What is the difference between polychaeta and oligochaeta?

What is the difference between polychaeta and oligochaeta?

Polychaetes refer to the marine annelids, with unsegmented swimming appendages with many chaetes. Meanwhile, oligochaetes refer to the hermaphroditic terrestrial or aquatic annelids that lack a specialized head.

What are the 3 classes of segmented worms?

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

What belongs to oligochaeta?

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. They live in the sea, in fresh water, and in moist soil.

What four ways do Polychaetes differ from Oligochaetes?

Polychaete: mostly marine segmented worms. well developed head, each segment usually has parapapodia with chaetae, tube-dawelling and free moving. Oligochaeta: freshwater, marine, and terrestrial segmented worms such as earthworms, reduced head, no parapodia, chaetae present.

What is the largest annelid class?

The polychaetes comprise the largest class of annelids with more than 10,000 species, most of them marine. paired appendages = (parapodia; see fig. 18.)

Are segmented worms the most advanced group of worms?

Annelids show the presence of a true coelom, derived from embryonic mesoderm and protostomy. Hence, they are the most advanced worms. A well-developed and complete digestive system is present in earthworms (oligochaetes) with a mouth, muscular pharynx, esophagus, crop, and gizzard being present.

Do segmented worms have a complete digestive system?

Segmented worms have a well-developed body cavity filled with fluid. Segmented worms also tend to have organ systems that are more developed than the roundworms’ or flatworms’. Earthworms, for example, have a complete digestive tract with two openings, as well as an esophagus and intestines.

Is called segmented worm?

Annelid, phylum name Annelida, also called segmented worm, any member of a phylum of invertebrate animals that are characterized by the possession of a body cavity (or coelom), movable bristles (or setae), and a body divided into segments by transverse rings, or annulations, from which they take their name.

Is Oligochaeta a parasite?

The Oligochaeta are the second largest group of the Annelida. With 3,100 known species, they make up about one third of the phylum. There are also a few parasitic species. The ‘Oligo’ in Oligochaeta means ‘few’ just as the ‘Poly’ in Polychaeta means ‘many’.

Does leeches reproduce asexually?

All leeches are hermaphroditic, and reproduction is always sexual.

How many species of Oligochaeta are there in the world?

With around 10,000 known species, the Oligochaeta make up about half of the phylum Annelida. These worms usually have few setae (chaetae) or “bristles” on their outer body surfaces, and lack parapodia, unlike polychaeta .

What’s the difference between a polychaete and an oligochaete?

Polychaetes are mainly free-living, while oligochaetes can be either free-living, commensals or parasites. Polychaetes are dioecious with temporary or seasonal gonads, while oligochaetes are monoecious with permanent gonads. Polychaetes undergo external sperm transfer and external fertilization.

What are the functions of Polychaeta segmented worms?

Class Polychaeta 1 Circulation and Respiration. Polychaetes show considerable diversity in both circulatory and respiratory structure and function. 2 Excretion. 3 Nervous System and Sense Organs.

What’s the difference between an earthworm and an Oligochaeta?

The Oligochaeta consists of aquatic or terrestrial earthworms. The Hirudinea consists of leeches. An earthworm is shown in figure 1. Arthropoda refers to another phylum of kingdom Animalia, consisting of animals with jointed appendages and a chitinous exoskeleton.