Currently the world is made up of seven land masses, or continents. Their locations are not fixed, though. Rather, they are constantly shifting due the movements of tectonic plates.
Sometimes all of the continents in the world come together to form a ‘supercontinent’, and then later they separate again. This seems to happen in cycles, and geologistsbelieve that there have been four supercontinents in the last two billion years. The most recent supercontinent, Pangaea, existed from about 335 to 175 million years ago,coinciding with the early age of the dinosaurs. It was formed when two large continents, Gondwana (consisting of today’s Antarctica, South America, India, Africa, and Australia) and Laurasia (modern Asia, Europe, and North America) collided.
In contrast to today’s Earth, most of it was located in the southern hemisphere. It was surrounded by one superocean called Panthalassa. The interior may have been very dry and desert-like, while areas closer to the equator would have been lush and tropical. Besides dinosaurs, insects and the ancestors of modern mammals also lived in Pangaea. Most of these animals thrived well after a great mass extinction event that occurred 252 million years ago, killing off over three quarters of all life on Earth.
And what evidence do we have to support the existence of Pangaea? Well, anybody can look at a world map and notice how well the world’s present-day continents seem to fit if you were to push them together. But more scientifically, both the geological and plant/animal fossil records indicate unmistakable similarities between lands that were once beside each other.
1. geologist (n) a rock/Earth expert 地質學家
Tina loves learning about rocks so she wants to become a geologist.
2. collide (v) smash/come together unintentionally 碰撞
The two cars collided but nobody was hurt.
3. hemisphere (n) the northern, southern, eastern, or western half od the Earth 半球
The Dominican Republic is the poorest country in the western hemisphere.
4. equator (n) the imaginary line that goes around the center of the Earth 赤道
Countries near the equator usually have hot, tropical climates.
5. lush (adj) very green with plant life 草木茂盛
The palace garden was lush and full of plants.
6. thrive (v) to grow, live, or develop well 茁壯成長
Bamboo thrives in the Central Mountain Range of Taiwan.
7. fossil (n) bones or plant remains that have to changed to stone over time 化石
Many dinosaur fossils have been found in this desert.
8. unmistakable (adj) impossible to deny or mistake for another thing 明確的
The students could hear the unmistakable sound of their teacher walking towards the classroom in the hallway.
Phrases and Sentence Patterns句型解析
1. coincide with (phr) happen at the same time 與…相符
This year my birthday coincides with the Lunar New Year.
2. in contrast to (phr) in the opposite/very different way 與…相反，相比之下
In contrast to most of his friends, Jeff doesn’t like basketball.