Monday, 11 June 2018

Origin and evolution of life..additional information 3
progenote life tree

Latimeria (coelacanth) it is a living Fossil which watch taken off from the coast of South Africa on December 22, 1938 by some fishermen. fisherman could not identify it's so they brough the specimen to miss Courtenary latimer curator of the local museum. when she failed to identify it, and it sketch to Professor .J.L.B. Smith, an eminent ichthyologist of Rhodes University college at Grahams town. he recognised is surviving member of crossopterygii (subclass of class osteichthyes) and named it latimeria chalumnii, after the discoverer and locality. its Discovery is of special interest because it is believed that crossopterygains (fleshy finned fish) were the ancestors of the first amphibians. latimeria is believed to be the oldest amongest living fishes.
latimeria(living fossils)
wallace's line
weber line
The Ancon Sheep. in seth wright's farm in Massachusetts, America, a normal sheep gave birth Ram( male sheep) with very short and curved legs in 1791. by artificial breeding from this ram seth wright raised are different sheep called ancon sheep ( very short legs sheep). after several generations, this character suddenly disappeared.formation and disappearance of ancon sheep is good example of mutations (discontinuous variations).
Ancon sheep
Mimicry. it is a kind of adaptation. the term mimicry was introduced introduce in biology by Bates 1862. it is defined as "the resemblance of one organism to another objects or to any natural object for the purpose of concealment, protection or for some other advantage. the organism which exhibit mimicry is called a mimic. ther organism or object which is mimicked or imitated is called a model.
peripatus- Phylum Arthropoda
limulus - Phylum Arthropoda
neopilina -phylum mollusca

latimeria - Bony fish
sphenodon- class reptilia