Sacoglossa

Now I know I said nudibranchs were my favorite gastropod, but some of these gastropods really made me have reconsider that comment. The gastropods that belong in the sacoglossa category are very interesting to say the least. They are also called "sap-sucking sea slugs", that are called this because their food source is the cellular contents algae. They are divided into two groups, one of which has a shell and are called Oxhynoacea. The other group that does not have a shell (called Plakobranchacea) is the reason why I had to reconsider my favorite gastropod. Plakobranchacea have evolved to use kleptoplasty, which allows them to maintain chloroplasts from the algae that eat and actually use the photosynthetic products as their primary food source for months. Some have "wing-like" structures to increase the surface area for photosynthesis. Some have also adopted the color of algae (because of the chloroplasts in their bodies).

Plakobranchacea with "wings" spread:

Plakobranchacea with "wings" unspread:

Green Sacoglussan:

Nudibranch

Nudibranchs are my personal favorite type of gastropods because of their stunning colors and shapes. Nudibranchs are what people think of when  they think sea slugs (not surprisingly because of their stunning features). The name nudibranch came from the latin "nudus" (naked) and the greek "branchia" (gills). Just from the definition of their names you can tell that they have exposed gill structures on them. Nudibranchs are divided into two main kinds: dorids, which have a branchial (gill) plume, and aeolids, which have cerata speed across their backs instead of a plume.

Dorids:

Aeolids:

Gastropods

Now that we have gone through cephalopods now we can move on to gastropods. Gastropods are most likely the most known class of mollusk, as it is the class that makes up of snails and slugs. Gastropods (unlike cephalopods) have evolved to live in freshwater and saltwater, as well as on land. Gastropods are the most diverse class out of the mollusk phylum, coming in at about 60,000-80,000 species (second only in diversity to insects). The name gastropod comes from the ancient greek words gastér (stomach) and poús (foot).

Snail:

Sea Slug:

Cephalopod Genetics and Evolution

By now I am sure (if you read my blog) that you know cephalopods are awesome. The thing that makes these creatures so amazing is that they have evolved to be top-of-the-line predators through thousands of years of making evolutionary advantages that  eventually lead to them being an important part of most oceanic ecosystems. One of the more useful features is their use of a jet-propelled locomotion system that lets them get away from less than desirable situations very quickly. Another useful mechanism is their astounding ability to rapidly change skin color and texture with great ease. This ability is used for hunting, hiding, and intimidation. One of the more impressive evolution under their belt is the highly sophisticated eyes they possess, which are very keen and much like vertebrate eyes. Possibly the biggest step most have taken is the shedding of their shells. Which now lets them be lightweight and streamlined as well as allowing them to slip into cracks where they can hunt from, and avoid predators.