シャドーイング練習: The Columbian Exchange Explained: How 1492 Changed the World - 動画で英語スピーキングを学ぶ

Picture a different reality. There are no cows in the US,  no potatoes in Ireland, no chili peppers in India, and no tomatoes in Italy. Actually, a few  centuries ago, that was reality. Before the 1500s, the inhabited world was basically divided into  four world zones. Afrourasia, the Americas, Australasia, and the Pacific Islands.  Each zone developed distinct ecosystems, plant and animal species, and human societies.  And for the most part, they all stayed in their zone. That means potatoes, chilies, and tomatoes  only lived in the Americas. Cows only lived in Afroureasia. And most people only lived in the  zone they were born. But people did travel, connect to new places, and trade goods between  regions within those world zones. For example, road networks in the Andes and Meso America  supported trade among the Inca and Aztec people, and Polynesians traveled and traded across the  vast distances separating Pacific islands. Some of the most well-developed trade routes were in  Afrourasia. There people built up networks like the Silk Roads, a series of routes that stretched  from modern China to the Mediterranean Sea, as well as the Indian Ocean and Trans Saharan  networks. These roots helped goods and ideas spread across Afrourasia. People shared  ship building technology, nautical maps, and navigation tools. They made weapons and  gunpowder, and they built up resistance to diseases like smallox. The technologies moving  across these routes eventually helped Europeans develop the navigation and ship building  technology needed to cross oceans. Then Spain and Portugal used this technology as they  sought sea routes in the Indian Ocean and China.

But when Christopher Columbus sailed across the  Atlantic Ocean to find a path to Asia in 1492, he accidentally ended up in the Americas. That  slight miscalculation would change the world.

The arrival of Europeans in the Americas set off  what became known as the Columbian Exchange. Now ideas, people, plants, and animals weren't just  spreading within world zones. They were also regularly spreading between them for the first  time in history. And it increased complexity in the Americas, in Europe, and across the entire  world. When Europeans went back to Afroureurasia, they brought stuff with them from the Americas.  The tomatoes and chilies that had lived in Peru, Ecuador, and Mexico soon found new homes in  Italian and Indian kitchens. Pineapples left their tropical homes and became a status  symbol in Europe, and potatoes and corn moved across the ocean to quickly become some of  the most important crops across Afroureurasia.

These new foods helped the Afrourasian population  grow, leading to more workers and more people who wanted to travel between world zones in search  of new opportunities. And as Afroureasians poured into the Americas, they brought stuff,  too. They introduced crops like sugarcane and wheat and animals like cows, horses, and even  honeybees. But this incredible exchange of resources also had some significant downsides. In  the Americas, European conquerors and colonists broke up communities, forced people from their  homes, and enslaved them. They brought diseases like smallox and measles, which killed millions  of people. And they used their advanced weapons and formed alliances with local populations to  take over the weakened indigenous communities.

And while the Columbian Exchange gave people  in both Europe and the Americas access to more kinds of food and animals, biodiversity began to  shrink. People prioritized crops like potatoes, sugar, and wheat, which led to less variety in  native plants, and it eventually caused problems.

For example, while there were thousands  of types of potatoes in the Americas, Ireland only grew one type. And when a disease  swept through their crops in the 1800s, Ireland fell into famine. In the Americas, the  newly introduced cattle grazed and trampled native plants, wiping them out and making  way for European crops to take their place.

As European colonizers prioritized the growth  of monoculture cash crops like tobacco, sugar, and cotton, they also forced tens of millions of  people from Africa to migrate to the Americas as a labor force in the transatlantic slave trade.  This practice devastated African communities and broke up families. Millions of enslaved Africans  did not survive the middle passage voyage across the Atlantic Ocean. Those who did lived hard lives  of forced, brutal labor in a system that persisted for generations. And while they used and destroyed  African and indigenous people and communities, European nations grew wealthy. They gained  influence and power that would shape history.

The Colombian exchange increased complexity  across the world. The movement of people built new connections, allowing for the spread  of ideas and food and shaping economies and industries. But that connection came  at a steep price. It wiped out species, devastated communities, and increased inequality.  Ultimately, it changed the world forever.