Equatorial forests and savannas
In Africa the zone of constantly humid equatorial forests occurs once, while seasonally humid forests, savannas and open woodlands occur twice. Equatorial forests (gileya) grow around the equator and on the Gulf of Guinea coast. Red-yellow ferralitic soils formed on iron-rich rocks; they are poor in humus, so plants take nutrients mostly from fallen leaves. The forest is evergreen, dense and multi-layered: the top layer (35–50 m) has ceiba and palms, the middle oil palms, and below tree ferns, lianas and shrubs. Most animals live in trees (monkeys, chimpanzees, birds); on the ground there are gorillas, okapi, forest elephants and pygmy hippos. Savannas cover about 40 % of Africa. They consist of tall grass, clumps of trees (spreading acacia, baobab) and shrubs; rain falls mainly in summer, and humid and dry seasons alternate. The savanna holds more large animals than anywhere else in the world: antelopes, zebra, giraffe, elephant, rhinoceros, hippopotamus, lion, cheetah, hyena and the Nile crocodile; among birds, the African ostrich. Many national parks and reserves have been set up to protect nature.
“Forest layers”: draw a four-layer forest on the wall; students stick animal and plant cards onto the right layers.