Home » Evolution, News » Can the eye-tipped tentacles of starfish shed light on early eye evolution?

Can the eye-tipped tentacles of starfish shed light on early eye evolution?

each red tip cup is an eye/Nilsson, Lund U

Recently, researchers first documented visually guided behaviour in starfish:

A study has shown for the first time that starfish use primitive eyes at the tip of their arms to visually navigate their environment. Research headed by Dr. Anders Garm at the Marine Biological Section of the University of Copenhagen in Denmark, showed that starfish eyes are image-forming and could be an essential stage in eye evolution.

The researchers removed starfish with and without eyes from their food rich habitat, the coral reef, and placed them on the sand bottom one metre away, where they would starve. They monitored the starfishes’ behaviour from the surface and found that while starfish with intact eyes head towards the direction of the reef, starfish without eyes walk randomly.

They think that their find may help us understand the evolution of eyes because the starfish eyes (at the tips of the tentacles), which lack true optics, are close to the theoretical “eye” of early evolution, and how they are used today might determine the earliest tasks that eyes were used for.

Maybe. The problem is, what starfish use tentacle eyes for today may or may not be the tasks that the earliest sighted organisms used their eyes for. Maybe soft fossils will shed some light down the road.

  • Delicious
  • Facebook
  • Reddit
  • StumbleUpon
  • Twitter
  • RSS Feed

2 Responses to Can the eye-tipped tentacles of starfish shed light on early eye evolution?

  1. OT: Here is a very well done presentation of the Kalam Cosmological Argument:

    The Kalam Cosmological Argument – video
    http://www.youtube.com/watch?v=COJ0ED1mV7s

  2. From an objective standpoint, the only thing we see is starfish that are very successful in life that have a unique “eye”.

    If this is indeed a step in eye evolution, why didn’t the starfish go on to develop real eyes?

    Does the very simple eye of the starfish predate the very complex trilobite eye?

    It looks like the starfish eye is just what they need to thrive. I don’t see any evolution here, just a well suited and designed eye for the starfish.

    How do we know that eyes evolved?

    Do we find primitive eyes in the lower rocks with a steady progression of more complex eyes as we get higher in the rock layers?

    I doubt it. So, if not, how do we know that each eye was not designed for the animal it exists in?

Leave a Reply