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

Limerick, how do we write a limerick spell?

how do we write a limerick spell?

Male reproductive disorders-testicular hypoplasia, Testicular Hypoplasia ...

Testicular Hypoplasia Hypoplasia refers to testicular disorders related to congenitally underdeveloped and underactive spermatic epithelium of one or both testes even though t

Explain the metabolic alterations during cancer, Explain the Metabolic Alte...

Explain the Metabolic Alterations during Cancer? As we have studied earlier, patients with advanced cancer experience profound anorexia, early satiety, changes in the structure

How are ecological interactions classified, Q. How are ecological interacti...

Q. How are ecological interactions classified? Ecological interactions are classified as interspecific or intraspecific interactions and as harmonious or inharmonious interacti

Biotechnology... what is the answer/, At a biotechnologist, employment oppo...

At a biotechnologist, employment opportunities can be found in many areas. In addition to biotechnology companies, where can a scientist with a biotechnology background find employ

Sugarcane, what the by products of sugarcane

what the by products of sugarcane

Exogenous pathway, In the typical Western diet approximately 80-140 G trigl...

In the typical Western diet approximately 80-140 G triglyceride and 0.5-1.5 G cholesterol are eaten daily. Following digestion, absorption and reesterification, triglyceride and c

Hydrogen bonds important for making water cohesive liquid, Hydrogen bonds a...

Hydrogen bonds are important for all of the following except:: a) Allowing carbohydrates to dissolve in water b) Stabilizing the three-dimensional shape of proteins. c) Ma

What is hypertrichosis of the ear, In humans, attached earlobes are a domin...

In humans, attached earlobes are a dominant feature over free earlobes while hypertrichosis of the ear is a holandric (Y-linked) feature. A person with attached earlobes and extens

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