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

Define utilization of soy protein concentrate, Define Utilization of Soy Pr...

Define Utilization of Soy Protein Concentrate? Soy protein concentrates are used in food products for their nutritional characteristics or for their functional properties or fo

Rapport - building, Rapport-Building Here the Counsellor tries to esta...

Rapport-Building Here the Counsellor tries to establish a rapport and gain the client's trust. Let us see how we make friend? When we meet someone we take time to react, we ob

Define role of nutrients in controlling gene expression, Define Role of Nut...

Define Role of Nutrients in Controlling Gene Expression? The role of several nutrients in controlling gene expression, as mentioned earlier, is in infancy, but with advancing b

Respiratory distress syndrome, Respiratory Distress Syndrome: Respirat...

Respiratory Distress Syndrome: Respiratory distress in a  newborn is  a challenging problem.  It  accounts for significant morbidity and mortality. It occurs  in  4 to 6 per c

Explain about the term accommodation, Explain about the term accommodation....

Explain about the term accommodation. Normally, the human eye focuses at objects at infinity, without exerting any power. This implies that while a person is observing an objec

Self- vs. cross-pollination, Self- vs. Cross-Pollination A major adva...

Self- vs. Cross-Pollination A major advantage of self-pollination is its certainty. Continued self-pollination over many generations, however, results in weaker progeny. This

Clinical features of tricuspid regurgitation, Q. Clinical Features of tricu...

Q. Clinical Features of tricuspid regurgitation? Patients with severe primary tricuspid regurgitation will have symptoms of fatigue, dyspnoea and effort intolerance, abdominal

Cellular and molecular events of bone formation, Q. Summarize the cellular ...

Q. Summarize the cellular and molecular events of bone formation? The events involved in osseous wound healing at implants recapitulate the events of wound healing. Haemostasi

Arthropods, what are the general characteristics of arthropods?

what are the general characteristics of arthropods?

Experiment, I need an idea for a Biology experiment

I need an idea for a Biology experiment

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