Coral Polyps

Facts About Corals:

· coral polyps are very small: ¼ to 2 inches· two types of corals

~hard and soft polyps

· billions of coral polyps make up a reef· reefs are mainly made up by hard corals

·phylum cnidaria: stinging cells

· corals can live in solitary environments

Hard Corals (stony corals)

·secrete a hard external skeleton·have tentacles in multiples of six·live individually or in colonies·both large polyp and small polyp corals·usually reproduce by spawning and budding·calcareous skeletons have been deposited over many years and cemented together to form reefs

Hard Corals (stony corals)

~where water is calmer and deeper the branches are more delicate or formed into plates to absorb maximum light

·shapes are influenced by water movement~where wave crash the reef front the corals have thick branches or massive boulder shape

Large Polyp Hard Corals

Usually branching or plated

Small Polyp Hard Corals

Usually branching or plated

Soft Corals - Octocorals

·grown in colonies on the reef, but do not build reefs·soft and flexible skeleton that sways in the water·grow well in strong currents with access to a lot of plankton·have eight tentacles

Soft Corals - Octocorals

·not all corals are actually soft·have feathery look from the sided branching pinnules

Structure of the Coral Polyp

                                               

                

Structure of Stony Coral Polyps

·opening at one end is the mouth ·opens directly into the stomach

·mouth surrounded by tentacles ·digestive filaments called mesenteral fibers

·waste expelled from same opening

Structure of Stony Coral Polyps

·tentacles with nematocysts paralyze prey

                                                          

        

Endosymbionts•Zooanthallae, microscopic algae, grow on coral polyps• Through photosynthesis food and oxygen are produced for coral•Consumes some of polyp’s waste

Coral Skeletons·Polyps secrete calcium carbonate forming skeletons

·grow vertically and can retreat into their exoskeleton

Coral SkeletonsCoral growth can be traced through rings in its skeleton

Coral Reproduction•Sexual: release of sperm into water that might meet with eggs- called spawning

•Asexual: budding or when a coral breaks off and grows in a new location