Invertebrates are animals without a backbone yet they account for 95% of all known animal species. Amazing isn’t it?
To introduce you to the wonderful world of marine invertebrates, our Education Team is starting this series of blog posts called Marine Invertebrates 101 to highlight the amazing collection of marine invertebrates in S.E.A. Aquarium. So that on your next visit here, apart from admiring our wide range of fish, you’ll also be able to recognise and better appreciate these marine invertebrates.
To start off this series, we have the fascinating sea sponges.
8 things you probably don’t know about sea sponges
1. They’re animals, not plants
Sea sponges are members of the phylum Porifera [paw-rif-er-uh], which means “bearing pores” in Latin.
Contrary to their appearance, sea sponges are not plants but animals. These multi-cellular animals (made up of different cell types) function just as well as any other animal – even without tissues and organs such as brain or heart. What’s more, they are estimated to have existed on this Earth for at least 500 million years!
2. Not just squares
SpongeBob, whose character was inspired by sea sponge, may be square in shape but in reality most sea sponges are irregularly shaped.
3. Needle-like skeleton
There are approximately 5000 known species of sponges, and they can be classified into 3 distinct groups based on the material of their ‘skeleton’: Hexactinellida, Demospongia and Calcerea.
The skeleton of sea sponges comprises of small, needle-like structures called spicules. Sea sponges classed under Hexactinellida have glass spicules, while those classed under Demospongia have either silica spicules or spongin fibres. Sea sponges classed under Calcerea have spicules made of calcium carbonate.
4. They obtain food and oxygen through filtration
Every day, sea sponges filter large amounts of water, about 20,000 times their own volume, to obtain food (e.g. bacteria, plankton) and oxygen.
Although the majority of sea sponges are filter feeders, a few species (such as the Harp Sponge) are carnivorous and have developed active means to grab food like small shrimps from the water.
5. Toxic, with few predators
Sea sponges have few predators because they are toxic to many animals except sea turtles.
6. Important in the development of anti-cancer drugs
Sea sponges have huge roles to play in the medical field. They contain chemicals that are useful models for the development of a number of anti-viral and anti-cancer drugs.
7. Used for cosmetic purposes
Before synthetic sponges were invented, sea sponges were (and still are) harvested to be used as bath and cosmetic sponges.
Before synthetic sponges were invented, sea sponges were (and still are) harvested to be used as bath and cosmetic sponges.
8. They can regrow broken parts
Just like Wolverine, sea sponges have tremendous self-regenerating powers. Even when broken in two, their cells are capable of reconstructing themselves to regrow the broken parts.
Here’s an interesting video to help you learn more about sea sponges: