Sally M. Walker

Introduces Antarctica, presenting the history of its exploration and the current research efforts underway to investigate its geography, climate, and fossils of the past, and monitor the effects of global warming on its glaciers.

Fossils give us a window to the past. Water, sediments, and pressure work together over time to preserve the shape of things that lived long ago. Studying these ancient plants and animals tells us more about our own existence. Have you ever searched for fossils? Unearth some in this book. -From the publisher.

Soil can be found almost everywhere on Earth. Sand is a soft soil that is found in deserts. Loam is soil that is great for growing plants. But how are these types of soils different? And how are they made? Explore the amazing world of soil in this book.

Discusses the processes used by scientists to discern the identity of the Kennewick Man and what this nine thousand-year-old skeleton revealed about the arrival of humans in North America.

An introduction to the physical characteristics, habits, and natural environment of the common and the pygmy hippopotamus.

Describes the physical characteristics, life cycle, behavior, and conservation of rhinos.

Describes the physical characteristics, life cycle, behavior, and conservation of manatees, also known as sea cows.

Examines the physical features, processes, and many different species of plants and animals that make up the ecosystem of the largest estuary in the United States, the Chesapeake Bay.

Introduces these aquatic mammals by describing their physical characteristics, life cycle, behavior, relations with humans, and threats to their survival.