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Molluscs

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Methods of Reproduction

(slugs mating)
slugs1.jpg

  • Reproduction methods vary depending on classes of molluscs and characteristics
  • Hermaphrodites possess the organs of both sexes, such as land snails who may pass sperm from one snail to another
  • Most molluscs follow this pattern: eggs and sperm are released into the water, fertilization occurs without contact

Marine Molluscs

  • because most molluscs are water molluscs, this was the main focus point
  • reproduction occurs in a variety of stages, first stage occurs in in the water column where sperm flows with the water, a female finds it and fertilizes her eggs
  • after fertilization, it takes one to ten months for the larva to develop in the female
  • when finally developed, the glochidia are released where they will drift until finding an acceptable habitat 

  • they are divided into two distinct groups depending on where they are released: bradytictic and tachytictic
  • Bradytictics are long-term breeders in which hold their larvae through the winter until spring or summer
  • Tachytictics are short-term breeders who release their larvae later that same year, namely July and August

 
  • Timing and the disperment of the eggs are crucial to the survival of the glochidia because they cannot survive for a long period of time outside the mother's womb
  • A fish host is therefore necessary, the glochidia act like a parasite to the fist host, attaching themselves to its gills or gills and feed upon them
  • The cells on the host will lyse, fluid coming from these cells provides essential nutrients needed for glochidia survival

(squid reproduction)
squid1.jpg





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