Science Questions

Are there any moving animals that have chlorophyll in their skin cells that they use as an energy source? Chris Burgess

Chris: Yeah, this is really exciting.  I remember reading about this eight years ago when people began to discover this sort of thing.  There are some sea slugs which have evolved to eat algae (these are plant micro organisms) and these plants have chlorophyll in them because that’s how they capture the energy from the sun and turn it into chemical energy in the form of glucose.  These sea slugs have evolved to graze on the algae.  They have little outpouchings called diverticula in their gut.  They can put the chloroplasts which are the green bits in the algal cells that contain the chlorophyll into these little sacks.  They extend all the way to the surface of the slug’s skin.  So the chloroplast which can capture the sun’s energy like a miniature solar panel ends up under the skin of the slug.  The slug also has some genes in its body which it stole from the algae donkey’s years ago so it can keep these things alive.  They can persist in the body of the slug for up to four months.  So the slug can effectively photosynthesise.  It can capture energy from the sun and use it in its own body.

Dave: In a slightly less extreme way I think there are some forms of jellyfish which will keep whole algae inside them.  They swim up to the surface in the summer during the day and absorb lots of sun in the algae.  They eat the algae at night when they go down and hide away from all the predators.

April 2008