Petrified fossil - form when minerals replace all or part of an organism. Water is full of dissolved minerals. It seeps through the layers of sediment to reach the dead organism. When the water evaporates, only the hardened minerals are left behind.
Sessile - (of an organism, e.g., a barnacle) fixed in one place; immobile.
Colonial - of, relating to, or characteristic of a colony or colonies.
Cilia - a short, microscopic, hairlike vibrating structure. Cilia occur in large numbers on the surface of certain cells, either causing currents in the surrounding fluid, or, in some protozoans and other small organisms, providing propulsion
Amorphous - without a clearly defined shape or form
Benthic - The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers
Nektonic - aquatic animals that are able to swim and move independently of water currents
Sessile - (of an organism, e.g., a barnacle) fixed in one place; immobile.
- (of a plant or animal structure) attached directly by its base without a stalk or peduncle
Colonial - of, relating to, or characteristic of a colony or colonies.
- (of animals or plants) living in colonies
Cilia - a short, microscopic, hairlike vibrating structure. Cilia occur in large numbers on the surface of certain cells, either causing currents in the surrounding fluid, or, in some protozoans and other small organisms, providing propulsion
Amorphous - without a clearly defined shape or form
Benthic - The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers
Nektonic - aquatic animals that are able to swim and move independently of water currents