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

What do you understand by chromosome behaviour, Q. What do you understand b...

Q. What do you understand by Chromosome Behaviour? When we study meiosis. we not only observe the regularity of pairing which is important' for' the fertility of the plants, we

Glycolysis, define glycolysis.describe the various steps of glycolysis

define glycolysis.describe the various steps of glycolysis

Describe in detail about the huntington''s disease, Describe in detail abou...

Describe in detail about the Huntington's disease The brain of a person who has died as a result of Huntington's disease or Alzheimer's disease will look abnormal even to the

What do you mean by subxiphoid long axis sweep, Q. What do you mean by Subx...

Q. What do you mean by Subxiphoid Long Axis Sweep? This sweep begins with keeping the transducer at subxiphoid region, positioning directly posterior with marker pointing towar

What do you mean by recovery period, Q. What do you mean by Recovery Period...

Q. What do you mean by Recovery Period? At the instant exercise is discontinued, the ECG recorded is turned on and left running for a few seconds while the blood pressure is re

Define absorption, Define Absorption, Storage and Elimination of Vitamin D?...

Define Absorption, Storage and Elimination of Vitamin D? As we have already mentioned earlier, all fat-soluble vitamins share a common metabolic fate. Vitamin D is absorbed al

Explain the characteristics of starch granule, Explain the Characteristics ...

Explain the Characteristics of Starch Granule Starch granules, primarily, are made up of amylose (20-30%) and or amylopectin (70-80%) molecules arranged radially. Each granule

Setting priorities for action - functions of consciousness, Setting priori...

Setting priorities for action: It is not enough for our actions to be coordinated with events in the outside world; they must reflect our internal needs. Pain can flood conscious

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