life in the sea

Cambrian era references the geographical and biological origins of various organisms, notably mollusks.
Deep sea organisms observed here are still alive today, showing long-term survivability.
Polyclacophora
- Also known as chitons.
- Characterized by a shell with many plates.
- Primarily found in intertidal zones.
- They are algae eaters, playing a role in marine ecosystems.

Aplacophora
- These mollusks lack true shells, instead possessing reduced structures like spicules.
- Typically found in deep waters with high salinity, exhibiting worm-like body forms.
- Behave differently than traditional worms despite surface similarities.

This class includes organisms that possess two shells, hence the name bivalves.
Common examples included in human diets: mussels, clams, oysters, and scallops.
Majority of bivalves are filter feeders, utilizing two shells to aid in feeding.

Known as tusk shells.
Reside in benthic zones, often beneath the sand.
Exhibit tentacles near their upper parts, used for filtering organic material from sand.

A highly diverse group including nautilus, cuttlefish, squid, and octopus.
Notable characteristics exist between primitive and advanced forms:
- Nautilus: Primitive, multiple arms lacking suction cups, featuring simpler eye and heart structures.
- Octopus: More advanced, fewer arms but equipped with suckers, demonstrating high intelligence and complex behavior (e.g., problem-solving).
Videos displaying octopus behaviors illustrating their capabilities available for additional study (e.g., breaking glass, rhythmic camouflage changes).
Discussion of Paul the octopus, known for ‘predicting’ outcomes in sporting events.