ISC 11>CONTENT>1 DIVERSITY OF LIFE>6.ANIMAL KINGDOM

SCOPE OF SYLLABUS

Animal Kingdom: 
animal construction - body plan, symmetry, coelom development, segmentation; 
Distinguishing characters of Porifera, Coelenterata, Platyhelminthes, Nematoda, Annelida, Mollusca, Arthropoda, Echinodermata.
chordata

KINGDOM ANIMALIA 

Kingdom animalia is divided into two sub kingdoms-

Parazoa (cellular level) and Eumetazoa (tissue level)

Subkingdom Parazoa includes the Phylum Porifera.

Subkingdom Eumetazoa includes all the Phyla from coelenterates to chordates.

Phylum Porifera 

Features of porifera:
1. Sessile, sedentary and marine.
2. Body is perforated by numerous pores, called Ostia.
3. One large opening called osculum.
4. Shows cellular level of organisation.
5. Shows presence of canal system.
6. No mouth, no anus.
7. Has choanocytes in the radial canals.
8. Inner part is hollow or permeated by canals, cavity is called spongocoel.
9. Body has skeleton made up of spongin or spicules.
10. Reproduction is by budding and fragmentation.
Eg. Leucosolenia, Euplectella, Euspongia.

EXAMPLES OF PORIFERA

LEUCOSOLENIA
EUSPONGIA

Phylum Coelenterata or Cnidaria 

Features of Cnidaria
1. Aquatic, mostly marine with few fresh water forms.
2. Sedentary or free swimming and colonial or solitary.
3. Individuals are radially or biradially symmetrical.
4. Gastrovascular cavity present, communicates outside by mouth. No anus present.
5. Tentacles present surrounding the mouth to capture food.
6. Diploblastic animals, showing polymorphism.
7. Presence of nervous system showing nerve cells.
8. Reproduction both sexual and asexual methods.
9. Life history shows alternation of generation (Metagenesis).
Eg. Physalia, Aurelia (jelly fish),Adamsia (sea anemone).

METAGENESIS

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Metagenesis is the type of life cycle in which there are two different forms of individuals of the same species, one haploid and the other diploid. In one of these stages gametogenesis occurs and fecundated gametes give birth to the zygote that then develops into the other form. (Obelia)
Metagenesis is also known as alternation of generations or as diplobiont life cycle.

EXAMPLES OF COELENTERATA

OBELIA
PHYSALIA
SEA ANAEMONE

 Phylum Ctenophora 

Features of Ctenophora:
1. Acoelomate, triploblastic marine forms.
2. They show biradial symmetry.
3. Body is transparent, gelatinous and unsegmented.
4. Body may be cylindrical, flat or ribbon like.
5. Two tentacles present, locomotion by rows of comb like structures. (also called comb jellies)
6. Gastrovascular cavity opens outside by the stomodaeum.
7. Presence of sense organs at the aboral end.
8. Hermaphrodite animals, reproduce by sexual means.
Eg. Pleurobranchia, Beroe

EXAMPLES OF CTENOPHORA

PLEUROBRANCHIA
BEROE

Phylum Platyhelminthes 

Features of Platyhelminthes:
1.Bilaterally symmetrical and dorsoventrally flattened, triploblastic and acoelomate.
2. Body shape worm like but varies from flat ribbon like to leaf like.
3. Anterior end differentiated to form head which bears hooks and suckers.
4. Skeleton absent.
5. Acoelomate with protonephridia or flame cells for excretion.
6. Hermaphrodite shows both sexual and asexual method of reproduction.
7. Free living or parasites.
Eg. Planaria, Liver fluke, Taenia (Tape worm)

ADAPTATIONS FOR PARASITIC LIFE

  1. Resistant horny cuticle, no epidermis
  2. Adhesive structures present.
  3. Locomotory, circulatory and respiratory system absent.
  4. Alimentary canal, incomplete or absent.
  5. Sense organs absent or poorly developed.
  6. Highly developed reproductive organs.

EXAMPLES OF PLATYHELMINTHES

PLANARIA
LIVERFLUKE
TAPEWORM

Phylum Aschelminthes 

Features of Aschelminthes:
  1. Bilaterally  symmetrical, unsegmented worms.
  2. Triploblastic, microscopic with cylindrical or flattened body.
  3. Alimentary canal straight with mouth and anus.
  4. Excretory system with protonephridia for osmoregulation.
  5. Nervous system simple with some sense organs like bristles and eye spots.
  6. Sexes separate females longer than the males.
  Eg Ascaris, Wuchereria bancrofti
ASCARIS
WUCHERERIA

Phylum Annelida 

Features of Annelida:
  1. Mainly aquatic, marine or fresh water, burrowing or living in tubes, some free living forms.
  2. Triploblastic, bilateral, elongated and vermiform.
  3. Metamerically segmented body covered with cuticle.
  4. Locomotary organs are setae or parapodia parasitic forms do not have either.
  5. True coelom present, respiration through body surface.
  6. Closed blood vascular system, haemoglobin present.
  7. Nervous system consists of brain and segmental ganglia.
  8. Excretion by nephridia.
  9. Sexes separate in polychaetes, earthworms and leeches are hermaphrodite.
  10. Eg. Nereis Earthworm. Leeches

METAMERIC SEGEMENTATION

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Linear series of body segmentation fundamentally similar in structure. Each metameric segment is referred to as metamere or somite. 
Earthworms show heteronomous metamery where the metameres are grouped to perform similar tasks.
Nereis shows homonomous metamery where the metameres are in serial succession.

LOCOMOTORY ORGANS IN ANNELIDA

Setae or chaetae: These are tiny bristle like structures present on the segments of animals of Oligochaetes (class of Annelid). The setae are present on all the segments except the first and the last. These structures help the earthworm to move. 
Parapodia:  These are fleshy lobes present on each segment in Polychaets (class of Annelid). Parapodia are paired, lateral appendages extending from the body segements. A parapodium is basically biramous or uniramous, having one branch or two branches.

EXAMPLES OF ANNELIDA

NEREIS
EARTHWORM
LEECH

Phylum Arthropoda 

Features of Arthropods:
  1. Triploblastic, coelomate, metamerically segmented.
  2. Body covered with chitinous exoskeleton.
  3. Body segments bear paired jointed appendages.
  4. Body consists of head, thorax and abdomen.
  5. Body cavity is haemocoel, digestive tract complete.
  6. Circulatory system open, respiration by gills, trachea or book lungs.
  7. Excretion by malphigian tubules or green glands.
  8. Sexes separate and shows sexual dimorphism.
  9. Animals show moulting or ecdysis.
  10. Fertilization is internal.
Eg. Spider, Scorpion. Paleamon, Crab, Centipede, Millipede,Butterfly, Moth

METAMORPHOSIS 

Holometabolous- complete metamorphosis- the larva does not resemble the adult.
ex- Butterflies. moths, beetel etc.
Hemimetabolous- incomplete metamorphosis- larva resemble the adult.
ex- Dragon flies, Grasshopper

EXAMPLES OF ARTHROPODA

SPIDER
SCORPION
CENTIPEDE

DIFFERENCE BETWEEN BUTTERFLY AND MOTH

BUTTERFLY
1. Butterflies are brightly coloured.
2. They are diurnal (Active during day).
3. The wings are arranged vertically at rest.
4. Antennae are long, filamentous and clubbed.
5. Body slender and scaly.
MOTH
1. Moths are dull coloured.
2. They are nocturnal (active during night).
3. The wings at rest are arranged horizontally.
4. Antennae are short and feathery.
5. Body is broad and stout.

Find out and list the differences between anopheles and culex mosquitoes

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Phylum Mollusca 

Features of Mollusca:
  1. Aquatic, marine, few terrestrial and fresh water forms.
  2. Body soft, unsegmented, triploblastic, bilaterally symmetrical.
  3. Body consists of head, foot, mantle and visceral mass. 
  4. Commonly protected by exoskeleton made of one or more calcareous pieces.
  5. Body cavity called haemocoel, with open circulatory system.
  6. Respiratory system with gills and pigment is haemocyanin.
  7. Excretory system consisting of metanephridia and nervous system well developed.
  8. Sexes are separate.  
Eg. Neopilina, Chiton, Pila (Apple snail), Dentalium,Unio Sepia, Octopus

EXAMPLES OF MOLLUSCA

CHITON
UNIO
SNAIL
OCTOPUS
Body globular and without fins.
Head is surrounded by eight equal long and powerful arms.
Suckers present are large.
Shell is absent. 
SEPIA
Body elongated with pair of lateral fins.
Head is surrounded by ten arms, two long arms and remaining eight short.
Suckers are short and stalked.
Shell is internal.

Phylum Echinodermata 

Features of Echinodermata:
  1. Marine, radial symmetry, pentamerous, triploblastic.
  2. Body is without distinct head, thorax and abdomen.
  3. Body shape cylindrical or star shaped, with a central disc and branched arms.
  4. Exoskeleton made up of closely fitted plates called theca.
  5. Coelom is called enterocoel.
  6. Shows presence of water vascular system and tube feet for locomotion.
  7. Alimentary canal complete with mouth and anus.
  8. Excretory system absent, nervous system primitive.
  Eg. Asterias (Star fish), Ophiothrix (brittle star), Echinus (sea urchin)  Holothuria (sea cucumber) Antedon (Sea feather)

EXAMPLES OF ECHINODERMATA

STAR FISH
SEA URCHIN
SEA CUCUMBER
CHORDATA>