What are the classes of annelids?

Most authors accept the annelids as having three major classes: Polychaeta, Oligochaeta, and Hirudinea.

1. How many classes belong to Annelida?
2. What are the two classes of phylum Annelida?
3. On what basis phylum Annelida is classified into five classes?
4. How are segmented worms classified?
5. How many annelids species have been identified?
6. What animals are in the class oligochaeta?
7. Why are leeches classified as annelids?
8. What is the difference between Polychaetes and oligochaetes?
9. What are the characteristics of phylum Annelida and Arthropoda?
10. Which class of annelida has free larval stage?
11. What are the 3 types of segmented worms?
12. How many species of earthworms are there?
13. How do the segments of the arthropods differ from the annelids segments?

How many classes belong to Annelida?

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 the two classes of phylum Annelida?

Phylum Annelida contains the class Polychaeta (the polychaetes) and the class Oligochaeta (the earthworms, leeches and their relatives).

On what basis phylum Annelida is classified into five classes?

About 8,700 known species of Annelida are divided into four main classes, primarily on the basis of presence and absence of parapodia, setae, metameres, and other morphological features.

How are segmented worms classified?

Earthworms are segmented worms. Segmented worms are in the phylum Annelida, which has over 22,000 known species. These worms are known as the segmented worms because their bodies are segmented, or separated into repeating units. Besides the earthworm, the segmented worms also include leeches and some marine worms.

How many annelids species have been identified?

aka: Segmented Worms. The phylum Annelida consists of over 22,000 living species of segmented worms. They include earthworms, leeches, and ragworms.

What animals are in the class oligochaeta?

Specifically, oligochaetes comprise the terrestrial megadrile earthworms (some of which are semiaquatic or fully aquatic), and freshwater or semiterrestrial microdrile forms, including the tubificids, pot worms and ice worms (Enchytraeidae), blackworms (Lumbriculidae) and several interstitial marine worms.

Why are leeches classified as annelids?

Helobdella sp. Leeches are segmented parasitic or predatory worms that comprise the subclass Hirudinea within the phylum Annelida. ... The body is muscular and relatively solid, and the coelom, the spacious body cavity found in other annelids, is reduced to small channels.

What is the difference between Polychaetes and oligochaetes?

The main difference between polychaetes and oligochaetes is that the polychaetes have a pair of parapodia per body segment that bear many bristles. But, oligochaetes have few bristles on their outer surface of the body but, no parapodia. ... Polychaetes and oligochaetes are two subclasses of phylum Annelida.

What are the characteristics of phylum Annelida and Arthropoda?

A distinguishing characteristic shared by annelids and arthropods is their body segmentation. At some point in development, segmented animals possess a body plan with repeating segments of identical or similar structures. Later in development, some segments may form more specialized structures.

Which class of annelida has free larval stage?

A free-swimming immature form called the trochophore larva develops in the polychaete annelids and during the development of certain other invertebrate groups—mollusks, sipunculids, and lophophores.

What are the 3 types of segmented worms?

The phylum Annelida contains the segmented worms. Annelida is further divided into three subclasses: Oligochaeta, Hirudinea and Polychaeta. Thousands of species of segmented worms comprise these three subclasses.

How many species of earthworms are there?

earthworm, also called angleworm, any one of more than 1,800 species of terrestrial worms of the class Oligochaeta (phylum Annelida)—in particular, members of the genus Lumbricus. Seventeen native species and 13 introduced species (from Europe) occur in the eastern United States, L. terrestris being the most common.

How do the segments of the arthropods differ from the annelids segments?

Annelid species typically have tubelike bodies consisting of numerous segments, known as somites, covered in stiff hairlike structures called setae that help the annelid move forward. ... On the other hand, arthropods have more complex segmented bodies covered in an exoskeleton that protects their organs and muscles.