0_Apprentice
I just love the beach do you know anything about it's coral reefs?
1_Wizard
well the particles composing a beach are typically made from rock, such as sand, gravel, shingle, pebbles, or cobblestones.
0_Apprentice
Where do those materials come from?  Are they washed up from the ocean?
1_Wizard
they are mostly biological in origin, such as mollusc shells or coraline algae.
0_Apprentice
Do any animals live on the beach?
1_Wizard
yea well they typically occur in areas along the coast where wave or current action deposits and reworks sediments that can contain crawfish and crabs
0_Apprentice
I just love to eat crabs for dinner.  I wonder what attracts them to the area.
1_Wizard
coconut crab is the largest land living arthropod in the world, and is probably at the upper size limit for terrestrial animals with exoskeletons in recent times.
0_Apprentice
I wonder how big these animals could have gotten in ancient times.
1_Wizard
these crabs are found in indonesia, island across the indian ocean and parts of the pacific coeans as far east as the gambier islands mirroring the distribution of the coconut palm.