Reproductive organs, Biology

Assignment Help:

Reproductive Organs

In several metazoans, gonads are well-defined. Testes and ovaries take up dissimilar shapes and anatomical dispositions. In cases of certain hermaphrodites similar reproductive tissue from one part may generate sperms and from another part the ova. In sponges, gonads are poorly defined. Sperms and eggs arise from choanocytes and archaeocytes that are transformed into spermatogonia. Sperms leave the sponge by water currents. They enter choanocytes of other sponges that transport the sperms to the egg. Thus fertilisation takes place in situ by the intervention of choanocytes. In cnidarians, testes and ovaries are distinct. In a number of species of Hydra both tests and ovaries may be formed in the same individual (monoecious, bisexual) or in dissimilar individuals but in most species they are found in different individuals (dioecious unisexual). A single ovum produced in the ovary is fertilized in situ by the sperms generally coming from a different hydra. In colonial cnidarians the gonads are formed on the medusae from interstitial cells below the radial canals. They are formed in the epidermis of sub-umbrella. Fertilization is generally external, in water.


Related Discussions:- Reproductive organs

Functions of ecosystem, Ecosystems main functions are physical, chemical an...

Ecosystems main functions are physical, chemical and biological processes. Which is required for if maintenance of ecosystem. Some important function- 1.        Production of bi

Etiological factor of malabsorption syndrome, Q. Etiological factor of mala...

Q. Etiological factor of malabsorption syndrome? The causes cited for malabsorption can be associated with a number of diseases. Many of these diseases you may not know presen

Taxonomy, what arachnid is beneficial

what arachnid is beneficial

How sequences of events occur to activate protein kinase a, When glucagon b...

When glucagon binds to it's receptor on a liver cell, which one of the following sequences of events occurs to activate protein kinase A? -activation of G protein, activation of

How to decreases the rate limiting, When the product of a metabolic pathway...

When the product of a metabolic pathway decreases the rate limiting earlier in the pathway it is called?

Explain the solubility in water of dietary fibre, Explain the Solubility in...

Explain the Solubility in Water of dietary fibre? Fibres that dissolve in hot water are soluble and those that do not, are insoluble. Several structural features affect solubil

Define eye balling, Q. Define Eye Balling? Ans. Two-dimensional ec...

Q. Define Eye Balling? Ans. Two-dimensional echocardiography provides a good visual perception of cardiac functions. With experience, the echocardiologist learns to percei

Non-ketotic hyperosmolar diabetic coma, Non-Ketotic Hyperosmolar Diabetic C...

Non-Ketotic Hyperosmolar Diabetic Coma (NKHDC) is another acute complication of diabetes mellitus. In this condition, the coma (loss of consciousness) is developed due to high blo

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