The document compares different ecosystems by describing their climates and key characteristics. It discusses deserts, forests, wetlands, and oceans. Deserts have hot, dry climates and plants/animals like camels, snakes, and cacti that have adapted to the heat and lack of water. Forests include tropical rainforests with hot, wet climates supporting tall trees, and temperate forests with warm summers and cold winters. Wetlands are covered in water and found near water sources, helping to absorb flood waters and cleanse dirty water. Oceans, the largest ecosystem, have most life in the sunlit shallow areas where plants can photosynthesize.