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Platyhelminthes
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∙ 12y ago
Wiki User
∙ 13y agothe sponge.
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What invertebrate group was the first to show cephalization?
platehelminthes (flat worms)
Which phyla do not have cephalization?
Porifera (sponges), Ctenophora (comb jellies), and Placozoa do not exhibit cephalization, which is the development of a head region with sensory organs. These organisms typically lack centralized nervous systems and instead have dispersed nerve cells throughout their bodies.
List the phyla that show cephalization?
The phyla that show cephalization include Chordata (which includes vertebrates), Arthropoda (including insects, crustaceans, and spiders), Annelida (segmented worms), and Mollusca (which includes snails, clams, and octopuses).
Do nematodes show cephalization?
Phylum Nematoda does exhibit cephalization. Cephalization is a evolutionary trend in development in which the sensory and neural organs of a species becomes concentrated on one end of an organism.
In what two ways do planarian show cephalization?
Yes, they have (primitive) sense organs anteriorally placed - this represents cephalisation, as does the aggregation of nervous tissue to monitor and respond to impulses from the anterior sense cells/organs.
Annelids show what by having bilateral symmetry?
cephalization for segmented worms, but idk about anything else
What does annelids show by having bilateral symmetry with an anterior head where most sense organs are found?
Cephalization
Do bivalves show cephalization of a clam?
No - class Bivalvia of phylum mollusca have no head examples are clams, oysters, and mussels
Within which taxonomic group do members show at least varition and withim which group do they show the most?
Members within a species show the least variation, while members within a kingdom show the most variation.
What two animal phyla show radial symmetry?
The two animal phyla that show radial symmetry are Cnidaria (such as jellyfish and sea anemones) and Echinodermata (such as starfish and sea urchins). Radial symmetry means that the body parts are arranged symmetrically around a central axis, like spokes on a wheel.
Is trematoda or nematoda evolutionarily more advanced?
Trematoda are more evolutionarily advanced because they show the traits of cephalization, an organ system, and have a lophophore. While nematoda have none of these traits.
What do fossil forms of evolution show?
The transition of phyla of organisms over time. That is the great strength of the fossil record; evolution shown in the sedimentary rock.
