Tags

, , , , ,

Just 2 million years after diverging from the gibbons (or about 400,000 generations) Apes diverged from the Orangutan (0.014 bya). In this case, the Orangutans made a quicker journey from Africa back to Asia, 31 million years after the primates left (0.04 bya) to find a richer life in Africa. Orangutans now struggle to find habitat in the expanding plantation landscapes of Asia. One of the major threats to Orangutans survival is the clearing of land for palm oil plantations. Primates and apes had begin to spread around by now, with a possible human uncle or ancestor (0.013 bya) found as far afield as Spain, which was, at the time, attached to Africa. This was the critical period where human ancestors diverge from modern apes (0.01 bya) and Chimpanzees (0.08 bya). The first bipedal primate, Sahelanthropus tchadensis, was located in Chad, which as a mixture of forests and open savannah at the time (0.007 bya). Though we only have fossil skulls for this species, we can tell by the location of the spinal cord entry that S. Tchadensis stood upright, not on all fours.

It was also in this period that we evolved our second economic adaptation, the evolution of laughter (0.01 bya). The first was the evolution of the smile, developing from a grimace 0.03 bya. At least that’s what the comparative cladistics tells me.

Something else to mention and keep track of at this point is the evolution of our modern vegetables. Brassica, our most diverse, if not most plentiful, vegetable crop diversified for a second time in this period (0.012 bya). They had first diversified 124 million years ago and 47 million years ago, but this final diversification would bring them to their modern form of broccoli, cauliflower, cabbage, turnips, and collard greens, to name <a few.

The potato and tomato split within the nightshade family in the Americas 0.008 bya, setting the stage for their later use by humans. This was of course unlikely use, as the majority of the nightshade family, including the bodies of the tomato and potato plants, are deadly poisonous to eat. I was remiss in my treatment of mulberries and figs, which began their lines almost 30 million years before (0.04 bya). Every crop species has its history, my ability to find those histories is of course limited.

The climate in this 7 million year period began to dry out by 0.01 bya and cool down from the hot maximum 0.015 bya. By 0.012 bya, the last vegetation had disappeared from Antarctica, covered in glaciers.

The most important thing that happened in this period was the closing of the Central American isthmus 0.007 bya. This connection would allow the well developed carnivores of the northern continent to overcome the previously marsupial populations of South America. When South America separated from Africa (0.1 bya) Marsupials and placental (live birth) mammals had only just diverged, and mammals were still 7 million years (0.093 bya) from diverging into the precursors to primates, carnivores, ungulates and the like. More on that with the next post.

Now 511/512ths through the history of life.

 

Advertisements