Worms are
neither insects nor amphibians
; they are annelids.
What organisms are annelid?
The annelids include
earthworms, polychaete worms, and leeches
. 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.
What class do annelids belong to?
Phylum Annelida contains the
class Polychaeta
(the polychaetes) and the class Oligochaeta (the earthworms, leeches and their relatives). Earthworms are the most abundant members of the class Oligochaeta, distinguished by the presence of the clitellum as well as few, reduced chaetae (oligo– = “few”; –chaetae = “hairs”).
Are annelids Acoelomates?
The protostome coelomates (acoelomates and pseudocoelomates are also protostomes) include the mollusks, annelids, arthropods, pogonophorans, apometamerans, tardigrades, onychophorans, phoronids, brachiopods, and bryozoans. Deuterostomes include the chaetognaths, echinoderms, hemichordates, and chordates.
Are annelids vertebrates?
| Brachiozoa Brachiopoda Phoronida | Bryozoa s.l. Entoprocta Ectoprocta |
|---|
Who named Annelida first?
1. History of Annelida: The annelids were by early zoologists included with other worms in the group Vermes but were separated by Cuvier in 1798 from the un-segmented worms. The name Annelida was first of all used by
Lamarck
in 1809 for the higher segmented worms.
What are the 3 major classes of annelids?
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.
Is earthworm is an acoelomate animal?
Animals with three tissue types, which lack a body cavity, are the only true acoelomates. 2. …
Earthworms have a true coelom
. Flatworms
Are humans Coelomates?
Coelomates are animals that have internal body cavities, or coeloms.
Humans are coelomates
, since we have an abdomenal cavity containing digestive organs, some of the excretory and reproductive organs, and a thoracic cavity that contains the heart and lungs.
Are jellyfish Acoelomates?
Phylum Cnidaria – Jellyfish – about 9,000 species, all aquatic, and mostly marine. –
radial symmetry
, acoelomate (remember – a gastrovascular cavity
What does the word Annelida mean in English?
: a phylum of coelomate and usually elongated segmented invertebrates (as
earthworms
, various marine worms, and leeches)
Do annelids have eyes?
Pigmented ocelli and eyes in Annelida.
Most polychaete species have an eye of one type or another
, whereas these organs are a rare exception in the large taxon Clitellata. In this group, only leeches and certain species of Naidinae possess pigmented eyes (Purschke, 2002, Purschke, 2003a).
Do annelids have a hydrostatic skeleton?
Annelids creep along or burrow by coordinating two sets of muscles. Their segmented body cavity acts as a
hydrostatic skeleton
for the muscles to work against.
Where do most annelids live?
Annelids are found worldwide in all types of habitats, especially
oceanic waters, fresh waters, and damp soils
. Most polychaetes live in the ocean, where they either float, burrow, wander on the bottom, or live in tubes they construct; their colours range from brilliant to dull, and some species can produce light.
Do earthworms have parapodia?
The basic features of locomotion in annelids are most easily observed in the earthworm because
it lacks appendages and parapodia
. Movement involves extending the body, anchoring it to a surface with setae, and contracting body muscles.
