Why are sponges considered animals?

[Sikz]

Why are sponges considered animals? They should most definitely be given a class of their own- they lack all of the characteristics of animals except for being multi-celled and being consumers... I would go into this in detail, but I'm sleepy :P

 

[Monique]

Hi Sikz. Sponges are basically the most primitive animals. People think that the precursor of animal life would have started like that, since sponges are most genetically diverse among other marine life forms. What is it like to be an animal? I think that being a multicellular organization with different cell types comes very close. It has got two cell types, the one causes water to flow over the other cells, the water flows through the holes, the sponge strains the food and eats it.

 

[iansmith]

To add an extra info for classification (simplified for easy classification):

Animal ingested their food
Plant produce their food
The other aborsed nutrient and do not degrate most of their food

Their are also animals because their 18rRNa tells us they are very close to human

Check the classification (Sponge are porifera and if you click on the image you can find links with extra info)
http://cas.bellarmine.edu/tietjen/images/general_overview_of_animal_phyla.htm

 

[Monique]

Where does yeast and fungi fall?

 

[iansmith]

They neither plant nor animal and classification for fungi and yeast is hell to discuss.

 

[Sikz]

Fungi are actually classified in their own kingdom- There are currently five, I believe. Kingdom fungi (fungi), kingdom animalia (animals), kingdom plantae (plants), kingdom protista, kingdom monera. I think scientists are considering a sixth group, but it isn't concretely established. :)

 

[gcn_zelda]

Sponges...

You mean those things I use to wipe my table with?

Just kidding.

Well, I guess sponges are in a separate branch of animals... Porifera, I think. Sponges actually have a sort of skeleton to hold them up. I guess. Yeah. And sponges can communicate with other sea animals as shown in Spongebob Squarepants.

Yup.

 

[FZ+]

Maybe there is a genetic connection here.

Perhaps Plants etc represent a different branch of the tree of life, and animals/sponges share a branch, being shown by genetic retracing of evolution?

 

[Jeebus]

Sponges..animals with many pores, without definite form of symmetry, and do not contain organs or true tissues. They are all sessile. The humble bath sponge, used for centuries particularly in the Mediterranean region were originally thought of as plants but are now considered animals (only in 1765)(even its own subkingdom ..Parazoa) They probably originated from flagellated protozoans or primitive metazoans. They are the simplest of multicellular marine animals. They are so poorly organized that they are not even included in the direct line of animal evolution.

The sponges single purpose in life is to pass water through itself, the water yielding food and oxygen, minerals, and carrying away waste products. The sponges are unchanged since they evolved and were ancient 300 million years ago and appear to be natures orphans. Rachel Carson wrote that "nature seems to have gone back and made a fresh start with other materials" with no evidence of any relationship between them and coelenterates, leaving sponges in an evolutionary blind alley.

Structure.. most are similar in structure, simple body wall containing cells and connective tissues and cell types like amoebocytes which wander through the inner tissue secreting and enlarging the skeletal spicules and laying down spongin threads. Most have a skeleton of spongin, elastic, but resistant fibers of protein which may be the only means of support but can be found together with spicules. The internal skeleton can be made of hard rod or star shaped calcareous or siliceous spicules, the shapes genetically determined for each sponge, and/or the meshwork of protein fibers called spongin (bath sponge) which is similar to silk and the horns of many animals.

Sponges are filter feeders straining off bacteria and fine detritus from the water. O2 and dissolved organic matter are also absorbed and waste materials are carried away. Water is pumped inward through small pore cells into the inner chambers lined by flagellate cells called collar cells. They ingest the food particles and water is expelled through the sponges surface through the osculum.

Thus they can be considered animal-like.

 

[theriddler876]

Sponges are animals because they have the characteristics of life, however do not create their own food so they are not plants, they are filter feeders, they have a skeleton like structure made of calcium carbonate I believe, they exhibit growth, basically they are born they grow they reproduce and they die, which is a characteristic of all animals

 

[Monique]

Originally posted by FZ+
Maybe there is a genetic connection here.

Perhaps Plants etc represent a different branch of the tree of life, and animals/sponges share a branch, being shown by genetic retracing of evolution?

Actually, it is thought (I am not sure how widely) that plants came from an ancestral fungia and that animals came from an ancesteral sponge-like structure.

 

[iansmith]

Originally posted by Sikz
Fungi are actually classified in their own kingdom- There are currently five, I believe. Kingdom fungi (fungi), kingdom animalia (animals), kingdom plantae (plants), kingdom protista, kingdom monera. I think scientists are considering a sixth group, but it isn't concretely established. :)

That is old classification. With 18s and 16 s ribosomal RNA, there is 3 domain Bacteria, Archea and Eucarya, then each Domain is separated in kinggom. rigth now the kingdoms for Eucarya are animalia, plantae, fungi and protista but many fungi migth be displaced and prostita migth be exploded into different kingdom.

Originally posted by Sikz
Actually, it is thought (I am not sure how widely) that plants came from an ancestral fungia

I would say that green algae are more likely to be the ancestor of plant but it seems that plants, animal and fungi have a common ancestor closer than previously though.

 

[russ_watters]

Originally posted by gcn_zelda
Sponges...

You mean those things I use to wipe my table with?

Just kidding.

Yes, actually. Most sponges we use are synthetic, but not all.

 

[theriddler876]

you can call those pseudo porifera

 

[selfAdjoint]

or maybe spongebob squarepants? (you knew that was coming, no?)

 

[Loren Booda]

Many single cell consumers might be called animals. Just replace the term "multicellular" with "multiorganellic." Organelles are probably just incorporated archetypal cells.

Also, what is the classification for slime molds with regard to sponges?