Generic Name
- Flying fish I. Pristis
- Saw fish II. Raja
- Hammer headed III. Sphyrna
- Skate IV. Exocoetus
A B C D
(1) IV I III II
(2) II I III IV
(3) III I IV II
(4) IV III II I
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