Levels of carbon isotopes in teeth from giraffes and other animals found among Ardipithecus fossils resemble those of browsing animals that range today from woods bordering rivers to
savannas, the scientists say, noting that aridity and rainfall estimates for Ardi's ancient homeland are compatible with such a habitat.
McPherson begins chapter 3, which examines
savanna genesis and maintenance, by asking the question, "Why do
savannas occur?" He then examines the effects of climate, soil, fire, and grazing animals on the formation and maintenance of
savannas.
Mark Twain National Forest's efforts to preserve midwestern biodiversity began nearly 20 years ago in southwest Missouri, where
savannas are associated with extensive glades, another fire dependent ecosystem.
Before the settlers arrived, there were several similarities between
savannas found in North America and those in Africa.
In the final comparisons of DNA from cell nuclei, the forest and
savanna elephants fell into distinct groups.
Drawings and paintings from the presettlement era also depict
savanna, an ecological term that describes a grassland habitat that includes several scattered large trees per acre.
Since 1980, South American ranchers have planted roughly 35 million hectares with these varieties because they tap water and nutrients from the poor
savanna soils more efficiently than native species.
Our adaptation to the
savanna habitat (it was then a bit more wooded and lush than the driedout East Africa of today) enables us to spot the animals wishing to prey upon us soon enough to elude them (by climbing one of those trees) or kill them in self-defense.
"But the grasses and plants that make up
savannas had already existed for millions of years in much more variable environments."
Vrba of Yale University, combined with pollen and oxygen isotope analyses, indicate global cooling caused an expansion of open, grassy
savannas in southern and eastern Africa about 2.5 million years ago.
An analysis of fossil soils and grasses at a site in southwestern Kenya demonstrates that extensive
savannas -- the habitats of early human ancestors--have existed in East Africa for at least the past 14 million years, emerging long before the evolutionary split of apes and hominids.
Some clues may be found in modern African
savannas. "You need to go out to the real world and see what's available to eat and what the nutritional worth of various animal parts is," says Blumenschine.
As one of the first spirit flavour mixes in the cider category, the Special Release
Savanna Loco, with its vibrant turquoise packaging, opens up a new world of upbeat drinking occasions.
