The Asteroid that Killed the Dinosaurs Also Changed the Forest
by Dani Garduno, age 10
People are familiar with the asteroid that killed off dinosaurs; however, that asteroid also killed 75 percent of life on Earth, including many trees. The forests eventually transformed into the rainforests we see today.
Before the asteroid, there were a lot of different plant species populating the Earth. Half of the plants were conifers and ferns, while the other half were flowering trees and shrubs. When it rained, nutrients flowed out of the soil. The conifers could grow despite the lack of nutrients. These trees had the unique ability of being able to grow with very little food, which was helpful for survival. Herbivores, specifically sauropods, the largest animals ever to walk our planet, helped prevent the trees from over expanding by opening gaps in the top of the forests. Insects also lived in the forests. Some insects only ate one type of plant leaf and other insects were generalists, which meant they ate many types of plants and were able to survive after the impact.
66 million years ago, the fireball hit overnight and triggered a massive extinction event. Plants, animals, and the soil were changed into present day Colombia. Woodlands were changed into rainforests like the Amazon. It took six million years for the rich diversity to return. The woodlands were replaced by dark, moist, green trees and shrubs. Many of these types of trees are seen today. When the asteroid hit, ash from the fires fertilized the soil and grew flowering trees and shrubs. These species evolved to create canopies, which blocked sunlight from the forest floor.
Although the asteroid was destructive, it recreated life on Earth. Scientists are now able to know more about the cause of diversity in the rainforest.
[Source: Science News for Students]