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

From which structures is the nuclear membrane composed, Eukaryotic cells ha...

Eukaryotic cells have nucleus delimited by two juxtaposed membranes that start with the membrane of the endoplasmic reticulum. The nuclear membrane, or karyotheca, represents pores

What conclusion can draw about microorganisms, What conclusion you can draw...

What conclusion you can draw about microorganisms that you saw under microscope from the plaque of your teeth?

Explain the reduction in cancer risk, Explain the Reduction in cancer risk?...

Explain the Reduction in cancer risk? Different cancers, especially colon and breast cancer, has been linked not only to phytates but also to protease inhibitors. In vitro stud

Northern blot, Northern blot is a technique for analyzing mixtures of RNA ...

Northern blot is a technique for analyzing mixtures of RNA by transfer of size-separated RNA fragments to a synthetic membrane, the presence and rough size of one particular type

Chamaleon, how does chamaleon change its colour

how does chamaleon change its colour

Determine the parathryroid hormone receptors, Which of the following serves...

Which of the following serves as an effector, or part of an effector, that functions in a negative feedback system? A. 1,25-dihydroxyvitamin D Receptors located intracellularly

What are respiratory pigments, Q. What are respiratory pigments? What is th...

Q. What are respiratory pigments? What is the respiratory pigment present in some arthropods? Which is the analogous molecule in humans? Respiratory pigments are molecules able

Explain the cyclosporin, Q. What is the cyclosporin? How are fungi related ...

Q. What is the cyclosporin? How are fungi related to this substance? Cyclosporin is a drug discovered in the 1970's that revolutionized organ transplantation in Medicine, It is

Explain the steps for injecting insulin injection, Explain the Steps for In...

Explain the Steps for Injecting Insulin Injection It is important to teach patient to take injections at regular times, 30 to 60 minutes before meals. Take insulin everyday, ev

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