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 prophylaxis - fungal infection, Prophylaxis   High-risk neutrope...

Prophylaxis   High-risk neutropenic patients, such as those undergoing allogeneic and certain autologous stem cell transplants, and those with hematologic malignancy who are exp

Explain tertiary butylhydroquinone, Tertiary Butylhydroquinone (TBHQ) T...

Tertiary Butylhydroquinone (TBHQ) TBHQ is moderately soluble in oil and slightly soluble in water. In many cases, TBHQ is more effective than any other antioxidant in providing

Describe the number of implants, Number of Implants The use of more imp...

Number of Implants The use of more implants decreases the number of pontics and the associated mechanics and strains on the prosthesis, and dissipates stresses more effectively

What are the main human degenerative diseases, What are the main human dege...

What are the main human degenerative diseases? The main human degenerative diseases are separated into three groups: cardiovascular diseases, neoplastic diseases and degenerat

Tell us about three kinds of dna, There are 3 types of DNA sequences. Genom...

There are 3 types of DNA sequences. Genomic DNA comes from the genome and haves both genes and extragenic material. cDNA is reverse transcribed from mRNA and corresponds only

What do you mean by herbaria and museums, Q. What do you mean by Herbaria a...

Q. What do you mean by Herbaria and Museums? A herbarium is a collection of pressed and dried plants arranged according to some valid system of classification and available for

Define bacterial photosynthesis, Cyanobacteria carry out photosynthesis usi...

Cyanobacteria carry out photosynthesis using two photosystems as in green plants. Furthermore, other photosynthetic bacteria, like as the purple photosynthetic bacterium Rhodospiri

Zoonotic diseases-japanese encephalitis, Japanese encephalitis Japanes...

Japanese encephalitis Japanese encephalitis (JE) is a mosquito-borne encephalitis and is caused by  flavivirus belonged to the family Flaviviridae. It is a zoonotic disease, i

What is starch , Starch exists in plants as insoluble starch granules in c...

Starch exists in plants as insoluble starch granules in chloroplasts.  Each starch granule   holds   a   combination   of   two   polysaccharide    forms, amylopectin and amylose.

Explain the techniques of operation in post myocardial, Explain the Techniq...

Explain the Techniques of Operation used in post myocardial infarction ventricular septal defect? Normal 0 false false false EN-IN X-NONE X-NONE

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