Overview
Different shells that vary in ___.
size, form and pattern combination
A seashell is usually the exoskeleton of an invertebrate (an animal without a ___).
backbone
Apart from mollusk shells, other shells that can be found on beaches are those of ___, horseshoe crabs and brachiopods.
barnacles
If you put a seashell up to your ear, the echoes sound like ocean waves, even miles away from the ___…
beach
You can boil them down to two major types and ___ general shapes.
2
To this day, one can use cowry shells as money in Papua, ___ if aiming to honor ancient customs.
New Guinea
A shell is typically composed of calcium carbonate or ___.
chitin
Marine annelid worms in the family ___ create shells which are tubes made of calcium carbonate cemented onto other surfaces.
Serpulidae
Scientists believe that mollusks use these patterns and colors to figure out where to place their ___, ensuring they grow their shell in the right spots.
mantle
The first common shape is a smooth, ___ design.
round
A shell is an exoskeleton often made by a sea dwelling ___.
animal
Most shells that are found on beaches are those of marine ___.
mollusks
The shells of sea urchins are called “___.”
tests
A seashell isn’t an ___ but a portable home for a wide variety of such.
animal
Mollusks w/shells allowing for fast scooting around the ocean rely on stealth & speed to avoid lurking ___.
predators
The ___ of the animal includes the shell.
body
Most shells that are found on beaches are those of marine mollusks, partly because these shells are usually made of ___.
calcium carbonate
Most seashells are ___.
external
___ craft only one shell throughout their lifetime.
Mollusks
The 2nd shape is the ___, uneven surfaces.
spiky
Beachcombers often find ___ seashells washed up on beaches.
Empty
Most shells that are found on beaches are those of marine mollusks, partly because these shells endure better than shells made of ___.
chitin
Some cephalopods have ___ shells.
internal
Seashell identification is no easy task; there are possibly over ___ mollusks in the world (all of them create unique types of shells).
200,000
Some mollusks rely on the thickness or ___ of their shell to dissuade bigger creatures from attacking them.
heaviness