Living Environment Regents Practice Test

Why are green sea slugs able to produce their own chlorophyll?

1. They have a unique relationship with bacteria

2. The gene for chlorophyll production is part of their DNA

3. They absorb chlorophyll from water

4. They are able to synthesize it from sunlight alone

The correct answer is: The gene for chlorophyll production is part of their DNA

Green sea slugs, specifically Elysia chlorotica, demonstrate a remarkable ability to produce their own chlorophyll due to a unique evolutionary adaptation that allows them to incorporate chloroplasts from the algae they consume into their own cells. This process is known as kleptoplasty, where they essentially 'steal' chloroplasts from green algae and retain them, making it possible for the slugs to engage in photosynthesis. The option indicating that the gene for chlorophyll production is part of their DNA is accurate because the green sea slugs have incorporated genetic material from the algae. This allows them to not only retain the chloroplasts but also to maintain the necessary functions for chlorophyll production as part of their own genetic machinery. This means they can leverage these chloroplasts to produce the energy they need from sunlight, similar to how plants function. This evolutionary trait showcases a fascinating case of adaptation, as these slugs can supplement their diet through photosynthesis, enhancing their survival in the aquatic environment where they thrive.