R vs K: Mollusca tend to lean towards the R side of R and K strategy. Mollusca produce many offspring, banking on the few offspring that survive. This means that instead of only having a few offspring, and spending time raising them, the children are born and then have no support from their parents whatsoever.
Cycle of Life: The life cycle of a Mollusk starts with a sperm cell penetrating an egg cell, which, when fertilized, divides. The next stage is the Trochophore stage, followed by the Veliger, in early stage. The Veliger stage post torsion is next, followed by the Veliger in settlement stage.
Population growth: The number of Mollusks is exponentially decreasing recently, as shown by studies. This global decrease is due to two factors: the introduction of Alien species into their habitats, and Habitat destruction.
Unique Adaptations: Among the adaptations Mollusks have gained over time, the most obvious, and most important, is the muscular foot all mollusks posses. This foot adaptation is also something that differentiates all different species of Mollusks. There is a lot of variation in this adaptation, so species to species, Mollusk feet will look different.
Range in Habitat: Most Mollusks are found in marine environments, be it freshwater or the Ocean. This however does not mean Mollusks are unable to live on land: some major Gastropod Clades live on land. Mollusks are very versatile creatures, and can be found in many aquatic (and non-aquatic!) atmospheres.
Relationships: Recent, extensive research into Mollusca phylogeny shows that Mollusks have a "deep animal relationship" with snails (Phylogenesis is the study of the diversification of animal species). Other than that, it is hard to track what other species Mollusks are related to.
Niche: Mollusks can be found in an abundance of places around earth, because the species is extremely diverse. 3000 different species of Mollusks were once found in a reef in Cambodia, all living harmoniously. The conclusion reached from that is that Mollusks have little effect on the environment around them, and they live harmoniously with many other animals.