SQ's + answers-L10-Cnidaria

SQ's + answers-L10-Cnidaria - BIS 1B (Winter 2008) Study...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
BIS 1B (Winter 2008) Study questions: Cnidaria (lecture 10) 1. What is a cnida, and what is its function? This is the term for the intracellular stinging organelle of cnidarians. Cnidae are produced by specialized cells called cnidocytes, and consist of a capsule containing a long coiled thread-like tube. The thread frequently bears barbs or spines. After being triggered by a mechanoreceptor (usually a sensitive bristle-like or hair-like structure), the cnida discharges explosively, as a result of hydrostatic pressure. The cnida can entangle prey and/or inject them with toxins. There are many kinds of cnidae. Those with a double-walled capsule containing toxins are called “nematocysts”. 2. Distinguish between polyp and medusa forms of a cnidarian. A polyp is a tube-shaped and (usually) sessile form, anchored to a substrate, with the oral end away from the substrate. Polyps frequently occur in colonies. Examples include sea anemones (solitary) and corals (colonial). A medusa is a bell- or umbrella-shaped organism, usually free-
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/15/2008 for the course BIS 1b taught by Professor Kimsey during the Spring '08 term at UC Davis.

Page1 / 2

SQ's + answers-L10-Cnidaria - BIS 1B (Winter 2008) Study...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online