Biodiversity Part-3, Std-9

 

➤Kingdom Animalia
 :- Overview of features of kingdom Animalia.
1. They are true multicellular organisms.
2. They are heterotrophic.
3. They are mostly motile ( can move from one place to another ) & etc.
*Basis of Classification
:- Kingdom Animalia is  classified on the basis of different features like,
1. Level of Organization
  [ Cellular ( Sponges ), Tissue ( Hydra ) or         Organ system ( Humans ) level of organization ].
2. Symmetry
 :- It means dividing the body into equal and identical parts.
:- It is of two types,
 i. Radial Symmetry 
 :- Dividing body through center. Or
     The arrangement of the body of an animal in which parts are arranged symmetrically around a central axis. ( e.g. Starfish )
ii. Bilateral Symmetry
:- Body is divided into two equal halves laterally( right and left sides ). e.g - Humans 
Note:- Asymmetry - Organisms body do not divide into equal halves, like Amoeba. 
3. Body Cavity Or Coelom 
:- A cavity between the body wall and the food canal is called coelom.
:- There are three types of organisms on the basis of presence of coelom.
i. Acoelomates :- Organisms having no body cavity between epidermis and food canal are called acoelomates.
E.g. Hydra, Obelia
ii. Pseudocoelomates :- Organisms having
             false body cavity are called pseudocoelomates.
:- E.g. Wuchereria, Ascaris.
iii. Coelomates :- Organisms with true coelom or body cavity are called Coelomates.
:-> E.g. Human being

4. Embryonic layers 
:- There are three layers of cells - Ectoderm (outer layer ), Mesoderm ( middle layer ), and Endoderm ( inner layer ).
On the basis of presence of embryonic layers there are two types of animals -
i. Diploblastic :- The animals which have  two layers of cells are called diploblastic.
ii. Triploblastic :- The animals which have three layers of cells are called triploblastic.
5. Notochord 
:- It is a stiff rod running along the body, close to dorsal surface.
:- Also known as backbone.

➤Major Phyla of Kingdom Animalia

1. Phylum Porifera
:- The word 'Porifera' means Organisms with pores ( holes ) in the body.
:- They are commonly called Sponges.
Features
1. These are non - motile organisms and fixed to the solid surface.
2. Their body has many  pores, canals and Chambers through which water flows I.e called canal system.
3. Their body possesses a large aperture called osculum at the upper end and the lower end is fixed to the surface.
4. Their body covered with a hard outer skeleton and encloses a large cavity I.e known as spongocoel.
5. Level of organization - Cellular level.
6. They reproduce asexually by budding and gemmules and sexually through fertilization. They also possess great regenerating capacity.
E.g. Sycon, Euplectella, Euspongia, Spongilla, Leucosolenia, etc.

2. Phylum Coelenterata
:- They are also known as Cnidaria.
Features:-
1. Level of organization - Tissue level.
2. They are diploblastic and acoelomates.
3. Their body is surrounded by a ring of tentacles.
4. Their body has a gut cavity called coelenteron with a single opening for food and waste materials.
5. Some of their species live in colonies, while some others live a solitary life.
6. Reproduction may be Asexual or Sexual.
7. Their body shows radial symmetry.
E.g. Hydra, Obelia, Sea anemone, Aurelia,etc.
3. Phylum Platyhelminthes
 :- Their bodies are dorsoventrally flattened.
:- They are also known as Flatworms.
 Features:-
1. They are first triploblastic animals.
2. Symmetry - Bilateral.
3. They possess a mouth but no anus.
4. They are acoelomates.
5. They are either free living or parasitic and possess suckers or hooks or both for attachment to the body of host.
6. They are mostly Hermaphrodite, i.e, both male and female reproductive organs occur in the same individuals.
E.g. Planaria, Tapeworm, Liver fluke,etc.
4. Phylum Nematoda
:- They are also known as Aschelminthes.
Features:-
1. Symmetry - Bilateral
2. Level of organization - Tissue level.
3. Body Cavity - pseudocoelome.
4. They are mostly parasites having slender, elongated bodies, tapering at each end.
5. They are triploblastic animals.
6. Mode of reproduction - Sexual.
7. Most of them are pathogenic, meaning they produce diseases ( like elephantiasis ) in the hosts.
E.g. Ascaris ( roundworm ), Wuchereria bancrofti ( filarial worm ), Enterobius ( pinworm ), Hookworm, etc.

Note - Ascaris and Enterobius live in the human intestine and cause ascariasis and enterobiasis respectively in humans.

5. Phylum Annelida 
:- The term 'Annelid' means 'ringed'. They have segmented body.
Features
:- They are elongated, segmented, worm-like animals.
:- They are triploblastic and true coelomates.
:- Symmetry - Bilateral.
:- Level of organization - Organ level.
:- Their alimentary canal is tube-like, complete and extends straight from mouth to anus.
:- They have well-developed brain, ventral nerve cord, dorsal and ventral blood vessels.
:- Their body is provided with setae for locomotion.
:- Habitat - freshwater, marine water, and land.
:- Mode of reproduction - Sexual, Sexes maybe unite ( hermaphrodite ) or separate.
E.g. Neries ( sandworm ), Aphrodita ( sea mouse ), Pheretima ( Earthworm ), Leech etc.
6. Phylum Arthropoda
:- The term 'Arthro' means 'Jointed' and 'pod' means legs.
:- They have jointed legs ( appendages ).
:-This is the largest invertebrate phylum.
:- Insects, centipedes, millipedes, spiders are the common organisms belonging to phylum Arthropoda.
Features
:- Their body is bilaterally symmetrical and segmented.
:- They are triploblastic and coelomates.
:- Their body cavity is filled with blood thus called hemocoel.
:- They do not have well-defined blood vessels.
:- Their body is segmented and can be differentiated into head, thorax and abdomen.
:- Symmetry - bilateral.
:- They are triploblastic animals.
:- Mode of reproduction - Sexual.
:- They have jointed appendages ( legs ).
:- They possess a hard exoskeleton made of Chitin. 
E.g. Crab, Butterfly, Dragonfly, Housefly, Prown, Scorpian, Spider, etc.

7. Phylum Mollusca
Features:-
:- They are triploblastic true coelomates. ( but coelomic cavity is reduced).
:- Symmetry - Bilateral
:- Their body is soft.
:- They have a muscular foot for moving around.
:- Their body is protected by a hard calcareous shell.
:- They have an open circulatory system.
:- They have kidney like organs for excretion.
E.g. Snail, Pila, Unio, Octopus, Chiton, Squid, etc.
8. Phylum Echinodermata
:- This word has been derived from two Greek words - 'echinos' meaning hedgehog, and 'derma' meaning skin.
:- They are a free marine and bottom dwellers.
Features
:- They are triploblastic and coelomates.
:- Their body is not differentiated into head, thorax and abdomen.
:- Symmetry - Pentamerous ( body surface has five radial arms ).
:- They possess calcareous exoskeleton made up of Calcium Carbonate with spiny skin all over the body.
:- They have a water-driven tube system that they use for locomotion.
:- Their body cavity has water vascular system.
:- They have peculiar features of regeneration of lost parts.
E.g. Starfish, Sea Urchin, Antedon, Holothuria etc.

➤Sub - Phylum Protochordata
:- The word 'Protochordata' means primitive chordates.
Features
:- They are triploblastic and true coelomates.
:- Symmetry - Bilateral.
:- They have notochord at least at some stage of life. They are marine animals.
E.g. Balanoglossus, Herdmania, Amphioxus, etc. 

➤Phylum Chordata ( Sub - Phylum Vertebrata )

*Features
:- They are triploblastic and true coelomates.
:- Symmetry - Bilateral.
:- They possess notochord or backbone with cord ( spinal cord ).
:- They have dorsal tubular nerve cord.
:- They have paired gill pouches at some stages of their life.
:- They include mainly five classes - Pisces ( Fishes ), Amphibians, Reptiles, Aves 
 ( bird ) and Mammalia. 

1. Class Fishes or Group Pisces
:- This group contains many classes like Chondrichthyes for cartilaginous fishes and Osteichthyes for bony fishes . They are all exclusively water living animals.
:- Some well-known examples are
   i. Cartilaginous Fishes ( E.g - Sharks & 
   ii. Bony Fishes ( E.g - Tuna or Rohu )

➧Features
:- They have a cartilaginous or bony skeleton. Their body is streamlined.
:- Habitat - aquatic.
:- Locomotion - by fins and muscular tail.
:- Their skin is covered with scales.
:- They have 4 to 7 pairs of gills which help them to respire by taking dissolved oxygen from water.
:- They are cold-blooded and their hearts have only two chambers.
:- Their eyes are without eyelid and they possess nostrils which help in olfaction.
:- They lay eggs.
E.g. Mandarin fish, Angler fish, Lionfish, Torpedo, Sting ray, Dogfish, Rohu, Sea horse, Anabas, Hilsa, Mullet, etc.

2. Class Amphibia
:- The word amphibia has been derived from two Greek words 'Amphi' meaning double or both and 'bios' meaning life.
:- They have evolved from fishes.
Features
1. They live partially on land and partially
   in water.
2. They have smooth skin, rich glands, and slippery cover with mucous.
3. They have two pairs of limbs, and webbed feet.
4. Respiration takes place either through gills ( in water ) or lungs ( on land ).
5. They have a three-chambered heart.
6. They are cold-blooded.
E.g. Frog, Hyla, Salamander, Toad,  etc.

3. Class Reptilia
:- This word has been derived from a Greek word 'Reptere' meaning to crawl.
Features
1. They are cold-blooded animals.
2. Their body is divided into head, neck, trunk, and a tail.
3. Their body is dry and covered with horny scaly epidermal skin.
4. They have two pairs of limbs on their trunk.
5. They have lungs for breathing and respiration.
6. Most of them have a three-chambered heart ( crocodiles have four-chambered heart ).
7. They lay eggs covered with waterproof shells, so they need not lay eggs in water like Amphibians.
E.g. Wall lizards, Snakes, Turtle, Flying lizard, Chameleon, Crocodile, etc. 

4. Class Aves 
:- This word has been derived from the Greek word 'Avis' meaning Bird.
:- They have evolved from reptiles.
Features
1. They have feathers and scales covering their bodies. Their two forelimbs are modified for flight.
2. They are warm-blooded animals.
3. Their body is divided into three parts - head, neck and trunk.
4. Their heart is four-chambered.
5. Their jaw is with horny beak, no teeth present.
6. They have lungs for respiration.
7. They lay eggs.
E.g. Pigeon, House sparrow, Crow, White stork, Oestrich, Male tufted duck, etc. 

5. Class Mammalia 
:- This word has been derived from the word 'Mamma' meaning Breast.
Features
1. They possess mammary ( milk) glands. They secrete milk to feed their young ones.
2. Their body is covered with hair and also have sweat and oil glands on the skin.
3. Their body is differentiated into head, neck, trunk, and tail. The tail is absent in some animals.
4. Sexes are separate - male & female.
5. Their young ones usually develop inside the uterus of the mother.
6. They are warm-blooded animals.
7. They have a four-chambered heart.
E.g. Rat, Man, Tiger, Elephant, Cat, Cow, Whale, Bat, etc.
Note:- i. Except two mammals, the Platypus and the Echidna ( spiny anteater ) which lay eggs.
ii. Kangaroo gives birth to very poorly developed young ones.

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