Morphological changes, Biology

Assignment Help:

Morphological changes

Regressive changes-These changes include the gradual reduction and ultimate disappearance of all those larval structures or organs that become redundant in adults. The ventral suckers, external gills, the long tail along with fin folds are reabsorbed during early functional life. The peribranchial cavities, the gill clafts are closed; the horny teeth and horny lining of the jaws are lost. The shape of the mouth changes, the cloacal tube shortens and gets reduced. The lateral line organs of the skin of tadpole disappear and some blood vessels are reduced.

Progressive changes-A number of organs and structures become functional during and after metamorphosis. In the anurans these alters are tabulated in Table and include the development of the fore and the hind limbs, the middle ear in connection with the first pharyngeal pouch (the pouch situated among the mandibular and hyoid arches), the tympanic membrane supported through the circular tympanic cartilage. The eye protrudes on the dorsal surface of the head and makes an upper eyelid. The tongue develops from the floor of the mouth.

Remodeling -Some structures and organs that occur and function both before and after metamorphoses, get transformed or remodeled throughout the process in order to meet the requirement of the adult mode of life. These changes, affect primarily the skin, intestine and brain. The skin thickens, and turns into glandular by developing multicellular mucous and serous glands. It also develops an outer keratinized layer also characteristic color and pattern of pigmentation. The brain gets highly differentiated. The intestine that was long and coiled in the herbivorous tadpole shortens and straightens out: Other notable changes which take place are the change in the blood vascular system in order to supply the lungs, the change in the portal system the alteration in the heart as it becomes three chambered from being two chambered earlier.

 


Related Discussions:- Morphological changes

Prevention - rheumatic fever, Acute GAS pharyngitis should be treated promp...

Acute GAS pharyngitis should be treated promptly by penicillin or other antibiotics. Indian Council of Medical Research (ICMR) recommends that all cases of pharyngitis must receive

Trophic structure-structure of community, Trophic structure Organisms i...

Trophic structure Organisms in a community are closely interrelated with each other through feeding relationships. Another aspect which is quite obvious in a community is th

Excretory system, What are the excretory organ in protozoa,coelenterates, i...

What are the excretory organ in protozoa,coelenterates, insects,spider,and arthropods

Reroduction, describe and compare reproduction in all the kingdoms except k...

describe and compare reproduction in all the kingdoms except kingdom animalia

Explain immunogenicity, Immunogenicity  The safety and immunogenicity o...

Immunogenicity  The safety and immunogenicity of the new vaccine was evaluated in two unpublished studies that are summarized in the package insert. Among 1280 adults (18-55 ye

What are organogenesis and histogenesis, Q. What are organogenesis and hist...

Q. What are organogenesis and histogenesis? Histogenesis is the procedure of tissue formation in the embryonic development. Organogenesis is the procedure of organ formation. B

New Technology, What is the best microscope to get a detailed view of the p...

What is the best microscope to get a detailed view of the parts inside of a preserved plant cell

Female reproductive system from the external vulva, Q. What are the anatomi...

Q. What are the anatomical relationships between the organs of the female reproductive system from the external vulva to the ovaries? The external female genitalia are called t

What is a homologue, Single chromosome of a pair is known as homologue.In H...

Single chromosome of a pair is known as homologue.In Homologous pair two identical chromosomes are there. Each one chromosome in a Homologous pair is known as Homologue.

What kind of eye defect can give rise to short-sightedness, What kind of ey...

What kind of eye defect can give rise to short-sightedness? Long eyeballs, large eyeballs, too powerful a lens or a combination of these defects can give increase to short-sigh

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd