introduction: describe trends in human evolution as 90719 level 3 – 3 credits

Introduction: Describe trends in Human Evolution AS 90719

Level 3 – 3 Credits

Keywords: Ape Dentition Australopithcine Dexterity Gracile Zygomatic Arches Robust Bipedalism Hominid Prognathism Hominins Foramen Magnum Primate Domestication Nomadic Arboreal Brachiation Quadrupedal Phylogeny

What we will cover:

Identifying the characteristics of Hominins and Hominids.

Describe patterns of evolution, human lineage (characteristics and trends) and dispersal.

Changes in hominin habitat due to selection pressures.

Inferences that have been made from anthropologic evidence.

Evolution and the key ideas that are used to formulate the theory of evolution.

Evolution:

Evolution is the process where different kinds of living organisms have gradually developed and diversified, from earlier forms.

The Evolution of Humans.

“The evolutionary design of man has intrigued humans for many years. It has lead anthropologists to travel the world in search of fossil evidence to learn who we have evolved from.

Human evolution began roughly 5-10 million years ago when the human line split from the apes. Slowly scientists have tried to put the pieces together to give us an idea of our evolutionary line.”

Classifications of Humans:

Kingdom – Animalia Phylum – Chordata Class - Mammalia Order - Primates Family – Hominidae (Hominids) Genus - Homo Specie - sapiens

Hominins vs Hominids Hominins: living or fossil species of the human lineage.

– Hominins are species that have contributed to the evolution of humans or are included in the human phylogeny

– Examples: Australopithecus afarensis, Homo Habilis

Hominids: are humans and African apes – Hominids are species that currently exist (or recently extinct)

and are identified as being Human or part of human phylogeny.

– All hominids are endangered except humans

– Examples: Bonobo, Gorilla and Chimpanzee’s

Hominids

Hominins

Human Lineage

Humans are a relatively young species in geological terms. The earliest known humans date back approximately 170,000 years ago.

The development of the human species is often depicted as a straight line from Apes to Humans, this is not correct.

Common Depiction of

Human Evolution from the 1960’s

A more accurate depiction of Human Evolution

Back to the beginning: Primates

Humans are currently one of 200 Primate species that inhabit earth today.

Primates are classified using a series of distinct physical features that can be identified.

Primates

Order Suborder Infraorder Superfamily Family Examples

PRIMATES

Prosimii(prosimians)

Plesiadapiformes(archaic primates)

extinct plesiadapiformes(Purgatorius)

LemuriformesLemuroidea Lemuridae

Indriidaelemurindri

Adapoidea Adapidae extinct adapiformes

Lorisiformes Lorisoidea Lorisdae loris, galago (bush baby)

Tarsiiformes TarsioideaTarsiidae tarsier

Omomyidae extinct omomyiformes

Anthro-poidea

(simians or anthropoids)

Platyrrhini(New World

simians)

Ceboidea(New World Monkeys)

Callitrichidae marmoset, tamarin

Cebidae(true monkeys)

cebus monkey, spider monkey, howler monkey, capuchins, owl

monkey, sakis

Catarrhini(Old World Simians)

Cercopithecoidea

(Old World Monkeys)

Cercopithecidaecolobus, langurs, macaque,

baboon

Hominoidea(apes and humans)

Oreopithecidae extinct Oreopithecus

Hylobatidae gibbon, siamang

Pongidaeorangutan, gorilla, chimpanzee,

bonobo

Hominidae Homo sapiens, extinct Australopithecines

Primate Characteristics

List as many features you believe Primates display (physically and socially):– – – – – –

Social Features

-Superior intelligence

-Often complex social behavior

-A highly developed problem solving ability

- Use of a variety of communication methods

Physical Features-Tail anatomy-Skull anatomy, including:Brow ridgesVision (Binocular)NostrilsSnout and lips-Limb length-Hand and foot anatomy + nails instead of claws

Adaptive Radiation in Primates

Primate Groups

New & Old World Monkeys

Old World monkeys

Africa & Asia

Arboreal and ground dwelling

No prehensile tail

Nostrils open downward

Diurnal

Live in bands- very social

New World monkeys

South America

Arboreal

Prehensile tail

Nostrils open to the side

Diurnal

Live in bands- very social

Primate Locomotion

Primates can be broken into two main groups based on locomotion.

–Arboreal

–Ground dwelling

Arboreal

Locomotion of Primates who live primarily or permanently among trees.

It can be classified into more detailed groupings– Quadrupedalism– Modified Quadrupedalism– Brachiation

Arboreal Quadrupedalism

Walk on all four limbs along tree branches

Arms and Legs are almost equal in length

Example: Lemurs

Modified Quadrupedalism

Main mode of transport is leaping and clinging

Prefer to move along vertical trunks

Examples: Prosimians

Brachiation

Using arms to propel through trees Full brachiation (use only arms) Example: Gibbons

Semi-brachiation (hind limbs) Example: Spider monkey (Likely precurser to quadrapedalism and bipedalism)

Ground Dwelling Locomotion that occurs on the ground using

the following methods– Quadrupedalism

Using all four limbs at once Example: baboons

– Knuckle-walking Support using their hands specifically their knuckles Example: chimpanzees and gorillas

– Bipedalism (habitual) Walk only on hind legs all of the time Example: hominids, humans