Mollusca Meet-a-mate

For the more sophisticated invertebrates out there.

While some of you sexy mollusks out there are able to reproduce all on your own, I need a mate. I know what you need, not only a mate, but also a safe, moist storage for those oh so delicate eggs. For an invertebrate, I am fairly intelligent. We can communicate through colors and other signals!

I am pretty versatile, as far as living conditions go. I live in the sea, on land, and in fresh water. As for my body, I feature bilateral symmetry and have a muscular “foot”, a big body for all my organs, and a head housing cerebral ganglia.

As I said before, I am fairly versatile as far as habitat is concerned. I live in freshwater (clam) as well as salt water (cuttlefish) not to mention dry land (reef squid). Each of these branches of my phylogenic tree are interestingly adapted to there environments and can have unique qualities and adaptations to better suit them to there specific niche. Some traits are common to a certain group, others to the whole phyla.

Holler!

Sometimes I am in a cephlapod-ish mood, and I feel like moving around a lot, other times I feeling a little sluggish, and move around slow like a snail. Sometimes, when it’s clammy, I just sit around and don’t really move at all. When I have a little limpet in me, I like to home back on the same area several times in one life. In reality, I could do anything, I have a thousands of totally different organisms and a lot of them have unique behaviors, from transportation to reproduction to communication. Some crawl, some swim, some shoot ink, some even flutter throw water like butterflies.

At the left is a sea butterfly, it flaps it’s “wings” to push itself through water. Squid use a familiar adaptation in an unusual way. Squid can change body color at will, but don’t stop at using it for camouflage. Some squid use this color changing to communicate and signal each other, such as Humboldt squid, which flash different colors to signal things like anger to it’s peers.

The earliest of molluscs developed a trend seen in all mollusca today, the “head-mass-foot” organization. One fairly common evolution among my species is the growth of a shell. Calcium carbonate, secreted from the mantle skin, hardens into the shell. Moluscs are the only creatures on earth to grow calcium shells that can be removed without death. The nautilus uses it’s shell in an interesting way. Inside of it’s hard shell are soft gas pouches that control the creatures buoyancy. Yet other creatures, like the Sea Hare and the Sea Angel, have internal shells that just protect vital organ system. Notice the sea angel at the right.

You can see through the creatures body. Notice the discolored region in the thorax. That is actually a strong calcium carbonate shell protecting everything that can’t survive a light squishing.

Many varieties of snails and slugs in my phylum have developed a totally new system of collecting food from the outside world, called a radula. A radula is made of fibrous muscle tissue as well as a material called chitin. Muscle tissue is connected to small chitin spikes all along the interior of the mouth. When food is located, fibrous muscle is elongated outward along with the chitin spikes. These spikes work not unlike a conveyer belt. First, the chitin hits the food, and breaks of a piece. Now the spikes move in a pattern passing food back along the muscle and into the mouth. One advantage to a radula is that it takes less energy to absorb food. On the other hand, it severely limits the size of what can be eaten.

Molusca do have several other effective specializations. Some cephalopods use extreme size to there advantage. The Colossal Squid sports a body that grows more than 33 feet long and tentacles that trail hundreds of feet behind it. This monster ways over half a ton and has no natural predators. These cephalopods combine there giant size with the ability to live in incredible depths to avoid hunting predators and natural dangers. Many species in my phyla use ink or water jets as a predator deterrent. The sea hare pictured at the right squirts ink when hit to fend of predators. Water jets are capable of pushing off hungry enemies. Some moluscs are among the most poisonous animals on earth. Tropical cone snails and some conches have poisonous, sometimes even fatal stings. Octopus all have toxins in there systems, and often in high enough doses to kill a smaller predator or, in some cases, prey.

In an ideal mate, I am looking for someone who enjoys long filter feeds in tidal water, gentle drifts through deep water, and keen senses connected to a a fairly well developed ganglia. I am looking for another phyla drawing it’s roots from as early as the pre-Cambrian era. Keen senses and bi-lateral symmetry are both turn-on’s for me. I usually move around by siphon jets or crawling, so I hope those don’t bother you. On the further advanced end of my phyla I tend to get pretty smart, so an intelligent mate is a must. As a matter of fact, cephalopods are proven to be the most intelligent of all invertebrates! Almost all moluscs have open circulatory systems, so prepare for me to pore my heart out. I am a little messy, I leak excretory fluid everywhere I go. As far as respiration goes, I have lungs, gills, and can even absorb oxygen through my skin!

Bibliography

Barnes, R. D. (1987) Invertebrate Zoology (Fifth Edition), Saunders College Publishing, Philadelphia, USA.

“Is the octopus really the invertebrate intellect of the sea?” Doug Stewart. In: National Wildlife. Feb/Mar 1997, vol.35 no.2

PHYLUM MOLLUSCA. A. Richard Palmer. Jan. 7, 2007. University of Alberta. April 18, 2008. <http://www.biology.ualberta.ca/courses.hp/zool250/Clades/clade08-Mollusca.htm>

Amélie H. Scheltema, Klaus Kerth, Alan M. Kuzirian (April 2006). "Original molluscan radula: Comparisons among Aplacophora, Polyplacophora, Gastropoda, and the Cambrian fossil Wiwaxia corrugata". Journal of Morphology 257 (2).