Digital Atlas of Scientific Life
- Phylum Mollusca (digitalatlasofancientlife.org)
With over 70,000 living species (Rosenburg, 2014), the phylum Mollusca is second only to the Arthropoda in terms of total species diversity. The great diversity of mollusks is owed at least in part to their success in occupying most habitats on earth, including the marine realm, freshwater lakes and rivers, and even land. Some are filter feeders, some are herbivores, and some are deadly predators. The strong, easily-preserved shells of mollusks have left behind a rich Cambrian to Pleistocene fossil record and they have long been important subjects of macroevolutionary analyses of the fossil record.
- MOLLUSCS: THE SURVIVAL GAME (shapeoflife.org)
Their basic body plan includes a foot for mobility; a mantle that secretes a shell and a radula for eating. Molluscs today show many variations on this original body plan. An abalone escapes a sea star predator using its foot; and a moon snail hunts a cockle using its foot as a weapon. The radula has even evolved in an astonishing variety of ways to serve as a tool for feeding. The ancient nautilus was the first mollusc to leave the sea floor. Their ancestors evolved a way to swim using jet propulsion and evolved a way to maintain buoyancy. The evolution of speedy fishes drove the next step in the survival game: speed and loss of the shell, as seen in squid. Octopuses returned to live on the bottom and evolved intelligence and an ability to instantly camouflage itself in order to survive.
- Mollusca (Wikipedia)
Mollusca is the second-largest phylum of invertebrate animals, after Arthropoda; members are known as molluscs or mollusks (/ˈmɒləsk/). Around 76,000 extant species of molluscs are recognized. The number of fossil species is estimated between 60,000 and 100,000 additional species. The proportion of undescribed species is very high. Many taxa remain poorly studied.
