Coral Reefs!Coral Reefs!

Phylum Cnidaria and the class Anthozoa There are over 800 known Hermatipic

species◦ Hermatipic- reef building

Coral reefs are the most biologically diverse ecosystems on earth, ◦ Source of food ◦ Protect coastlines (from storms and erosion)◦ Gives homes and spawning and nursery

grounds for fish◦ Provide jobs to local economies from fishing,

recreation, and tourism◦ New medicines

Coral in General

◦ Also known as ahermatypic (non reef building) coral, they do not produce a calcium carbonate skeleton

◦ Often called octocorals◦ Mostly colonial◦ Contains sclerites in cells on

the outside of the colony found in coenenchyme, (jelly-like tissue) between polyps. Sclerites made of protein and

calcium carbonate.◦ Some are also encrusting

Soft coral!!

Hermatipic- Reef building coral◦ Contains a basal plate◦ Net benefit of the world's coral reef

ecosystems estimated to be $29.8 billion per year

◦ Have zooxanthellae Deep water and some cold water corals lack

zooxanthellae◦ Most corals feed at night

Similar to sea anemones. Polyps extend their tentacles to capture prey, first stinging them with toxic nematocyst cells, then drawing them toward their mouths.

Also collect fine particles in mucous film which are drawn by cilia into the polyp's mouth. Some species are entirely mucous suspension feeders

Prey ranges in size from small fish to zooplankton, depending on size of the coral

More coral, yippee

◦ Deep sea corals live on in deeper water from 50 m to over 3,000 m

◦ A few species also live in shallower, cold water in the northern latitudes. 

◦ Found in all oceans◦ Like their shallow-dwelling

relatives, deep-sea corals exhibit high biodiversity.

◦ Don’t contain zooxanthellae (no light)

◦ Don’t know the extent of communities because they live so deep

http://www.youtube.com/watch?v=PUbaVZRIS18

Deep Water Coral

◦ an algae that gives off oxygen

and other nutrients◦ polyp gives the algae carbon

dioxide That is why coral reefs grow near

the surface◦ Algae enhance the coral’s

ability to synthesize calcium carbonate

Coral Bleaching◦ When algae leave, due to

warmer than usual water or a change in pH

http://www.youtube.com/watch?v=aEdoizgeNJk

http://www.youtube.com/watch?v=60jof35WuAo

Zooxanthellae

Feed similar to sea anemones. Polyps extend their tentacles to capture prey, stinging them with nematocyst cells, then drawing them toward their mouths.

Also collect fine particles in mucous film which are drawn by cilia into the polyp's mouth. Some species are entirely mucous suspension feeders

Prey ranges in size from small fish to zooplankton, depending on size of the coral

Coral feeding

Can be either asexual or sexual Budding- asexual

◦ new polyps bud off from parent. This occurs when the parent polyp reaches a certain size and divides. Continues throughout the animal's life and produces polyps identical to the parent polyp.

Fragmentation- asexual◦ Allows a portion of an entire colony to establish a

new colony. The separated individuals start new coral colonies that are genetically identical to the parent colony

Reproduction, whoo babies

Broadcast Spawning◦ 3/4ths of all stony coral species are broadcast

spawners

◦ Produce male and/or female gametes that are released into the water in large numbers Allows them to spread their “children” over a broad

area.

Have lots of kids at one time to compensate for how many die a terrible depressing death, while their parents watch, and cant do anything about it.

occurs as a synchronized event, very important because male and female corals cannot move.

Usually occurs in response to environmental cues. Long-term cues may be related to temperature, day length,

or rate of temperature change. The short-term control is usually based on lunar cues

http://www.youtube.com/watch?v=1aX61LzmeYA http://www.youtube.com/watch?v=wsaZ8-I7akg

More babies

Remaining 1/3 of coral species are brooders◦ Only male gametes released into water.

◦ The gametes are negatively buoyant and transported by waves and current before sinking

◦ They are taken in by female coral polyps containing egg cells fertilization occurs inside the female coral and produces a small planula.

◦ The planula is released through mouth of female when it is old enough to settle very soon after its release.

Yet more chilrin

Overtopping◦ used mostly by fast growing

species◦ The faster growing coral just

grows over the other coral◦ The covered coral gets less light

and food. Aggression

◦ involves extruded digestive filaments and sweeper tentacles. Typically results in the death of some of the other’s polyps.

http://animal.discovery.com/video-topics/wild-animals/coral-nighttime-battle.htm

Two ways for coral to get space

◦ Cells are specialized to perform various functions

◦ Very limited organ development

◦ Have a simple stomach (gastrovascular cavity ) opens only on one end, and a ring of tentacles.

◦ No central nervous system.

◦ While appearing to be a single organism, many coral are actually a colony of many individual, identical, coral polyps.

◦ Are only a few millimeters in diameter

Coral polyps themselves

◦ The polyps of hard corals sit in a calyx that is produced by the coral with calcium carbonate

◦ The walls surrounding the calyx are called the theca and the bottom is the basal plate.

◦ Basal plate is a calciferous ring with six supporting ridges. The ridges grow vertically and project into the base of the polyp.

◦ Tabulae are horizontal partitions that allow for upward growth by isolating the surface from the skeleton.

More polyps