Molecular systematics based on rRNA sequences point to which of the following hypothesis about the origin of metazoans?
| 1. | Multinucleate hypothesis |
| 2. | Polyphylectic origin hypothesis |
| 3. | Colonial flagellate hypothesis |
| 4. | Catastrophic hypothesis |
Based on the phylogenies constructed on the basis of rRNA sequences, the Ecdysozoans include
(1) Flatworms and Mollusks
(2) Mollusks and Annelids
(3) Annelids and Arthropods
(4) Arthropods and Roundworms
Identify the incorrect statement regarding the phylum Porifera
| 1. | Very few species are found in fresh water |
| 2. | Most members completely lack symmetry |
| 3. | There is a high degree of coordination among sponge cells |
| 4. | Larval sponges are frec-swimming but adults are sessile |
What is not true about Cnidarians?
(1) Body is made of distinct tissue but true organs have not evolved
(2) They are carnivores
(3) They may have two body forms-polyps and medusae
(4) The digestion is totally intracellular
Hydra, Obelia, and Physalia belong to which class of Cnidaria?
(1) Hydrozoa
(2) Scyphozoa
(3) Cubozoa
(4) Anthozoa
The largest animals that use cilia for locomotion are
(1) Cnidarians
(2) Ctenophores
(3) Platyhelminthes
(4) Nematodes
All of the following are the characteristics of Platyhelminthes except
| 1. | They are flattened dorso-ventrally |
| 2. | They have a definite head at their anterior end and possess organs |
| 3. | The only internal space consists of the digestive cavity |
| 4. | They have a complete gut with two openings-a mouth and an anus |
Which of the following statements is not true about Nematodes?
(1) They are bilaterally symmetrical, unsegmented worms.
(2) They are covered with a flexible, thick cuticle that is molted four times as they grow
(3) They possess flagella or cilia on their reproductive cells
(4) They possess a hydrostatic skeleton
Coenorhabditis elegans, an organism favored for genetic studies, belongs to
(1) Annelids
(2) Nematodes
(3) Platyhelminthes
(4) arthropods
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