Polychaete, mollusca and echinodermata, Biology

Assignment Help:

Polychaete, Mollusca and Echinodermata

Polychaete and Mollusca

The polychaetes have a trochophore larva. A common trochophore larva is top shaped bearing a tuft of cilia at the apical end and a band or girdle of cilia termed as the prototroch which rings the body about one third to one half the distance from the apical tuft. It is the swimming organ and collects suspended food particles. The gut is a complete tube and mouth opens posterior to prototroch. Trochophore larva is characteristic of polychaetes and molluscs.

Echinodermata

Almost all larvae of echinoderms are planktonic. Not like the adults the larvae do not show pentamerous symmetry and do not have tube feet. They move by bands of cilia over the body and its projections. After a time of planktonic life a rudimentary skeleton starts to form and the larvae sink to the bottom to develop the adult shape and form.


Related Discussions:- Polychaete, mollusca and echinodermata

Express the term in brief protonephridia., Express the term in brief - Prot...

Express the term in brief - Protonephridia. An osmoregulatory-excretory structure found in some invertebrates. Also known as a flamecell, this tubule is closed at its distal en

Digestive system of mammals, DIGESTIVE  SYSTEM OF MAMMALS The tube f...

DIGESTIVE  SYSTEM OF MAMMALS The tube from mouth up to anus is called alimentary canal. Alimentary canal of man is about 9 meter and rabbit is about 6 meter. Digestive

Annuloplasty with a ring, Annuloplasty with a Ring :  The lings commo...

Annuloplasty with a Ring :  The lings commonly used are Carpentier- Edwards and Cosgrove's flexible half ring. The rings are C shaped and have incomplete circles to accommoda

What is cluster headache, What is Cluster headache This is a unilateral...

What is Cluster headache This is a unilateral pain in the head or face that rarely lasts longer than 2 hours but recurs repeatedly for a period of weeks or even months before d

Cow-pox (vaccinia), C o w - po x (vaccinia) E p ide...

C o w - po x (vaccinia) E p idemiology: This infection, although mostly occurring in cows, sometimes also occurs in buffaloes. Under natural conditions, t

Digestion of food materials, DIGESTION OF FOOD MATERIALS Digestion, you...

DIGESTION OF FOOD MATERIALS Digestion, you know, involves  the mixing of  food, its movement through the digestive tract and chemical breakdown of the large ntolecules of  food

Therapeutic dose of pyridoxine, Q. Therapeutic dose of pyridoxine? Ther...

Q. Therapeutic dose of pyridoxine? Therapeutic dose of pyridoxine (lg/day) is usually tried in all patients with hypermethioninernia and homocystinemia. For patients who do not

Why the enzymatic action is highly specific, Why can it be said that the en...

Why can it be said that the enzymatic action is highly specific? The enzymatic action is highly specific because only exact substrates of one enzyme bind to the activation cent

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