The earth, animal life and mankind

The building instinct of the first sedentary human beings developed from a certain intuition acquired by the hominids during their first attempts to walk upright and, even further back in time, from the experience of anthropoid apes and mammals of the tertiary as they advanced with difficulty on spongy soils, like those of the big deltas of Mesopotamia, the Nile and the Indus, where the first civilizations developed. For the very early period, the illustrations and text of the book ‘Sulle orme dei Dinausori’ (On the tracks of dinosaurs – Bonaparte et al., 1984 ) are fascinating: the foremost palaeontologists of the present day show how the dinosaurs left their mark in every continent (Photo 1). While man has lorded the earth for no more than a few millennia, the reign of the dinosaurs lasted some 150 million years, during which the heaviest animals ever known left their deep imprints in the soil. Thrilling too are the miraculously preserved footprints discovered by Dr. Mary Leakey (1979) (Photo 2), which represent two hominids walking side by side about three and a half million years ago and leaving the trace of their presence in the film of ash spewed from a volcano in the Laetoli plain of Tanzania. How tenderly we watch the first faltering steps of a child. And how could we fail to be moved by this glimpse of the creatures of Laetoli, who were perhaps the first ones to walk upright. The fine layer of ash that covered the clay moulding their footsteps has bequeathed to us a miraculous message, delivered intact after several million years. These footprints show that the human foot had completed its evolutionary process from that of a monkey ( Figure 1 ), making upright motion possible. In hunting for prey or escaping from a predator, man ( Figure 2 ) abandoned the taligrade or plantigrade postures to become digitigrade: the metatarsal bar bc and the hallux c form in the soil what amounts to a spring-board T. The visible element is the springing of the foot; what is invisible is the support provided by the soil which can give way (along the dotted line L) if necessary. The poet Valéry said: Only the body knows and only the body which responds without thought to obstacles possesses the highest knowledge’. Here the body has already found the principle of a mechanical coupling and the idea of the progressive rupture of a support. Photo 1 Toro Toro (Bolivia). The gigantic footprints of a dinosaur about 190 millions years old. The man in the background gives an idea of their size. By permission Centro Studi Richerche Ligabue, Venice. Gigantic dinosaur footprints in Toro Toro, Bolivia. A man is seen in the background. https://www.w3.org/1999/xlink" xlink:href=" https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003763161/fc2caaeb-0147-4905-81cb-dd41be0dd54b/content/pg3_1.jpg "/> Photo 2 Footprints of hominids in the Laetoli plain in Tanzania, discovered by Dr. Mary Leakey (about 3.6 million years old). A person crouching near ancient hominid footprints preserved in a layer of volcanic ash in the Laetoli plain, Tanzania. https://www.w3.org/1999/xlink" xlink:href=" https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003763161/fc2caaeb-0147-4905-81cb-dd41be0dd54b/content/pg4_1.jpg "/> Figure 1 Foot a) of the monkey b) of the human being An illustration shows a comparison between the foot of a monkey and the foot of a human being. The monkey&s;s foot, labelled as a, displays a more primitive structure with a pronounced thumb and a different arrangement of toes, adapted for grasping and climbing. The human foot, labelled as b, exhibits a more evolved structure with an arch and aligned toes, designed for walking upright. https://www.w3.org/1999/xlink" xlink:href=" https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003763161/fc2caaeb-0147-4905-81cb-dd41be0dd54b/content/pg4_2.tif "/> Figure 2 The three upright postures of man. An illustration shows the three upright postures of man&s;s foot-related drawings arranged in rows. The top row shows side views of a foot making contact with a flat surface in different positions. The middle row shows sole views of a foot with shaded regions indicating areas of contact, labelled with letters such as B and C. The bottom row shows skeletal side views of a foot and ankle interacting with a flat surface, with arrows indicating movement and numbered stages labelled 1, 2, and 3. https://www.w3.org/1999/xlink" xlink:href=" https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003763161/fc2caaeb-0147-4905-81cb-dd41be0dd54b/content/pg4_3.tif "/> 1: Taligrade 2: Plantigrade 3: Digitigrade Figure 3 The stone tool, precursor of the rock bit used for oil drilling, wielded by prehistoric man. Drawing by P. Vaughan published in ‘La Recherche’ (1983) . An illustration shows a hand gripping a pointed tool and pressing it into a rock surface. The hand is depicted in a detailed, realistic style, showing the fingers gripping the tool. The stone tool is a simple, primitive implement, likely used for cutting or digging. https://www.w3.org/1999/xlink" xlink:href=" https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003763161/fc2caaeb-0147-4905-81cb-dd41be0dd54b/content/pg4_4.tif "/> Figure 4 Cave of Choukoutien at time of first occupation. An entrance has been formed at the eastern end through erosion by the Choukou river. The cave was inhabited by Homo Pekinensis for 230000 years (from Wu Rukan and Ling Shenglong 1982). An illustration shows a landscape with a large cave opening at the centre of the scene. The cave interior is depicted with pointed formations hanging from the ceiling and rising from the floor. A river curves from the left side of the illustration toward the cave area. The surrounding terrain consists of rolling landforms with scattered vegetation. Directional labels E and W appear at the top, and the text Eastern entrance is labelled near the cave opening. https://www.w3.org/1999/xlink" xlink:href=" https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003763161/fc2caaeb-0147-4905-81cb-dd41be0dd54b/content/pg5_1.tif "/> Figure 5 Final stage before abandonment of cave. The eastern entrance is now blocked and access is via a crevice to the west. The cave has been filled by the detritus of generations of Peking Man (from Wu Rukan and Ling Shenglong 1982). An illustration shows a cave with its eastern entrance blocked and access now via a crevice to the west. The western entrance is labelled, indicating the new access point. https://www.w3.org/1999/xlink" xlink:href=" https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003763161/fc2caaeb-0147-4905-81cb-dd41be0dd54b/content/pg5_2.tif "/>