What is the body plan of phylum Annelida?
Annelids have a segmented body plan wherein the internal and external morphological features are repeated in each body segment. Metamerism allows animals to become bigger by adding “compartments” while making their movement more efficient.
What level of body organization is found in both the Platyhelminthes and Annelida?
Organ level
(iii) Platyhelminthes : Organ level of organisation. (iv) Annelids, Arthropods, Molluscs, Echinoderms and Chordates : Organ system level of organisation.
How are the bodies of Platyhelminthes different from annelids?
Flatworms (phylum Platyhelminthes) are simple animals that are slightly more complex than a cnidarian. Segmented worms (phylum Annelida) are the most complex animals with worm-like body plans.
Do Platyhelminthes have a body segmentation?
Taxonomic level: phylum Platyhelminthes; grade of construction: organs derived from three tissue layers; symmetry: bilateral; type of gut: blind; type of body cavity other than gut: none; segmentation: absent; circulatory system: none; nervous system: small bundles of nerves (ganglia), two ventral nerve cords; …
What does Annelida mean in English?
: a phylum of coelomate and usually elongated segmented invertebrates (as earthworms, various marine worms, and leeches)
Why is Annelida called so?
In annelids, the body surface is distinctly marked into ring-like segments. Hence, it is named as phylum Annelida. In Latin, annulus means little ring.
Do Platyhelminthes have nerves?
The nervous system of a free-living flatworm such as Planaria consists of a brain, longitudinal nerve cords, and peripheral nerve plexuses (interlacing networks of peripheral nerves; from Latin plectere, “to braid”).
What is the difference between Platyhelminthes and Nemathelminthes?
The main difference between Platyhelminthes and Nematoda is that Platyhelminthes consists of flatworms with a thin, dorso-ventrally flattened body whereas Nematoda consists of a cylindrical body, which is tapered to fine ends at each end.
What does Cnidaria mean in English?
: any of a phylum (Cnidaria) of radially symmetrical, aquatic, invertebrate animals that have a hollow digestive cavity opening to the outside by a single opening surrounded by one or more nematocyst-studded whorls of tentacles, that occur as single or colonial sessile, typically columnar polyps or usually free- …
What is another name for an annelid?
Oligochaeta – earthworms, etc. The annelids /ˈænəlɪdz/ (Annelida /əˈnɛlɪdə/, from Latin anellus, “little ring”), also known as the ringed worms or segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches.
What makes the phylum of Platyhelminthes more complex than the cnidarians?
What makes the phylum of Platyhelminthes more complex than the Cnidarians? Organisms in the phylum Platyhelminthes are triploblastic, this means they have 3 germ layers. This is a step up from the Cnidarians 2 germ layers, however they still have no coelom.
What kind of body plan does a platyhelminth have?
Type of Coelom: No coelom (acoelomate) . Type of Body Plan: Platyhelminthes have true organs and are unsegmented. Number of body layers: Three body layer – ectoderm, mesoderm and endoderm. Specialized Cells: Platyhelminthes have a unique specialized cell called ‘The Flame Cell’.
What kind of body plan does Annelida have?
Type of Body Plan: segmented and metamerism. Metamery is a term used to decribe when the the body segment are placed in groupings to help the animal better perform life functions. Number of body layers: Species within phylum annelida have 3 body layers: ectoderm, mesoderm and endoderm.
What kind of body plan does a cnidarian have?
A. Evolution of Body Plan. Cnidarians have two body plans: Polyp: A sessile form with mouth and tentacles facing upward. Ex. corals, sea anemone) Medusa: Free-floating (planktonic) form. Looks like a bell with tentacles and mouth facing downward.
