Cnidarians By Alexis Hodges
What is a Cnidarian?
- Are soft bodied, carnivorous animals that have stinging tentacles arranged in circles around their mouths. They are the simplest animals to have body symmetry and specialized tissues.
- Get there names from the Cnidocytes, or stinging cells, that are located along their tentacles.
- Cnidarians typically have a life cycle that includes two-different stages; a polyp and a medusa.
- A polyp is a cylindrical body with arm like tentacles.
- A medusa has a motile, bell-shaped body with the mouth on the bottom.
- Each have a body wall that surrounds an internal space called a Gastrovascular cavity.
- After a Cnidarian paralyzes its prey, it pulls the prey through its mouth and into the gastrovascular cavity. Which is a digestive chamber with one opening.
Respiration, Circulation, & Excretion
- The nutrients are usually transported throughout the body by diffusion.
- Cnidarians respire and eliminate the wastes of cellular metabolism by diffusion through their body walls.
- Cnidarians gather information from their environment using specialized sensory cells.
- Nerve net - is a loosely organized network of nerve cells that together allow cnidarians to detect stimuli such as the touch of a foreign object.
- Different Cnidarians move in different ways.
- Some Cnidarians , such as sea anemones, have a hydrostatic skeleton.
- Which consists of layer of circular muscles and a layer of longitudinal muscles that, together with the water in the gastrovascular cavity, enable the cnidarians to move.
- Reproduce both asexually and sexually.
- With most cnidarians , sexual reproduction takes place with external fertilization in water.
- Which takes place outside of the females body.