Notes Ghar

 Ecological Pyramid  Page -1 Page -2  

        Energy Flow                     Page - 1 Page - 2

  Prototheria (Gr., protos-first + theria- beast) Primitive, reptile like , oviparous (Eg. Echina ‘spiny anteater’) General feartures  :- Marsupials brood pouch on the ventral side occupy a wide variety of niches and varied in diets Viviparous  warm blooded Body covered by hair Pinna well developed Mammary  glands have tits All digits are clawed Skull dicondylic Mandible is a single bone called is Dentary Orbital  and temporal fossa and are congruent  Seven cervical vertebrae is Y shaped bones in caudal vertebrae  4 th toe is largest in hind limb, serves as axis of foot Clavicle is well developed. Inter- clavicle is absent Penis is present in  some animal it is bifurcated Fertilisation and initial development is internal Young ones are born in an immature state Affinity with prototheria :-                                                                 Cloaca presents                                                Play vehicle present.                        Corpus callosum absent.    

 Canal system in sponges  There are three different types of canal system found in sponges are as follows :- 1.Ascon type:- eg. Leucosolenia Simplest type of canal system Spongocoel is lined by flagellated caller says or chanocytes Ostia open into is Spongocoel  which is a single , large , spacious cavity in the sponge body Spongocoel open to outside through a narrow circular opening called the osculum  located at the distal free end Flow of water is slow because the large is Spongocoel  contains much water that cannot be pushed out readily  through a single osculum Ingressing water - Ostia - spongocoel - Osculum - water outside 2.Sycon type :- eg - scypha, Grantia In more complex Sycon type  incurrent canals are irregular branching and anastomosing,forming large sub dermal spaces. There are two types of canals are found in as sycon type in current and radial Alernate with each other Incurrent pores (dermal Ostia) found on outer surface of the surface of the body open into prosopyles .

 Origin of Bilateria                                        First meta zones are very likely to radial animals Believed that bilateral symmetry evolved in radical ancestor when it is started creeping There are several theories given by many scientists for the Bilateria symmetrical animals are as follows:- 1.Ctenophore polyclad Theroy  :-  Ctenophores provided a a bridge or intermediate forms between                 radiate coelonterate and ancestors  and bilateral polyclad flat warms. Based on resemblance:- Oval flat and shaped with dorsal ventral differentiation Creeping on entire ventral surface Presence of two dorsal tentacles Centrally located ventral mouth Radiating, anastomosing nervous system Swimming larval stages of polycalds have eight ciliated lobes and comparable  to 8 comb rows of ctenophore  Limitations:- Cleavage is biradical in ctenophore but spiral in polyclad  Acoel flatworms are now regarded to be a most primitive 2.Planuloid-Acoeloid Theroy:-   Ludwig Von Graft form