TED-Ed: These animals are also plants ... wait, what? | Luka Seamus Wright

Elysia chlorotica, a unique slug, can photosynthesize by stealing chloroplasts from algae. It lives in salt marshes and can survive a year without eating, acting like a plant. This mixotrophic ability is rare, with Elysia holding chloroplasts longer than other slugs. The chloroplasts repair themselves, and the slug adjusts its genes to maintain them. Symbiotic relationships are common in marine life, with organisms like corals and clams hosting algae for nutrients. Some algae, like Triphosphorca, can consume animals, surviving in darkness. These processes mirror early plant evolution, where chloroplasts originated from cyanobacteria consumed by single-celled animals.

What makes Elysia chlorotica unique among other slugs?

• It lives in freshwater.

• It can fly.

• It can photosynthesize like a plant.

• It has a hard shell.

How does Elysia chlorotica obtain chloroplasts?

• By growing them internally.

• By piercing algal cells with specialized teeth.

• By eating other slugs.

• By absorbing them from the air.

What is a key factor in the longevity of chloroplasts in Elysia chlorotica?

• The chloroplasts' reliance on sunlight.

• The chloroplasts' ability to repair their own light harvesting systems.

• The slug's diet of insects.

• The slug's ability to fly.

Which organisms are known to have symbiotic algae living inside their cells?

• Birds and mammals.

• Corals, giant clams, and sponges.

• Fish and amphibians.

• Reptiles and insects.

What evolutionary process is suggested by the mixotrophy observed in Elysia and other organisms?

• The origin of all plants from single-celled animals.

• The development of wings in birds.

• The formation of mountains.

• The evolution of mammals from reptiles.