those magic changes
Day to day and throughout the day , we experience small changes in our environment . We ’ re used to having a warm , sunny day but having it cool down during the night . But changes in the environment are miniscule . However , throughout Earth ’ s history , large-scale changes in the planet ’ s physical environment have drastically affected the evolution of life . Below are some examples of how the physical environment has affected evolution .
Continental Drift : Today , everyone knows that there are seven continents on Earth . However , the according to the theory of continental drift , about 250 million years ago , the continents were joined together as one giant supercontinent known as Pangaea . The theory says that over the course of the next 150 million years , Pangaea slowly drifted apart into seven continents . Similar to the plate tectonics , continental drift allowed isolated organisms to migrate and then evolve into different species . For example , based on studies of marsupial fossils , marsupials migrated from South America land across Antarctica , and then to Australia before the continental drift broke these land masses into separate continents . As a result , today , the majority of the world ’ s marsupials are located and isolated in Australia .
Extraterrestrial Events : No , not UFOs or aliens . Yes , meteorites – meteors that managed to pass through Earth ’ s atmosphere and strike the ground . A prime example is the meteorite that likely wiped out the dinosaurs 66 million years ago in the Cretaceous mass extinction . The meteorite can cause impacts that could severely impact the evolution of life . In the Cretaceous mass extinction , the meteorite deposited lots of debris into the atmosphere which blocked sunlight and changed climate . According to studies , the majority of all extinctions are results of the impact from a meteorite . Just as importantly , a new eruption of species after a mass extinction develops , and surviving species evolve to adapt to the changed environment .
Changes in Oxygen Concentrations in the Atmosphere : Since oxygen is essential to life , and since too much oxygen and too little oxygen is harmful , any significant change in oxygen levels in the atmosphere would severely impact the evolution of life on Earth . When photosynthetic organisms were introduced on Earth , the atmosphere experienced a large increase in free oxygen . However , as oxygen levels became too high , it is likely that much of life died out . At the same time , those that survived the high oxygen levels thrived , and it is thought that this gave rise to the evolution of eukaryotes .
21 VOGUE JUNE 2013
By: Talia Liu