What primitive group of animals has no true tissues and no specific distinct shape?

Sponges (Porifera) have a primitive cellular level of organization and lack tissues and symmetry.

1. What is the only group of animals with no true tissues?
2. What animals do not have true tissues?
3. Which group of animals do not possess tissues?
4. What is the most primitive animal group?
5. What animal groups have true tissues?
6. Which of the following has no true tissues?
7. Does Cnidaria have true tissue?
8. Does arthropods have true tissue?
9. Do Mollusca have true tissues?
10. What is the only group of animals with specialized cells but lacks true tissues?
11. Do corals have true tissues?
12. What are true tissues?
13. What are primitive animals?
14. Is jellyfish primitive or derived?

What is the only group of animals with no true tissues?

Of all the branches of complex animals, sponges are the only group lacking TRUE TISSUE. Animal Phyla: Sponges (lack true tissue), Cnidarians (have radial symetry, not bilateral symmetry), Molluscs, Flatworms, Annelids, Roundworms, Arthropods, Echinoderms, Chodates (have a spinal cord: chordata).

What animals do not have true tissues?

Phylum Porifera: Sponges

Sponges are the simplest of the multicellular animals. They are the only animals that do not exhibit obvious symmetry in their body organization. They have aggregations of different cell types but do not have true tissues.

Which group of animals do not possess tissues?

Sponges: The Phylum Porifera | Back to Top. The phylum Porifera ("pore-bearing") consists of approximately 5,000 species of sponges. These asymmetrical animals have sac-like bodies that lack tissues, and are usually interpreted as representing the cellular level of evolution.

What is the most primitive animal group?

Sponges—from the phylum Porifera (Latin for porus, meaning “pore,” and fera, meaning “bearing”) are thought to represent the most primitive animals. These organisms are collections of specialized cells without true tissues or organs, and their bodies are not symmetrical.

What animal groups have true tissues?

Animals with true tissues are in the group Eumetazoa (“true animals”). When we think of animals, we usually think of Eumetazoans, since most animals fall into this category.

Which of the following has no true tissues?

Sponges have no true tissues and are filter feeders, while cnidarians have true tissues and a gastrovascular cavity.

Does Cnidaria have true tissue?

The cnidarians, or the jellyfish and their kin, are the simplest animal group that displays true tissues, although they possess only two tissue layers.

Does arthropods have true tissue?

Arthropods have a number of distinctive features in their body plan: Three tissue layers formed in embryo, like most animals. True coelom. Segmented body with specialized and fused segments.

Do Mollusca have true tissues?

Taxonomic level: phylum Mollusca; grade of construction: organs derived from three tissue layers; symmetry: bilateral; type of gut: complete, with anus; type of body cavity other than gut: coelom; segmentation: absent; circulatory system: usually open to large coelomic cavity; nervous system: brain, with nerve cords ...

What is the only group of animals with specialized cells but lacks true tissues?

The sponges and the cnidarians represent the simplest of animals. Sponges appear to represent an early stage of multicellularity in the animal clade. Although they have specialized cells for particular functions, they lack true tissues in which specialized cells are organized into functional groups.

Do corals have true tissues?

Lack true tissues; Asymmetric; Sessile (do not move about); Mostly common marine suspension feeders; The basal lineage and simplest of animals. ... Hydra, corals, and jellyfish; Radially symmetric; both sessile and motile forms; Have a central digestive cavity with a single opening surrounded by stingers.

What are true tissues?

true tissue (noun, pl. true tissues; synonym: parenchyma) – isodiametric cells joined together in three dimensions, always originating from organized meristematic growth of a single cell that is capable to divide into several, isodiametric planes, thus giving off new cells into several directions.

What are primitive animals?

Primitive animals are ones that have not changed dramatically over the millennia and remain very similar to their ancestors.

Is jellyfish primitive or derived?

Cnidarians constitute a phylum of primitive animals, including, for instance, jellyfish, corals, and sea anemones. The basic organization of the cnidarian nervous system is simple, with a plexus of neurons in the basal part of the epithelium that form centralizations in some strategic regions.