Biology
PHYLUM CHORDATA
- Comparison Between Amphibians And Reptiles
Differences between Amphibians and Reptiles Features Amphibians Reptiles Group They come under class Amphibia They come under class Reptilia Habit and habitat They usually stay near water sources to prevent drying out, and have smooth...
- Animal Kingdom: Model Questions
Animal Kingdom: Model Questions 1. An animal shows the following characters:· Body is dorso-ventrally flattened· Parenchyma cells are found between the body...
- Comparison Between Cartilaginous And Bony Fishes
Cartilaginous fishes (Chondricthyes) Bony fishes (Osteichthyes) 1. Exclusively marine. Marine & fresh water. 2. Heterocercal caudal fin. Homocercal...
- Respiratory Organs Of Animals
Phylum Respiratory organ Porifera Body surface Cnidaria Body surface Ctenophora Body surface Platyhelminthes Body surface Nemathelminthes Body surface Annelida Skin (integument) Arthropoda Aquatic insects (mayflies, nymphs...
- Larvae Of Different Animals
Phylum Organism Larva Porifera Sycon Amphiblastula Leucosolenia Parenchymula (Stereogastrula) Higher sponges Rhagon Cnidaria Aurelia (Jelly fish) Ephyra (Ephyrula), Planula, Hydratuba Obelia, Sea anemone ...
Biology
Animal Kingdom- Notes
Phylum | Name given by | No. of species | Levels of organization | Germ layers | Symmetry | Coelom |
Porifera | Robert Grant | 5000 | Cellular | Diploblastic | Asymmetrical/ radial | Acoelomate |
Cnidaria | Leuckart (1847) | 9000 | Tissue | -do- | Radial | -do- |
Ctenophora | Escholtz (1829) | <100 | -do- | -do- | -do- | -do- |
Platyhelminthes | Gegenbaur (1859) | 13000 | Organ/Organ system | Triploblastic | Bilateral | -do- |
Aschelminthes | Gegenbaur (1859) | 15000 | -do- | -do- | -do- | Pseudocoelomate |
Annelida | Lamarck (1809) | 9000 | -do- | -do- | -do- | Coelomate |
Arthropoda | Von Siebold | 9,00,000 | -do- | -do- | -do- | -do- |
Mollusca | Johnston | 60,000 | -do- | -do- | -do- | -do- |
Echinodermata | J. Klein | 6000 | -do- | -do- | Radial | -do- |
Hemichordata | Bateson | -do- | -do- | Bilateral | -do- | |
Chordata | 45,000 | -do- | -do- | Bilateral | -do- |
COMPARISON OF DIFFERENT PHYLA (NON-CHORDATES)
Phyla Features | Porifera (Sponges) | Cnidaria (Coelenterata) | Ctenophora (Acnidaria or Comb Jellies or sea walnuts) | Platyhelminthes (Flatworms) | Aschelminthes (Nemathelminthes/ Roundworms) |
Habit and habitat | Aquatic (mostly marine). Sedentary. Solitary or colonial. Coloured. | Aquatic (mostly marine). Solitary or colonial. Sessile or free swimming | Exclusively marine. Solitary and pelagic. | Mostly endoparasites. Some are free-living. Mainly aquatic. | Free living, aquatic and terrestrial or parasitic in plants and animals. |
Digestive system | Absent. Digestion is intracellular. Water transport (canal system) to gather food. | Incomplete. Carnivorous. Intracellular and extracellular digestion. | Incomplete. Intracellular and extracellular digestion. Mouth & 2 anal pores. | Incomplete. Branched alimentary canal with mouth. Anus absent. In parasites alimentary canal absent. | Complete. Tubular alimentary canal with mouth, muscular pharynx, intestine and anus. Mouth may possess teeth. |
Respiratory system | Absent. Respiration by canal system | Absent | Absent | Absent | Absent |
Circulatory system | Absent. Circulation by canal system | Absent | Absent | Absent | Absent |
Excretory system | Absent. Excretion by canal system. Ammonotelic. | Body surface. Ammonotelic | Body surface. Ammonotelic | Flame cells for excretion and Osmoregulation. Ammonotelic | An excretory tube to remove body waste through excretory pore. Ammonotelic |
Nervous (Neural) system | Absent. | Only a network of neurons. | Only a network of neurons. | Ladder-like. A brain and nerve cords, connected by transverse nerves | Circumpharyngeal ring with dorsal and ventral nerves. |
Reproductive system | Hermaphrodite. ARP by fragmentation budding or by gemmules (internal buds). SRP by the formation of sperms and ova. Fertilization internal. | Polyp reproduces asexually (budding) and medusa sexually. Medusa forms monoecious or dioecious. Fertilization external. | Only SRP. Hermaphrodite. Fertilization external. | ARP (by fragmentation & regeneration) and SRP. Hermaphrodite. Fertilization is internal. | Sexes are separate (Dioecious). Sexual reproduction. Internal fertilization. |
Larva | Leucosolenia: Parenchymula Sycon: Amphiblastula Higher sponges: Rhagon. | Aurelia: Ephyra Obelia & Adamsia: Planula Hydrula, Hydratuba | Ciliated Cydipid larva | Taenia: Bladder worm (Cysticercus), Hexacanth & Oncosphere Fasciola: Miracidium, Sporocyst/Gamocyst/ zoocyst, Redia, cercaria, & metacercaria | No |
Other features | 1cm-1m length. Millions of minute pores (ostia). Body wall with outer layer of flat cells (pinacocytes) and inner layer of flagellated cells (choanocytes or collar cells). Body is supported by calcareous or siliceous spicules and spongin fibres. Spongocoel (body cavity) and canals are lined with choanocytes. Spongocoel opens out by osculum. Highest degree of regenerating capacity. | Tentacles with cnidoblasts (stinging cells). A central gastro-vascular cavity (coelenteron) with a single opening (mouth) on hypostome. Polyp & Medusa are 2 kinds of body forms. Show polymorphism and alternation of generation (metagenesis). Corals have a skeleton made up of CaCO3. | Locomotion is by 8 vertical external rows of ciliated comb plates. Tentacles present. Special adhesive cells (colloblasts) on tentacles. Mesoblast present. Shows Bioluminescence. | Unsegmented, dorso-ventrally flattened body (except in tape worms). Hooks and suckers in parasitic forms. Some of them absorb nutrients from the host through their body surface. The first group showing cephalization. | Syncitial epidermis. Thick cuticle. Sexual dimorphism (females are longer than males). |
Examples | Sycon (Scypha), Spongilla (fresh water sponge), Euspongia (Bath sponge) | Hydra, Obelia, Physalia (Portugese man of war), Aurelia, Adamsia (Sea-anemone), Pennatula (Sea pen)), Gorgonia (Sea fan), Meandrina (Brain coral) etc. | Ctenoplana, Pleurobrachia, Cestum, Hormiphora | Taenia solium (Tape worm), Fasciola (Liver fluke), Planaria, Blood fluke (Schistosoma), Dog tapeworm (Echinococcus) | Ascaris (Roundworm), Ancylostoma (Hookworm), Enterobius, Wuchereria (Filarial worm) |
COMPARISON OF DIFFERENT PHYLA (NON-CHORDATES)
Features | Annelida (Segmented worms) | Arthropoda (Joint-legged animals) | Mollusca (Soft bodied animals) | Echinodermata (Spiny skinned animals) | Hemichordata |
Habit and habitat | Terrestrial, fresh water or marine. Free living or parasitic. | Cosmopolitan. | Generally aquatic. Few are terrestrial. | Exclusively marine. | Marine |
Digestive system | Complete. Pharynx, oesophagus, stomach, intestine etc. | Complete and well developed. Well developed mouth parts. | Complete and well developed. Salivary glands and liver. | Complete. Ventral (lower) mouth and dorsal (upper) anus. | Complete |
Respiratory system | Cutaneous respiration. Some have branchial (gill) respiration | Either by Gills or trachea, or book gills or book lungs. | Gills in aq. forms and pulmonary sac in terrestrial forms. | Dermal branchiae (gills) or papulae and tube feet. | Gills |
Circulatory system | Closed type | Open type | Open type | Reduced and open type. | Open type |
Excretory system | Nephridia for excretion and Osmoregulation. Aq. forms ammonotelic & terr. forms ureotelic | Either Antennary glands or Malpighian tubules or coxal glands. Aq. forms ammonotelic and terr. forms uricotelic. | By Metanephridia. Ammonotelic or ureotelic. | Absent. Diffusion through gills. Ammonotelic. | Proboscis gland |
Nervous (Neural) system | A pair of cerebral ganglia (brain) and a double ventral nerve cord connected by lateral nerves. | A nerve ring followed by a double ventral ganglionated nerve cord. | Paired ganglia and their connectives. | Circum oral nerve ring and radiating nerves No brain. | Simple |
Reproductive system | SRP. Earthworms & leeches are hermaphrodites. Neries is dioecious. | Sexes are separate. External fertilization in aq. forms. Internal fertilization in land forms. Mostly oviparous. | Sexes are separate. Oviparous. | Sexes are separate. Fertilization external. Ciliated free swimming larva. | Sexes are separate. Fertilization external. |
Larva | Free swimming trochophore larva. | Squilla: Alima Butterfly, Silk moth: Caterpillar Lepas: Cypris Hermit crab: Glaucothoe Beetles & Honeybee: Grub Housefly: Maggot Crab: Megalopa Simplest crustacean larva: Nauplius Rock Lobster: Phyllosoma Lobsters: Schizopod or Mysis Mosquito: Wriggler Cancer (Crab): Zoea Limulus: Trilobite | Glochidium, trochophore and veliger. Some have no larva. | Starfish: Bipinnaria Ophiura: Ophiopluteus Echinus: Echinopluteus Holothuria: Auricularia Antedon: Doliolaria | Tornaria |
Other features | 1mm ? 2.5 m length. True segmentation. Longitudinal and circular muscles which help in locomotion. Locomotory organs are setae (in earthworm) or parapodia (in Neries). | Largest phylum. Jointed appendages. 3 regions: head, thorax & abdomen. Body is covered by chitinous cuticle (exoskeleton). Sensory organs (antennae, compound & simple eyes, statocysts or balance organs) are present. | Second largest phylum. Body has head, visceral mass (visceral hump) & muscular foot. Anterior head region has sensory tentacles. Univalve or bivalve calcareous shell. Feather-like gills have respiratory and excretory functions. Mantle & radula seen. | Body is covered with spines for protection. Head absent. Calcareous endoskeleton (ossicles) present. Water vascular system for locomotion, respiration & food capture & transport. Great power of autotomy and regeneration. Larva bilaterally symmetrical. | Worm-like cylindrical body composed of an anterior proboscis, a collar and a long trunk. |
Examples | Pheretima (Earthworm), Hirudinaria (Blood sucking Leech), Neries, Aphrodite, Chaetopterus, Bonellia | Spider, Scorpion, Crab, Prawn, Insects etc. Economically important insects: Apis, Bombyx, Laccifer. Vectors: Mosquitoes (Anopheles, Culex & Aedes), Housefly etc. Gregarious pest: Locusta. Living fossil: Limulus (King crab) | Pila (Apple Snail), Achatina (Land snail), Pinctada (Pearl Oyster), Sepia (Cuttlefish), Loligo (Squid), Octopus (Devil fish), Aplysia (Sea Hare), Dentalium (Tusk shell), Chaetopleura (Chiton) | Asterias (Starfish), Echinus (Sea Urchin), Echinocardium, Antedon (Sea Lily), Cucumaria (Sea Cucumber), Ophiura (Brittle Star). | Balanoglossus (Tongue worm), Saccoglossus, Glossobalanus |
Phylum chordata is divided into 3 subphyla: Urochordata, Cephalochordata and Vertebrata
PROTOCHORDATA (ACRANIATA) | VERTEBRATA (CRANIATA) | |
Urochordata (Tunicata) | Cephalochordata | |
· Notochord present only in larval tail · Body is covered by test made up of tunicin · Exclusively marine · Retrogressive metamorphosis · Hermaphrodite · E.g. Ascidia, Salpa, Doliolum etc | · Notochord from head to tail region and is persistent throughout the life · Exclusively marine · Fish-like · No definite coelom · Sexes are separate · E.g. Branchiostoma (Amphioxus or Lancelet) | · Possess notochord during the embryonic period · Notochord is replaced by a cartilaginous or bony vertebral column in the adult · Ventral muscular heart · Kidneys for excretion & osmoregulation · Paired appendages which may be fins or limbs |
Vertebrata: Has 2 divisions- Agnatha and Gnathostomata
Agnatha (Jawless): Includes 1 class: Cyclostomata:
· All are ectoparasites on some fishes.
· Elongated body.
· 6-15 pairs of gill slits for respiration.
· Sucking and circular mouth without jaws.
· No scales and paired fins.
· Cartilaginous cranium and vertebral column.
· Circulation closed type.
· Marine, but migrate for spawning to fresh water. After spawning, they die. Their larvae, after metamorphosis, return to ocean.
· E.g. Petromyzon (Lamprey) and Myxine (Hagfish).
Gnathostomata (bears jaw):2 super classes (Pisces & Tetrapoda) | |||||
Pisces (Fishes- bears fins): 2 classes | Tetrapoda (bear limbs): 4 classes | ||||
Chondricthyes | Osteichthyes | Amphibia | Reptilia | Aves (Birds) | Mammalia |
· Marine. · Heterocercal caudal fin. · Cartilaginous endoskeleton. · Gill slits without operculum. · Skin with placoid scales. · Teeth are modified placoid scales which are backwardly directed. · No air bladder so they have to swim constantly to avoid sinking. · Sexes are separate. In males pelvic fins bear claspers. · Internal fertilization. · Many of them viviparous. Examples Scoliodon (Dog fish), Pristis (Saw fish), Carcharodon (Great white shark), Trygon (Sting ray), Torpedo (Electric ray- have electric organ). | · Marine & fresh water. · Homocercal caudal fin. · Bony endoskeleton. · Terminal mouth. · 4 pairs of gills covered by an operculum on each side. · Scales are Cycloid, ctenoid etc. · Air bladder for buoyancy. · Sexes are separate. · Fertilisation external. · Mostly oviparous. · Development direct. Examples Marine: Exocoetus (flying fish), Hippocampus (sea horse), Sardine, Mackeral, Tuna, Remora (sucker fish), Pomfret, Cybium Fresh water: Labeo (Rohu), Catla (Katla), Clarias (Magur), Tilapia, Anabas (Climbing perch) Aquarium: Betta (Fighting fish), Pterophyllum (Angel fish) etc. | · Aquatic larval life & terrestrial adult life. · For breeding they require a watery environment. · Pentadactyl limbs. · Moist skin without scales. · A tympanum represents ear. · Alimentary canal, urinary & reproductive tracts open into a Cloaca which opens to exterior · Respiration is by gills (in larva), lungs & skin · 3-chambered heart (2 auricles + 1 ventricle). · Poikilotherms · Sexes are separate. Fertilisation external. · Oviparous. · Development is indirect. Examples Bufo (Toad), Rana (Frog), Hyla (Tree frog), Salamandra (Salamander), Ichthyophis (Limbless amphibia), Ambystoma (Tiger salamander), Rhacophorus (Flying frog) | · Dry & cornified skin, epidermal scales or scutes. Snakes and lizards shed their scales as skin cast. · Tympanum represents ear · Limbs- 2 pairs (if present). · 3-chambered heart (but a septum partially separates ventricle). Heart is 4-chambered in crocodiles. · Poikilotherms. · Fertilisation internal. · Oviparous. · Development is direct. Examples Chelone (Turtle), Testudo (Tortoise), Chameleon (Tree lizard), Calotes (Garden lizard), Crocodilus (Crocodile), Alligator, Gavialis (gharial) Hemidactylus (Wall lizard), Sphenodon (Tautara), Draco (flying dragon or flying lizard), Phrynosoma (horned lizard), Varanus (monitor). Poisonous snakes: Naja (Cobra), Bangarus (Krait), Vipera (Viper), Crotalus (rattle snake), Enhydrina (sea snake) etc. Non-poisonous snakes: Python, Typhlos (blind snake), Dryophis (tree snake) | · Presence of feathers. · Possess beak. · Forelimbs are modified into wings. · Hind limbs have scales and are modified for walking, swimming, or clasping tree branches. · Skin is dry without glands except the oil gland at the base of the tail. · Long, hollow and pneumatic bones. · Digestive tract with additional chambers, the crop and gizzard · Heart is 4-chambered · Homoiotherms (warm-blooded) · Double respiration. Air sacs connected to lungs. · No urinary bladder. · Fertilisation is internal. · Oviparous. · Development is direct. Examples Corvus (Crow), Columba (Pigeon), Psittacula (Parrot), Struthio (Ostrich), Pavo (Peacock), Gullus (Fowl), Bubo (Owl), Aptenodytes (Penguin), Neophron (Vulture) etc. | · Presence of mammary glands (milk producing glands). · 2 pairs of limbs for walking, running, climbing, burrowing, swimming or flying. · Skin with hair · External ear (Pinnae) · Heterodont, thecodont, diphyodont. · 4-chambered heart. · Homoiotherms. · Respiration by lungs. · Sexes are separate. · Fertilisation internal. · Viviparous (except Echidna and Platypus). · Development is direct. Examples Ornithorhynchus (Platypus), 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) |
- Comparison Between Amphibians And Reptiles
Differences between Amphibians and Reptiles Features Amphibians Reptiles Group They come under class Amphibia They come under class Reptilia Habit and habitat They usually stay near water sources to prevent drying out, and have smooth...
- Animal Kingdom: Model Questions
Animal Kingdom: Model Questions 1. An animal shows the following characters:· Body is dorso-ventrally flattened· Parenchyma cells are found between the body...
- Comparison Between Cartilaginous And Bony Fishes
Cartilaginous fishes (Chondricthyes) Bony fishes (Osteichthyes) 1. Exclusively marine. Marine & fresh water. 2. Heterocercal caudal fin. Homocercal...
- Respiratory Organs Of Animals
Phylum Respiratory organ Porifera Body surface Cnidaria Body surface Ctenophora Body surface Platyhelminthes Body surface Nemathelminthes Body surface Annelida Skin (integument) Arthropoda Aquatic insects (mayflies, nymphs...
- Larvae Of Different Animals
Phylum Organism Larva Porifera Sycon Amphiblastula Leucosolenia Parenchymula (Stereogastrula) Higher sponges Rhagon Cnidaria Aurelia (Jelly fish) Ephyra (Ephyrula), Planula, Hydratuba Obelia, Sea anemone ...