SciShow: Photosynthesizing Animals

Introduction

• Presenter: Hank Green
• Topic: Discovery of animals capable of photosynthesis, a trait typically associated with plants.

Key Points

General Concept

• Plants are autotrophs: harness solar energy through photosynthesis.
• Surprisingly, some animals are also capable of photosynthesis.

Eastern Emerald Elysia (Sea Slug)

• Location: East coast of the United States.
• Characteristic: Looks like a floating leaf.
• Diet: Eats yellow-green algae.
• Process:
  • Absorbs chloroplasts from algae.
  • Uses algae's genes for photosynthesis.
  • Slugs inherit algal genes, needing to feed only about two weeks per year.
  • Rest of the time, they utilize sunlight for energy.

Pea Aphid

• Color Variants: White, orange, or green based on environmental conditions.
• Notable Traits: Can manufacture carotenoids.
  • Carotenoids assist in light absorption and protecting chlorophyll.
  • Most animals obtain carotenoids only through diet.
• Energy Production:
  • Some aphids produce ATP from sunlight, similar to plants.
  • Green aphids produce more ATP than white; orange produce more in sunlight than darkness.

Spotted Salamander

• Location: Eastern United States and Canada.
• Unique Trait: First known photosynthetic vertebrate.
• Discovery:
  • Contains chlorophyll-containing algae within its cells.
  • Algae appear in fertilized eggs, bloom inside embryo's body.
  • Algae enter embryo possibly during the nervous system development.
• Immune System Tolerance:
  • Vertebrates usually destroy foreign cells but not in this symbiotic relationship.

Conclusion

• These findings challenge the assumption that photosynthesis is exclusive to plants.
• Raises the possibility of other organisms, potentially even humans, harnessing photosynthesis in the future.
• Encourages further exploration and understanding of photosynthesis in animals.

Call to Action

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