A sponge is a colony of cells that show a slight degree of specialization within the colony with some of the cells developing flagella to assist with filtering food out of the water for the rest of the colony. How does this justify placing them in the animal kingdom rather than with the other colonial protists?

Question

anonymous · Answer

Colonial protists generally lack specialized cells, so sponges fit slightly better with the animals.

 All of the cells in a sponge have nuclei, which makes them more like animals than like protists.

 Filter feeding is a common practice among marine invertebrates, so sponges belong with animals.

 All the colonial protists are plantlike algaes, so having flagellated cells puts sponges with animals.

anonymous · Answer

wat u think??

anonymous · Answer

i think its B.

anonymous · Answer

Protists have nuclei too, so it's definitely not B.

anonymous · Answer

hmm y not others? share ur views :)

anonymous · Answer

well I'm not to familiar with this topic, i just had a nitch for B

anonymous · Answer

Ok, do you know what makes a group of a cells an actual multicellular organism and not just a colony of single-celled organisms that happen to live together?

anonymous · Answer

differentiation

anonymous · Answer

Right, and what does that mean?

anonymous · Answer

cells develop specialized functions

anonymous · Answer

Yep: specialisation is key. Now... do you know what protists look like?

anonymous · Answer

yes

anonymous · Answer

So, with these things in mind, what do you think the answer is?

anonymous · Answer

D

anonymous · Answer

Algae typically have flagella, I'm afraid, so it's definitely not D...

anonymous · Answer

hmm...possibly C? im not good with this subject

anonymous · Answer

ok den let have a look do u knw how ponge looks like @sammy90210

anonymous · Answer

*sponges

anonymous · Answer

yes

anonymous · Answer

have u ever seen flagella in their str.?

anonymous · Answer

Here's what algae look like:|dw:1337105163557:dw|

Each circle with two little tails is an alga. The tails are flagella. The cells are held together by some slime, as I recall, which I tried to draw around the group. This is not a multicellular organism: it's just four single-celled algae that happen to live together. Larger groups can stick together in fancy structures, by the way, but I don't feel confident in my drawing ability on here.

As you correctly pointed out, multicellular organisms have specialised cells. Look at the algae now: do you see any specialisation? Any cells that look different?