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Age of Animals

Tertiary Period, 66.0 - 2.588 MYA

Mammals All the special features in mammals (Figure 10q) can be summarized into one word - "activity". The ancestors of the mammals were carnivores, leading lives in which speedy locomotion was a necessity. The limb development has given effectiveness to this kind of activity. Brain growth has given it intelligent direction. The maintenance of a high body temperature and the various changes associated with this are related to the need of a continuous supply of energy in animals leading a constantly active life. Even the improvements in reproductive habits, which are a prominent feature of mammalian development, seem related to the needs for a slow maturation of the complex mechanisms (particularly the brain) upon which the successful pursuit of an alert and active life depends.

Figure 10q Mammals [view large image]

Oldest Hominid Hominids
  • The oldest hominid (upright-walking primate) remains was discovered recently (July 2002) in northern Chad, Africa with a complete cranium and dated back to nearly seven million years ago (see Figure 13). It may thus represent the earliest human forebear on record and is dubbed Sahelanthropus tchadensis. It is generally believed that human has its root in Africa. Figure 14 depicts groups of different species foraging in the same area around Lake Turkana, Northern Kenya 1.8 million years ago.

Figure 13 Oldest Hominid

Figure 14 Hominids in Africa [view large image]

It was announced in 2009 that a 47x106 years old fossil (called Ida) has been discovered in Germany. It might be the ancestor of monkeys, humans and other primates. Other paleontologists suggest that it could be the early member of the lemurs family (Figure 15a).

An even earlier primate fossil in central Hubei (), China was unveiled in 2013. It is linked to a period of extremely hot climate about 65 million years ago (soon after the extinction of the dinosaurs). Analysis so far places it in the tarsier lineage but it my turn out to be a human ancestor (Figure 15a). The discovery suggests that humanity started first in south-east Asia and migrated into Africa before another migration out of Africa 65000 years ago.

Figure 15a Family Tree, Early [view large image]

Figure 15b shows the family tree of the hominids. The 4.2 million years old Australopithecus anamensis is the descendant of Sahelanthropus tchadensis. It looks similar to the 3.5 million year old A. afarensis, a small-brained, big-faced bipedal species to which the famous "Lucy" belonged. Lucy and her kind were upright walkers but retained many ape-like characteristics. They probably represent the transition from tree
Family Tree Human Evolution dwelling to bipedal walking in the savannas as East Africa dried up. A report in 2009 identified fossils for even earlier hominid - Ardipithecus ramidus (known as 'Ardi') at 4.5 MYA. Reconstruction shows that the hands and wrists don't have many of the distinctive chimp characteristics. The foot, with its big toe sticking out sideways, would have allowed Ardi to clamber in trees, walking along limbs on her palms. And the teeth show no tusk-like upper canines, which most apes have for weapons or display during conflict. Thus, Ardi is most probably not in the lineage of modern chimps. Figure 15c shows the Homo lineage starting from about two million years ago. The use of tool

Figure 15b Family Tree
[view large image]

Figure 15c Human Evolution

and fire started about the same time. The first exodus of hominids from Africa soon followed. There were at least four waves of emigration since then with
new arrival supplanting the indigenous one. This multiple species description is different from the scenario of "Australopithecus africanus begat Homo erectus begat Homo sapiens" that prevailed 40 years ago.

Peking Man The Peking Man belongs to the genus of Homo Erectus living in a cave (the Zhoukoudian, see Figure 16a and 16d) some 500,000 years ago. This lineage seems to have reached its dead end around 150,000 years ago, but some still consider it as the ancestor of modern human. Figure 16b compares the skulls of the gorilla, modern human, and the Peking Man, which seems to be in the middle of the evolutionary sequence. Extensive excavation works from 1927 to 1937 has uncovered some skulls, teeth, jaws, and skeletal bone together with animal remains and evidence of fire and tool usage. The original fossils were lost during an attempt to ship them to the US just before the onset of the Pacific War leaving only plaster casts (Figure 16c) for further study.

Figure 16 Peking Man
[view large image]

Renewed excavation in the caves, beginning in 1958, brought new specimens to light. In addition to fossils, core tools and primitive flaked tools were also found.

Figure 17 Peking Man Video Recapitulation [view large image]

    Figure 17 is the recap of a 30 minutes Youtube video on the Peking Man produced by CCTV. Since the narration is in Chinese, a short summary is presented below following roughly to the sequence in Figure 17.

  1. The scene is the re-enactment of the cave living some 500,000 years ago. The threatening animal is a sabre tooth tiger or a giant hyenas.
  2. This is the cave in Zhoukoudian found by the Swedish geologist J. G. Andersson and American palaeontologist W. W. Granger in 1921.
  3. The skull was found in 1927 and identified as Homo Erectus. Fossil datings for this genus varies from 2 million to 140000 years ago.
  4. The excavations came to an end in 1937 with the Japanese invasion. By then few ten thousands of fossils and tools have already been collected and stored in the basement of "Peking Union Medical College Hospital (北京協和醫院)".
  5. As the war in Pacific is imminent by December 1941, the fossils were packed and shipped to the US via Qinhuangdao (秦皇島) by train on December 5. Hostility had begun already on the 7th when the shipment arrived there on December 8. The escorting US marines became prisoners of war and the cargo disappeared without a trace. The Japanese government announced that the lot had been stolen and assigned a detective to have it recovered. He eventually committed suicide by harakiri for delinquency of duty.

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