Sessile means nonmotile. Animals in this category include reef-building corals, mollusks, barnacles, and sponges. On land, scale insects mature as sessile animals.
One example of a sessile land animal is the barnacle. Barnacles are marine arthropods during their larval stage, but once they settle on a surface, they become sessile and attach themselves to rocks, docks, or other substrates. They filter feed using their feathery legs.
immobile animal/plant
a hydra as a polyp is not sessile but when it grows to be a hydra it is sessile
mobile, the opposite (antonym) is sessile.
Their larvae stages are motile stages.
Humans.
they are sessile
Sessile means attached. So a sessile organism is attached to a substrate.
Terrestrial animals cannot be sessile because they live on land. Sessile animals are aquatic and live in the water. +++ That's no the definition of "sessile". A sessile organism is one that anchors itself to one place for its life, or most of its life. Most do live in water but by no means all aquatic animals are sessile. Fish are not!
A starfish is a free-moving animal. It can use its tube feet to move slowly along the ocean floor.
The type of animals that are typically absent in a soft bottom subtidal community are sessile. A sessile animal is not able to move and is permanently attached to something solid.
Alternanthera sessilis is an aquatic plant known by several common names, including sessile joyweed and dwarf copperleaf.