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

Demand and supply of medical care, Normal 0 false false fal...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Explain pericardial effusion, Q.Explain Pericardial Effusion? The confi...

Q.Explain Pericardial Effusion? The configuration of the heart in pericardial effusion depends on the volume of fluid and its distribution. It may have a globular or non-speci

Explain hypertensive response, Q. Explain Hypertensive Response? Hypert...

Q. Explain Hypertensive Response? Hypertension at rest has long been known to be a risk factor for the development of coronary artery disease (CAD). Significant elevation of B

What do you mean by bone implant interface, Q. What do you mean by Bone Imp...

Q. What do you mean by Bone Implant Interface? It consists of remodelled bony tissue. For making it strong implant should not be overloaded during its organization period i.e.

Explain linolenic acids, Linolenic Acids Fats in this group contain sub...

Linolenic Acids Fats in this group contain substantial amounts of linolenic acid (C18 triunsaturated). Examples are soybean, mustard, rapeseed, flaxseed and wheat germ hemps

Foliose lichen stage - xerarch, Foliose Lichen Stage - Xerarch As ment...

Foliose Lichen Stage - Xerarch As mentioned earlier, the weathering of the rocks and the decaying of the crustose lichens results in the formation of soil on the otherwise bar

Radiolarians - protozoan, Radiolarians - Protozoan Radiolarians are en...

Radiolarians - Protozoan Radiolarians are entirely marine planktonic species with spherical bodies and radiating pseudopodia known as axopods. The spherical body is divided in

Cells, What physical and metaboloic constraints limit cell size?

What physical and metaboloic constraints limit cell size?

What are the inferior trophic levels, Can the amount of available energy in...

Can the amount of available energy in a given trophic level be larger than the available energy in inferior trophic levels? What does that condition means to the conformation of th

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