Mollusks are divided into several classes, each with its own unique characteristics:
Gastropods: This class includes snails and slugs. They typically have a single, coiled shell or are shell-less.
Bivalves: Examples of bivalves include clams, oysters, and mussels. They have two hinged shells that are connected by a flexible ligament.
Cephalopods: This class includes squid, octopuses, and nautiluses. They have well-developed heads and tentacles, and most have internal shells or none at all.
Polyplacophorans: These are commonly known as chitons and have a unique shell composed of eight separate plates.
Monoplacophorans: These are deep-sea mollusks with a single, cap-shaped shell.
Scaphopods: Also known as tusk shells, these mollusks have tubular, tusk-shaped shells.
Commercial Value: Certain mollusks, such as clams, oysters, and scallops, are cultivated for their pearls, shells, and meat, contributing to the economy.
Environmental Indicators: Some mollusks, like certain species of snails, are used as indicators of environmental health due to their sensitivity to pollution and habitat degradation.
Study Guide
When studying mollusks, it's important to focus on the following aspects:
Learn the key characteristics that define mollusks, including their body structure, feeding mechanisms, and locomotion.
Understand the major classes of mollusks, their defining features, and examples of species within each class.
Explore the ecological and economic importance of mollusks, including their roles in ecosystems and their value to human societies.
Examine specific examples of mollusks and their adaptations to different environments, such as the specialized structures of cephalopods for predation and defense.
Energy - A. Energy is involved in all physical and chemical processes. It is conserved, and can be transformed from one form to another and into work. At the atomic and nuclear levels energy is not continuous but exists in discrete amounts. Energy and mass are related through Einstein's equation E=mc 2 . B. The properties of atomic nuclei are responsible for energy-related phenomena such as radioactivity, fission and fusion. C. Changes in entropy and energy that accompany chemical reactions influence reaction paths. Chemical reactions result in the release or absorption of energy. D. The theory of electromagnetism explains that electricity and magnetism are closely related. Electric charges are the source of electric fields. Moving charges generate magnetic fields. E. Waves are the propagation of a disturbance. They transport energy and momentum but do not transport matter.
Relate temperature to the average molecular kinetic energy.