Islands in the Sky: Evolutionary Pressures Beyond Traditional Islands

We’ve been exploring island biogeography, but every example so far has been… an island. Today we’ll look at three places that aren’t surrounded by water but still experience similar evolutionary pressures.

1. Lake Baikal

Lake Baikal in Siberia is the world’s oldest and deepest lake. It’s home to a unique ecosystem that includes the Baikal seal, the world’s only freshwater seal. The Baikal seal has evolved to survive in the lake’s cold, dark waters. It has a thick layer of blubber and can hold its breath for up to an hour.

Lake Baikal is also home to a variety of other endemic species, including the Baikal amphipod, a small crustacean that lives on the lake floor. The Baikal amphipod is an important part of the lake’s food chain and is a food source for the Baikal seal.

2. Mount Kilimanjaro

Mount Kilimanjaro is the highest mountain in Africa. It’s located in Tanzania and is home to a variety of ecosystems, from rainforest to alpine desert. The mountain’s high altitude and isolation have created a unique environment that is home to a number of endemic species, including the Kilimanjaro chameleon.

The Kilimanjaro chameleon is a small, brightly colored lizard that lives in the mountain’s rainforest. It has evolved to survive in the rainforest’s high humidity and low temperatures. The Kilimanjaro chameleon has a long, prehensile tail that it uses to grip branches and leaves.

3. The Patagonian Steppe

The Patagonian Steppe is a vast, arid region in southern Argentina and Chile. It’s home to a variety of plant and animal species that have adapted to the region’s harsh conditions. One of the most iconic animals of the Patagonian Steppe is the guanaco, a camelid that resembles a llama.

The guanaco has evolved to survive in the Patagonian Steppe’s cold, dry climate. It has a thick coat of fur that protects it from the cold and a long neck that allows it to reach vegetation that other animals can’t.


These are just a few examples of places that experience the same evolutionary pressures as islands, even though they’re not surrounded by water. These places are home to a variety of unique and fascinating species that have adapted to their unique environments.