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

Respiration, comparitive chart on different types of respiration obserbed i...

comparitive chart on different types of respiration obserbed in different type of respiration organ of respiration , types of respiration,energy obtained , by product formed

DEVELOPMENTAL BIOLOGY, DIFFERENCE BETWEEN VEGETATIVE AND GENERATIVE CELL

DIFFERENCE BETWEEN VEGETATIVE AND GENERATIVE CELL

Define the toxicity of vitamin k, Define the Toxicity of Vitamin K? Vi...

Define the Toxicity of Vitamin K? Vitamin K, does not produce any toxic effects in doses (10-20 mg) normally used for the treatment or subjects suffering from disorders of liv

How does plasma membrane regulate, How does a plasma membrane regulate move...

How does a plasma membrane regulate movement of molecules into and out of a cell?

Carditis, It has been shown by prospective studies that Rheumatic heart dis...

It has been shown by prospective studies that Rheumatic heart disease (RHD) is linked to the occurrence of carditis during the first episode of ARF. If the first episode is accompa

Explain clinical dietetics, Explain Clinical Dietetics Clinical Dietet...

Explain Clinical Dietetics Clinical Dietetics   is  the  application of dietetics  in  a  hospital  or Health care institutional  setting. Clinical dietetics focuses on an ind

Growth at different levels, GROWTH AT DIFFERENT LEVELS - 1.      Molec...

GROWTH AT DIFFERENT LEVELS - 1.      Molecular level - It involves synthesis of new molecules and their aggregation into organellae. 2.      Cellular level - It includes

What are the three main types of rna, What are the three main types of RNA?...

What are the three main types of RNA? What is meant by heterogeneous RNA? Messenger RNA, or mRNA, transfer RNA, or tRNA, and ribosomal RNA, or rRNA, are the three main kinds of

What do you mean by fixation?, What do we mean by fixation? Fixation is...

What do we mean by fixation? Fixation is the process of preserving internal and external structures of microorganisms.  It leads to the killing of microbial cells and their fir

The cerebrum, The cerebrum is clearly the most interesting part of the brai...

The cerebrum is clearly the most interesting part of the brain from the point of view of cognitive neuroscience. The cerebrum consists of highly symmetrical left and right hemisphe

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