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Group Description

"Learn Biology" is an interactive journal for the study of biology.

Update: Tidbits from Mac's book are being posted at this page (visit and "like"): http://www.facebook.com/biology4everyone

Book "Biology for Everyone" is available for Kindle:

This group was formed in February '08, and since then we have moved from simple to complex according to cladistics. We have covered molecular biology, genetics, cell behavior, cladistics, evolution, botony, zoology, anatomy, nutrition and ecology. Mac is an expert in this field and he has posted 35 essays to guide the group, which have become 64 chapters in a book called "Biology for Everyone". The latest copies are in the files section.

I invite anyone to join, read, and post on biology, especially those who would like to learn more! I reserve the right to moderate any member. Thanks for understanding.


Photo: Nematocyst Discharge

The diagram above shows the anatomy of a nematocyst cell and its “firing” sequence, from left to right. On the far left is a nematocyst inside its cellular capsule. The cell’s thread is coiled under pressure and wrapped around a stinging barb. When potential prey makes contact with the tentacles of a polyp, the nematocyst cell is stimulated. This causes a flap of tissue covering the nematocyst—the operculum—to fly open. The middle image shows the open operculum, the rapidly uncoiling thread and the emerging barb. On the far right is the fully extended cell. The barbs at the end of the nematocyst are designed to stick into the polyp’s victim and inject a poisonous liquid. When subdued, the polyp’s tentacles move the prey toward its mouth and the nematocysts recoil back into their capsules.

Group Information

  • 63
  • Students
  • Feb 24, 2008
  • English

Group Settings

  • This is a public group.
  • Attachments are permitted.
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  • Listed in Yahoo Groups directory.
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  • Messages from new members require approval.
  • All members can post messages.

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