AP Biology class blog for discussing current research in Biology

Tag: starfish

Starfish are Strong?

When on the beach, sometimes you can see a starfish on the beach. Assuming it was brought by the tides of the water, if a starfish is able to be pushed by water, how does it survive in the water that is pushing it around?

Well, Starfish are actually quite strong. Their anatomy is essentially a central disk which grows out arms, commonly 5, that have spikes on them.  They have an endoskeleton consisting of many ossicles, made of Calcite,  which strongly boost the structural integrity of the starfish.  But to understand the strength of a small starfish, we need to look into the ossicles and calcite that make up a starfish. This is helpful to humans as starfish have inspired ideas like hydraulic movement.

Simple Sea Star Body Plan

Since Calcite, made of carbons and calcium, make up the ossicle, the integrity of a starfish is dependent upon the placements of carbon molecules. Similar to a diamond, the carbon molecules of the starfish are strongly bonded by covalent bonds, giving strength to each surface. Diamonds are one of the hardest structured natural material. More so, each calcite in the ossicles resemble a stack of carbon hexagons. Because calcite cannot be uniformly bonded, pushing on areas of a starfish will break these calcite bones. Although the starfish does have its integral flaws, the diamond-like structured ossicles make up for most of it. The strongly covalent bonds of carbon atoms create a mesh-like surface and hold the starfish together.

By studying the starfish’s simple yet complex anatomy, we may be able to make breakthroughs for “creating stronger porous materials” like ceramics says Material Scientist Ling Li at Virginia Tech. Starfish seem frail and pushed upon, by the water, but in reality, starfish are strong predators which root from their complex anatomy.

The Great Barrier Reef Not So Great?


Image By Paul Holloway, Flickr

The first adjective I use when thinking about the Great Barrier Reef is great. But, according to a new study published by the Australian Institute of Marine Science (AIMS) in Townsville, Australia, it is rapidly shrinking. The shrinking is due in part to the recent storms, an increase in the number of crown of thorns starfish in the reef and coral bleaching.

The Great Barrier Reef has lost half its coral in just over 27 years. John Gunn, the CEO of AIMS, said that we must “… adapt to the challenges of rising sea temperatures and ocean acidification.” He goes on to say, “We can’t stop the storms but, perhaps we can stop the starfish.”

Another concern for the Great Barrier Reef is that if this trend of shrinking continues at the rate it is going, then by 2022 the coral could shrink in half again.

But, there is some good news for the reef. It is able to regenerate itself. It will take about 10-20 years for the reef to fully recover, that is if it does not shrink in size anymore than it has already. This is quite near impossible though because there is no way to stop storms or ocean warming, which causes coral bleaching. The ocean warming stems from Global Warming, which is an epidemic in itself. The only thing that we can help to prevent is the crown of thorns starfish from destroying the reef. Scientists can continue to study them to find out how to reduce their numbers in the reef. Without the crown of thorns the reef with increase by 0.89% per year, a small recovery for the Great Barrier Reef. The whole process will take time, but if successful we can save the Great Barrier Reef from becoming a thing of the past.


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