Human Evolution

Hominid Skull Comparison Video

Skull Comparison Activity

For each skull:Write the name of the organismRecord the approximate age of the fossilRecord information about the following

sagittal creast, nuchal crest, facial prognethism, canine diastema, chin, nasal bones, brow ridge, incisor angle, and foramen magnum Determine if the skull is more ape-like or human-like

Human evolution began approx. 60 million years ago with the earliest PRIMATES.Three notable traits that appeared in primates were Flattened teeth - plant diet Grasping hands and feet with  opposable first digits Forward-directed eyes

Gray-shanked Douc - Native to Vietnam (1000 remain)

Over the next 20-30 million years these mammals evolved into prosimian and anthropoid organisms.

 Prosimian - lemurs, pottos, and tarsiers

Prosimians are the most primitive of the primates - sometimes they are referred to as "pre-monkeys". There name means "before monkeys".

Prosimians have:A well developed sense of smell, and a more prominent snout. Partial binocular vision (using two eyes together, as apes and monkeys do). Often nocturnal vision. Some claws and developed manual dexterity. Immobilized upper lips. A different dental formula - 2:1:3:3 Prosimians only live in the 'Old World'. (area that don't include North and South America): Lemurs live only on the island of Madagascar, Tarsiers live on the islands of the Philippines, Borneo, Celebes Islands, and Sumatra, and Lorises live in areas of Africa and South/Southeast Asia .

 Anthropoid - monkeys, apes, and humans

5 - 10 million years later the anthropoid lineage split a number of times to give rise to the Old World monkeys and New World monkeys and the hominoids.

Old World Monkeys: Old World Monkeys make the family Cercopithecinae. They are larger than the New World monkeys. They are diurnal, and are physically different as well. Old world monkeys have:Narrow and downward pointing nostrils. Longer hind legs than forearms. Flattened nails on fingers and toes. Prominent buttock pads that they can sit on. Tails, but not prehensile (adapted for grasping or holding) ones. They are generally larger than the New World monkeys.

New World Monkeys: These monkeys live in the neotropical forests of the "new world".New World Monkeys range vastly in size - some are quite tiny, like the 6 inch pygmy marmoset, and some are larger - the howler monkey can be up to 3 feet in length. New World Monkeys are called platyrrhines. Characteristics of New World Monkeys:Wide nostrils which are circular and spaced apart. They are small to medium sized. Long tails which are sometimes prehensile. No buttock pads. No cheek pouches.

Includes the great apes - orangutans, chimpanzees, gorillas, humans and bonobos (shown below in order). These great apes are included under the family Hominidae.

Hominoids:

Also includes the Lesser Apes - GibbonsLike the great apes, they lack tails, and have the same dental formula. Their skulls are also similar to those of great apes, having enlarged braincases and huge eye orbits that face forward. Siamangs are the largest type of gibbon.

Apes are usually larger and heavier than monkeys. Apes have no tail. Apes have a more upright body posture than monkeys, and are often able to walk on 2 legs. Apes have a broad chest. Apes rely on vision rather than smell, and thus have shorter noses than some monkeys. Apes have a large brain to body size ratio compared with other animals. Apes only live in Africa and Asia (monkeys also live in South America).

Monkeys vs Apes

Emergence of Humans

The fossil record shows that the HOMINID clade (humans and extinct members who arose from the most recent common ancestor that humans share with apes.) has a rich history of many branching lineages and related species.

The oldest known biped Ardipithecus ramidus, 5.2-5.8 million years oldAustralopithecine footprints date to 3.7 million years. Our ancestors were walking upright before large brains developed.There were at least 6 different species of australopithecines in Africa between 4.2 and 10 million years ago.

3 million years ago australopithecine ancestor gives rise to 2 lineages. One of which goes on to form the genus Homo.

Oldest fossils of Homo are all found in Africa. 2.4-1.6 million years. Generally classified as Homo habilis. First human ancestor to use stone tools.

Homo habilis gave rise to Homo erectus who is known for their use of stone tools and fire. H. erectus shows many human features. Same average brain size, rounded head, and smaller teeth.

Approximately 2 million years ago H. erectus spread out from Africa to Europe and Asia.

Within the last 600000 years H. erectus may have evolved into 3 species of early humans. H. heidelbergensis, H. neanderthalensis and H. sapiens.

By 130 000 years ago H. sapiens appeared in Africa when H. neanderthalensis was already living in parts of Europe and Asia.H. neanderthalensis were skilled tool makers, they performed burial ceremonies and may have been capable of complex speech.

The Minds Big Bang PBS Evolution