Hydra – metazoa, Biology

Assignment Help:

Hydra – Metazoa

The animals of phyla Cnidaria and Ctenophora are made up of only two germ layers: ectoderm which forms the outer covering of the animal and endoderm which is the inner layer and is also known as the gastroderm. However, a non-cellular jelly like substance mesoglea is present between ectoderm and endoderm which acts as a cement to bind the two layers. This layer should not be confused with the third germ layer i.e. mesoderm. Since animals of these two phyla do not have mesoderm, they are said to be diploblastic.

2474_Hydra – Metazoa.png

Figure: L.S. Hydra

If we cut a longitudinal section through 'Hydra we see two distinct layers bound together by a non-cellular mesoglea. The two germ layers give rise to many different cell types - as evident from figure. Rest of the animals (platyhelminths to mammals) are all made up of three germ layers viz. ectoderm, endoderm and mesoderm. These animals are triploblastic. If we cut a section say through a horse (a mammal and triploblastic) can we expect to see three layers like you see two layers in diploblastic Hydra? No we will net, because these three germ layers do not .remain as such, they differentiate and modify to give rise to different structures and organs in the body of the horse. The three layers will be distinct only during early embryology. Hence we call them the embryonic layers or the germ layers.


Related Discussions:- Hydra – metazoa

Explain procedure for checking the presence of rhodamine b, Explain Procedu...

Explain Procedure for Checking the Presence of Rhodamine B? Conduct the experiment following the procedure given herewith: 1. Pour liquid paraffin or mineral oil in a Petri

Science class, Im learning about difference cell structures in science. I w...

Im learning about difference cell structures in science. I was wondering if I might be able to get some information about the epithelial tissue, and the connective tissue. Thankyou

Secretion of hormones, Secretion of Hormones The secretion of most hor...

Secretion of Hormones The secretion of most hormones (except steroid) is by the process of exocytosis. Figure summarises the formation, transport, release and reconstitution o

Explain about derived proteins, Derived Proteins These are not naturall...

Derived Proteins These are not naturally occurring proteins and are obtained from simple proteins by the action of enzymes and chemical agents, heat, mechanical shaking, UV or

Illustrate mitral stenosis and pregnancy, Q. Illustrate Mitral Stenosis and...

Q. Illustrate Mitral Stenosis and Pregnancy ? Since mitral stenosis is often seen in young women, it is not uncommon to see young women with pregnancy complicated by mitral ste

What is the significance of pronephric, What is the significance of Proneph...

What is the significance of Pronephric? The first, or ancestral, kidney that appears in the anterior part of the coelomic cavity and is connected to the archinephric duct. In a

Define isolated soybean proteins in cereal products, Define isolated soybea...

Define isolated soybean proteins in Cereal products? ISP is sometimes used instead of, or in combination with isolates and soy flour, in the formulation of milk replacer mixtur

Genomic dna from the sea urchin, Eric Davidson isolated and compared the se...

Eric Davidson isolated and compared the sequences of mRNA transcripts and genomic DNA from the sea urchin. Which of the following is a true statement regarding his findings? A.

Describe tr murmur and vsd murmur in details- heart diease, Describe TR Mur...

Describe TR Murmur and VSD murmur in details? TR Murmur :   Characteristic: Holosystolic murmur, loudest at left lower-sternal border and becomes louder with inspiration (Carv

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