Marine Invertebrates
The ocean includes a great variety of animals. One major group of animals is theinverte-
brates. Invertebrates are animals with no spinal column. Marine invertebrates include sea
slugs, sea anemones, starfish, octopi, clams, sponges, sea worms, crabs and lobsters. Most
of these animals are found close to the shore, but they can be found throughout the ocean.
In fact, scientists were amazed to discover invertebrates that thrived in the deep ocean near
hydrothermal(hot water) vents, including giant tube worms, crabs, and shrimps (Figure
14.30).
Figure 14.30: Giant tube worms have been found a mile deep in the ocean. They can grow up
to 8 feet long and can withstand the very high water temperatures heated by hydrothermal
vents. ( 3 )
Fish
Like us, fish arevertebratesthat have a spinal column and a hard skull. They are animals
that have adapted to life in the water. Most fish are ”cold-blooded” animals that have fins
with which to move and steer, scales that protect them, gills with which to extract oxygen
from the water, and a swim bladder that lets them float at particular depths within the
ocean. Included among the fish are sardines, salmon, and eels, as well as the sharks and rays
(which lack swim bladders)(Figure14.31).
Reptiles
Reptiles are air-breathing, ”cold-blooded” vertebrates. A few groups of reptiles have adapted
to life at sea. These include sea turtles, sea snakes, a few saltwater crocodiles, and the marine