(1940) : - Proposed New Systematic
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ANIMAL DIVERSITY-I
IN TRODUCTION : –Taxomony (Gr.) - study of nomenclature, classification and their principles. This word was given by ''Candolle'' (Taxis – arrangements. Nomos - Law)
HISTORICAL BACKGROUND OF TAXONOMY :
–Aristotle : - ''father of zoology ''. (Book : Historia Animalium) Father of ancient animal – Classification. He classified animals into two groups on the basis of their natural similarities and differences into –
(i) Anaima :- Those animals which don't have Red blood or in which RBC are absent e.g. Sponges,
Cnidaria, Mollusca, Arthropoda. Echinodermata like Invertebrates.
(ii) Enaima :- These animals have red blood. This group includes all vertebrated and it has been further divided into two sub groups.
(a) Vivipara :- It incldues animals which give birth to young-ones e.g. Man, Whale and other mammals.
(b) Ovipara :- It includes animals which lay eggs. e.g. Amphibians, Pisces, Aves, Reptiles etc.
–Pliny :- He classified animal into groups : -
(a) Flying (b) Non-flying
–John-Ray :- He gave & defined the term '' species'' as the smallest unit of classfication. He gave ''concept of species ''. According to him, the organisms which develop from the similar type of parents, belong to the same-species.
–Mayr : - According to him similar species are those which are capacble of interbreeding in natureal condtions. Modern definition of species is conied by ''Mayr''.
–Binomial system of Nomenclature was devised by Gesparrd-Bauhin. But the detailed information about Binomial system was given by Linnaeus. In 1758 in the 10th edition of his book ''Systema Naturae'' he gave the classification of known 4236 animals and presented the Binomial system of nomenclature of animal. He is also known as ''Father of Modern-Taxonomy''
–In binomial system the name of each animal has two parts. First part has its genus name and second part has its species name. First letter of genus name must be written in Capital letter and species name is written in small letters eg. Canis familiaris. In certain species, sub-species are also found. For naming the sub species three words are used. First name is for genus, second for species and third for sub- species. The method of nomenclature of Sub-species is termed as the Trinomial nomenclature and it was given by ''Huxley and Strickland''. eg. Homo sapiens sapiens.
– G.L. Cuvier : - Coined the term Phylum.
– Julian-Huxleyhttps://www.studiestoday.com (1940) : - Proposed New systematic.
– Engler and Prantl : - Proposed Phylogenetic classification.
– Key for identification of animal was developed by John Ray.
– Invertebrate and Vertebrate term was given by Lamarck.
–Robert Whittaker (1969) : - Proposed Five-Kingdom system classification to show phylogenetic relationship.
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(1) Monera (2) Protista (3) Fungi (4) Plantae (5) Animalia
– Linnaeus classified animal kingdom into 6-classes.
(1) Mammalia (2) Aves (3) Amphibia (4) Insecta (5) Pisces (6) Vermes
SEQUENCE OF CLASSIFICATION :
–Smallest unit of classification is ''Species''. Genus includes various types of species. Family is made up of various genera. Many families join together to form an Order, many order join together to form a class and many classes form a Phylum. All the phyla unite to form the largest unit i.e. Kingdom.
Various grouping levels or ranks in classification known as Obligate categories.
e.g. kingdom –– Phylum –– Class –– Order –– Family –– Genus –– Species
–Based on this, all animals are included in the animals kingdom – groups and written in the following Hierarchical manner. For example obligate category of man can be written as
TAXA Category Kingdom Animalia Phylum Chordata Class Mammalia Order Primates Family Hominidae Genus Homo
Species Sapiens
IMPORTANT PHYLA :
Storer and Usinger classified whole animal kingdom into 31 phyla. Out of which 10 are major and 21 are minor phyla. Main phyla are :
1. Protozoa - e.g. Amoeba, Paramoecium etc. 2. Porifera - Sponges etc. 3. Coelenterate - Hydra, Jellyfish etc. 4. Ctenophora (minor phylum) - Beroe etc. 5. Platyhelminthes - Tape worm etc. 6. Nemathelminthes-Nematoda - Ascaris etc. 7. Annelida - Earthworm, Leach etc. 8. Arthropodahttps://www.studiestoday.com - Insects, Scorpion, Fly etc. 9. Mollusca - Snail, Pila, Octopus etc
10. Echinodermata - Star fish etc. 11. Hemichordata - Balanoglossus 12. Chordata - Fish, Snake, Birds, Monkey etc.
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Basis of Classification.
METAZOA :
– Animal groups are characterized by mobility, and the presence of a sensory or a nervous system. These systems receive stimuli from the environment and respond by exhibiting some behaviour.
– The only exception are the porifers (pore-bearers) or the sponges. They have no cell that can be termed as nerve cell.
– Like plant life, early animal life also arose in sea.
– The animals which live on the sea floor are called Benthonic (e.g., echinoderms, corals and deep sea fishes), whereas, which swim about actively in sea are called Nektons.
– The multicellular eukaryotic organisms with holozoic mode of nutrition are called as metazoans.
– Based on complexity of organization, metazoans are further sub-divided into two sub-kingdoms, the Parazoa and Eumetazoa.
–Parazoa : Parazoa includes the sponges in which the cells are loosely aggregated and do not form tissues or organs. –Eumetazoa : Eumetazoa includes the rest of the animals, the cells are organized into structural and functional units called as tissues, organs and organ systems.
SYMMETRY :
– Two type of symmetry are usually seen in the animals :
(i) Radial symmetry : The animals with radial symmetry are called as Radiata. For example, Cnidarians (hydra, jellyfish and starfish). Biradial symmetry is present in sea anemone.
For sessile animals, radial symmetry is advantageous, as it allows food to be gathered from all sides.
They may develop appendages all round the mouth to capture and push prey into it.
Their sensory and nerve coordination surrounds the mouth. We see this in coelenterates.
(ii) Bilateral symmetry : - The animals with bilateral symmetry are called as Bilateria. The body can be divided into right and left halves in only one plane.
Bilateral symmetry arose when animals on the ocean floor became mobile.
A crawling animal is most likely to encounter food with the end that goes first. So the mouth https://www.studiestoday.com developed at this end.
With the mouth, sensory organs and a coordinating brain also development at the front end.
These organs helped in sensing food. So we see how the head, enclosing the brain, became associated with the mouth end. This is cephalization.
Asymmetric organisms cannot be divided in any plane to produce two equivalent halves.
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Radial symmetyry Bilateral symmetry
GERM LAYERS
Mesoglea Ectoderm Endoderm
Mesoderm Diploblastic Triploblastic
–Germ layer give rise to all the tissues/organs of the fully formed individuals. On the basis of germ layers, animals can be
(i) Diploblastic : In Diploblastic animals the body cells are arranged in two layers, an outer Ectoderm and an internal Endoderm with an intervening Mesoglea.
(ii) Triploblastic : If the body wall in animals is made up of three germ layer i.e. ectoderm, mesoderm and endoderm, they are called as triploblastic animals.
BODY PLAN
– Animals have three types of body plan :
(i) https://www.studiestoday.com Cell aggregate : Cell aggregate type of body plan is present in sponges.
(ii) Blind sac : Blind sac type of body plan is present in Platyheiminthes and Coelenterates, where the alimentary canal has only one opening.
(iii) Tube within tube : Tube within tube type of body plan is present in Nemathelminthes, Annelida, Arthropoda, Mollusca, Echinoderms Hemichordates and Chordates. The digestive system is a continuous tube with an opening at each end.
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Tube-within-a-tube body plan has been achieved in two different ways in two evolutionary lines.
In one called the Protostomes, the first opening to develop in the embryonic digestive tube is the mouth; the anus develops later. This is seen in the annelid, mollusc and arthropod line. In the other, the Deuterostomes, the anus develops first and the mouth is formed later. This occurs in the Echinoderms Hemichordates and Chordates (including the vertebrates).
BODY CAVITY OR COELOM
– On the basis of coelom, animals can be
(i) Acoelomate : The animals in which the coelom is absent are called as Acoelomates, for example flatworms. In them the space between ectoderm and endoderm is filled with parenchyma eg. Platyhelminthes.
(ii) Pseudocoelomate : The body cavity is not completely lined with mesoderm. Instead, the mesoderm is present as scattered pouches in between the ectoderm and endoderm. Such a body cavity is called as pseudocoelom e.g roundworm.
(iii) Eucoelomate : The true coelom is a body cavity which arises as a cavity in embryonic mesoderm. In this case, the mesoderm of the embryo provides a cellular lining, called as coelomic epithelium or peritoneum, to the cavity. The coelom is filled with coelomic fluid secreted by the peritoneum. The coelom is found in Arthropods, Molluscs, Annelids, Echinoderms, Hemichordates and Chordates. True coelom is of two types : (a) Schizocoelom : It develops by the splitting up of mesoderm. It is found in annelids, arthropods and molluscs. Body cavity of arthropods is called heamocoel.
(b) Enterocoelom : The mesoderm arises from the wall of the embryonic gut or enteron as hollow outgrowths or enterocoelomic pouches. It occurs in Echinoderms, Hemichordates and Chordates.
Coelom Pseudocoelom
Coelomate Pseudocoelomate Acoelomate
Segmentation – In some animals, the body is externally and internally divides into segments or metameres with serial repetitionhttps://www.studiestoday.com of atleast some organs. For example, in earthworm, the body shows metameric segmentation and the phenomenon is known as metamerism.
Notochord
–Notochord is mesodermally derived rod-like structure formed on the mid-dorsal surface during embryonic development in some animals. Animals with notochord are called chordates and those animals which do not form this structure are called non-chordates, e.g., Porifera to Echinoderms or Hemichordates.
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BLOOD VASCULAR SYSTEM
–Blood vascular system is basically of two types : Open and Closed.
(i) Open type : In open type, the blood is pumped by the heart into the blood vessels that open into blood spaces (sinuses). There is no capillary system (i.e., most arthropods, some molluscs except cephalopods and tunicates). These sinuses are actually the body cavitites, and are called haemocoel. The pressure of the blood is low; it moves slowly between the tissues, and finally, returns to the heart via the opened veins. In fact, distribution of blood in the tissues is very poorly controlled. The pigments, which carry oxygen, remain dissolved in blood plasma. Body tissues and visceral organs exhange respiratory gases, nutrients and waste products, directly with blood.
(ii) Closed type : Many invertebrates and all the vertebrates, including humans, have a closed circulatory system. In closed type, the blood flows around the body through the specific blood vessels. In this system, the same blood regularly circulates in the body under high pressure, and returns back to the heart without leaving the system of tubes. The heart pumps the blood into the aorta, which branches in the body into the arteries, and in the tissues into the arterioles, to form the capillary network. The venules of the capillary network carry the blood back to heart via veins and vena cava. This helps in supplying the nutrients and oxygen to the tissues, and removing waste materials and caron dioxide from it reveals a comparison between open and closed circulatory systems.
Comparison of Open and Closed Circulatory Systems
Open System Closed System
These are usually low pressure systems. These are usually high pressure systems.
Blood conveyed directly to the organs without Blood is conveyed directly to the organs through formation of capillaries. capillaries.
Distribution of blood to different organs is not well Distribution of blood to different organs is well regulated. regulated.
Blood returns to the heart slowly. Blood returns to the heart rapidly.
Found in most arthropods, non cephalopod Found in cephalopods (octopus, squids) and mollusks and tunicates vertebrates.
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THE LIVING WORLD KINGDOMS
MONERA PROTISTA FUNGI PLANTAE ANIMALIA Unicellular Unicellular ; Multicellular ; eukaryotic ; Prokaryotic eukaryotic. no chlorophyll and no Eg. Bacteria, Phylum - Protozoa cellulose cell wall. PPLO Motility and sensitivity BRANCHES developed. MESOZOA PARAZOA EUMETAZOA Cillated cells only Cellular grade of organization. Tissue or organ-grade of Eg. Dicyema No obvious mouth and digestive organization. Mouth and (Minute worm like Cavity. digestive cavity present. Parasite of marine Phylum-Porifera (On the basis of Symmetry) Invertebrate) DIVISIONS RADIATA BILATERIA Tissue-grade. Radial symmetry Organ-grade. Bilateral Body cavity and digestive cavity Symmetry.Separate Common, Diploblastic digestive cavity, Triploblastic Phylum – Cnidaria (Coelentrates) Phylum – Ctenophora (Comb jelles) SUBDIVISION
PROTOSTOMIA DEUTEROSTOMIA Cleavage of zygote spiral and determinate. Cleavage of zygote radial and Indeterminate. Mouth from or near blastopore. Anus from or near blastopore. Mesoderm from primordial mesodermal Mesoderm from wall of archenteron. Cells. Coelom enterocoelic, or secondarily Coelom Schizocoelic. Schizocoelic.
SECTIONS ACOELOMATA PSEUDOCOELOMATA EUCOELOMATA Eucoelomata No body cavity Body cavity pseudocoel True coelom present
Phylum – Nematoda Schizocoel True coelom (Round worms) Hemocoel Enterocoel
Phylum – Platyhelminthes Phylum – Nemertes or Rhynocoela (Flat worms) (Ribbon worms)
Phylum – Annelida Phylum – Mollusca Phylum – Arthopoda https://www.studiestoday.com(Segmented worms) (Soft body in hard shell) (Jointed legs)
Phylum – Echinodermata Phylum-Hemichordata Phylum – Chordata (Spiny skinned) (Tongue-worm/Acorn worm) (Notocord)
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PHYLUM - PROTOZOA
–It is 3rd largest phylum. One celled performed all the biological activities like multicellular animals. So they are termed as ''Acellular'' organism, proposd by Dobell. – Protozoans were first studied by Leeuwenhoeck.
– And the name Protozoa was coined by Goldfuss.
– Study of protozons is known as Protozoology. – They are world wide, Cosmopolitan and mostly Microscopic, Aquatic, Terrestrial, free living (Amoeba) or parasitic (Plasmodium).
– Solitary or colonial (Proterospongia).
– Many causes serious diseases or pathogenic.
–Protozoans are samll microscopic, Eukaryotic Unicellular, Colourless, Spherical, Oval, Bell shaped, Spindle shaped slipper like having irregular Symmetry
– Level of body organisation of Protozoans is Protoplasmic level.
– Consists of uninucleate or multinucleate protoplasm mostly nacked or some have body bounded by delicate membrane or a firm pellicle/Test/Lorica/shell.
– In few groups of protozoa CaCO3 & Silica shell as exoskeleton is found. e.g. Radiolarian group & Foraminiferan group.
– Number of nuclei vary from one to many. Few show nuclear dimorphism. e.g. Paramoecium.
– Body performs all necessary biological activity so in them subcellular – Physiological division of Labour is found.
–Locomotion by means of (1) Finger-like Pseudopodia e.g. Amoeba (2) Whip like Flagella e.g. Euglena (3) Hairy cillia e.g. Paramoecium (4) By contraction (5) No locomotory organelles
–Nutrition of Protozons are mainly holozoic (Amoeba), Mixotrophic. (Euglena), Parasitic, Saprozoic (Plasmodium) and Digestion is intracellular take place in food vacuole. – Respiration and Excretion takes place by exchange of gases through body surface. Some excretion may occur through contractile vacuole.
– Nitrogenous waste is Ammonia.
– Some fresh water protozoans get rid of excess water through contractile vacuole and phenomenon known as Osmoregulation. Amoeba has one and Paramoecium has two vacuoles.
–Reproduction takes place by Asexual Sexual (1) Binary fission (Amoeba) (1) Syngamy (Plasmodium)
(2) Transverse fission (Paramoecium) (2) Conjugation (Paramoecium) (3)https://www.studiestoday.com Longitudinal fission (Trypansoma, Euglena)
(4) Multiple fission (Plasmodium) (5) Budding
Some also form cyst which help in unfavorable condition for reproduction of organism. They do not have natural – death because in unicellular animals there is no division of somatoplasm & germplasm so these are considered as immortal.
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https://www.studiestoday.com Hyaline layer
Plasmagel Ectoplasm Ectoplasm
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PHYLUM – PORIFERA (Common Name - Sponge)
WITNESS FEW COMMON SPONGES
– Ellias proved that sponges are animals.
– Robert Grant gave the name Porifera.
– Study of sponges is known as Parazoology.
– Phylogenetically evolved from choano flagillates (Proterospongia)
–Mostly marine but few are found in fresh water also. They are sessile, solitary or colonial. Entire body with pores i.e. numerous mouthlets Ostia and one opening for exit Osculum.
– Sponge have various body form and shapes i.e. Vase shape, cylindrical with radial symmetry (Leucosolenia)https://www.studiestoday.com, irregular shape (asymmetrical).
–Sponges have Cellular level of organisation with two germ layer i.e. Diploblastic and do not posses head and appendages.
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–Body wall consists of
(i) Outer Dermal layer or Pinacoderm
(a) Pinococytes (Flat cell)
(b) Porocytes (oval)
In case of Sycon pinacoderm is divided into exopinacoderm and endopinacoderm. Endopinacoderm lines the incurrent canal.
(ii) Inner Choanocytic layer or Choanoderm / Gastral layer
Collar cell or Choanocytes (Flagellated)
– Characteristic of Porifera
https://www.studiestoday.com– Choanocytes discovered by - H.J. Clark
(iii) Between these two layers gelatinous material Mesenchyme (Mesohyl) is present which is non-cellular. It Consist of Amoebocytes = gives rise to different types of cells of both pinacoderm and Choanoderm
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Scleroblast – For skeleton Spongioblast – For skeleton Thesocytes – For food storage (Glycogen) Phagocytes – To engulf by phagocytosis Trophocytes – For Distribution of food Amoebocytes Archaeocytes – Formation ova & spermatozoa (Totipotant cells) Collenocytes – Connective tissue cell Chromocytes – Pigmented Myocytes – Highly contractile (at osculum) Gland cells – Secrete shiny substance
Germ cells (Sex cells) – Form sperm & ova during breeding season.
BODY WALL OF PORIFERA
–Body wall enclose a large cavity the spongocoel or paragastric cavity.
Choanocytes with flagella is lined in Spongocoel and radial canal.
Ceaselless beating of flagella cause current of water which enter through ostia perforating porocytes and various canals and enters in spongocoel and finally leave through large aperature osculum.
–Canal system : Canal system of porifera helps in nutrition, respiration, excretion and reproduction. Canal are developed due to folding of inner wall. There are four types of canal systems.
https://www.studiestoday.com (i) Asconoid (Simplest canal)
Ingressing water Canal Spongocoel Osculum Ex. Lencosolenia, Olynthus
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(ii) Syconoid dermal ostia prosopyles Ingressing water incurrent canals radial canals
apopyles
osculum to outside spongocoel Ex. Scypha
(iii) Leuconoid (complex and most efficient canal system) Ingressing water dermal ostia incurrent canals prosopyles flagellated chambers
Apopyles
osculum to outside excurrent canals Ex. Euspongia Spongilla
(iv) Rhagon Ex. Larva of Demospongia
Osculum Ocsulum Mesoglea Ostium Appoyle Central cavity (spongocoel) Water curren Chamber Flagellated Central cavity collar cells
Asconoid Syconoid
Flagellated chamber Surface pore Subdermal cavity Excurrent canal Incurrent canal
Leuconoid https://www.studiestoday.com –Skeleton is internal, consist of tiny calcarious Spicules (calcoblast) or siliceous spicules (silicoblast) or fine spongin fibre (spongioblast ), or of both located in mesenchyme.
There are four types of spicules in sponges
(1) Monaxon (Usually at osculum) (2) Triaxon
(3) Tetraxon (4) Polyaxon [Hexa - radiated]
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Scleroblat secrets spicules and Spongioblast secrets spongin fibre.
–Digestive cavity and mouth is absent. Nutrition is holozoic. Digestion is intracellular and occurs in food vacuoles of choanocytes.
Food particle is taken by collar cell and pass them to amoebocyte.
Food is stored in thesocytes.
Distribution of food from ingestive cell to other is brought about by the movable amoeboid cell. - Trophocytes
–Respiration and Excretion takes place by diffusion of gases through body surface. Excretory matter is Ammonia. –Sponges do not have nervous system. –Reproduction takes place by means of
(i) Asexual - By Fragementation, Regeneration in sponges was demonstrated by Wilson. It is brought about by archacocytes. By Budding – Special cell mass Gemmules containing Archaeocytes. Also called as Endogenous budding and the process is known as Gemmulation.
(ii) Sexual - Sponges are Hermaphrodite, fertilization internal and cross fertilization, Protogynous condition is found .
Formation of ova & spermatozoa Zygote (From Archaeocytes) Fertilization – Internal, takes place in another sponge through water Cleavage – Equal and Holoblastic https://www.studiestoday.comcurrent Segmentation
Free living larva escapes from osculum Sponge (1) Amphiblastula hollow larva (scypha) Larva Parenchymula Solid larva (Leucosolenia) (2) Stereogastrula (Euplectella)
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PORIFERA
(On the basis Skeleton divide into three classes)
Classes Calcarea Hexactinellida Demospongia
Skeleton - Calcareous spicules 6 rayed siliceous spicular 1 or 4 rayed silicious spicules (Glass sponge) or sponging fibre or both
Small collar cells Choanocytes - Relatively large. Collar cells small
Inhabit - Exclusively marine in Exchesively marine and Marine or fresh water in deep or
shallow water inhabit in deepwater shallow water.
Canal system - Ascon or sycon type C.S. Leucon type Leucon/Rhagon
e.g. Leucosolenia Euplectella - (Venus flower *Spongia (Euspongia) - (Bath (smallest) basket, Bridal gift in Japan) sponge)
* Scypha (Sycon-Urn sponge Hyalonema - (Glass rope *Spongilla - (Fresh water sponge) sponge)
Leucilla Pheronema -(Bowl sponge) Ephydatia - (Sulphur sponge)
Clathrina Freshwater Cliona - (Boring sponge) harm Grantia ful to Oyster Hippospongia - (Horse-sponge or Horny sponge) Chalina - Marmaid's gloves Poterion - Neptune's Cup Oscarella - Skeleton absent Chondrosina – Skeleton absent Halichondria – Bread sponge Haliclona – Finger sponge
Proterospongia = connective link between Protozoa-Porifera
Largesthttps://www.studiestoday.com sponge – Spheciospongia
Hypothetical simple sponge & between larva & sponge – Olynthus
Shrimps – ( also called as Spongicola fish) A crustacean, shows commensalisms with Euplectella
* NCERT
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PLYLUM-COELENTERATA
– Leuckart coined name Coelenterate.
– Hatschek named Cnidaria on the basis of stinging cells. Peyssonal & Trembley established animal nature of Coelenterata.
– Cnidology-Study of cindaria – Mostly marine, few fresh-water (Hydra.) Carnivorous, some are fixed or free floating.
– Coelenterates have two types of forms (Dimorphic)
(1) Polyp (2) Medusa
- Cylindrical in shape - Umbrella like - Mostly sessile, but some are motile - Free swimming - May be solitary or Colonial - Always solitary - Types of structures : - - Types of structures : - Gastrozooids (Hydranth) - For Nutrition Phyllozooids - For Protection Dactylozooids - For Protection Nectophore - For swimming Gonozooids - For Reproduction Gonophore - For Reproduction Pneumatophores - For Swimming
Aurelia (Medusa) Adamsia (Polyp)
Either or both zooids may occur in a species.
If both forms are found in a group it is called Cormidia.
If both are found in a species, two form alternate in life cycle. (Alternation of generation or Metagenesis)
– Group of different types of zooids in polyp or medusa shows polymorphism.
– Coelenterates are usually having radial symmetry, Some Anthozoans have Biradial symmetry. – Coelenterates have two Germ layers (1) Ectoderm (2) Endoderm i.e. They are Diploblastic
– Coelenterateshttps://www.studiestoday.com have Tissue level of organisation.
– No head and appendages. The oral end (mouth) often bears slender, flexible process hollow tentacles.
– Body wall consists of -
(a) Epidermis (Outer layer) - Formed of 7 different types of cells.
Stinging cells or Nematoblast or Cnidoblast (for offence & defence) characteristic of coelenterata. Inject Hypnotoxin.
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Cnidoblasts : A – Undischarged ; B – Discharged discovered and regeneratin in Hydra.
– Interstitial cells (Totipotent and act as reserve to replace worn out cells/germ cells/Nematocyst) ; Epithelio - muscular cells ; Glandulo – muscular cells ; Sensory cells ; Germ cells
(b) Gastrodermis (Inner layer) - Formed of 5-different types of cells such as – Endothelia - muscular cells or Nutritive cells (with food vacuole) ; Interstitial cells ; Sensory cells ; Nerve cells ; Germ cells
Between these two layers, gelatinous Mesogloea is present which contain free cells. Mesogloea is secreted by both the above layers.
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– Body of coelenterates may be supported by horny or calcareous exoskeleton. – Cavity of the Coelenteron is having single aperture. Mouth serve both purpose i.e. incomplete digestion tract (Blind sac).
Digestion is Extra-cellular as well as Intracellular i.e. takes place in Coelenteron as well as food vacuole. Coelenteron is also responsible for distribution of food besides partly digesting it. This dual role named coelenteron as Gastrovascular cavity.
– Respiration and Excretion takes place by diffusion of gases through body surface.
Excretory matter is Ammonia.
– Nervous system present both in polyp & medusa and form a loose net work of nerve fibres on either side of mesogloea (Diffused type). Neurons are non-polar. Sensory cell are also present. Medusa have sense organ Rhopalia or statocyst/Tentaculocyst. –Sexes may be separate or united. Coelenterates can reproduce Asexually by Budding (Polyp) and by Sexually-(Medusa).
Gonads have no duct. Fertilization may be External or internal.
Cleavage is Holoblastic.
Development includes larva.
Larva of Obelia – Planula (free living) and scyphistoma larva fixed polyp like.
Larva of Aurelia – Ephyra , Scyphistoma
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Skeleton 3 - Stag-Horn coral - Brain coral - Skeleton absent - Sea anemone -sea penthe - Sea feather - Organ- pipe coral -sea fanthe - sea anemone - the star coral Anthozoa (Actinozoa) - Sea pansy - Mushroom coral - CaCO Pennatula coral) Anemones Coral Gorgonia Meandrina Adamsia Madrepora Pteroides Renilla Tubipora Alcyonium - Dead man's finger (Soft Corallium - Red coral (Moonga) Astraea Fungia Metridium Cnidoblast presentis in epidermis & Gastrodermis Gastro vascular cavity have compartment compartment have cavity vascular Gastro digestive tract escape via mouth mouth via escape tract digestive mesenteries i.e. Exclusively marine Only polyp form No manubrium Mesogloea contains cells & fibres the into gametes shed and -Endoermal Gonads * * * – – – – – Velum absent. – . – – e.g. This hasclass two types of animal (1) * (2)
Scyphozoa the Jelly fish, Moon jally, Larva - Ephyra Many mouth (Polystomum) Sun JellySun
Aurelia - * Exclusively marine small manubrium gametes into the digestive tract when cells. Medusa form more is common Velum absent. [Acraspedote] contains and gelatinous thick, is Mesogloea Cnidoblast present is in epidermis &
– – – Polyp form reducedor absentand have – – – Gastrovascular cavity undivided. – Gonads are Endodermal and escape through mouth. the shed – the Gastrodermis e.g Rhizostoma - Cyanea -
Coelenterata classified is into three classes -war. (Neurotoxic, -war. (Neurotoxic, of
https://www.studiestoday.comHydrozoa Freshpolyp water Little Little sail the sea fur, (Polyp, Blastostyles, the Portuguese man- the Portuguese metagenesis. Hydra - Obelia- & Medusa shows metagenesis) * Physalia- Physalia-
Bougainvillea Vellela - Millipora (Sting coral) Medusa havevelum a (Craspedote) Mesogloea Acellularis Gastrovascular cavity undivided. and Gonads are shed Ectodermal directly gametes Cnidoblast presentis only in epidermis Fresh water as well as marine Polyp& medusa often show polymorphism Polyps with manubrium – – – – water. surrounding the to in – * gland present) gas – – –
* e.g.
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PHYLUM – CTENOPHORA :
–Ctenophora name was given by Eschescboltz. Commonly called ‘‘Sea-gooseberries’’ or ‘‘Comb- jellies’’ or ‘‘Sea-walnuts’’.
– Nematoblasts are absent, so they are also called ‘‘acnidaria’’
– Exclusively marine and pelagic (float on sea surface) and show Bioluminescence.
– Body form may be spherical, cylindrical or Pear-shaped.
– Body is soft transparent jelly like having Biradial symmetry with tissue grade body organization.
– Triploblastic Mesoglea contains amoeboid mesodermal cells called Colloblast, Amoeboid cells and smooth muscle cell.
– Locomotion takes place by the presence of 8 ciliary comb plates on the body surface.
– Special sensory structure statocyst at the opposite end (absoral end) of the mouth is present. – Tentacles may be present or absent. When present, the number of tentacles are 2. They are solid and possess adhesive cells called as colloblasts (lasso cells).
– Digestion is both extracellular and intracellular. These are carnivorous animals
– The animals move by cilia, which join together to form comb plates, there are eight median comb plates forming locomotory organs.
–Resp. system, skeletal, circulatory & excretory system are absent. Nervous system is diffuse type.
–All animals are Bisexual. Complex type of sexual reproduction is found. Metagenesis is absent. Gonads = endodermal, Fertilization is external.
– Regeneration is normally found.
– Development is of indirect type. Life cycle involves a free living Cydippid larval stage.
– Cleavage is Holoblastic determinate and unequal.
– Asexual reproduction is absent.
– Regeneration & paedogenesis is normally found. Figure : Pleurobrachia
Ctenophora is divided into two classes on the basis of presence or absence of tentacles
TENTACULATA (Tentacles present) NUDA (Tentacles absent)
e.g.https://www.studiestoday.com *Pleurobrachia Beroe - Swimming eye of cat. Velamen Cestum – ‘‘Venus's girdle’’ *Ctenoplana – Commensal with Alcyonium. Hormiphora Euchlora rubra – with cnidoblast (Exception)
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PHYLUM – PLATYHELMINTHES :
– Gagenbaur suggested the name Platyhelminthes. Includes flat worms, free living (terrestrial, fresh water or marine) or parasitic.
– Study of worms causing parasitic infestation in human is Helminthology. Most members of this phylum are the parasites of vertebrate. Some are found in aquatic habitat.
– Body organisation is of organ and organ system level of organisation.
– Body is Triploblastic.
– Body is Bilaterally symmetrical. Ist bilateral animals.
– Anterior and posterior parts are clear. (Ist phylum to have cephalization).
– Locomotary organs are absent in these animals but adhesive organs are present like suckers, hook etc.
– Epidermis is syncytial and is some times ciliated. On the body wall of parasitic animals a thick cuticle is present which protects from the digestive-enzymes of the host. It is secreted by Epidermis.
– Muscles in the body-wall are mesodermal. Below the epidermis longitudinal, circular and oblique muscles are present.
– Nervous system is Primitive and ladder like having brain ring and 1-3 paired longitudinal nerves connected at intervals by transverse commissures. Sense organs occur in free living form.
– These are acoelomate. In between various organs a solid, loose mesodermal tissue called Mesenchyma or Parenchyma is present, which helps in transportation of food material.
– In Turbellaria and Trematoda classes an incomplete (Blind sac body plan and without anus) digestive systemhttps://www.studiestoday.com is present. In animals of class Cestoda, digestive system is completely absent.
– Skeleton and circulatory systems are absent. Turgidity of the fluid in the parenchymal meshes maintains the form of the body (Hydroskeleton)
– Animal respire through body surface. Anaerobic respiration in internal parasite like Taenia.
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– Excretory organs are protonephridia or flame-cells. Flame - cells are also termed as the Solenocytes. They also help in osmoregulation.
Nucleus Cytoplasmic processes
Excretory globules Basal granules
Cell body or flame bulb Flagella
Intracellular canaliculus Excretory capillary
Fig. A flame cell
– All animals of this phylum are Bisexual except Schistosoma (blood fluke). Reproductive system is complex and well-developed. Fertilization may be self or cross and internal. Cleavage is spiral & determinate.
– Development may be direct or indirect. In indirect development, larva may be one or of more types. In these animals yolk/vitelline glands are present which provide nutrition to the eggs.
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(a) (b)
Figure Platyhelminthes : (a) Tape worm (b) Liver fluke
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Divided into three classes
Turbellaria Trematoda Cestoda
– Free living fresh water or – Endo-Parasite, known as flukes, Endo-Parasite Intestinal parasite, marine known as Planarians or or flat worms. – known as tape worms Eddy worm.
– Body is unsegmented and leaf – Body-Unsegmented and leaf – Body-Ribbon like, covered by like covered by delicate ciliated like, covered by tegument, tegument. No epidermis in epidermis.Rod shaped Rhabdites (Fine spines) No epidermis in adult in epidermis. adult.
– Mouth is often ventral and anus – Mouth - anterior & anus is – Mouth and Anus absent (food absent. Alimentary canal is absent. Alimentary canal- from body surface). Alimen present. (Branched) branched. tary canal absent.
– Reproduction - asexual sexual – Life history - includes larval – Life history - includes larval and shows good power of stage & involve, more than stage & involve, more than regeneration, no larva. one host. one host. Each proglottids has
one or two sets of male & Suckers - absent – Suckers - for attachment in the – female reproductive organ. host Scolex has suckers & hooks e.g. e.g. – for attachment * Dugesia (Planaria) - fresh water, *Fasciola (Sheep liver flukes) – Body divided into scolex, neck Nocturnal, Cannibalism, slow Cause liver rot disease and strobilla of few to creeping omnivorous. Sexual Prim. Host - Sheep & Goat numerous proglottids. No true as well as asexual (Transverse Sec. host – Snail (Planorbis ; segments Binary fission), good power of Limnea ; Bulinus) *Taenia solium - Pork tapeworm regeneration. Pharynx can be Show polyembryony , Life- Prim. Host = Man (cysticercus everted. Reproduction cycle involves, Micacidium, in the infective stage) Sporocyst, Redia, Cercaria and Sec. Host = Pig (Concosphere is Microstomum - Enemy of Metacercaria larval form the infective stage) Hydra Miracidium (free-swimming Shows multiplication in larva Gunda larva). stage namely Convoluta - Symbiont on Schistosoma (the blood flukes) – Oncosphere, Hexacanth, Zoochlorella and Diatoms, algae. Paragonimus (Lung fluke Bladderworm and Cysticercus. worm) (In lungs of man and Causes disease Taemiasis or pig) Cysticercosis. Diplozoon - Ectoparasite on Taenia saginata - Beef tapeworm the gills of fish. (Monogenetic) Echinococcus - Dog tapeworm Opisthorchis - Human liver Hymenolepis - Smallest tapeworm fluk or chinese liver fluk in man's intestine - 10 cm, 200
https://www.studiestoday.com proglottids (Monogenetic) Moniezea - Endoparisite of ruminates
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PHYLUM - ASCHELMINTHES (NEMATHELMINTHES OR NEMATODA) : – Grobben gave the name = Aschelminthes – Gagenbaur nameditas as Phylum Nemathelminthes. Phylum includes round worms.
– Aquatic, tarrestrial, free-living or parasites.
– Animal of this phylum are Cylindrical, tapering at both end without segmentation.
– Bilaterally Symmetrical - Triploblastic, Organ-system level and having tube within tube plan.
– Anterior end does not show distinct head.
– No appendage.
– Body wall consist of
Cuticle - Firm, non living, resistant to digestive enzymes of host.
Moult (changed) many times during growth period (usually four times).
Epidermis - Syncytial
– Muscle layer - Longitudinal fibres divided into four quadrants. (each with 150 muscle cells)
– Body cavity is Pseudocoel (developed from blastocoel) and contain Pseudocoelomic fluid.
– High fluid pressure in the pseudocoelom maintains body shape. It is called Hydroskeleton. https://www.studiestoday.com – Digestive tract is complete and differentiated into mouth, pharynx, intestine & Anus. Mouth is surrounded by 3 - lips having sensory papillae and amphids. Pharynx is muscular. It is used to suck food. Intestine is non muscular.
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– Respiration is through body surface by diffusion.
– Circulatory system is undeveloped
– Nervous system comprises of circum pharyngeal ring (Brain).
– Sense organs like Papillae (Tangoreceptors), Amphids (chemoreceptor) are present on lip. Paired unicellular Phasmids (chemoreceptor) are found near hind end of body.
– Excretory system is H-shaped formed by single cell called Renette cell. Excretory substance is ammonia.
– Reproductive system is developed and sexes are generally separate. Sexual dimorphism is present.
Male is smaller than female and curved from its caudal end.
Male has penial spicule for copulation. Genital tract joins digestive tract to form cloaca.
Female is larger than male and straight. Genital tract open independently. Female lays numerous eggs with Chitinous shell.
Fertilization is internal and development is mostly direct.
Cleavage is Holoblsatic spiral and determinate type.
Number of cells are fixed from larva to adult such development is known as Eutely.
CLASSIFICATION :
On the basis of caudal receptor or phasmids, Aschelminthes can be divided into 2 classes-
https://www.studiestoday.com Aschelminthes Class
Aphasmidia Phasmidia
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Class–Aphasmidia
– Members of this class lack phasmid.
– Many types of amphids are found.
– One pairs of excretory canal are present.
– Caudal adhesive glands are found.
Ex.
Enoplus , Desmoscolex , Trilobus , Lapillaria
Class–Phasmidia
(i) Phasmid is present.
(ii) Caudal adhesive glands are not found.
(A) Male, (B) Female
Ex – Ascaris*
– It is parasite of small intestine.
– It is also called roundworm.
– Rhabditiformhttps://www.studiestoday.com larva exists in the life cycle of Ascaris.
– Ascaris leads to disease called Ascariasis.
– Infective stage of Ascaris to man is embryonated egg with 2nd stage juvenile.
– Trichinella spiralis (Trichinia worm) : occur in voluntary muscles cause trichinosis.
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– Trichuris trichiura
– It is also called whipworm.
– It is parasite of large intestine of man.
– No larval stage in the life cycle.
– It leads to anaemia and Diarrhoea.
Enterobius
– It is also called pinworm or seatworm.
– It is parasite of human intestine.
– It causes enterobiasis.
– No intermediate host.
*Ancyclostoma
– Cause - Ancyclostomiasis.
– It is also called hookworm.
– Its larva penetrate through sole of the person.
– Live in intestine and suck tissue fluid.
*Wuchereria
– It is also filaria worm.
– Its life cycle gets completed in two hosts. Man is the primary host, while female culex/Aedes mosquito is the secondary host.
– It leads to a disease called Elephantiasis.
– Adult worm blocks lymph duct this leads to swelling of limbs.
– Females are ovoviviparous. Female lays juvenile microfilaria.
– Infective stage to man is microfilarae.
Dracunculus
– They are also called Guinea worm and also referred to as “fiery serpent”.
– They are digenetic, man is the primary host while waterflea (Cyclops) is the secondary host. https://www.studiestoday.com – Completely eradicated from India (eye worm)
Loa-loa (eye worm)
– Found in subdermal connective tissues. Some times they pass across eye ball.
– Tabanas fly act as vector.
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PHYLUM – ANNELIDA : – Lamarck coined the term Annelida.
– Free living found in moist soil, fresh water, sea or few are parasite.
– Body is Soft, elongated, cylindrical or flattened divided into segments or metameres by ring like, grooves called Annuli.
– Symmetry – Bilateral, Triploblstic, Organ-system level having tube within tube plan, metamerically segmented.
–Anterior end forms a distinct head with sense organ in few annelids.
–Appendages are simple unjointed, and locomotory having Chitinous Setae and Parapodia with setae. –Body wall consist of
(i) Cuticle – Thin moist albuminoid cutical allow free exchange of gas.
(ii) Epidermis – Single layered epidermis made up of supporting cell, sensory and glandular cell.
(iii) Muscle layer – (1) Circular layer, (2) Longitudinal layer. Muscle are smooth/unstriated.
Body wall may have minute chitinous setae.
– Locomotion by means of setae or parapodia or both. Absent in leeches
– First Protostomi animals.
Body cavity is true coelom lined by mesodermal coelomic epithelium (Schizocoel.)
It is divided by transverse septa into compartment. It is filled with coelomic fluid that contains cells.
– As such there is no Skeleton. Fluid filled coelom serves as a hydrostatic skeleton. – Digestive tract is complete, straight and extends through entire body. The gut has both circular and longitudinal muscles. Few annelids are sanguivorous. Digestive gland are developed for the first time in Annelida.
–Respiration is through moist skin i.e. Cutaneous respiration. Some have gills (branchial respiration).
–Circulatory system is closed. Some blood vessels enlarge to act as pumping heart. (Heart appear first time in annelids) The blood is red with haemoglobin dissolved in plasma (Erythrocruarin). It has amoeboid corpuscles only.
– Few Annelids like Sabella have Chlorocruarin as a respiratory pigment.
– Hirudinaria has circulatory system with haemocoelomic system.
– Excretory organ is Nephridia. Coiled tubules also helps in osmoregulation. NEPHRIDIA
https://www.studiestoday.com Exonephric Endonephric
Integumentary – Pharyngeal nephridia Nephridia – Septal Nephridia
Excretory matter (1) Ammonia in aquatic form (2) Urea in land form
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– Nervous system consist of a circumentric nerve ring, double, midventral, nerve cord with ganglia. Sense organ chemoreceptor, photoreceptor & tentacle, palp, eyes may be present.
–Sexes may be separate or united. Asexual reproduction by budding or fission. In some cases. Atoke (asexual), Epitoke (sexual) phenomenon also found (Nereis). – Cleavage is spiral and determinate unequal & holoblastic. Regeneration is usually found. Life history includes a trochophore larva in few annelids.
Nereis Inhabits in sea - shore between tide mark, burrower, nocturnal, carnivorous, gregarious, fertilization - in sea. Parapodia in each segment except first & last. During breading body divides in two parts. Anterior asexual part - Atoke and posterior sexual portion Epitoke. This change is known as epitoky.
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Based on presence or absence/of Parapodia, Setae and Sense organs
Polychaeta Oligochaeta Hirudinea Archiannelida Echiuridia
1. Almost all are marine 1. Most of the members 1. Aqatic, terrestrial, 1. All Marine – without external and are terrestrial, but ectoparasite and internal segmentation. some are aquatic. sanguivorous.
2. Cephalisation is more 2. Cephalisation absent. 2. Cephalisation absent. 2. Cephalistion absent. – Seate are rare and distinct. Head with No distinct head, No distinct head, No distinct head, usually have long well developed eyes, eyes, tentacles and eyes, tentacles and eyes, tentacle present prostomium tentacles and olfactory olfactory palps. olfactory palps. and olfactory palps. or proboscis.
palps. e.g., Bonelia, Echiuris
3. Setae numerous and are p 3. Setae for locomotion. 3. Parapodia and seate 3. Parapodia and setae parapodia helps in Number of seate is are absnt. Suckers at are absent. locomotion and also limited and situated both the ends. in respiration. Suckers in setal sac present
are absent. in body wall, a single setae is present
in a bag. Parapodia & sucker are absent.
4. Clitellum absent 4. Clitelium is present 4. Clitellum 4. Clitellum absent. permanently for (9-11 segments) cocoon formation. develop only in Fertilization is external breeding season. and is held in cocoon.
5. Animals unisexual 5. Bisexual or 5. Animals of this class 5. Animals are unisexual and gonads are formed hermaphrodite are bisexual. Fertili- only during breeding cross fertilisation & zation is external.
season. external.
6. Development is 6. Development is 6. Development is 6. Development is indirect. Larval stage is direct. No larva. direct. indirect. Larval stage called Trochophore. is called Trochophore.
– Segmentation is e.g. – Number of segments Mainly intermal e.g.*Nereis – Sand are fixed ie. 33 *Pheretima worm/clamworm segments. Each Eutyphaeus Aphrodite - Sea segment subdivided Lumbricus mouse – into numberous European earthworm Arenicola - Lug rings. called Dravida worm ''Secondary external Megascolex Seballa - Peacock – annulation'' Largest earth worm worm – Anticoagulant (S. India) Chaetopterus - Hirudin – in the saliva Dero – Fresh watered paddle worm – Saw like chitinous e.g Polygordius Nais Fresh watered – Shows bio- – teeth in buccal cavity Tubifex Blood worm Connecting-link florescence, – Circulation with (Fresh water) between Annelida great power of haemo-coelomic Indicator of organic & Mollusca (living regeneration. system. loading fossil) Larva known Eunice - Palalo – Coelom is divide in https://www.studiestoday.com as Loven's Larva worm tubes having coelomic Polynoe - Scale fluid and haemoglobin. Protodrillus worm A special mesodermal Dinophilus Terebella - tissue Botryoidal tissue Nerilla
respire by gills made up of adipose Glycera – Smooth tisssue for fat storage / blood worm supposed to be excretory.
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e.g.*Hirudinaria – Fresh water leech Pontobdella – Skate sucker. Hirudo – Medicinal leech (Highly modified) Glossiphonia – Fresh water leech Haemadipsa – Terrestrial leech Haemopis – Horse leech Acanthobdella – Extroparasite with setae connecting-link between oligochaeta – Hirudinea
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PHYLUM – ARTHROPODA :
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–It is the largest phylum in the animal kingdom, including 900,000 species. The largest class is insecta with 750,000 species. General characters are
– They are triploblastic coelomate and bilaterally symmetrical animals.
– The body cavity is full of haemolymph (blood) and it's known as haemocoel. The true coelom is restricted to gonals. – The body is covered by chitinous cuticle, which forms the exoskeleton. Strengthen by deposition of minerals (Cal. Phosphate & Carbonate).
– They have a segmented body, each segement bearing a pair of jointed appendages covered by a jointed exoskeleton.
– Exoskeleton is made of chitinous cuticle that is shed at intervals.
– The process of casting off of skin or integument is known as ecdysis or moulting. Chitnnous exoskeleton is secreted by the underlying epidermis.
– The body is divided into head, thorax and abdomen. In some cases the head and thorax is fused to form cephalothorax. In insects the thoracic segments have legs and wings, the abdomen has no legs in insects.
– Muscles are striated. – Respiratory organs are gills, book gills, book 1st time developed in Arthropoda. lungs or tracheal system.
– Excretion takes place through green glands or malpighan tubules coxal gland.
– Excretory matter = Ammonia (Aquatic) ; Uric Acid (Terrestrial) Nephridia (Perpatus)
– Sensory structures in arthropods are antennae for perceiving odour, eyes, statocysts or balance organs and sound receptors (in chirping crickets and cicadas). Eyes are compound. In honey bees, butterflies and months and insects, the gustatory receptors are present on their feet.
– The heart is dorsal pulsatile, many chambered and the circulatory system is open (Haemocoel). Blood haemolymph colourless.
– The central nervous system consists of a circumentric ring formed by paired pre-oral ganglia connected by commissures to a solid, dorsal ganglionated, ventral nerve chord.
– In land arthropods, the fertilization is always internal. Few aquatic has external fert.
– Arthropods are oviparous. In some like the scorpion, the eggs hatch within the female body. They bring forth the young ones alive. They are viviparous.
Advancement Over Annelida
– Distinct-head in all species.
– Jointedhttps://www.studiestoday.com appendages serving a variety of functions. – Jointed exoskeleton for protection and muscle attachment.
– Striped muscles arranged in bundles for moving particular parts.
– Special respiratory organs such as gills, trachea, book lungs in majority of cases.
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– Endocrine glands and pheromone secretion for communication
CLASSIFICATION :
–The phylum arthropoda is divided into five classes.
Class 1. Crustacea
– The body is divisible into cephalothorax (head + thorax) and abdomen.
– Dorsally, the cephalothorax is covered by a thick exoskeletal carapace.
– There are present two pairs of anternnae and a pair of stalked compound eyes.
– Respiration is carried out either by body surface or by gills.
– Excretion takes place usually by antennary glands ( = green glands)
– Sexes are usually separate. Sexual dimorphism is also seen.
– Development is usually indirect
Examples : Palaemon (Prawn), Macrobrachium (Prawn), Atacus (Cray fish), Palinurus (Lobster), cancer (Crab), Lucifer (Shrimp), Eupagurus (Hermit crab), Oniscus (wood louse), Daphnia (Water-flea), Cyclops, Balanus (barnacle). Tiny crustaceans such as Daphnia and Cyclops act as zooplankton which form important link in the food chain in water.
Class 2. Chilopoda
– Body is long and segemented, which is divisible in to head and trunk.
– Each trunk segment bears a pair of legs. The first pair of legs are modified in to poison claws.
– There is a single pair of antennae and ocelli.
– There are present many legs.
– Respiration occurs by tracheae.
– Excretion takes place by Malpighian tubules.
– Development is direct
Examples : Scolopendra (Centipede)
Class 3. Diplopoda
– Body is divisible into head, thorax and abdomen.
– There is a single pair of antennae and ocelli.
– Except first thoracic segment, (It does not have legs) each thoracic segment bears a pair of https://www.studiestoday.com legs, however each abdominal segment has two pairs of legs
– Respiration occurs by tracheae
– Excretion takes place by Malpighian tubules
– Development is generally direct e.g. julus (Millipede)
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Class 4. Insecta (Hexapoda) [Largest number of species]
– Body is divisible into head, thorax and abdomen.
– There is a pair of antennae, and a pair of compound eyes.
– The thorax consists of three segments with three pairs of legs and usually two pairs of wings. Mesothorax has thick and leathery false wings called as tegmina and membranous metathoracic wings.
– The abdomen may consists of ten segments.
– Respiration usually takes places by tracheae. (No respiratory pigments).
– Heart is tubular and divided into chambers
– Malpighian tubules are the excretory organs. Uric acid is chief excretory waste.
– Sexes are separate.
– Development may be direct or indirect e.g. silverfish, cockroach, bedbug, locust, termites, butter flies, rat flea, beetle , wasp, aphid, glow worm etc.
– Maggot is the larva of Housefly Insects communicate with each other by ectohormone called as Pheromones. Pheromones are chemicals secreted to the outside of the body and perceived (as by smell by other individuals of same species). They help in communication amongst the organisms of same species.
Ex. Musa domestica – House fly
Tachardia lacca (Lacifer) – Lac Insect
Dactylopis – Cochineal bug
Lytta – Blister Beetle https://www.studiestoday.com Apis – Honey bee
Bombyx – Silkworm
Anopheles
Culex Aedes Locusta – (Locust)
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The insects may be divided into four groups on the basis of their mode of development. – Insects without Metamorphosis (Ametabolous Development). Certain insects, such as silver fish, does not undergo metamorphosis. These insects are most primitive and wingless. There are present three stages in the life history; egg, young and imago (adult) – Insects with gradual Metamorphosis (Paurometabolous Development). In this type of metamaophosis, the life history includes egg, nymph (young) and imago (adult). The nymph resembles the adult in its mode of life but differs in structure, the young being without wings. Gradual metamorphosis. Occurs in cockroaches, grasshoppers, locusts, termites, stick insects, praying mantis, bed bug and lice. – Insects with incomplete Metamorphosis (Hemimetabolous Development). In this type of metamorphosis the life history includes egg, naiad (young) and imago (adult). The naiad differs from the adult in both mode of life and structure. Incomplete metamorphosis occurs in dragon flies and may flies.
– Insects Complete Metamorphosis (Holometabolous Development). In this type of metamorphosis the life history includes egg, larva, pupa and imago (adult). Complete metamorphosis occurs in butterflies, moth, beetles, house flies, mosquitoes, fleas, honey bees, ants , wasps. The larvae of butterflies and moths is called caterpillar. The larva of houseflies is known as maggot. The larva of beetles is termed grub and the larva of mosquito is called wriggler. The young one formed after every moulting is called as instar. The period between two molting is stadium.
– Hypermetabolous. Each larval stage differs from the others in habits, food and mode of living e.g. Blisterbeetle
Type of Mouthparts in insects
–Generally mouth parts of an insect are one labrum, one labium, one hypopharynx, two mandibles and two maxillae. Following type of mouth parts are found is insects.
– Biting and chewing type e.g., Grass-hooppers, cockroaches and crickets.
– Piercing and sucking type.e.g. mosquitoes, bedgugs
– Chewing and lapping type. Lap means to drink by scooping with tongue and lapper is that which laps liquid e.g. honey bees.
– Sponging type. eg. House fly. (Musca domestica.) It lacks mandibles. Feeds on sugar by dissolving in saliva and sucking.
– Siphoning type e.g. Butterflies and moth. Here the proboscises formed by the modification of maxilla.
Lac Insect
– Lachttps://www.studiestoday.com is produced commercially by an insect Tachardia lacca (Laccifer lacca).
– Lac is actually secreted for its protection and not for the food of the insect.
– Male insects are winged and structurally complete, but females are degenerated.
– Lac or shellac is an exuviate (secretion) of mainly female.
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Cochineal Bug
– Dactylopis cocccus lives upon cactus. Dead and dried bodies are used for making a dye called cochineal dye.
Blister Beetle
– Lytta is a genus of blister beetle. The drug cantheridine is prepared from its blood.
– Cantheridine is widely used for healthy growth of hair
Red Ants
– Red ants are used for the production of formic acid.
Glow worm
Wingless female and larva of certain beetles like Lymphyris notiluca which emits greenish light. Also yields luciferin
Honey Bee : A hive consists of a vertical sheet of wax with a number of hexagonal cells for rearing young bees (brood cells), storing food (storage cells), royal chamber and chamber of themselves.
Bee is a social, polymorphic and colonial insect. It has three main castes – queen, drones and workers. https://www.studiestoday.com Queen is the only fertile female of the colony which continues to lay eggs for 2–5 years.
Drones are male honey bees. They develop from unfertilized eggs. Drones and virgin queens take part in nuptial flight. After copulation the drones are not allowed to come back into hive.
Workers are sterile females.
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Scout bees search for food and intimate the same to worker bees by dances-round dance for less than 75m and tail wagging dance for longer distances.
Prof. karl von Frisch got Nobel prize 1973 for decoding the language of bee dances. Workers have pollen collecting apparatus, honey storing mechanism and wax secreting glands.
Young workers secrete royal jelly. Royal jelly is given to queen or potential queens.
Honey contain simple sugars (fructose and levulose), Vitamins and minerals. It is a tonic, laxative and sweetening agent. True product of honey bee is bees wax.
Class 5. Arachnida
– The body is usually divisible into cephalothorax and abdomen.
– The cphalothorax bears simple eyes and six pairs of appendages (One pair of chelicerae, one pair pedipalpi and four pairs of legs)
– Antennae are absent.
– Respiratory organs are book lungs or trachea or both
– Excretion takes place by Malpighian tubules or coxal glands or both https://www.studiestoday.com – Development is generally direct.
Examples : Scorpion, spider, Tick, Mite, Aranaeus (garden spinder), Palamneus (Scorpion), Buthus (Scorpion)
– Spiders spins the web by means of a secrection of abdominal glands.
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– There are two more classes in the phylum Arthropods. These classes are Onychophora and Merostomata. Peripatus is an important examples of the class Onychophora, which has characters of Phylum Annelida and Arthopoda. Hence it is called "connecting link" between annelida and arthropoda . It breathes by trachea.
– *Limulus. (the king crab or horseshoe crab) is good example of class Merostomata which respires with book gills. The king crab are called "living fossils". A living fossil is a living animal of ancient origin with many primitive characters.
– Larvae of different Arthropods
(a) Bombyx (Slikworm) Caterpillar / Silkworm (b) Beetles, honey bee Grub (c) Musca (Housefly) Maggot (d) Culex, Anopheles Wriggler (e) Pennaeus (Marine prawn) Mysis, nauplius, protozoea (f) Cancer (Crab) Megalopa metanauplius, zoea – Arthopoda is the biggest phylum. About 9,00, 000 species are there . Largest class is insecta. – Von Siebold established phylum Arthoropoda. – Arthopods are Aquatic (Freshater/marine), Terrestrial, burrower, parasitic.
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PHYLUM – MOLLUSCA : – It is second largest Phylum.
– Mollusca (Soft bodied) are marine or fresh water or terrestrial. Johnston coined the name Mollusca.
– Study of this phylum is known as Malacology & study of shells of molluscan is known as Conchology.
– Body is unsegmented with variety of shapes. Neopilina is exceptionally segmented. (connecting link).
– Molluscs are usually bilateral. Few are secondarily asymmetrical (snail) due to twisting (Torsion) during growth.
– Triploblastic with Organ system level.
– Body wall includes one layered epidermis (usually cilited) with unstripped muscles found in bundles.
– Body parts consist of
(i) Head with sense organ. Head is absent in Pelecypoda & Scaphopoda.
(ii) Dorsal visceral mass containing organ system.
(iii) Ventral foot for locomotion.
(iv) Thin fleshy fold or outgrowth of dorsal body wall covers the body. This fold is called mantle or pallium. It encloses a space mantle or pallial cavity between itself and the body. The mantle usually secretes an external limy shell. Shell is made up of Calcium carbonate and Concheolin protein.
Shell may also be internal (Cuttle fish), reduced and even absent (Octopus)
– Coelom is greatly reduced. It is represented by cavities in the pericardium, kidneys and gonads. Space among the viscera contain blood and form haemocoel.
– Digestive tract is complete. Buccal cavity contain a rasping organ the Radula, with transverse row of teeth.
– Anus opens into the mantle cavity.
– Digestive glands are known as hepatopancreas.
– Respiration is usually by gills i.e., Ctenidia. But respiration may takes place by body surface also. Dentalium respire by Mantle.
– Pila respire by pulmonary sac on land and by gills in water.
– Circulatory system is open. It includes dorsal pulsatile heart and a few arteries that open into sinuses. Cephalopoda has closed type of circulatory system Bloodhttps://www.studiestoday.com has a copper containing, blue respiratory pigment Haemocyanin. Blood is colourless with amoebocytes. – Excretory system includes 1 or 2 pairs of sac like kidneys, which open into the mantle cavity. Kidney of molluscans are Metanephridia known as Kaber's organs or Organ of Bojanus. Excretory matter is ammonia or uric acid.
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– Nervous system comprises three paired ganglia
(1) Cerebral (above the mouth) (2) Pedal (In the foot) (3) Visceral (in visceral mass)
These are inter connected by (1) Commissure (Joins similar ganglia)
(2) Connectives (Joins dissimilar ganglia)
Senses organ includes (1) Eye - Present over a stalk called ommatophore (Gastropoda).
(2) Statocyst/Lithocyst - For equilibrium in foot
(3) Osphradia - Chemoreceptor/Olfactory as well as for testing chemical & physical nature of water.
– Sexes usually separate (snail has ovotestis). Gonads have ducts.
– Fertilization may be external or internal.
– Cleavage is spiral, determinate, unequal and holoblastic.
Development is - Direct or indirect.
Trochophore is very common larva of Mollusca phylum.
Larva - Glochidium (Fresh water mussel) and Veliger (Pila)
Precious pearl of the size of tennis - ball is made by a mollusk - Tridekna
‘‘Nacre layer’’ is called ‘‘Mother of Pearl’’. This layer is made up of CaCO3 and choncheolin protein.
Father of pearl industry - Kokichi Mikimoto
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Molluscs are classified on the basis of shell, Foot, Nervous system and Gills into seven classes
Dorsal shell opening Apex of shell Penultimate whort Sutures
Body-whort Peristome Shell Lines of Operculum growth or Varices Umbilicus Outer lip Inner of Captacula columellar lip GASTROPODA Foot (PILA) SCAPHOPODA (DENTALIUM)
Calcareous Mantle edge spicules Umbo Hinge ligament Lines of growth
Calcareous shell plates
Foot Left shell value PELECYPODA (UNIO) POLYPLACOPHORA (CHITON)
Left shell value
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OCTUPUS
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e.
*
Cuttle fish Cuttle Sea-fly Sea-fly Squid Squid - Present Present - Cephalopoda - Modified into a funnel funnel a into Modified - Sepia- ell-Internal and reduced it it reduced and ell-Internal Octopus Devil -
oot 0 arms having having arms 0 Chromatophores. Chromatophores. - Tethys - Loligo absent) (Radula * - Marine Marine - Sh (Nautilus) external be may (Octopus) or absent Redula F sucker 10 or 8 into and partly surround that arms bearing the mouth by expelling is Locomotion siphon through in jet water propulsion). (Jet squids in some glands Ink defense. and offense for attacked, is the squid When fluid of inky a cloud emits it This siphon. its through interferes 'smoke screen' and vision with the chemoreceptors thereby and predator the of to escap squid the helps blood Closed - circulation. for Hectocotyle - transfer sperm absent Larva - e.g. 1 arms 8fish Tiger Nautilus - shell
-mussel -mussel - -Highest economic economic -Highest -Mussel (marine) (marine) -Mussel -Absent -Absent - worm. -Ship - Scallop Scallop - - pearl Indian - Bivalvia or - Pelecypoda -Consist of two valves valves two of -Consist -Mussel (fresh water) water) (fresh -Mussel amellibranchiata Pinctada oysters. Pearl nio L - Marine/fresh water water Marine/fresh - Head Shell Absent dorsally. hinged Movably Redula Mytilus Lamellidens Ostrea Teredo Foot-Plough or Wedge or Wedge Foot-Plough burrowing for shaped Redula absent Larva Trochophore Glochidium e.g. U * Pteria oyster. Tridekna value Pecten
* p Shankh Shankh Ap Land snail snail Land Old currency currency Old
Land snail snail Land – - Sea hare Sea -
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T - - - absent. absent. - - Conical and use use and Conical - Scaphopoda ot Dentalium- shell. usk Redula Fo Present - Marine - Marine Head Shell-Tubular, open at both end. Trochophore e.g. * for digging digging for Larva (Respire by mantle) mantle) by (Respire
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– -The coat of mail shell mail of coat -The
Amphineura -Trochophore -Trochophore
- - Present or absent. 8 Polyplacophora/ - Marine Marine - Head tentacles. and eyes Shell without reduced - present. plates dorsal (Multivalved) Radula Foot Present Reduced/absent. Larva e.g. Chiton (Sea-mica) Chaetopleura-
Trochophore Trochophore - Absent. Absent. - -Small without eyes eyes without -Small Aplacophora -Reduce/absent. -Reduce/absent. Neomenia Neomenia
https://www.studiestoday.comlike Worm Marine, - Head & tentacles Shell Redula Foot Present - Larva- e.g. -
- Present Present - - Trochophore Trochophore - - Indistinct Indistinct - - - Dome-shaped Dome-shaped -
Mollusca and only only and Mollusca adula adula Neopilina Neopilina
Monoplacophora R Foot muscular Flat Larva e.g. - fossils Living of link Connecting and Annelida mollusk segmented nephridia. with
common Marine, - Annelida of character and Arthropoda. H Shell ead mantle. with 45 Downloaded from https:// www.studiestoday.com
PHYLUM – ECHINODERMATA :
– Name Echinodermata was given by Jacob Klein.
All are Marine except Synapta similis.
Generally live at bottom and slow moving.
– Body shape is star like, cylindrical like, melon-like, disc-like, flower like.
– Body unsegmented with bilateral symmetry in larva and radial pentamerous (arranged in five or multiple) in adult.
Echinoderms are triploblastic with organ - system level of organization
– Echinoderms do not have head. Tube feet (podia) which comes out through radial area i.e. Ambulacral used for locomotion. They are extended and retracted by variation in hydraulic pressure of fluid in them and by contraction of their muscle.
– Body wall of echinoderms consists of
(i) Epidermis - Single layered & ciliated.
(ii) Dermis - Below the epidermis thick dermis having mesodermal endoskeleton of calcareous plate (Ossicles). It has spines.
(iii) Muscles - Smooth and lie below dermis. Minute pincerlike structure pedicellariae comes out through skin. They keep body surface clear of debris by opening & closing. These are made up of three calcareous plates.
– Echinoderms have true Coelom lined by ciliated mesothelium. Enterocoelous contain fluids with free amoeboid cells called coelomocytes.
– Coelom is divided into many tubes and sinuses, which together form 3 systems.
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(i) A unique water filled ambulacral or water vascular system with tube feet to help in locomotion. A perforated plate madreporite permits entry of water into ambulacral system which also help in food and gas transport system. Structures like Pollian vesicle, tiedmann body or recemose, stone canal are also found in water vascular system.
(ii) Haemal system.
(iii) Perihaemal system.
– Respiration takes place by gills called dermal branchiae or papulae in most of Echinoderms like Starfish, genital bursae in Brittle star, cloacal respiratory trees Sea- Cucumber, Peristomial gills - Sea urchin. tube - feets also helps in respiration in all Echinoderms
– Digestive tract is complete, (incomplete -brittle star). Circulation system is reduced and open type called haemal system /Perihaemal system. No heart or pumping vessel.
– There is no specialised excretory organ system. Nitrogenous waste (ammonia) diffuses out via gills, bursae, respiratory tree and tube feet. Amoeboid cells in coelomic fluid also perform excretory function by absorbing excretory matter.
– Nervous system is simple and primitive type includes a Nerve ring and radial nerve cord with simple sense organ. (No brain)
– Echinoderms resemble chordates in early embryonic development.
– Echinoderms have separate sexes.
– Fertilization is external (no copulation). Life history includes ciliated, bilaterally symmetrical larva that undergoes metamorphosis and change into a adult (Deuterostome).
Larva
Star fish Bipinnaria, Brittle star Ophiopluteus Sea urchin Echinopluteus, Sea cucumber Auricularia Feather star Doliolaria,
Few echinoderms (star fish) have great power of regeneration. They break off their arms for defence purpose. This phenomenon is known as Autotomy
Echinoderms in angry or frightened state vomits out viscera (internal organ). This phenomenon is known as Evisceration. Heart urchin has lophophore (Ciliary structure) https://www.studiestoday.com
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ea lilly lilly ea S Feather star star Feather Crinoidea
– Oral Oral – Antedon - Antedon Spines - Absent Absent - Spines Absent - Pedicellariae Body form - Plant like fixed with cirri. cirri. with fixed like Plant - form Body branched Highly - Arms ciliated and Oral - groove Ambulacral Absent - Madreporite Anus arms upto Extend - Viscera feet Tube - Respiration Suckers Doliolaria Larva - Absent * primitive) (most Holopus - Neometra Neometra star Feather -
Absent Absent – - Sea cucumber cucumber Sea -
Holothuroidea – Aboral Aboral – Cucumaria espiration-Cloacal tree espiration-Cloacal Holothuria Holothuria Synapta Auricularia Larva - Present * Internal - Madreporite Anus arms. into Viscera No - Viscera R Suckers Body form-Long & cylindrical cylindrical & form-Long Body Absent - Arms Absent Spines Absent - Padicellariae groove Ambulacral
Aristotle's Aristotle's Absent Absent –
-sand dollar dollar -sand -heart urchin urchin -heart - Cake urchin urchin Cake - -
Echinoidea – (Masticating apparatus Aboral Aboral – i Echinus urchin sea outh outh - with biting & chewing espiration - Peristomium gills gills Peristomium - espiration Sp nes Present - Present - Pedicellariae Body form - Globular/disc like. Globular/disc - form Body Absent - Arms groove Ambulacral Aboral - Madreporite Anus arms. into Viscera No - Viscera R Suckers Larva Pluteus - M Present tooth apparatus lantern teeth) with 5 * Clypeaster Echinarachinus Echinocardium Salmacis
Divided into Five classes classes Five into Divided
(Brittle star) star) (Brittle Ophiuroidea Absent Absent – hiothrix hiothrix Ophiura Ophiura * Body form - Flat & star like like star & Flat - form Body of five. or multiple Five - Arms disc the central with marked Sharply Present - Spines Absent - Pedicellariae visible Not - groove Ambulacral Oral - Madreporite Absent - Anus arms. into Viscera No - Viscera bursae Genital - Respiration Suckers Ophiopluteus Larva - Op
https://www.studiestoday.com - Sea pentagen pentagen Sea - - starfish starfish - Asteroidea - Sea star star Sea - A sterias Madreporite - at Aboral surface surface at Aboral - Madreporite end. aboral At - Anus Body Flat & star like. like. & star Flat Body Arms - Five or multiple of five not sharply marked with the central Autotomy). disc (Show Present. - Spines Present. - Pedicellariae Ambulacral groove - Situated at surface. oral arms upto Extend - Viscera Respiration - Dermal branchiae or papulae Suckers Present - Brachiolaria - Bipinnaria Larva - Dipleura - * Solaster Pentaceros Astropecten
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PROTOZOA - HEMICHORDATA
–The term Hmichordata was given by Bateson.
– Animals of this phylum are all fossorial, and their tunnels are ‘U’ - shaped.
– Body worm like, and soft.
– Body is divided into three parts. A - proboscis B - Collar C - Trunk –Body wall has single layered epidermis. No dermis
–Body cavity is enterocoelus, that is divided into Protocoel, Mesocoel and Metacoel. –Mostly ciliary feeders. Complete alimentary canal is present in digestive system. This is straight or ‘U’ - shaped. –Circulatory system is open type. Blood is colourless with ameoboid corpuscles. – Heart is dorsal.
https://www.studiestoday.com –Skeletal tissue is absent.
– True notochord is absent.
– A notochord like structure is found in their buccal cavity, that is called ‘‘Buccal diverticulum’’ or ‘‘Stomochord’’ (a hollow out-growth arises from roof of buccal cavity).
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–Post anal tail is Absent.
– Dorsal heart, ventral nerve cord, no respiratory pigment.
–Respiration by gills.
–Excretion is done by a single glomerulus. This single glomerulus is situated in the proboscis known as Proboscis gland.
– Central nervous system is just like non chordates. Brain is present in the form of nerve - ring.
–Mostly animals are unisexual and reproductin is sexual.
– Fertilization is external. Cleavage holoblastic.
–Development is direct or indirect because some animals have tornaria larva just like bipinnaria larva or echinodermata in their developmental stages.
Hemichordata is divided into two Classes (1) Enteropneusta (2) Pterobranchia e.g. e.g. – *Balanoglossus. (Tongue worm or Acorn worm) – Rhabdopleura
– *Saccoglossus –Earlies included Hemichordata in Chordata phylum. Hyman (1959) kept in separate phylum Hemichordata in invertebrates. –Hemichordata is connecting link between Non-Chordata & Chordata. https://www.studiestoday.com
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