4 hominids-human evolution-(i)

4. Hominids

THE HUMAN EVOLUTION

What do you know about it?

Which species or group does “Lucy” from the story belong to? Which relationship has her species with Homo sapiens?

Which primates is human species descended from, chimpanzees or gorillas? Why? How do we know it?

In the story “The Clan of the Cavern Bear” two species live together. Homo sapiens (the wounded girl) and people of the group. Which species do you think they belong to? In what age and where did they live together?

In the world there are humans with big differences in their skin color, their eyes’ shape, their height, etc. How was this diversity originated? Do we all belong to the same species? Why? How do we know it?

Do you believe that human species is the culmination of evolution? Discuss it

CLASSIFICATION OF HUMAN SPECIES AS AN ANIMAL ORGANISM

According to its features compared to the rest of animals, human species’ taxonomic classification would be like this:

TYPE ChordatesSUBTYPE Vertebrates

CLASS MammalsSUBCLASS Placentalia

(Eutheria)ORDER Primates

SUBORDER AnthropoidsFAMILY Hominids

GENDER HomoSPECIES Homo sapiens

ORDER PRIMATES

It is an order of mammals with the following features:

1) Their eye orbits are directed forwards, so they have a stereoscopic vision

2) Their forearm has a bone structure that allows them to do supination movements (climbing)

4) They have flat nails instead of claws

3) They have an opposable thumb in all four extremities (excepting in human species)

ORDER PRIMATES

ORDER PRIMATES

It’s a set of adaptations to a tree environment and a kind of feeding based on eating fruits and little animals

The order of primates is very old. Probably they already existed some 60 million years ago, say, soon after de extinction of large reptiles. At that age they were little insectivores living in trees and having nocturnal habits

PHYLOGENETIC TREE OF PRIMATES

PHYLOGENETIC TREE BASED ONGENETIC DIFFERENCES

HOMINIDS IN AFRICAMain archaeological sites

HOMINIDS IN AFRICAMain archaeological sites

Australopithecus afarensis‘s fooprints on volcanic ashes from 3.75 m.y. ago in Laetoli

Reproduction of Laetoli’s australopithecines

The famous skeleton of australopithecine “Lucy” some 3.5 million years old

Hominid Lucy is the name of a partial skeleton of what once was an adult 1.07 m high of a simian species. It was discovered in 1974 at the remote desert region of Afar in north-east Ethiopia. It is classified as an exemplar of Australopithecus afarensis who lived in Africa some 3 or 4 million years ago and is the first known hominid

HOMINIZATION

It is an evolutionary process started some 4 million years ago that has finally produced the appearance of human species

This process has been characterized by a set of anatomical, psychic and cultural changes

http://www.museuprehistoriavalencia.es/

HOMINIZATION

Main anatomical changes

Acquisition of a bipedal walking with the consequence of releasing anterior extremities

Major cranial capacity (skull) and major encephalic volume (brain)

Decreasing of prognathism (prominent mandible) and the ciliary arches

HOMINIZATION

Main psychic changes

Anatomical changes allowed the acquisition of:

Rationality

Intelligence

Capacity of abstraction

Language

Control of instinctive behaviors

HOMINIZATION

Cultural evolution

Besides all these changes, the last 35 000 years, human species has experienced a complex cultural evolution process that has been expressed through the making of tools and artistic and mythical expressions

Castro de Baroña (A Coruña) Taula (Menorca)

Naveta (Menorca)

Altamira (Cantabria)

MAIN ACHIEVEMENTS IN HUMAN EVOLUTION

-4.2 m.y. ............... bipedalism

-2.5 m.y. ............... early tools

-400 000 y ............ fire control

-120 000 y ............ early burials

-35 000 y .............. artistic expressions

Cranial capacity in cubic centimeters of different hominids and chimpanzee

ANCESTORS OF HUMAN SPECIES

AUSTRALOPITHECINES

They are the oldest known hominids. They lived more than 3.7 million years ago and extinguished 1.1 million years ago

Their skull had almost no forehead and their ciliary arches were very prominent

They had an outstanding prognathism and his cranial capacity was very small (450 cm3)

Australopitecus afarensis- 3 million years

They were omnivores and didn’t know any hunting techniques. They wandered through the eastern African savannahs where they inhabited

They had a bipedal walking but they didn’t walk upright yet

They had a low stature, between 1.10 m and 1.5 m

AUSTRALOPITHECINES

Australopitecus africanus- 2.5 million years

Australopitecus afarensis- 3.7 million years

HOMO HABILISHe appeared some 2.5 million years ago and extinguished some 1.6 million years ago

His skull was similar to the australopithecines but had a larger cranial capacity (750 cm3)

He had already an upright bipedal walking

His stature was between 0.9 m and 1.80 m

He was a hunter and already used some tools, splinters and pebbles, usually

He lived in Africa

HOMO ERECTUS

He appeared some 1.8 m.y. ago and extinguished some 0.2 m.y. ago

His skull had less prognathism than the species before

His cranial capacity was 1000 cm3

He had already an upright bipedal walking

His stature was near 1.70 m

He was a hunter and used splinters and pebbles, cut stones and controlled fireHe lived in Africa, Asia and Europe

Beijing Man(Pithecanthropus)

He appeared some 200 000 years ago and extinguished some 35 000 years ago

His cranial capacity was already 1500 cm3, larger than modern man’s skull

He practiced ritual burials

His stature was near 1.55 m

He made knife blades and arrowheads

He lived in Africa, Asia and Europe

HOMO NEANDERTHALENSISNeandertal

He extinguished when Cro-Magnon arrived

He appeared some 150 000 years ago

His cranial capacity was 1400 cm3

…and also by his artistic sense (cave paintings)

His stature was near 1.65 m

He is characterized because he manufactured hunting, decorative and home tools made of wood, bones, ivory, stone...

HOMO SAPIENSCro-Magnon

He coexisted with Neandertals

He is already a modern human

HOMO SAPIENS SAPIENSCRO-MAGNON

He emerged 40 000 years ago

Cranial capacity 1490 cm3

He spread all over the continents and originated peculiar cultures

His oldest rests are known as Cro-Magnon in Europe

Changes in skull1. A (Australopithecus), B (H. habilis),

C (H. erectus), D (H. neanderthalensis), E (H. sapiens)

2. Bipedalism, increase in cranial capacity, prehensile hand, articulated language. The tools they wear in their hands show the greater handling capacity. Changes happened gradually through evolution from early primates by means of natural selection: features that conferred a better capacity to survive and reproduce were inherited by the next generations

...and in the last second, we appear!

Human species only stands for a short episode in life’s history on earth

1. If 200 000 years stand for 5 seconds in a 24 hours clock, the year we are in (f.e. 2010) will be the result of operation: 2010 y X 5 s / 200 000 y = 0.05 s . Thus the year 0 of our calendar should begin 5 hundredths of a second before midnight of the “day” when life’s history on earth is fulfilled

2. If we take the most probable age of a student (at its due level), say 16 years old, calculations are:

16 years X 5 s / 200 000 years = 0.0004 s

He should have been born 4 tenthousandths of a second before New Year

HOMO SAPIENS’ ART

http://www.atapuerca.tv/

Atapuerca (GEC)

Archaeological site at “La Sima de los

Huesos”

Homo antecessor (between 1.2 m.y. and 800 000 y)

Juan Luís Arsuaga

Eudald Carbonell

José María Bermúdez de Castro& Eudald Carbonell

Archeological site at “La Gran Dolina”

Archeological site at ATAPUERCA (Burgos) (www.atapuerca.tv)