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

Explain about the endocrine system, Why is the endocrine system considered ...

Why is the endocrine system considered one of the integrative systems of the body? What is the other physiological system that also has this function? The endocrine system is s

Explain about the colour sense, Explain about the Colour Sense Colour S...

Explain about the Colour Sense Colour Sense  is  the faculty whereby we are enabled  to  distinguish colours as  excited by  light of  different wave  length. The ability  to a

Classification of anaemia based on etiology, Classification of Anaemias Bas...

Classification of Anaemias Based on Etiology   Anaemia  can be classified  as   Impaired Production of Red Blood Cells and Hemoglobin: This can be due to nutritional  def

What is pollen, What is pollen? Pollen grains are the male gametophytes...

What is pollen? Pollen grains are the male gametophytes of the phanerogamic (flowering) plants. Thus within the pollen grains the male gametes of these plants are produced by m

General biology , What organic molecules make up the cell membrane?

What organic molecules make up the cell membrane?

Regulation of breathing and blood pressure, Q. Which is the brain region re...

Q. Which is the brain region responsible for the regulation of breathing and blood pressure? The neural regulation of breathing, blood pressure and other physiological paramete

Gene therapy, In experimental studies, gene therapy has been shown to impro...

In experimental studies, gene therapy has been shown to improve failing human myocardial function. The abnormal function of  myocytes obtained from patients with dilated cardiomyop

Eastern/western/venezuelan equine encephalitis, Eastern/Western/Venezuelan ...

Eastern/Western/Venezuelan equine encephalitis This encephalitis causing group of viral diseases of wild birds including pheasants, chickens, turkeys, ducks and pigeons with a

Which period of life does the formation of gametes begin, Q. In which perio...

Q. In which period of life does the formation of gametes begin in women? The meiosis that forms female gametes begins in the cells of the ovarian follicles before birth after t

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