Protists

Chapter 25 The History of Life on Earth Lecture Outline Overview: Lost Worlds The largest fully terrestrial animal in Antarctica is a 5-mm-long fly. Five hundred million years ago, Antarctica was surrounded by warm ocean waters filled with tropical invertebrates. Later, the continent was covered with forests. Dinosaurs and, later, predatory ?terror birds? hunted in these forests. All over the world, past organisms differed from those alive today. Macroevolution is the broad pattern of evolution above the species level. Macroevolutionary changes include the evolution of terrestrial vertebrates, the impact of mass extinctions on the diversity of life, and the origin of key adaptations such as flight in birds.