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 the needs for enteral feeding, Define the needs for Enteral Feeding?...

Define the needs for Enteral Feeding? For enteral feeding following need to be considered: - In preterm calorie density to be 0.8 Kcal/ml, - LBW formulas used: protein -

Define salient modifiable factors which affect birth weight, Define salient...

Define salient modifiable factors which affect birth weight? The following are the salient modifiable factors which affect birth weight and gestation adversely: Iron deficiency

System that permits movement and fixation to echinoderms, What is the syste...

What is the system that permits movement and fixation to echinoderms? The system that allows movement and fixation to substrates in echinoderms is known as the ambulacral syste

Listeriosis, Listeriosis The organisms have an extensive host range which ...

Listeriosis The organisms have an extensive host range which includes mammal, poultry, fish, crustaceans and ticks including man. The organism has been isolated from sheep, goats,

Define the food processing, Define the Food Processing? We are all awar...

Define the Food Processing? We are all aware that delay in the use of fresh foods, alters its freshness, palatability and nutritive value. Therefore, it becomes very important

Which animals make tracheal respiration, Q. Which animals make tracheal res...

Q. Which animals make tracheal respiration? Is there a blood-like fluid that participates in this process? Arachnids and Insects are the arthropod animals that make tracheal re

Define the term ancestral characteristic, Define the term Ancestral charact...

Define the term Ancestral characteristic A character shared by all members of a taxonomic group of organisms (taxon) and used to define the unique nature of the group. The cha

Cytokinesis, Simultaneously with the formation of two daughter nuclei, a cl...

Simultaneously with the formation of two daughter nuclei, a cleavage furrow appears in the middle of the cell. The furrows gradually deepen and divide the cell into two daughter ce

Defects of heart, DEFECT S OF HEART 1 .      Blue Baby syndrome (Cya...

DEFECT S OF HEART 1 .      Blue Baby syndrome (Cyanosis) - Due to persisting foramen ovalis in atrial septum even after birth, the impure blood from right auricles comes to

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