Formation of cocoon in earthworm, Biology

Formation of cocoon in earthworm:
  • In earthworm segments from 14 to 17 are swollen. Skin on these segments is thick and glandular. This is called clitellum.
  • When ovaries mature, the clitellum secretes a viscous substance in the form of a girdle.
  • This girdle hardens into a cocoon around the clitellum.
  • Earthworm wriggles out of the cocoon - cocoon moves anteriorly and the worm moves posteriorly.
  • Ova are discharged into the cocoon. When the cocoon moves over the spermathecae openings. Spermatozoa received from another animal are stored in the spermathecae are discharged into it.
  • The cocoon finally comes out of the body and both ends of cocoon get closed.
  • Fertilization takes place in cocoon. Since fertilization is taking place outside the body, it is external fertilization.
  • After about 8 to 10 weeks, young earthworms come out of the cocoon.

 

981_Formation of cocoon in earthworm.png

Posted Date: 9/3/2012 3:28:37 AM | Location : United States







Related Discussions:- Formation of cocoon in earthworm, Assignment Help, Ask Question on Formation of cocoon in earthworm, Get Answer, Expert's Help, Formation of cocoon in earthworm Discussions

Write discussion on Formation of cocoon in earthworm
Your posts are moderated
Related Questions
Q. Why is meiosis significant for the maintenance of the normal quantity of chromosomes of a species with sexual reproduction? A reduction to a half of the maximum normal quant

Why Pulses are important for human - nutritional factor? Pulses are rich sources of proteins (20-25 g/100 g), the limiting amino acid being methioniize. However, protein quality

Myeloid immunodeficiency causes phagocytic function, which is impaired. Those who are affected with this will undergo with enhance in susceptibility to bacterial infection.

Describe the properties of gum ghatti Important property of gums referred to as 'viscosity' and the effets of pH. Gum ghatti does not form true aqueous solutions but form visco

Are the arterial pulsations normal? Is the pulse volume normal or increased? Is there a discrepancy of pulsation in any of the four extremities? A careful evaluation of pulsati

What is an etiological agent of disease? An etiological agent of disease is the agent that causes the disease. It might be a living being, substance or environmental fact.

General Characteristics of Protozoans The protozoans, are eukaryotes that form a group of about 80,000 single-celled organisms under the kingdom Protista. The unicellular leve

Describe how enzymes assay is helpful in milk and meat Wheat seeds a) Determination of  α-amylase, content: an increase indicates sprouting/ germination of stored wheat;

Endocrine glands Endocrine glands have no ducts - so these are also called as ductless glands Eg.Pituitary etc., These glands secrete chemical substances called HORMONES