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 the importance of vitamin E, Explain the Importance of Vitamin E ...

Explain the Importance of Vitamin E Vitamin E has a pronounced antioxidizing effect. Because of this property, vitamin E decreases the basic metabolism of the tissues or the ox

What are the types of neurons, According to the function of the transmitted...

According to the function of the transmitted neural impulse which are the types of neurons? How different are the concepts of afference and efference of the neural impulse transmis

Efficiency of feed utilization on complete feeds, Efficiency of feed utiliz...

Efficiency of feed utilization on complete feeds The complete diet concept is based on group rather than individual feeding and usually involves much fewer changes in diet for

Explain the absorption, Explain the Absorption, Storage and Elimination of ...

Explain the Absorption, Storage and Elimination of thiamin? After a meal, thiamin is found in the intestine in the free form. Its absorption involves two mechanisms- both acti

Aids associated and adolescent crisis emergencies, Other Psychiatric Emerge...

Other Psychiatric Emergencies:   1) Psychotropic Drug Withdrawal Abrupt cessation of antipsychotic, benzodiazepines result in symptoms of withdrawal including abdominal pain, i

Dietary guidelines fur hyperlipidemic patients, Q. Dietary Guidelines fur h...

Q. Dietary Guidelines fur hyperlipidemic patients? • Calories: to maintain ideal body weight. • Carbohydrates should constitute 55-65% of calories with emphasis on • polysacc

What do you man by extracellular digestion, Q. Concerning extracellular dig...

Q. Concerning extracellular digestion what is meant by chemical digestion? Chemical digestion is the series of enzymatic reactions to break macromolecules into smaller ones.

Continuous wave doppler, When a ventricQlar septa1 defect (VSD) is present,...

When a ventricQlar septa1 defect (VSD) is present, with no aortic stenosis, the peak velocitgr  across the defect reflects the difference in pressure between the right ventricle an

Metazoans., explain the different types of symmetry in metazoans.

explain the different types of symmetry in metazoans.

Composed of proteins and dna, Chromosomes, colored bodies, are composed of ...

Chromosomes, colored bodies, are composed of proteins and DNA; so are chromatids. At metaphase I there are 46 chromosomesaligned in pairs along the human cells equatorial plate. At

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