“Welcome back,” Cutter began that week’s class, “this week we’re going to be covering Mollusks fossils, Mollusks are a phylum of protosomic invertebrate animals, whose members are known as molluscs or mollusks,” he explained, “Around 76,000 species of molluscs are recognised, making it the second largest animal phylum after anthropoda, The number of additional fossil species is estimated between 60,000 and 100,000 and the proportion of undescribed species is very high. Many taxa remain poorly studied.”

“Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms, They are highly diverse, not just in size and anatomical structure but also in behaviour and habitat as numerous groups are freshwater and even terrestrial. The phylum is typically divided into 7 or 8 taxonomic classes, two of which are entirely extinct, Cephalopod molluscs such as squid, cuttlefish, and ocotopuses are among the most neurologically advanced of all the invertebrate and either the giant squid or the colossal squid is the largest known extant invertebrate species. The gastropods such as snails, slugs and abalone are by far the most diverse class and account for 80% of the total classified molluscan species”

“The four most universal features defining modern molluscs are a soft body composed almost entirely of muscle, a mantle with significant cavity used for breathing and excretion, the presence of a radula except for bivalves, and the structure of the nervous system, Other than these common elements, molluscs express great morphological diversity, so many textbooks base their descriptions on a "hypothetical ancestral mollusc".

“Good evidence exists for the appearance of gastropods, celaphods and bivalves in the Cambrian Period, 541–485.4 million years ago. However, the evolutionary history both of molluscs' emergence from the ancestral Lophotrochozoa, and of their diversification into the well-known living and fossil forms are still subjects of vigorous debate among scientists.

“For the rest of the class I’d like you to work on your moddable worksheets and as always i’ll be around if anyone has any questions they’d like answered,” Cutter said as he finished that week’s class.