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

Define key concepts and facts about disaccharides, Define Key Concepts and ...

Define Key Concepts and Facts about Disaccharides? 1. All disaccharides contain 2 monosaccharides. 2. Disaccharides are linked by glycosidic linkage. 3. If both the functional

Renal parenchymal disease, Renal parenchymal disease is the commonest cause...

Renal parenchymal disease is the commonest cause of secondary hypertension.  Hypertensive and diabetic nephropathy and chronic glomerulonephritis are the main causes. Eventually, t

What are the processes that autotrophic beings, What are the processes that...

What are the processes that autotrophic beings use to produce organic material from inorganic substances? The Autotrophic beings make organic material by photosynthesis or by c

Double vessel disease, Double Vessel Disease (DVD) :  Percutaneous interve...

Double Vessel Disease (DVD) :  Percutaneous intervention with stetting is usually advised for these patients. However if it is left main equivalent disease or when block is close

Explain protein deficiencies in nutritional care, Explain Protein Deficienc...

Explain Protein Deficiencies in Nutritional Care? A depleted amino acid pool leads to poor wound healing (dehiscence), delayed healing of fractures, anaemia, depressed pulmonar

Explain barrier techniques - personal protective equipment, Q. Explain Barr...

Q. Explain Barrier Techniques - Personal Protective Equipment? The use of personal protective equipment (PPE) - clothing, masks, eyewear, and gloves - is part of routine dental

Classification, what is the mode of nutrition in fungi?

what is the mode of nutrition in fungi?

Explain briefly pinocytosis , Unlike the phagocytosis, that is a regul...

Unlike the phagocytosis, that is a regulated form of endocytosis carried out by a small number of cell category, pinocytosis is a constitutive process which happens continuously in

What is ecology, What is Ecology? Ecology is the field of Biology that ...

What is Ecology? Ecology is the field of Biology that studies the relationship among living beings and among living beings and the environment.

The importance of buffer systems in the human body, Outline the importance ...

Outline the importance of buffer systems in the human body. In addition, describe the main biological buffer systems and how they function.

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