Page 403 - General Knowledge

GENERAL KNOWLEDGE 2019

 Nervous system –normal.
 Blood is red and flows in closed vessels.
 In earthworm, five pairs of blood vessels are together called as ‗heart‘.

 In some animals, respiration takes place through coelom.
 Excretion takes place by nephridia.
 Earthworm, Nereis, leech are some examples.
Phylum Arthropoda
 Largest phylum.
 Main feature is its jointed leg.
 Body is divided into three parts - head, thorax and abdomen.
 Circulatory system is open type.
 There are 13 chambers in cockroach‘s heart.
 Trachea and body surface are respiratory organs.
 Cockroaches, prawn, crab, bug, fly, mosquito, bees etc are some examples.
 Insects have six feet and four wings.
Phylum Mollusca
 Body is soft and divided into head and muscular foot.
 Mantle - a secreted, hard calcareous shell.
 Alimentary canal is well developed.

 Respiration takes place through gills or ctenidia.
 Blood is colorless.
 Excretion by kidneys.
 Pila, Aplysia, Doris, Octopus are some examples.
Phylum Echinodermata
 All animals are marine in this group.
 Have water vascular system.
 In nervous system, brain is not developed.
 Special capacity of regeneration.
 Only vertebrate animals, contains proper bones like ossicles.
 Star fish, Sea urchin, Sea cucumber are some examples.
Phylum Chordata

 They have notochord.
 A hollow tubular nerve cord and paired pharyngeal gill slits.
 In advanced chordates, notochord changes to vertebral column, nerve cord develops to
brain and spinal cord gill slits to structures of jaw attachment.
 Divided into two sub-phylum – Prochordata and Vertebrata.
Class Pisces
 Aquatic animals.
 Heart pumps only impure blood and contains two chambers.
 Respiration by gills.
 Trygon, Scoliodon, Torpedo etc. are examples.
Class Amphibia
 First land vertebrates.
 Found both on land and in water.

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