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

Show water permeability of the luminal membranes, Healthy Person H takes a ...

Healthy Person H takes a new drug named ANTICAMPCOLLDUCT that blocks the production of cyclic AMP (cAMP) in collecting duct epithelial cells in response to vasopressin binding to V

Explain the terms - sulphur and boron, Sulphur and Boron Boron is extra...

Sulphur and Boron Boron is extracted with hot water. Sulphur is extracted with 500 ppm solution of P solution (prepared from potassium dihydrogen orthophosphate or monocalcium

A protein is normally found inside of a lipid bilayer, A protein is normall...

A protein is normally found completely within the inside of a lipid bilayer. The protein likely has: a) Mostly hydrophobic side chains, pointed outwards, with the peptide backbo

Liquid manure handling, L iq uid manure handling This involves use of...

L iq uid manure handling This involves use of lot of water to flush the manure in to collection tank. Storage capacity depends on type of farm, irrigation facility, storage t

How does the absence of a nuclear envelope in prokaryotes, How does the abs...

How does the absence of a nuclear envelope in prokaryotes prevent prokaryotes from controlling gene expression by modifying RNA after transcription? Without a nuclear envelope

Management with insulin, Type 1 Diabetes Mellitus occurs when the body's im...

Type 1 Diabetes Mellitus occurs when the body's immune system destroys beta cells. Beta cells produce insulin, a hormone that helps to move the glucose contained in food into cells

Metalimnion - summer stratification, Metalimnion - Summer Stratification ...

Metalimnion - Summer Stratification This zone lies below the epilimnion and above the hypolimnion and thus forms the intermediate layer which is non-circulating. The metalimni

What do adp and atp mean, Q. What do ADP and ATP mean? What are the functio...

Q. What do ADP and ATP mean? What are the functions of these molecules for the cellular energetic metabolism? ADP is an short form of adenosine diphosphate, two molecules of ph

Define potential health benefits from resistant starch, Define Potential He...

Define Potential Health benefits from resistant starch? Like dietary fibre, RS can also play a potential role in helping to maintain or improve health of an individual. As you

How is the gastric mucosa protected from the acid ph, How is the gastric mu...

How is the gastric mucosa protected from the acid pH of the stomach? The gastric epithelium is mucus secretory, i.e., it makes mucus. The mucus covers the stomach wall preventi

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