The Fantastically Weird World of Photosynthetic Sea Slugs | Michael Middlebrooks | TED

Summary

In this insightful presentation, an invertebrate zoologist explores the fascinating world of sea slugs and their unique ability to photosynthesize. While most animals rely on photosynthesis indirectly, some have evolved to capture solar energy directly, like corals and jellyfish. The highlight is the study of sea slugs, particularly sacoglossan species, which steal chloroplasts from algae in a process known as kleptoplasty, enabling them to photosynthesize. The speaker delves into the mysteries of this process, highlighting ongoing research and the many unanswered questions about how these animals harness solar power.

Takeaways

• 😀 Invertebrate animals are those without a backbone, comprising most of Earth's species, from insects to sea sponges.
• 🌞 Most biological energy on Earth ultimately comes from the sun, through the process of photosynthesis.
• 🌱 Some animals, like corals, jellyfish, and sea slugs, can photosynthesize by forming symbiotic relationships with algae.
• 🐚 Corals rely on zooxanthellae algae, which capture sunlight and provide the corals with sugar, allowing them to be photosynthetic.
• 🌊 Upside-down jellyfish can photosynthesize by harboring zooxanthellae within their cells, contributing most of their energy from sunlight.
• 🌿 Mollusks, particularly snails and clams, are the second most diverse animal group, with some species also engaging in photosynthesis.
• 🐌 Slugs, including sea slugs, have evolved to lose their shells over time, making them a highly diverse and fascinating group to study.
• 🦠 Some sea slugs, like nudibranchs, steal zooxanthellae or stinging cells from other animals, making them photosynthetic or using the cells for defense.
• 🍃 Sacoglossan sea slugs engage in kleptoplasty, stealing chloroplasts from algae to photosynthesize, allowing them to survive without constant feeding.
• 🔬 The process of kleptoplasty is still not fully understood, but certain sea slugs can photosynthesize for months after a single meal, producing chlorophyll.
• ❓ The molecular and biochemical processes that allow sea slugs to photosynthesize are a current area of scientific investigation, with many unknowns yet to be uncovered.

Q & A

What is an invertebrate zoologist, and what do they study?

An invertebrate zoologist is a scientist who specializes in studying animals that do not have a backbone. This includes a wide range of animals, such as insects, clams, sea sponges, worms, and many others.

How do animals typically obtain energy, and how does photosynthesis fit into this process?

Most animals obtain energy through consumption, either by eating plants directly or by eating other animals that consume plants. Photosynthesis is the process by which plants convert sunlight into energy, which forms the base of the food chain.

What is photosynthesis, and which animals have evolved to utilize it?

Photosynthesis is the process by which plants convert sunlight into energy, producing sugar and oxygen. Some animals, like certain corals, jellyfish, sea sponges, and flatworms, have evolved to capture solar energy through symbiosis with algae or by other means.

How do corals use photosynthesis to survive?

Corals survive by forming a symbiotic relationship with a type of algae called zooxanthellae. These algae live inside coral cells, capture sunlight, and provide sugar to the coral, allowing them to thrive in nutrient-poor waters.

What are upside-down jellyfish, and how do they obtain energy?

Upside-down jellyfish are a type of jellyfish that live in shallow mangroves. They can photosynthesize by harboring zooxanthellae inside their cells, allowing them to obtain energy directly from sunlight rather than feeding.

What are mollusks, and why are they important in the study of sea slugs?

Mollusks are a diverse group of animals that include snails, clams, squids, and octopuses. Sea slugs, which are a type of mollusk, are particularly interesting because they have unique abilities, such as photosynthesis through symbiosis or stealing chloroplasts from algae.

What makes sea slugs unique compared to other mollusks?

Sea slugs are unique because, unlike most mollusks, they have lost their shells through evolution. This has occurred multiple times in different mollusk groups, leading to a variety of fascinating forms and behaviors.

What is kleptoplasty, and how does it allow sea slugs to photosynthesize?

Kleptoplasty is the process by which sea slugs steal chloroplasts from algae and store them in their own cells. This allows them to photosynthesize, using the chloroplasts to capture sunlight and produce energy, much like plants.

How long can certain sea slugs continue photosynthesizing after consuming algae?

Certain sea slugs, such as the emerald sea slug, can photosynthesize for up to nine months after consuming algae. Other species, like the lettuce sea slug, can continue photosynthesizing for three to four months.

What are some of the mysteries still surrounding sea slugs' ability to photosynthesize?

There are still many unanswered questions about how sea slugs manage to photosynthesize. For example, it's unclear how they produce chlorophyll, a substance typically only found in plants, and why some slugs appear blue. Scientists are working to unravel these mysteries.