The “Evolving Planet Exhibit” took me on a journey through 4 billion years of life on earth, from the Precambrian singled cell organisms to the Mesozoic towering dinosaurs and extended hominid human family. The unique fossils, concrete interactive displays and recreated sea and terrestrial landscapes help the compelling story of evolution- the single process that connects everything that has ever lived on earth. Evolution of life on Earth occurred 4.5 billion years ago, the Precambrian Eon. This Eon makes up ninety percent of Earth’s history. Organic compounds were the building blocks on Earth; two theories exist of how these forms came to be; they may have formed on Earth, through underwater thermal vents, or carried to Earth through meteorites. What followed, were prokaryotes, single celled organisms, and eukaryotes, multi-cellular organisms. The development of prokaryotes caused transformations to Earth, through the process of photosynthesis, which allowed for the development of oxygen in our atmosphere. Through Eukaryotes, natural selection was possible, due to genetic variation. During the Paleozoic era, which occurred 543 million years ago, there was an explosion of life, which led to the wide variation of life that we see today. Throughout this period there was a significant outburst in marine life. As time evolved, skeletons had evolved structurally, which allowed for larger bodied organisms to grow. Their chemical composition includes the minerals calcium and phosphate. Although evolution allowed for new adaptations, they weren’t significant enough to withstand the first extinction on Earth, which wiped out 70% of species, known as the ice age. After the ice age, plants, from green algae, developed on land. The marine life diversified, developing placoderms, acanthodians and osteoderms. This did not last for long, for a second massive extinction occurred because of cold climates all year, wiping out 70% of marine life, including placoderms and osteoderms. After the earths’ continents had assembled into Pangaea, which had a major effect to the diversity of plant. Two new groups emerged, reptiles and synapsids. Four legged animals walked the Earth, and would continue to do so because of the evolution of a new egg, amniotes had formed. A third extinction occurred due to volcanic eruptions and global warming, wiping out 80% of the terrestrial animals and 90% of marine animals.
The Mesozoic Era began 248 million years ago the first mammals came to a rise. Molars and 3 bones in the middle of the ear were major indictors of mammal. Not only did mammals come to a rise but also did the reptiles. The Mesozoic era is called the age of the reptiles where snakes, crocodiles, turtles and made their first emergence. A fourth extinction then occurred, the shifting of the continents. Marine life was wiped out to 50% because the sea levels dropped and 95% of terrestrial animals died due to volcanic eruptions and global warming. The Mesozoic was also called the age of dinosaurs. Dinosaurs are thought to be ancestor of reptiles but they differ in the hip structures; reptiles having a cup shape and dinosaurs having a hip socket. Dinosaurs where the largest animals to have walked this earth and gave a rise to the birds. Which are known as our living fossil of dinosaurs today. During this era not only was animal life diverse but, flowering plants began to bloom which are known as angiosperms. Meteorites then occurred the fifth mass extinction wiping out more than 50% of life including the dinosaurs.
The age of mammals was among the Earth, 65 million years ago; the Cenozoic era. Habitats evolved in different regions, including warm tropical forests, and cool, drier grasslands. These habitats allowed for mammals to succeed, populate, and build diversity. Following the evolution of apes, arose what we are today, humans, falling under the classification of hominids. Beginning 10000 years ago, and currently still underway, is the 6th mass extinction of Earth. Today, the leading cause is humans, dilapidating habitats, leading to the extinction of species.
The evolution of Earth, and life on Earth began 4.5 billion years ago. To this day, evolution continues to contribute to the diversity and successes that both the planet and species of the planet have acquired. As time has progressed, we have seen the addition of many new species to the planet, as well as extinctions. Those species most fit to survive have adapted to their surrounding environment allowing them to thrive. However, those adaptations may not be enough to withstand the current extinction rates. To this day, twenty-three species are extinct. One species every four years.