N°1 – The corridor of time
Welcome to Xploria!
This corridor allows you to observe our frieze of time and to immerse you into the history of what you are now going to xplore as you walk through the forest.
On the illustration which represents the scale of time and of the main eras of our history, you will see a large number of species on display at Xploria.
Do not hesitate to touch the real fossils. Observe their various shapes.
Almost all that we know about the ancient history of animals or about plant life comes to us as fossils (from the latin fossilis meaning dug up).
N°2 – The creation of the universe
13.7 billion years ago
Big bang is a term used by scientists to describe an incredibly fast expansion of matter and energy, which reminds you – but wrongly so – of an explosion. From this event, the universe grew, evolved, and was transformed . But its origin still remains unknown.
In 2006, scientists, after carrying out the most distant ever observations, came to the conclusion that there existed proto galaxies a billion years after the big bang.
The period seems to have been propicious to the formation of stars.
Our galaxy, the milky way, formed then, 13 billion years ago. The expression » milky way » both refers to the part visible to the naked eye, and to the milky -white aspect of our galaxy (galileo,1610)
N°3 – Creation of the solar system – The grey planet
4,5 billion years ago
Reference point earth
After the formation of the sun, particles of ice and dust began swirling around. For a billion years, these bodies were subjected to bombardments of meteorites, which caused them to conglomerate. They became rocks in collision, then planets.
Mercury, venus, earth and mars, grey rocky planets, were born. Farther away, millions of light years away, the gaseous planets, jupiter, saturn, uranus and neptune, were born too.
The bombardments of asteroids continued and favoured the formation of the earth nucleus. A final collision defined the axis, the position, the size and the atmosphere of our planet.
The air became breathable and planet earth started to cool down.
N°4 – The early stages of life on earth
3.8 billion years ago
Reference point earth
Water – the cradle of life – fell in the form of warm acidic rain and covered the planet
The light from the sun entered the atmosphere , meeting air molecules, in which blue light propagated . Seen from the earth , the sky then looked blue whereas seen from space it is the earth that looked blue.
Three scientific hypotheses argue about the origins of life on earth:
– hydrothermal springs located at the bottom of the oceans offered ideal conditions to promote underwater fauna .
– fragments of comet entering earth’s atmosphere acted as » fertilizers » ( lithospermia )
– molecules fixing the first bacteria developed in the shallow acidic waters thanks to a fair amount of sunlight and electric shocks.
The future will probably tell us that the origin of life is linked to a combination of these three hypotheses .
Did you know ?
After the first appearance of bacteria in aquatic environment, algae – the result of the addition of simple elements set in the right order – were born . They were blue and uncomplicated . We have to wait an additional 2 billion years for bacteria to combine and give rise to green algae.
Gradually, concretions of chlorophyllian bacteria gave birth to bio marine formation called stromatolites . Their growth was slow but led to the formation of numerous bigger reefs and massifs.
Due to rainfalls and tectonic movements , a super- continent assembled : rodinia .
The ediacaran site in australian mountains , gives us one of the oldest fossils of multicellular forms of this period, namely over 1500 amazing species , all of aquatic origin .
545 million years after the appearance of life on earth , 90% of the history of planet earth had already taken place …
N°5 – The primary era
The development of underwater life
500 million years ago
Underwater life expanded.
Molluscs ruled the seas. Without predators and protected by their shells , they were able to reach huge sizes. Such was the case for ammonites and orthoceras . Nautiluses fended off all the dangers and are still alive at a depth of 150 and 300 metres.
The first proto-fish then came into existence together with strange-looking invertebrates with faceted eyes : trilobites .
N°6 – The first steps of life out of water
430 million years ago
Mosses and sphagnia were the first plants to colonize the land. They had no roots but they had a stem and their breeding was dependent on water . With algae, they contributed to the formation of oxygen on the planet.
Recently, worldwide traces of giant mushrooms were discovered . Some of them, 420 million years old, could reach 6 metres in height .
400 million years ago , the first plants with leaves came into existence. They were mainly ferns and horsetails . At the same time , as a result of the combination of an alga and a fungus, lichens were born ,and their resistance to extreme conditions was unequaled.
Reference point earth – Reference point crisis
The highest traces of sea level that we found date from this period . A supercontinent , gondwana , seemed to attract others to the south pole. Partly covered with water , these rocks consisted mainly of marine sediments.
450 million years ago, gondwana was very close to the pole : the temperatures dropped , the continent was covered with glaciers. 85 % of marine species disappeared. That was the first major ecological crisis that the planet came across .
N°7 – From the ocean bottom to terra ferma
400 million years ago
Reference point crisis
When temperatures rose , the oceans were covered with sea lily and dominated by new predators : sea scorpions and armoured fish.
The development of plants changed the climate , increasing heat and the greenhouse effect . As the waters were poor in oxygen, some fish were forced to adapt.
One must mention tiktaalik , which developed lungs and sort of jointed legs which enabled him to draw air and food out of water. Acanthostega and tulerpeton developed four legs with fingers. They are the ancestors of tetrapods.
400 million years ago , the climate cooled down, inducing new species to come out of the water. 70 % of marine species were affected. That was the second big crisis .
N°8 – The development of life on earth
350 million years ago
Reference point earth
During the carboniferous era , two continental blocks collided and formed pangea. The south was covered with glaciers and at the equator ,which enjoyed a warm and humid climate , life form abounded. Forests extended . With lignin, a new component of wood, ginkgo trees reached up to 50 metres and could live for millenniums.
The development of wetlands also contributed to the appearance of reptiles. Like our frogs, these tetrapods live close to the water , where they lay eggs . For the first time a vertebrate called hylonomus came out of the water .
But bacteria capable of digesting lignin were few and the slow decomposition of plants raised the propotion of dioxyde in the air . Invertebrates adapted : they grew in size and acquired large rib cages .
The atmosphere was conducive to spontaneous fires . Woody plants were then reduced to charcoal , hence the name given to the carboniferous period . The appearance of a lignin -degrading fungus terminated these phenomena.
N°9 – Modernization of life on earth
300 million years ago
Reference point crisis
Weather conditions were changeable and living beings had to adapt.
Plants provided themselves with a vasculature , which allowed them to fetch water for themselves and the first modern trees appeared. Most were conifers. Their leaves slowed down evaporation and protected them from the cold .
The coelurosaurus was the first vertebrate to live in the open air.
Many reptiles freed themselves from the water and then conquered land. At the same time mammalian reptiles such as dimetrodon and the therapsids , the ancestors of mammals, appeared.
N°10 – Did you know ?
About 260 million years ago , giant eruptions caused acid rain , a cloud of dust and gas was released . That was the third major crisis that the planet came across .
The biosphere was profoundly affected : 95 % of marine species and 70% of terrestrial species vanished.
N°11 – The mesozoic era
Triassic: the first dinosaurs …
250 million years ago
Reference point crisis – Reference point earth
The forest became denser around water points, even if the rediversification of species was slow and difficult.
As they competed for light, trees grew, which induced the growth of herbivores such as masospondilus. The araucaria appeared.
Tanystropheus used his nearly 3- metre- long neck to fish from the shore.
N°12 – Dinosaurs survive
The fall of a meteorite, probably coupled with a major volcanic eruption, marked the end of this period: 50% of terrestrial species disappeared … But the dinosaurs survived!
200 million years ago, pangaea was divided again into 2 blocks. This fragmentation of continents caused a fall of temperatures and of the sea level
N°13 – The golden age of dinosaurs
During the jurassic era , high conifer forests expanded . Moisture favoured the development of coastal plants, insects, herbivores and predators. The first flower appeared and is known by the name of williamsonia .
During the cretacious era; the deciduous trees such as yews, fig trees as well as flowering plants settled for good. The flowers were large and isolated so as to attract pollinating insetcs ( magnolias, water lilies). The seed was protected in its pod ; carnivorous plants could be found at all latitudes.
N°14 – The greatest discovery
Over the last 25 years, 250 new species of dinosaurs have been discovered . Among those, a major discovery took place in china : feathered dinosaurs.
Thus, the oviraptor, whose name means the egg thief, was , in fact, covered with feathers which probably protected its brood from the sunshine. Similarly, the velociraptor, one of the largest predatory dinosaurs, was covered with feathers.
In 2003, the discovery of the microraptor in china, and then of hundreds of fossils of confuciusornis confirms that birds descend from dinosaurs. They were endowed with a beak, their tail was superseded by a rump and pectoral muscles allowed them to fly.
As for the iberornis, it had an opposable toe, which allowed him to hold on to branches.
Evolutionary relationships are still difficult to demonstrate, all the more so as the acquisition of characteristics was progressive. However, it is now certain that parrots, pigeons and owls appeared some 80 million years ago.
N°15 – The Titanosaure
In 2010, in Angeac (Charentes – France), scientists discovered an over 2.4-metre-long femur. This titanosaurus is thought to have been almost 45 metres long.
Sauropod dinosaurs are the longest and most impressive animals that ever lived on earth, but the most famous dinosaur remains the most daunting of carnivorous animals, namely the t- rex….
N°16 – The conquest of the waters
The freshwater expanses became hunting land and fishing grounds for terrestrial carnivores .
Ichnology (the science of trace fossils) has brought many elements which are not obvious in fossils . Thus, a range of traces found in spain shows that carnivorous dinosaurs swam in shallow waters in search of food. Besides, a tooth belonging to a sawfish, the onchopristis , was found in the jaw of a baryonix …
The first freshwater turtles also appeared during the triassic era and moved out into the warm ocean waters 140 million years ago . The biggest on, the archelon , was 4 metres long !
Incidentally, it is also the time when large marine predators such as plesiosaurs , ichthyosaurs and mosasaurs appeared . They were fast and powerful and conquered the oceans. The mosasaur was probably the largest , measuring up to 18 metres …
N°17 – The other animals of the mesozoic era
Pterosaurs, which are neither reptiles nor birds, ruled in the air. Their adaptation was manifold : they could fish as well as hunt. The quetzalcoaltus was the largest living animal which has ever flown.
Crocodiles, which are as ancient as dinosaurs, colonized almost every continent. Their sizes varied widely, going from the small crocodile cerin (30 cm) to the huge sarchosuchus (14 metres).
Descendants of mammalian reptiles appeared 230 million years ago. They were the pélicosaures. 110 million years later, a new group was born: marsupials. They carry their young in a pouch.
N°18 – The great crisis
Reference point: crisis
65 million years ago
Our planet experienced its last great biological crisis which lasted for 500,000 years. Two major causes were identified: on the one hand the fall of a meteorite and on the other hand huge volcanic explosions. The particles which were released blocked the sun rays and photosynthesis.
That caused the mass extinction of the dinosaurs except for birds, and of nearly 75% of marine species, including ammonites.
N°19 – The tertiary
The survivors of the crisis
Reference point earth
The cataclysmic events that caused the end of the reign of the dinosaurs, hardly affected some species : amphibians , mammals , turtles , lizards, snakes , crocodiles and birds survived at that time. None of them weighed over than 25 kg.
Soon, their size grew as there were no predators in their environment. So, the Titanoboa could measure up to 12 meters and feed on small crocodiles.
Birds, descending directly from dinosaurs conquered the world. With the Phororacos and their powerful beaks , they became the ultimate predators and reigned supreme over land and in the air.
50 million years ago , the world as we know it (oceans and continents) was taking shape. Climatic zones , specific to continental areas , set up.
The carbon dioxide contained in the atmosphere decreased, thus opening an ecological niche for mammals and flowering plants, which left their dark and damp environment in which they had been confined so far .
The indricotherium , a mastodon , became the largest mammal of all times (6m ) . It lived 30 million years ago . Here , you can climb on the back of a four-metre-high young one, after its discovery on the paleontological excavation site of messel (germany).
N°20 – From the explosion of flowering plants to the current flora
Reference point earth
Floral diversity expanded and adapted because of increasing predation , pollinators and also because they had to fight the drought or the cold.
Vegetation took modern forms of deciduous forest trees and perennials spread on all continents , flowering plants proliferated .
The trend then was one of miniaturization. The more one moved away from the tropics , the more species endowed themselves with the capacity to generate flowers and fruit before they became adults. Thus , from the warmest to the coldest places, one found from the biggest to the smallest : tree ferns , bamboos , palms , banana trees , canes , reeds and grasses.
Far from magnolias , small inflorescences of grasses or orchids , constitute a very recent botanical family . Almost exclusively pollinated by insects, they put forth infinite ingenuity to attract them.
N°21 – The end of the tertiary era
5 million years ago.
Reference point earth
Europe consisted of subtropical islands with hot and humid summers and cool winters and the antarctic was colonized by plants. Temperatures were close to minus 15 ° c.
The inlet separating the americas closed : northern wildlife (smilodon, llamas and horses) dominated the fauna of the south (tylacosmilus, sloths and giant armadillos). Similarly, one can note the appearance of animals with huge canines.
At the same time, chad saw the first hominidae, namely Toumaï , a sahelanthropus, discovered in 2001. The grip of his skull to his vertebrae shows that, like all men, he walkeds on two legs.
And so opens up a new era: that of humankind.
N°22 – The quaternary
The position of the continents has hardly changed. Global climate cooled down . The antarctic froze completely.
The advent of man
Faced with glaciations, neanderthal adapted and used the resources of his environment. He built seasonal camps and organized his activities such as hunting and flint making workshops, etc.. He reigned over europe for 150,000 years.
40,000 years ago , homo sapiens arrived in europe. He made many objects and produced large quantities of images and symbols. He could sculpt, grave and paint on bones and cave walls. He invented cave painting. That was the upper paleolithic.
In those days, men were hunters and gatherers. Their vegetable intake was never zero.they picked all they could find : leaves, roots, fruits, seeds, etc…
N°23 – Würm : the glacial maximum
18 000 years ago
Reference point earth – Reference point crisis
At the beginning of the quaternary , the climate experienced four glaciations , alternating with periods of warming.
During the last glaciation –Würm -the glacial maximum was reached in about 18,000 b.c. the sea level dropped . As a result, japan and korea were linked by land , such was the case too for australia and tasmania , as well as siberia and alaska.
With each glaciation , living species were affected. The vegetation seemed to resist better , as it reappeared with each warming episode starting from warm and humid areas . During the first two glaciations ,the arctic wildlife invaded europe while elephants , rhinos and felines moved towards africa and the middle east.
10, 000 years ago , the climate warmed up : the glaciers melted , the fauna and the flora conquered higher latitudes , the sea level rose. Mammoths , woolly rhinos and cave bears disappeared. For the first time man was present to witness a biological crisis .
N°24 – The neolithic revolution
The change from picking to a structured organization was a revolution. It consisted in the selecting and the growing of once – wild species which were deemed interesting .
Agriculture and breeding came to birth in the near east about 12, 000 years ago, followed by china and central america.
The process expanded thanks to animal domestication and farming on burnt land, which degraded the soil for long periods of time.
N°25 – The islands
The colonization of islands by man was progressive .
It started 40,000 years ago by land glaciations or by sea during the warming periods . In australia, as on other islands , people used fire to beat up the game ( rabattre le gibier )and deeply modified ecosystem.
In the fifteenth century , vasco da gama opened the spice route . It was the time of colonization.the activities which were linked to it caused a rapid loss of unique ecosystems.
Darwin, in the early nineteenth century , took an interest in it and discovered that their balance is fragile and depends on biodiversity. Most species have adapted , creating original , isolated and unique forms :they are endemic species like the dodo , galapagos tortoise , etc. . ) .
N°26 – Today on earth
Earth is the only known planet capable of sustaining life . The diversity of its relief and its climate guarantees a high biodiversity . Over the past 65 million years , the extinction rate was 1 per year per million species.
Today that figure is multiplied by 100. Nearly 17,000 known species are threatened with extinction, one of them being the east indian king crab. For the first time , a mammal , man , threatens and destroys the environment that surrounds him.
Since its creation , earth has experienced five major crises and some thirty intermediate crises. We know the importance of major crises but underestimate the minor ones. And yet , 40% of species extinctions are due to these crises.
Today , perhaps more than ever, the trend is picking up speed. The pizzly , a real hybrid between a grizzly and a polar bear , is here to prove it . Is it to be viewed as an error in evolution or the future development of the polar bear?
Scientists estimate that there are still between 10 and 100 million species to discover. But the number of varieties is shrinking . Our resources are actually affected.
It is urgent to maintain biodiversity which is essential to the balance of our planet.
N°27 – Projection
According to scientists, the near future of our planet is primarily linked to global warming and the movement of continents. But on the scale of the universe , the future of the earth is essentially linked to the sun. It is doomed to become a red giant planet and should produce more and more light and heat.
What of life on earth then ?