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10 Isolated Regions Where Life Evolved Differently

Isolated Regions Where Life Evolved Differently

In 1831, Charles Darwin boarded the HMS Beagle and went on a voyage around the world visiting strange new lands and studying exotic flora and fauna. After his return in 1836, he began formulating what has become the most well-known and accepted theory about the origins of life on Earth. The basis for his understanding of evolution came from his visit to the Galapagos Islands, an archipelago that has been so isolated that it became home to vastly diverse endemic wildlife. There are several other isolated regions where life evolved differently from what we commonly see and here are a few of them.

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1. Between the 63rd and 76th streets of New York City, scientists discovered a new species of ant that isn’t found anywhere else on Earth. They call it the “ManhattAnt.” New York is also home to unique species of centipede, sweet bee, and white-footed mouse.

Ants (Not ManhattAnt)
Ants (Not ManhattAnt). Image Source: Fir0002/Wikimedia Commons

According to Rob Dunn, a biology professor at North Carolina State University, the ant is a relative of cornfield ant. Though it looks like it’s from Europe, the scientists couldn’t match it to any European ant nor does it match any of the known 13,000 other species of ants. The ManhattAnt might have evolved in isolation in the “concrete jungle” and adapted to the warmer, drier environment of the city. Another factor is their diet of urban food rich in corn syrup, which scientists believe to be the reason for high levels of carbon in their bodies.

The ManhattAnt isn’t the only new species found in New York City. In 2002, scientists discovered a new species of centipede in Central Park. In 2010, a new species of sweet bee was found in Prospect Park. Scientists studying the white-footed mouse, a native of North America, found that the mice of the city are quite different genetically from their counterparts in the country. In fact, according to Jason Munshi-South of Baruch College, “…every park in New York has a genetically different population because they’re so isolated and change over time.” (source)

2. The Himalayas which make up the transition zone between the Palearctic and Indomalayan realms is a hotspot for biodiversity and endemism. It is home to 3,160 species of plants and 147 species of animals that are endemic.

Takin or Gnu Goat
Takin or Gnu Goat. Image Source: Eric Kilby/Wikimedia Commons

The Himalayan climate ranges from being a tropical one at the base to permanent ice and snow at the top. Just as the climate varies, so does the flora and fauna. The mountain range is home to endemic species of animals such as the Himalayan serow, Himalayan tahr, the takin, the Himalayan musk deer, and the Himalayan goral. It also boasts many native species that are becoming endangered due to over-exploitation, habitat loss, and climate change. (1, 2)

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3. Lake Tanganyika, an African Great Lake, is so old and deep that it has evolved to be an ocean unto itself. It is home to over 300 species of fish, reptiles, mollusks, and crustaceans that cannot be found anywhere else in the world. 

Colorful Cichlid Fish of Lake Tanganyika
Colorful Cichlid Fish of Lake Tanganyika. Image Source: Rufus46, Jocke Sternborn, Michael K. Oliver, Ph.D., GFDL/Wikimedia Commons

Lake Tanganyika is an ancient lake that was formed over 10 million years ago when a rift opened as the central and eastern subsections of African tectonic plates drifted apart. Because of its incredible depth (1,470 meters average to 4,820 feet maximum depth) and since it endured for millions of years, life in the lake had the opportunity to evolve into an abundance of new species. It is often referred to as the freshwater equivalent of an ocean.

The lake is known for its wide variety of fish, especially the 250 species of colorful cichlid fish of which 98% are endemic. The threatened subspecies of cobra known as “Storm’s water cobra” is also only found in the lake. Several freshwater species of snails, crabs, shrimp, leeches, sponges, jellyfish, and many other animals that aren’t anywhere else can be found here. (1, 2)

4. Outside the town of Cromwell, New Zealand, there is a farm home to a beetle called ‘Cromwell Chafer.’ This beetle isn’t found anywhere else on Earth except that 81-hectare land which has been declared a nature reserve for it. 

Cromwell Chafer Beetle
Cromwell Chafer Beetle. Image Source: Siobhan Leachman, Emma Curtin/Wikimedia Commons

The beetles’ natural habitat is a small area of low sand dunes known as the Cromwell shallow land on the Cromwell river terrace. The large, reddish-brown beetles live underground as larvae for a year feeding on plant roots and emerge as adults during humid nights of spring and summer. Their original habitat was a 500-hectare which was destroyed following the construction of Clyde Dam and the formation of Lake Dunstan.

Several of the beetles were caught and relocated in the 1970s. The small, 81-hectare area is fenced off and was declared protected in 1979, and designated as Cromwell Chafer Beetle Nature Reserve in 1983. The protected residents, however, only utilize just about 12% of the land. They also must fight for survival because of introduced predators like little owls, hedgehogs, European earwigs, and redback spiders. (source)

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5. Madagascar has wildlife so unique that over 90% of the species are endemic owing to its isolation from other land masses for over 88 million years. 

Silky Sifakas of Madagascar
Silky Sifakas of Madagascar. Image Source: Jeff Gibbs, Simponafotsy/Wikimedia Commons

Over 135 million years ago when the Gondwanaland started to break apart, the landmasses of Madagascar, India, and Antarctica separated from that of Africa and South America. Later again, 88 million years ago, Madagascar separated from India. This isolation resulted in an abundance of plant and animal life that is so different from the neighboring continents that some ecologists consider it the “eighth continent.”

As of 2012, there are over 200 species of extant mammals. There are over 103 species and subspecies of lemurs including the most exotic looking silky sifaka, a lemur with long, silky, white fur. After the arrival of humans, at least 17 species of lemur have gone extinct. Another unique mammal is the fossa, a cat-like carnivore. Every single species of snail, and there are 651 of them, is endemic to the island and so are a vast majority of butterflies, spiders, dragonflies, lacewings, and scarab beetles. (source)

6. The Movile Cave, accidentally discovered by Romanian workers in 1986, was sealed for over 5.5 million years making it highly anoxic. Because of this, the cave is now filled with evolutionarily distinct species of eyeless albino creatures that feed off sulfur-producing bacteria.

The cave’s air is comprised of only 7 to 10% oxygen compared to the 21% in the outer atmosphere. The carbon dioxide levels are a hundred times that of the outer air. The cave also has high levels of methane both in the air and the water, as well as hydrogen sulfide and ammonia. The temperature in the cave is 25 °C. Over the millions of years, the animals in the cave have evolved to live in these toxic conditions.

Of the 48 species found in the cave, 33 are endemic and include different species of spiders, leeches, water scorpions, woodlice, and centipedes. Since it is pitch dark in the cave, many of these creatures are born without eyes but are equipped with feelers and antennas. Most of them have no body color, and some are even translucent. (source)

7. The Cape Floristic Region of South Africa, the smallest of the six floral kingdoms in the world, has such an extraordinarily high diversity that 69% of the 9,000 plant species are endemic. 

Cape Floristic Region
Cape Floristic Region. Image Source: Edweed/Wikimedia Commons

This floral kingdom covers the southwestern region of Western Cape and extends into the Eastern Cape of South Africa. Most of the region is covered with fynbos, a type of shrubland that occurs on acidic or nutrient-deficient sands. It contains the highest concentration of plant species in a non-tropical region. Apart from being home to many species of endemic protea, heath, and reed, it also the only place to find 12 plant families and 160 genera that are endemic to South Africa. (source)

8. Apart from being the deepest and most voluminous lake in the world, Lake Baikal is also home to at least 2,500 species of animals of which 80% cannot be found anywhere else on Earth. 

Baikal Seal or Nerpa
Baikal Seal or Nerpa. Image Source: Per Harald Olsen/Wikimedia Commons

The Baikal seal, also known as the “nerpa,” is one of the three types of freshwater seals found in the world and only found in this lake. Though there are less than 65 species of fish, more than half of them are endemic such as whitefish, Baikal black grayling, Baikal, white grayling, and Baikal sturgeon. Apart from that, it has innumerable invertebrate population (making 80% to 90% of the biomass) and hundreds of species of endemic crustaceans, snails, aquatic worms, and sponges.

Another interesting fact about the lake is that, unlike most other deep lakes, it is not stratified and is rich in oxygen even in deeper sections. It holds 23% of the world’s freshwater and is considered the clearest lake with visibility being as much as 30 to 40 meters in winter and almost 8 meters in the summer. (1, 2)

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9. There is a lake on an island in Palau that has been isolated from the sea for so long that the jellyfish evolved with almost no stingers. The golden jellyfish are quite harmless and people often swim with them. 

Jellyfish Lake and Golden Jellyfish
Jellyfish Lake and Golden Jellyfish. Image Source: National Park Service, ctsnow/Flickr

Based on sedimentation and depth, Jellyfish Lake is believed to be over 12,000 years old when the end of the Ice Age caused the sea levels to rise and fill it. The lake is home to two types of jellyfish – the moon jellyfish and the golden jellyfish. The golden jellyfish is a close relative of the spotted jellyfish found in the nearby lagoon, but it differs from the other in terms of morphology, physiology, and behavior. The evolutionary changes include the disappearance of spots, change in color, and decrease in the length of its clubs. Though both golden and moon jellyfish have stinging cells, they are not powerful enough to do any harm. (source)

10. Because of how isolated it is, the island of Socotra, Yemen, has plant life that cannot be found anywhere else on the planet. Often described as the “most alien-looking place on Earth,” it is considered the jewel of biodiversity in the Arabian Sea. 

Dragon's Blood Tree and Bottle Tree of Socotra
Dragon’s Blood Tree and Bottle Tree of Socotra. Image Source: Rod Waddington, Rod Waddington/Flickr

Socotra is the biggest island (95% landmass) in the Socotra Archipelago located between the Guardafui Channel and the Arabian Sea. According to a survey conducted by UN biologists in the 1990s, over 700 species of flora and fauna are endemic to the island. The combination of heat, humidity, and drought on the island has created unique plant species like the strange-looking, umbrella-shaped dragon blood tree which has sap as red as blood.

Other plants include the various species of aloe like the Aloe perryi or Socotrine aloe, Socotran pomegranate, Boswellia socotrana, the giant cucumber tree Dendrosicyos socotranus, and the giant succulent tree Dorstenia gigas. There are also several endemic species of mammals as well as birds such as the Socotra starling, the Socotra sunbird, Socotra sparrow, Socotra golden-winged grosbeak, Socotra cisticola, Socotra warbler, and Socotra bunting, many of which are endangered because of introduced feral cats. (source)

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