istoryworld
Events relating to evolution
The earth's surface settles into a heaving turmoil of rock and water
Fossilized bacteria have been found in rock 3.5 billion years old in Africa
Single-celled water creatures, such as algae, begin the 2-billion-year process of evolving into slightly more complex forms of life
Sponges and jellyfish drift in the sea, to be joined later by more purposeful shrimps and lobsters
The earliest known creature with a skeleton evolves as a form of fish
Plants, previously living only in the seas and rivers, begin to establish themselves on land
Insects become the first creatures capable of living their full life span out of the water - and the first to master flight
Amphibians develop lungs, enabling them to live on land as well as in the water
Reptiles develop evolutionary advantages for adaptation to a wide range of environments
The entire land surface of the earth merges into a single continent, known as Pangaea, which after about 50 million years splits in two
The dinosaurs dominate the planet in a way that no previous creature has been able to
Mammals begin to make their appearance
Archaeopteryx has the skeletal structure of a dinosaur and the feathers of a bird, intermediate between the two species
Primitive birds begin to feature in the fossil record
In a very short space of time the dinosaurs die out, for reasons as yet uncertain
Mammals evolve in many new forms on land and in the water, using opportunities made possible by the extinction of the dinosaurs
Primates evolve, from lemur-like animals to monkeys
A primate of this period, at ease both in the trees and on the ground, is probably the common ancestor of gorillas, chimpanzees and humans
Various species of ape develop the habit of walking upright on two feet
Certain primates, in eastern and southern Africa, are by now sufficiently like humans to be classed as hominids
Ardi, the earliest known individual of partially human type (or hominid), is of the species Ardipithecus, in the Awash valley region of Ethiopia
Two or three hominid individuals, probably Australopithecus Afarensis, walk upright through volcanic ash at Laetoli, 30 miles south of Olduvai Gorge, and their footprints are preserved within subsequent ash deposits
A female of the species Australopithecus Afarensis (nicknamed Lucy when her skeleton is found), lives in the Afar Depression in Ethiopia within 50 miles of where her predecessor Ardi was unearthed
The earliest known chipped stone tools are made by hominids at Gona, in the Awash Valley in Ethiopia, close to the region where Ardi and Lucy lived many millennia earler
The Palaeolithic era or Old Stone age begins, characterized by hominid and human use of unpolished chipped stone tools
