Booklist Top 10 Books on the Environment & Sustainability for Youth: 2020 Look around you—biodiversity is everywhere! From the tallest tree to the smallest microbe, Earth is home to more than 1.5 million known species of plants, animals, fungi, bacteria, and microorganisms. And scientists estimate there could be millions, if not billions, more that have not yet been identified. Biodiversity: Explore the Diversity of Life on Earth with Science Activities for Kids introduces middle schoolers to the evolution of life on Earth, beginning with the first single-celled organisms that emerged 3.8 billion years ago to the complex, multi-celled organisms that exist today and make up the tree of life. Biodiversity is found everywhere on the planet—on land, in the water, and even in extreme environments such as ice and volcanoes. Biodiversity can also be discovered by looking through a microscope at tiny worlds of organisms that can't be seen with the human eye. There are whole microbiomes beneath our feet, in puddles, and even in our belly buttons! All of this biodiversity on Earth helps keep the planet in balance. Biodiversity is also important to humans because it provides food, shelter, clothing, medicines, and more. However, the rates of biodiversity loss are increasing because of human activities. Climate change, pollution, habitat destruction, over-exploitation — these are all critical threats to biodiversity. There are, however, ways to slow or stop this loss through conservation and sustainable development.