Evolving Planet Evolution

“All available evidence which includes fossils, comparative anatomy, and DNA, support the theory of evolution as the scientific explanation for the rich diversity of life on earth.” – Charles Robert Darwin Upon entering the Field Museum of Natural History, Evolving Planet, Darwin's words are quoted to hint the person of all they will be seeing. Evolving Planet goes through the geological order of the planet earth starting in the Precambrian Age beginning four billion years ago. Every few million years are named, and visitors are introduced with evidence of life preserved for all that time in stone. To start, the exhibition introduced the viewer with two theories as to what may have started life on Earth. Scientists theorize that life started

According to the exhibition, living organisms did not come about until 3.5 billion years ago, from singled celled organisms called prokaryotes. They are the most ancient, and have been found fossilized in rock. From prokaryotes came bacteria two billion years. Bacteria began to use the sun as an energy source. Through photosynthesis, bacteria used the carbon, water, and sun as energy and would release the oxygen into the atmosphere. The oxygen from photosynthesis transformed the earth.. The oxygen created the ozone layer that helped the planet block off the sun's harmful

By sexual reproduction, the variation in genes allowed for more diversity among organisms, and different adaptations. Natural selection derives from genetic variation as the genes that were passed on either helped or crippled an organism. Those that lived and were able to adapt had the opportunity to pass on their genes. Those that could not, died off and became extinct. Because of early organisms' ability to adapt, many of the animals alive 543 million years ago, in the Cambrian Age, are alive today. Animals like Echinoderms, now the modern starfish and sea cucumber; annelids and priapulidas, now worms; chordates, mammals and anything with a backbone; arthropods, including insects and spiders, crustaceans and scorpions are such animals that have been evolved from early animals alive more than 500 million years ago. The Cambrian Age was the period where animals began to grow skeletal structures. Before, all organisms were soft bodied and small. Growing skeletons was an evolutionary advantage, as, skeletons provided protection from predators, and as a framework for muscles. Skeletons stored chemical for cell functioning. The fossilized skeleton of early animals have shown how animals an all life on earth has evolved and changed. Chordates are the early ancestors of all invertebrates. Backbones allows an animal's muscles to attach to it for movement and weight