The Galápagos Islands: A Volcanic Archipelago That Changed Science

The Galápagos Islands are an archipelago of volcanic islands in the Pacific Ocean, ~1,000 km (620 mi) west of mainland Ecuador. They are a living laboratory of evolution.

Geography

• 13 major islands (>10 km²)
• 6 smaller islands
• 100+ islets & rocks
• Total land: ~8,000 km²
• Marine Reserve: 133,000 km² (2nd largest)

Volcanic Origin

• Hotspot volcanism (like Hawaii) – Nazca Plate moves SE over mantle plume
• Youngest: Fernandina, Isabela (active; last eruptions 2009, 2018)
• Oldest: Española, San Cristóbal (~3–4 Ma, eroded, subsiding)
• Shield volcanoes, calderas, lava tunnels, tuff cones

Biodiversity & Endemism

• Species: ~9,000 known; ~80% land birds, 97% reptiles, 30% plants, 20% marine endemic
• Icons: Giant tortoises (12 spp.), marine iguanas (only sea-going lizard), flightless cormorant, Darwin's finches (13 spp.), Galápagos penguin (only equatorial penguin)
• Adaptive radiation: Finches' beaks = textbook natural selection

Darwin's Visit (1835)

5 weeks on HMS Beagle. Collected specimens; noted inter-island variation. Published On the Origin of Species (1859) – Galápagos central to argument.

Conservation Status

• National Park: 97% of land (1959)
• UNESCO World Heritage: 1978 (extended 2001)
• Threats: Invasive species (goats, rats, ants, blackberry), tourism pressure (275k/yr), climate change (El Niño, acidification), illegal fishing
• Management: GNPD + Charles Darwin Foundation + tourism quotas, biosecurity

Visiting

• Fly to Baltra (GPS) or San Cristóbal (SCY) from Quito/Guayaquil
• Live-aboard cruise (4–15 days) or land-based (island-hopping)
• Guide mandatory in Park; stay on trails
• Best: Dec–May (warm, calm); Jun–Nov (cool, nutrient-rich, whale sharks)

The Galápagos are not just islands—they're evolution in action.