User:Mateuszica/timelineour
From Wikipedia, the free encyclopedia
| Timeline of human evolution | ||||
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| Date | Event | |||
| 580 MYA | The movement of all animals may have started with cnidarians . Almost all cnidarians possess nerves and muscles , because they are the simplest animals to possess it , their direct ancestors were very likely the first animals to use of nerves and muscles together.Cnidarians are also the first animals with an actual body of definite form and shape.They have radial symmetry | |||
| 550 MYA | Study says that flatworms (Platyhelminthes) have evolved from early form of Jellyfish (a Cnidarian ).Flatworm are the earliest animals to have a brain. And the simplest animal to be bilaterally symmetrical. | |||
| 505 MYA | Acorn worms are considered more highly specialised and advanced than other similarly shaped worm-like creatures. They have a circulatory system with a heart that also functions as a kidney. Acorn worms have the gill-like structure it uses for breathing, a structure similar to that of primitive fish. Acorn worms are thus sometimes said to be a link between vertebrates and invertebrates. | |||
| 500 MYA |
The earliest known ancestor of the chordates is Pikaia.It the first known animal with a notochord.Pikaia is believed to be the ancestor of all chordates and vertebrates. Lancelet , that still lives today , retain some characteristics of the primitive chordates. It resembles Pikaia Other earliest known chordate-like fossils is from a conodonts a "eel-shaped animal of 4-20 cm long" with a pair of huge eyes at the head end were and a complex basket of teeth. |
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| 500 MYA |
Agnatha, the Ostracoderm was the first fishes (first vertebrates) Precursors to the bony fish.they was jawless such as arandaspis.Their internal skeletons were cartilaginous . They lacked the paired (pectoral and pelvic) fins of more advanced fish. |
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| 480 MYA |
The Placodermi were prehistoric fishes . Placoderms were the first of the jawed fishes, their jaws evolving from the first of their gill arches 1.Their head and thorax were covered by articulated armoured plates and the rest of the body was scaled or naked. |
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| 365 MYA |
Some fresh water lobe-finned fish (Sarcopterygii) develop legs and give rise to the Tetrapoda. The first tetrapods evolved in shallow and swampy freshwater habitats. Primitive tetrapods developed from a lobe-finned fish (an "osteolepid Sarcopterygian"), with a two-lobed brain in a flattened skull, a wide mouth and a short snout, whose upward-facing eyes show that it was a bottom-dweller, and which had already developed adaptations of fins with fleshy bases and bones. The "living fossil" coelacanth is a related lobe-finned fish without these shallow-water adaptations. These fishes used their fins as paddles in shallow-water habitats choked with plants and detritus. The universal tetrapod characteristics of front limbs that bend backward at the elbow and hind limbs that bend forward at the knee can plausibly be traced to early tetrapods living in shallow water. Panderichthys is a 90-130 cm long fish from the Late Devonian period . It have a large tetrapod-like head. Panderichthys exhibits features transitional between lobe-finned fishes and early tetrapods. |
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| 315 MYA |
Acanthostega is an extinct amphibian, among the first animals to have recognizable limbs. It is a candidate for being one of the first vertebrates to be capable of coming onto land. It lacked wrists, and was generally poorly adapted to come onto land. The limbs could not support the animal's weight. Acanthostega had both lungs and gills, also indicating it was a link between lobe-finned fish and terrestrial vertebrates. Ichthyostega is an early tetrapod. Being one of the first animals with legs, arms, and finger bones, Ichthyostega is seen as a hybrid between a fish and an amphibian. Ichthyostega' had legs but its limbs probably weren't used for walking , they may have spent very brief periods out of water and would have used their legs to paw their way through the mud. Amphibia were the first four-legged animals to develop lungs. Amphibians livin today still retain many characteristics of the early tetrapods. |
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| 300 MYA |
From amphibians came the first reptiles Hylonomus it is the earliest known reptile . It was 20 cm long (including the tail) and probabably would have looked rather similar to modern lizards. It had small sharp teeth and probably ate millipedes and early insects. It is a precursor of later amniotes and mammal-like reptiles. Evolution of the amniotic egg gives rise to the Amniota, reptiles who can reproduce on land and lay eggs on dry land. They dont need to return to water for reproduction. This adaptation gave him the capability to colonize the uplands for the first time. Reptiles have advanced nervous system, compared to amphibians. They have twelve pairs of cranial nerves. |
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| 256 MYA |
 Shortly after the aparence of the first reptiles, two branches split off. One is Synapsida , they had a pair of holes in their skulls behind the eyes, which were used to increase the space for jaw muscles. The other branche is Diapsida. From synapsyds came the Therapsida, that are the direct ancestor of mammals. They are often called mammal-like reptiles. The earliest mammal-like reptilian are the pelycosaurs. The pelycosaurs was the first animals to have temporal fenestra.pelycosaurs are not Therapsida but soon they gave rise to them. The therapsids have temporal fenestrae larger and more mammal-like than pelycosaurs , their teeth show more serial differentiation; and later forms had evolved a secondary palate. A secondary palate enables the animal to eat and breathe at the same time and is a sign of a more active, perhaps warm-blooded, way of life. |
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| 220 MYA | One sub-group of therapsids, the cynodonts have evolved more mammal-like characteristics.
The jaws of cynodonts resemble modern mammal jaws more closely and their teeth are multi-cusped and differentiated down the jaw. Cynodonts are the direct ancestors of all modern mammals. |
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| 220 MYA | From eucynodonts (cynodonts) came the first mammals .
Most early mammals were small and shrew-like animals that fed on insects. Constant body temperature. All mammals have milk glands for their young. Neocortex has evolved in mammals. This brain region is unique to mammals. The earliest mammals include:
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| 125 MYA |
Eomaia scansoria, a eutherian mammal, leads to the formation of modern placental mammals. It looks like modern dormouse, climbing small shrubs in Liaoning, China. |
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| 100 MYA | Common genetic ancestor of mice and humans. | |||
| 65 MYA |
A group of small, nocturnal and arboreal, insect-eating mammals called the Euarchonta begins a speciation that will lead to the primates, tree shrew and flying lemur orders. The Primatomorpha is a subdivision of Euarchonta that includes the primates and the proto-primate Plesiadapiformes. One of the early proto-primates is Plesiadapis. Plesiadapis still had claws and the eyes located on each side of the head, because of that they were faster on the ground than on the top of the trees, but they begin to spend long times on lower branches of trees, feeding on fruits and leafs. One of the last Plesiadapiformes is Carpolestes simpsoni. It had grasping digits but no forward facing eyes. |
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| 40 MYA | Primates diverge into suborders Strepsirrhini (wet-nosed primates) and Haplorrhini (dry nosed primates). Strepsirrhini contains most of the prosimians; modern examples include the lemurs and lorises. The prosimian tarsiers, along wth the simian monkeys and apes are the haplorrhines. One of the earliest haplorrhines is Teilhardina asiatica, a mouse-sized, diurnal creature with small eyes. | |||
| 30 MYA |
Haplorrhini splits into infraorders Platyrrhini and Catarrhini. Catarrhines mostly stayed in Africa as the two continents drifted apart. One ancestor of catarrhines might be Aegyptopithecus. Other ancient catarrhines include Bugtipithecus inexpectans, Phileosimias kamali and Phileosimias brahuiorum, which are all similar to today's lemurs. Soon catarrhine males gain color vision but lose the pheromone pathway. |
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| 25 MYA |
Catarrhini splits into 2 superfamilies, Old World monkeys (Cercopithecoidea) and apes (Hominoidea). Proconsul was an early genus of catarrhine primates. They had a mixture of Old World monkey and ape characteristics. Proconsul's monkey-like features include thin tooth enamel, a light build with a narrow chest and short forelimbs, and an arboreal quadrupedal lifestyle. Its ape-like features are its lack of a tail, ape-like elbows, and a slightly larger brain relative to body size. Proconsul africanus is a possible ancestor of both great and lesser apes, and humans. |
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