The perfect combination of temperature and geography gives South America more biodiversity than anywhere else on Earth.
Based on these factors and estimates from scientific data from museums and people, most scientists agree that South America has the highest number of animals. From the Amazon rainforest with its four layers of animal life to the Andes Mountains with dozens of different microclimates, South America has the perfect combination of temperature and geography, according to Live Science.
Scientists have identified and named more than a million species of animals, and there are millions more yet to be discovered across all seven continents. For hundreds of years, scientists have been classifying and locating species around the world. Before the digital age, most information about animal distribution came from museum collections, says Vítor Piacentini, an ornithologist at the Federal University of Mato Grosso in Brazil. Over the past 20 years, there has been a revolution in citizen science, with scientists using information from the public to fill in the gaps.
Using that information, they can map the distribution of species on the planet. In the late 1980s, scientist Norman Myers coined the term “biodiversity hotspots” to describe places with unusually high numbers of animals relative to their land area. Of the 36 hotspots around the world today, most are on continents that cross the equator, where the climate is warm and wet.
The reason for this has to do not just with animals, but also with plants. “Plants are the foundation of species,” says Barnabas Daru, an applied ecologist at Stanford University. “If a place has more diversity of plants, then other organisms that depend on plants will be more abundant.”
Although plants can live in all kinds of conditions, most thrive in hot, humid places. Temperature and humidity work together to provide the moisture needed. Warm air holds water molecules to create humidity. Warm temperatures are also better for many microorganisms, especially those that decompose the material that plants absorb nutrients from. On top of that, insects pollinate many flowering plants, which are adapted to warmer climates because they cannot regulate their own body temperature. More insects in the tropics means more pollination and more food for predators.
But Piancentini stresses that other factors also play a role. To accommodate many species, a continent must provide not only tropical conditions but also diverse environments. Places with high biodiversity have many suitable areas for animals to inhabit. For example, tall trees or large mountains allow vertical variation in temperature, sun exposure and terrain, allowing many species to coexist without competing for the same resources or habitat.
However, South America’s biodiversity may not have always been as vibrant as it is today. With deforestation, mercury mining, and climate change, South America’s animals are more endangered than ever.