what do the terms paleozoic, mesozoic and cenozoic mean
These three terms are geological eras, each representing a major division of time in the history of the Earth.
- Paleozoic Era: This era lasted from about 541 million years ago to 252 million years ago. It is sometimes called the "Age of Invertebrates" because it saw the emergence and diversification of many major groups of animals without backbones, such as trilobites, brachiopods, and early fish. The Paleozoic also witnessed the evolution of land plants and the emergence of amphibians and reptiles.
- Mesozoic Era: This era lasted from about 252 million years ago to 66 million years ago. It is sometimes called the "Age of Dinosaurs" because these reptiles dominated the land during this time and evolved into a wide variety of forms. The Mesozoic also saw the rise of birds, the emergence of flowering plants, and the development of many modern groups of animals, such as mammals and turtles.
- Cenozoic Era: This era began about 66 million years ago and continues to the present day. It is sometimes called the "Age of Mammals" because mammals have come to dominate many ecosystems in the last few million years, with humans being the most successful and influential species. The Cenozoic also saw the emergence of many modern groups of animals, such as primates, whales, and elephants, and the diversification of flowering plants.