Metazoa
Metazoa are multicellular and eukaryotic animals. This includes corals, sponges, barnacles and mussels. They are mostly heterotrophic organisms showing aerobic respiration. Most of them show sexual reproduction except for some animals like the cnidarians.
They typically have a flexible extracellular matrix made of elastic glycoproteins and collagen. Also, blastula formation during embryonic development is seen as a unique stage in the metazoans.
Eumetazoa
Eumetazoa is considered a sub-kingdom under Animalia. These animals have neurons, true tissue organisation, and even show embryo development. They comprise the bilaterians and the radiates. Some notable phylum under the Eumetazoa are – Echinodermata, Arthropoda, Nematoda, Platyhelminthes, Mollusca and Annelida.
Explore: Porifera
Difference between Metazoa and Eumetazoa
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Metazoa |
Eumetazoa |
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It is the major division or kingdom comprising all animals except protozoans. |
It is a sub-kingdom under Animalia (Metazoa) that includes bilaterians and radiates. |
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It includes parazoa and eumetazoa. |
It includes most animals under metazoa except for the parazoa. |
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They may or may not have true tissue organisation. |
They show true tissue organisation. |
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The blastula stage is a unique feature of metazoans. |
The eumetazoan embryo also shows the gastrula stage. |
Also see: Animal Kingdom – Phylum, Subphylum
Frequently Asked Questions on Difference between Metazoa and Eumetazoa
What are Parazoa?
Parazoa is a sub-kingdom under Animalia. It comprises organisms with primitive tissue organisation. Phylum Porifera comes under this sub-kingdom. Sometimes, even placozoa is categorised under this group.
What are diploblastic animals?
These animals show two germ layers during embryonic development (blastula). The layers are the ectoderm and endoderm. Usually, the ectoderm gives rise to the nervous tissue and epidermis. Likewise, the endoderm gives rise to true tissue and gland development. Examples – Sea anemones, Corals, Jellyfish, etc.
What are bilaterians?
Bilaterians include animals that are bilaterally symmetrical animals. Some, like the Echinoderms, are bilaterally symmetrical only as an embryo, and they still come under the clade Bilateria. The organisms with this symmetry can be equally cut into two mirror images on a single plane.
Also Read: Basis of Classification of Animal Kingdom
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