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chapter 4 -Animal Kingdom.

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01

DEFINITION
Phylum Coelenterata (Cnidaria)
  • Radially symmetrical, diploblastic multicellular animals with a tissue grade of organisation.
  • Aquatic, freshwater or marine solitary or colonial forms which may be free swimming or sedentary.
  • Locomotion and food capturing: tentacles.
  • Cnidoblasts, nematocysts or stinging cells used for offence and defence.
  • Coelom is absent. Hence, coelenterates are acoelomate animals
  • Reproduction is asexually or sexually.
  • For example, Hydra, sea anemone, jellyfish.
02

DEFINITION
Criteria for classification (notochord, segmentation, types of eggs)
Notochord
  • Animals with notochord in some stage of their life cycle are known as chordates whereas those which do not develop are called as non-chordates.
Body segmentation
  • Segmentation is an architectural body plan in which an organism is built by a series of segments known as metamers.
  • The segments can be both internally and externally.
Types of eggs
  • Homolecithal or Isolecithal: In this type, the quantity of yolk is very less and it is uniformly distributed all over the egg cytoplasm. For example, eggs of echinoderms. 
  • Heterolecithal: In these types of eggs, yolk is not evenly distributed in cytoplasm. They may be telolecithal, meiolecithal, centrolecithal.
03

DEFINITION
Phylum Protochordata/Hemichordata
  • Mostly marine, soft, unsegmented, triploblastic body having bilateral symmetry
  • Developed coelom and possess notochord only in embryonic stage
  • Body has three distinct parts i.e., proboscis, collar and trunk
  • Reproduction: Sexual
  • For examples, Balanoglossus, Herdmania, Amphioxus
04

DEFINITION
Non-Chordata
  •  Non-chordates are animals without a notochord. 
  • They are the most abundant and diversified of all animals living or extinct. 
  • Non chordata includes a number of phyla.
  • The major ones are Porifera, Coelenterata, Platyhelminthes, Aschelminthes, Annelida, Arthropoda, Mollusca and Echinodermata.
05

DEFINITION
Difference between chordates and non chordates
06

DEFINITION
Vertebrate
  • They have a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail.
  • Vertebrates are further differentiated from chordates by their vertebral column, which forms when their notochord develops into the column of bony vertebrae separated by discs.
  • Vertebrates are the only chordates that have a brain as part of their central nervous system.
07

DEFINITION
Difference between verterbrates and invertebrates
The difference between vertebrates and invertebrates are as follows:
VertebratesInvertebrates
Notochord is present in the embryo and vertebral column in the adult.Notochord and vertebral column are absent in embryo and adult.
Gill slits are present.Absent.
Nerve cord is single, hollow and non-ganglionated.Nerve cord is double, solid and ganglionated.
Cranium is present.Absent.
Post-anal tail is present.Absent.
Two pairs of appendages for locomotion.Many pairs when present.
Heart is ventral to the alimentary canal.Heart is dorsal to the alimentary canal.
Blood flows forward ventrally and backward dorsally.Blood flows forward dorsally and backward ventrally.
Haemoglobin is present in RBC.Haemoglobin if present is dissolved in plasma.
Endoskeleton is present.Absent.
08

DEFINITION
Phylum Chordata (Vertebrata)
  • Chordates possess a notochord, dorsal nerve cord, triploblastic, paired gill pouches and are coelomic.
  • Chordates that possess backbone are vertebrates.
  • Vertebrates are bilaterally symmetrical, triploblastic, coelomate with complex differentiation of body tissues and organs.
  • Vertebrates are grouped into six classes.
09

DEFINITION
Class Cyclostomata (Agnatha)
  • Marine animals having fishlike body with bilateral symmetry.
  • Have sectorial mouth and unpaired fins.
  • For example, petromyzon, myxine.
10

DEFINITION
Classification of Pisces
It is divided into three classes:
  • Class Placodermi (e.g., Climatius)
  • Class Chonrichthyes (e.g., Scoliodon,Torpedo, Chimaera)
  • Class Osteichthyes (e.g., Labeo, Hippocampus)
11

DEFINITION
Classification of Amphibia
Living Amphibians is divided into three orders:
  • Order Apoda (e.g., Uraeotyphlus, Ichthyophis)
  • Order Urodela (e.g., Salamandra, Proteus, Siren)
  • Order Anura (e.g., Alytes, Hyla, Xenopus)
12

DEFINITION
Classification of Reptilia
Living Reptiles are divided as follows:
Subclass 1: Anapsida
  • Order Chelonia (e.g., Chelone, Testudo, Trionyx)
Subclass 2: Diapsida
  • Order Rhynchocephalia (e.g., Sphenodon)
  • Order Squamata (e.g., Calotes, Bungarus)
  • Order Crocodilia (e.g., Crocodilus, Alligator, Gavialis)
13

DEFINITION
Classification of Aves
Class Aves is divided into two subclasses:
  • Subclass Archaeornithes (e.g., Archaeopteryx)
  • Subclass Neornithes (e.g., Bubo, Milvus, Pavo)
14

DEFINITION
Development in birds
  • In birds, as the fertilized egg or zygote travels down the oviduct, several layers of yolk and protective coverings are deposited around it by the wall of oviduct and uterus.
  • The hard shell is the outermost protective layer.
  • These shelled eggs are laid by the birds.
  • The development of chick takes place inside the egg shell.
15

DEFINITION
Classification of Mammalia
Living mammals are divided into two sub-classes.
  • Sub-class Prototheria (e.g., Ornithorhynchus)
  • Sub-class Theria (e.g., Macropus, Didelphis)

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