What is an Annelid?
Definition: segmented worms: earthworms; lugworms; leeches
Definition: segmented worms: earthworms; lugworms; leeches
Body Plan:
Annelids have complex organ systems. Many of these systems are unique because of the segmented body plan of this group. Feeding: Annelids range from filter feeders to predators. Many annelids get their food using a pharynx. There are carnivorous species and ones that feed on decaying vegetation. Circulation: Annelids typically have a closed circulatory system. An earthworm's blood circulates through two major blood vessels that run from head to tail. Respiration: Aquatic annelids often breathe through gills. Land-dwelling ones take in oxygen and give off carbon dioxide through their moist skin. |
Excretion:
They produce two kinds of wastes. Digestive waste passes out through the anus at the end of the digestive tract. Cellular waste containing nitrogen is eliminated by nephridia. Response: Most annelids have a well-developed nervous system consisting of a brain and several nerve cords. However, the sense organs are best developed in free-living marine annelids. Many of there species have a variety of adaptations for detecting stimuli: sensory tentacles, chemical receptors, statocysts that help detect gravity, and teo or more pairs of eyes Reproduction: Most annelids reproduce asexually. Some annelids are hermaphrodites. |