Question

1.Not all sponges are suitable for harvesting and selling for home use. Why not?

2.Why are the spicules of sponges being studied by engineers?

3.What is the significance of the medusa life history stage?

4.What triggers the firing of nematocysts?

5.Why is the parasitoid wasp group thought to have high species diversity?

6.Why are millipedes more diverse than centipedes?

7.Why are almost half of the animal phyla exclusively marine?

8. Once believed to be a primitive animal, modern research on Placozoa shows that this is not the case. Moreover (conversely) the study of Ctenophores has shown that this relatively complex animal may be as primitive as sponges. What does this indicate about the process of evolution?

Answer 1

1. All sponges cannot be harvested and sell for human use because some sponges are found to be toxic

2. Spicules are the structural elements of sponges . They provide structural support to sponges and protect them from predators. It has been found by researchers that spicules can bear a lot of pressure. This has drawn the attention of engineers as there is possibility that they can serve mechanical function.

3. Medusa is an umbrella shaped, free swimming and sexual stage of cnidarians.

4. A nematocyst is stimulated when a prey comes in contact with its tentacles thereby opening the flap of tissue covering the nematocyst.

5. Parasitoid wasp has high species diversity because of a large number of different species found in the group.

6.Millipedes are more diverse than centipedes because it as large number of different species and are present in abundance

7. Almost half of the animal phyla is exclusively marine because first living organisms first appeared in the sea overhundred million years ago and then evolution took place and animals started inhabiting land.