origin and evolution of species [4]![click to hear](/images/speaker.jpg)
Since its formation some 4.6 billion years ago, the Earth has witnessed the genesis of continents and oceans and the appearance of animals and vegetation.
Quaternary ![click to hear](/images/speaker.jpg)
The most recent geological period in the Earth’s history; it is marked by glaciations and the appearance of modern humans.
homo sapiens sapiens ![click to hear](/images/speaker.jpg)
The representative of the first modern man appeared about 100,000 years ago.
wooly mammoth ![click to hear](/images/speaker.jpg)
A cousin of the elephant, this fossil had a thick wooly covering and long curved tusks. It died out 10,000 years ago.
Tertiary ![click to hear](/images/speaker.jpg)
Period marked by the diversification and dominance of mammals (appearance of horses, whales and others). First primates also appeared.
basilosaur ![click to hear](/images/speaker.jpg)
About 65 ft long and somewhat resembling a snake, this marine mammal fossil was the ancestor of today’s cetaceans.
smilodon ![click to hear](/images/speaker.jpg)
Carnivorous feline fossil with prominent upper canines for tearing meat.
hyracotherium ![click to hear](/images/speaker.jpg)
About the size of a dog, this ancestor of the horse had four digits on its forelegs and three digits on its hind legs.
proconsul ![click to hear](/images/speaker.jpg)
Large primate fossil, thought to be the ancestor of the chimpanzee.
Cretaceous ![click to hear](/images/speaker.jpg)
This period was marked by the extinction of 75% of plant and animal species, including the dinosaurs.
triceratops ![click to hear](/images/speaker.jpg)
One of the last dinosaurs. This four-legged herbivore had three horns and a bony cervical collar.
tyrannosaur ![click to hear](/images/speaker.jpg)
Two-legged carnivorous dinosaur measuring about 50 feet in length, with powerful jaws. This extremely ferocious predator had sharp teeth.
flowering plants ![click to hear](/images/speaker.jpg)
Appearing at the end of the Jurassic period, these plant species diversified widely over time; today, they form the largest group of plants on Earth.