Adaptive radiation in Galápagos Islands

Definition

Adaptive radiation in the Galápagos Islands refers to the rapid evolution of diverse species from a common ancestor as they adapt to different ecological niches. This phenomenon is characterized by the emergence of various forms and functions among species, allowing them to exploit specific resources and environments within the islands, demonstrating the principles of natural selection and speciation.

5 Must Know Facts For Your Next Test

1. The Galápagos Islands are often considered a natural laboratory for studying evolution due to their isolation and unique biodiversity.
2. Adaptive radiation in the Galápagos is primarily illustrated by Darwin's finches, which evolved different beak shapes to exploit various food sources like seeds, insects, and flowers.
3. This process occurs when a small number of species colonize a new environment with diverse habitats, leading to rapid speciation as they adapt to specific niches.
4. Other examples of adaptive radiation in the Galápagos include marine iguanas and giant tortoises, which have also developed unique adaptations suited to their environments.
5. The concept of adaptive radiation helps explain how biodiversity arises from a limited number of ancestral species through mechanisms such as geographic isolation and ecological opportunities.

Review Questions

• How does adaptive radiation demonstrate the principles of natural selection in the Galápagos Islands?
  • Adaptive radiation illustrates natural selection by showing how species evolve different traits based on their environment. In the Galápagos Islands, various finch species developed distinct beak shapes to utilize specific food sources available on the islands. This diversification allowed each species to thrive in its ecological niche, emphasizing that those best adapted to their surroundings are more likely to survive and reproduce.
• Compare and contrast the adaptations seen in Darwin's finches with another species that underwent adaptive radiation in the Galápagos Islands.
  • Darwin's finches exhibit a range of beak sizes and shapes that correspond to their feeding habits, while marine iguanas have adapted by developing a flattened tail for swimming and specialized salt glands for excreting excess salt. Both examples highlight how different ecological pressures drive adaptations; however, the finches focus on feeding strategies while marine iguanas are adapted for survival in a marine environment. This shows how adaptive radiation leads to diversity based on ecological needs.
• Evaluate the impact of geographic isolation on the process of adaptive radiation in the Galápagos Islands.
  • Geographic isolation plays a crucial role in adaptive radiation by limiting gene flow between populations, allowing them to evolve independently. In the Galápagos Islands, the distance between islands and varied habitats create unique environmental pressures. This isolation fosters speciation as organisms adapt to their specific surroundings without competition from closely related species on other islands. Consequently, it promotes biodiversity as various traits emerge tailored to different niches.

Related terms

Darwin's Finches: A group of finch species found in the Galápagos Islands that evolved from a common ancestor, showcasing a variety of beak shapes and sizes adapted to different food sources.

Speciation:

The process by which new species arise from existing species, often as a result of evolutionary pressures and environmental factors.

Ecological niche: The role and position a species has in its environment, including all interactions with biotic and abiotic factors.