What are the 2 main groups of annelids?
Traditionally the annelids have been divided into two major groups, the polychaetes and clitellates.
How many types of annelid are there?
A major invertebrate phylum of the animal kingdom, the annelids number more than 9,000 species distributed among three classes: the marine worms (Polychaeta), which are divided into free-moving and sedentary, or tube-dwelling, forms; the earthworms (Oligochaeta); and the leeches (Hirudinea).
How many segments do annelids have?
The number of segments varies from seven in some aquatic species to 600 in the earthworms.
What are the segments of annelids called?
All members of the group are to some extent segmented, in other words, made up of segments that are formed by subdivisions that partially transect the body cavity. Segmentation is also called metamerism. Segments each contain elements of such body systems as circulatory, nervous, and excretory tracts.
What are the 3 classes in phylum Annelida?
annelid summary Known as segmented worms, annelids are divided into three classes: marine worms (Polychaeta; see polychaete), earthworms (Oligochaeta), and leeches (Hirudinea).
How are annelids divided into classes?
There are three classes of annelids: Class Polychaeta: marine annelids; Class Oligochaeta: marine, freshwater and terrestrial annelids including earthworms; Class Hirudinea: marine, fresh water and terrestrial leeches.
What are 5 examples of annelids?
Examples of Annelids
- Earthworm.
- Leeches.
- Lugworms.
- Polychaetes.
What are the three classes of phylum Annelida?
Critical appraisal. Most authors accept the annelids as having three major classes: Polychaeta, Oligochaeta, and Hirudinea. Older systems would place the polychaetes and oligochaetes under the class Chaetopoda because both groups possess setae.
What is the difference between metameres and septa?
What is the difference between metameres and septa? External segments are called metameres and internally, septa, or dividing walls, are located between the segments.
What are 5 characteristics of phylum Annelida?
Characteristics of Annelida
- The Annelids are coelomate and triploblastic.
- They exhibit organ system level organization.
- Their body is segmented.
- They respire through their body surface.
- Nephridia are the excretory organs.
- They have a well-developed circulatory and digestive system.
What are the classification of phylum Annelida provide description of each?
What is the subclass of earthworms?
oligochaete, any worm of the subclass Oligochaeta (class Clitellata, phylum Annelida). About 3,500 living species are known, the most familiar of which is the earthworm (q.v.), Lumbricus terrestris. Oligochaetes are common all over the world.