1 define serial homology how do the jointed appendages of...

1) Define serial homology. How do the jointed appendages of the crayfish illustrate this concept? 2) What is the scientific name for the large pincers of the crayfish? Including the pincers, how many pairs of walking legs does the crayfish have? Name the appendages found on the abdomen of the crayfish. How can you identify the sex of the specimen by examining these appendages? What special use do they have in the female? 3) What is the scientific name for the brain of the crayfish? Along what surface of the crayfish body does the nerve cord run? (Use anatomical terminology)

Transcript

00:01 The video is divided into three parts for three different questions.

00:04 So talking about the first part of the question, it is about the serial homology and how they jointed appendages which is present in cryfish illustrate this serial homology concept.

00:16 So firstly, talking about the serial homologi, serial homologi can be defined as the arrangement of homologous organs serially in an organism.

00:26 It can be seen in appendages in anthropology.

00:30 Limbs of tetrapods and the vertebra of the organism.

00:34 So this is about the serial homologi and these are its example in which the serial homologi is present.

00:41 Now talking about the joint appendages, the joint appendages of a cryfish is a typical example of serial homologi.

00:49 Cryfish appendages consist of antineals, antinear, mandibles, first maxilla, second maxilla, first maxilli ped, second max leiped, third max leiped, cephalipad, walking legs, swim rites, euro pots and telson.

01:07 So it is basically a kind of serial homologi.

01:12 So basically here, when we observe the development pattern of these appendages during the embryonic stages, the protein which help in the development of these structures are almost the same.

01:23 The embryonic tissue which give rise to such appendages are also similar.

01:27 But in the later stage of development they vary in morphology and perform different function.

01:33 Still they are called homologous because they have similar origin.

01:39 So they have the major term that they have the similar origin...

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