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4. Animal Kingdom 2

continued..

PHYLUM – CHORDATA

 

  1. The main features of chordates are the presence of notochord, a dorsal hollow nerve cord and paired pharyngeal gill slits. The body is bilaterally symmetrical, triploblastic, coelomate.

  2. Organ system level of organization is present. Closed circulatory system is present. A post anal tail is present.

  3. Phylum Chordata is divided into three subphyla which are as follows:

    • Urochordata or Tunicata,

    • Cephalochordata and

    • Vertebrata.

  4. Subphyla Urochordata and Cephalochordata are usually referred to as protochordates. These are exclusively marine animals. In Urochordata, notochord is present only in larval tail. In Cephalochordata, the notochord extends from head to tail region and is persistent throughout the life.

  5. Common Examples:- Urochordata – Ascidia, Salpa, Doliolum; Cephalochordata – Branchiostoma (Amphioxus or Lancelet).

 

VERTEBARATA

 

  1. Notochord is present during the embryonic period only. After that, the notochord is replaced by a cartilaginous or bony vertebral column in the adult.

  2. A ventral muscular heart is present as the main organ of the circulatory system. The heart can have two, three or four chambers. Kidneys are present for excretion and osmoregulation. Paired appendages are present for locomotion.

  3. Phylum chordata can be divided into two sub-phyla, viz. agnatha and gnathostomata.

    • Sub-phylum Agnatha: Jaws are absent.

    • Sub-Phylum Gnathostomata: Jaws are present.

  4. There is only one class; Cyclostomata in the sub-phylum Agnatha.

  5. Gnathostomata is divided into two super-classes, viz. pisces and tetrapoda. Fins are present in pisces for locomotion. Four limbs are present in tetrapoda for locomotion. Super-class tetrapoda is further divided into four classes, viz. amphibia, reptilia, aves and mammalia.

CLASS – CYCLOSTOMATA

  1. All the existing members of the class Cyclostomata are ectoparasites on some fishes. The body is elongated. There are 6 -15 pairs of gill slits for respiration. A sucking and circular mouth is present. The body is devoid of scales and paired fins.

  2. Cranium and vertebral column are composed of cartilage. Closed circulatory system is present.

  3. Reproduction: They are marine animals but migrate to freshwater for spawning. They die within a few days of spawning. The larvae return to the ocean after metamorphosis.

  4. Common Examples: Petromyzon (Lamprey) and Myxine (Hagfish).

CLASS – CHONDRICHTHYES

  1. These are also known as cartilaginous fish because of cartilaginous endoskeleton. These are marine animals. Mouth is ventrally located.

  2. Notochord is present throughout the life. Gill slits are separate and operculum (gill cover) is absent. Skin is tough and has minute placoid scales. Teeth are modified placoid scales and are backwardly directed.

  3. Jaws are very powerful. These are predaceous animals. Air bladder is absent and hence the animal has to swim constantly to avoid sinking.

  4. There are two chambers in the heart. Some animals of this class have electric organs, e.g. torpedo. Some animals, on the other hand, possess poison sting, e.g. Trygon. They are cold-blooded (poikilothermous) animals.

  5. Reproduction: These are dioecious animals. The pelvic fins in males bear claspers. Fertilization is internal and many of them are viviparous.

  6. Common Examples: Scoliodon (Dog fish), Pristis (Saw fish), Carcharodon (Great white shark), Trygon (Sting ray).

CLASS – OSTEICHTHYES

  1. These are also called bony fishes because of bony endoskeleton. The body is streamlined. Mouth is usually terminal. There are four pairs of gills which are covered by operculum on each side. The skin is covered with cycloid/ctenoid scales. Air bladder is present which helps in buoyancy. The heart is two-chambered. They are cold-blooded animals.

  2. Reproduction: These are dioecious animals. Fertilization is usually external and development is direct. Most of the bony fishes are oviparous.

  3. Common Examples:- Marine – Exocoetus (Flying fish), Hippocampus (Sea horse); Freshwater – Labeo (Rohu), Catla (Katla), Clarias (Magur); Aquarium – Betta (Fighting fish), Pterophyllum (Angel fish).

CLASS – AMPHIBIA

  1. The amphibians can live both in aquatic and terrestrial habitats. They need water for fertilization. Two pairs of limbs are present in most of the amphibians. Body is divided into head and trunk. Tail can be present in some of them. The skin is moist and scales are absent. Eyelids are present on the eyes. A tympanum represents the ear. There is a common chamber; called cloaca; in which the alimentary canal, urinary tract and reproductive tract open. Respiration is by gills, lungs and through skin.

  2. There are three chambers in the heart (two auricles and one ventricle).

  3. These are cold-blooded animals.

  4. Reproduction: These are dioecious animals. Fertilization is external and development can be direct or indirect. These are oviparous animals.

  5. Common Examples:- Bufo (Toad), Rana (Frog), Hyla (Tree frog), Salamandra (Salamander), Ichthyophis (Limbless amphibia).

CLASS – REPTILIA

  1. These animals show creeping or crawling mode of locomotion. Most of them are terrestrial animals. The body is covered by dry and cornified skin, epidermal scales (scutes). Tympanum represents ear. Limbs are in two pairs; when present.

  2. Three-chambered heart is present in most of the reptiles. Crocodiles have four-chambered heart. These are cold-blooded animals.

  3. Reproduction: These are dioecious animals. Fertilization is internal and development is direct. These are oviparous animals.

  4. Common Examples:- Chelone (Turtle), Testudo (Tortoise), Chameleon (Tree lizard), Calotes (Garden lizard), Crocodilus (Crocodile), Alligator (Alligator). Hemidactylus (Wall lizard), Poisonous snakes – Naja (Cobra), Bangarus (Krait), Vipera (Viper).

CLASS – AVES

  1. Presence of feathers and wings are the characteristic features of Aves.

  2. The forelimbs are modified into wings. The hind limbs usually have scales and are modified for walking, swimming or clasping the tree branches. Skin is dry without glands, but oil gland is present at the base of the tail. Beaks are present.

  3. The endoskeleton is composed of bones. Long bones are pneumatic, i.e. are hollow with air cavities. Air cavities in the long bones help in weight reduction and this is an important flight adaptation. Crop and gizzard are the additional chambers in the digestive tract.

  4. There are four chambers in the heart. They are warm-blooded (homoiothermous) animals. Respiration is by lungs, and air sacs; connected to lungs; supplement respiration.

  5. Reproduction: These are dioecious animals. Fertilization is internal and development is direct. They are oviparous animals.

  6. Common Examples:- Corvus (Crow), Columba (Pigeon), Psittacula (Parrot), Struthio (Ostrich), Pavo (Peacock), Aptenodytes (Penguin), Neophron (Vulture).

CLASS – MAMMALIA

  1. Presence of mammary glands is the most unique feature of these animals. The young ones are nourished by the mammary glands. Hairs are present on the skin and external ears are present. Different types of teeth are present in the jaw. The two pairs of limbs are adapted for walking, running, climbing, burrowing, swimming or flying.

  2. There are four chambers in the heart. They are warm-blooded animals.

  3. Respiration is by lungs.

  4. Reproduction: They are dioecious animals. Fertilization is internal and development is direct. Most of them are viviparous.

  5. Common 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).

  6. Distinct Characters of 4 classes of the Superclass Tetrapoda:

    • Amphibia: Capable of living on both land and water but need water for some stages of the life cycle. Respiration is through lungs, skin and gills. These are cold-blooded animals.

    • Reptilia: Creeping or crawling mode of locomotion. The skin is hard with scale like structures. These are cold-blooded animals.

    • Aves: Pneumatic bones, feathers and wings are the important flight adaptations. Forelimbs are modified into wings. These are warm-blooded animals.

    • Mammal: Milk is produced by the mammary glands in females and is utilised for nourishing the young ones. Hairs are present on the skin. External ears are present. These are warm-blooded animals.​

REVISION NOTES

 

CLASS 11 BIOLOGY

UNIT I – DIVERSITY IN THE LIVING WORLD

Chapter 1 – The Living World 

Chapter 2 – Biological Classification 

Chapter 3 – Plant Kingdom 

Chapter 4 – Animal Kingdom 

UNIT II – STRUCTURAL ORGANISATION IN PLANTS AND ANIMALS

Chapter 5 – Morphology of Flowering Plants 

Chapter 6 – Anatomy of Flowering Plants 

Chapter 7 – Structural Organisation in Animals 

UNIT III – CELL : STRUCTURE AND FUNCTIONS

 

Chapter 8 – Cell: The Unit of Life 

Chapter 9 – Bio-Molecules 

Chapter 10 – Cell Cycle and Cell Division 

UNIT IV – PLANT PHYSIOLOGY 

Chapter 11 – Transport in Plants 

Chapter 12 – Mineral Nutrition 

Chapter 13 – Photosynthesis in higher plants 

Chapter 14 – Respiration in Plants 

Chapter 15 – Plant Growth and Development 

UNIT V – HUMAN PHYSIOLOGY 

Chapter 16 – Digestion And Absorption 

Chapter 17 – Breathing and Exchange of Gases 

Chapter 18 – Body fluids and circulation 

Chapter 19 – Excretory Products and their Elimination 

Chapter 20 – Locomotion and Movement 

Chapter 21 – Neural Control and Coordination 

Chapter 22 – Chemical Coordination and Integration 

CLASS 12 BIOLOGY

Unit-VI Reproduction
  

Chapter 1 : Reproduction in Organisms 

Chapter 2 : Sexual Reproduction in Flowering Plants 

Chapter 3 : Human Reproduction 

Chapter 4 : Reproductive Health 

Unit-VII Genetics and Evolution

Chapter 5 : Principles of Inheritance and Variation 

Chapter 6 : Molecular Basis of Inheritance 

Chapter 7 : Evolution 

Unit-VIII Biology and Human Welfare

Chapter 8 : Human Health and Disease 

Chapter 9 : Strategies for Enhancement in Food Production 

Chapter 10 : Microbes in Human Welfare 

Unit-IX Biotechnology  

Chapter 11 : Biotechnology Principles and Processes 

Chapter 12 : Biotechnology and its Applications 

Unit-X Ecology and Environment 

Chapter 13 : Organisms and Populations 

Chapter 14 : Ecosystem 

Chapter 15 : Biodiversity and Conservation 

Chapter 16 : Environmental Issues 

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