Formation of cocoon in earthworm, Biology

Assignment Help:
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


Related Discussions:- Formation of cocoon in earthworm

How environmental temperature affect requirement of protein, How Environmen...

How Environmental temperature affect requirement of protein? Environmental temperature: As environmental temperatures rise or fall above or below the range of thermic neutralit

Define need of vitamin c during pregnancy period, Define need of vitamin C ...

Define need of vitamin C during pregnancy period? Vitamin C deficiency has not been shown to affect the course or outcome of pregnancy in humans, although low plasma levels hav

Social determinants of health - social exclusion, Social Determinants of He...

Social Determinants of Health - Social Exclusion Given that absolute poverty is a major determinant of ill-health, the resultant social exclusion is ‘psychologically damaging,

Define natural gums - hydrocolloids, Natural Gums These are derived fro...

Natural Gums These are derived from various plant as well as microbial sources and are divided into the following four basic categories: 1.  Seaweed gums:   Agar, Alginate,

Coeleterates, what are the characteristics of cleavage formed in coelentera...

what are the characteristics of cleavage formed in coelenterates?

Determine which seed is best for your lawn, Assume that your yard has many ...

Assume that your yard has many tall trees that result in about fifty percent of the yard being shaded and fifty percent of the yard being exposed to full sun. The shaded areas and

Does rna molecule have two polynucleotide chains like dna, Does RNA molecul...

Does RNA molecule have two polynucleotide chains like DNA? Only DNA has two polynucleotide chains. RNA is produced by just one polynucleotide chain. Nucleic Acid Review - Im

Nucellus - seed, Nucellus - Seed In a large majority of flowering plan...

Nucellus - Seed In a large majority of flowering plants the nucellus is gradually utilized by the endosperm or embryo. In leguminous seeds, for example, the nucellus degenerat

Patterns of cleavage, P A TTERNS OF CLEAVAGE - Patterns of cleavage d...

P A TTERNS OF CLEAVAGE - Patterns of cleavage depends upon amount of yolk & distribution of yolk. These are following types - 1 .       RADIAL CLEAVAGE PATTERN -

Why are agricultural fields often less stable, Why are agricultural fields ...

Why are agricultural fields often less stable than natural communities in the similar area? Because agricultural fields usually having one species of crop plant, they have low

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