Geology And Dating Methods

Before mounting an expedition, paleontologists first look to geologic maps of a region to determine if the right time period is actually present. Then, ideally, they look at aerial photographs or they make a visit by airplane, automobile, or foot to determine if those rocks are exposed and accessible and free of thick vegetation or water cover. Often paleontologists and geologists will explore regions of interest together. If they are interested in fossil hominins they look at rocks dating to...

Homo Erectus

The first H. erectusfossils to be discovered were a skullcap (the top portion of the cranium that does not include the face or the bottom where the foramen magnum is located), a molar, and a femur from Trinil, Java, in 1891. These finds comprise the missing link that Eugene Dubois set out from the Netherlands to find. Since then, paleoanthropologists have collected H. erectus specimens from Ethiopia, Kenya, Tanzania, South Africa, Morocco, Italy, India, China (Peking Man), and Indonesia (Java...

Homology and Analogy

The relationship between form and function in animals reveals how ancestry, or shared origin, affects the forms of animals. For instance, the human, whale, dog, horse, and bat forelimbs are similar despite their Figure 2.1 The human arm and the forelimbs of a whale, dog, horse, and bat are homologies because they all evolved from a common ancestral tetrapod. However, the wings of bats and birds are considered analogies because they did not evolve for flight from a common flying ancestor....

Body Size Shape And Strength

Many human adaptations follow the same patterns as other mammals around the world, especially those that are determined by thermoregu-latory rules. There are general mammalian-wide relationships between a body's surface area and volume (SA V) that are controlled by climate. Bergman's Rule states that mammals in colder climates tend to have larger bodies than animals in warmer ones. A larger body size decreases the SA V ratio and thus reduces heat loss. Based on a similar need for heat...

Paranthropus Robust Australopiths

It is becoming more popular to refer to the robust species of the australopiths with their own genus Paranthropus. According to the rules of Linnaean classification, groups must share a single ancestor, but it is possible that robust australopiths evolved independently in East and South Africa from the australopiths in each region (A. afarensis and A. africanus respectively), meaning they could have separate roots. But for clarity and for continuity with current trends, here the robust...

What Is A Fossil

Although they are usually hard to find, fossils are not hard to see. What is surprising to many first-time fossil hunters is how life-like a fossilized animal or plant appears. There is no need to use your imagination to spot fossils in the ground, as if conjuring animal-shaped clouds in the sky. Biological organisms are symmetrical, mathematical, patterned, and in most cases they fossilize having retained much of the appearance they had in life, even if they become flat and resemble...

Speciation

Accumulated microevolution, or changes in allele frequencies in a population, leads to macroevolution, which is speciation. In this sense, variation that exists within a population eventually increases to become variation between populations. Evolution at the species level is the result of cumulative microevolution. Fishes did not and do not evolve into humans, instead a fish-like ancestor gave rise to all amphibians, reptiles, birds, and mammals, including humans. Step-wise changes accumulated...

Scavenging And Hunting

Humans share a common herbivorous, or plant-eating, ancestor with living apes and early hominins were mostly vegetarians who ate fruit, nuts, tubers (roots), and also ate insects like termites. Like other herbivorous mammals, including monkeys and apes, humans cannot synthesize vitamin C an unnecessary skill with a diet comprised of vitamin C-rich vegetable matter. But the drastic shift in hominin brain and body size around 2 Mya is linked to a shift in diet toward carnivory. Scavenging and...

Archaic Homo Sapiens

Hominins that lived all over the Old World between 800 and 125 Kya belong to a category called Archaic H. sapiens. Archaics are a transitional group between H. erectus and modern humans and include the Neanderthals, which are discussed separately. Archaics were still anatomically distinct from modern people, mostly in their skulls, which were thick-boned and low-vaulted, and featured prominent browridges, sloping foreheads, and small chins. Reminiscent of earlier H. erectus, their skulls retain...

Teeth

Because tooth enamel is made of sturdy material (hydroxyapatite), teeth make good candidates for fossilization. As a consequence, teeth are the most common part of hominin skeletons that are discovered and collected. Teeth are distinguishable by species because their shape and size are linked to body size, diet (for shearing, cutting, crushing, grinding) and social behavior (long, sharp canines for mate competition). Differences in the number, size, shape, cusp patterning, and placement of the...

Monkeys And Apes

Monkeys are divided into geographic groups, New World The Americas and Old World Europe, Asia, Africa . Humans belong to the infraorder Catarrhini, which includes Old World monkeys Super-family Cercopithecoidea and apes Superfamily Hominoidea . Catarrhines have a 2 1 2 3 dental formula which means that per quadrant of the mouth there are four upper right jaw, upper left jaw, lower right jaw, lower left jaw adults have two incisors, one canine, two pre-molars, and three molars. Baboons Papio and...