Homo is the genus that all humans belong to. It began 2.3 million years ago and evolved from the genus australopithecus.

Australopithecus possessed two of three duplicated genes derived from SRGAP2 roughly 3.4 and 2.4 million years ago (SRGAP2B and SRGAP2C), the second of which contributed to the increase in number and migration of neurons in the human brain.

Australopiths shared several traits with modern apes and humans, and were widespread throughout Eastern and Northern Africa by 3.5 million years ago (mya). The earliest evidence of fundamentally bipedal hominins is a 3.6 Million years ago fossil trackway in Laetoli, Tanzania.

Living around 6 million years ago, Orrorin tugenensis is the one of the oldest early humans on our family tree. Individuals of this species were approximately the size of a chimpanzee and had small teeth with thick enamel, similar to modern humans.

The robust-faced Ouranopithecus macedoniensis (9.6 Ma), is the common ancestor of humans, chimpanzees, bonobos, and gorillas.

Pierolapithecus catalaunicus is an extinct species of primate which lived about 13 million years ago during the Miocene in what is now Hostalets de Pierola, Catalonia, Spain, giving it its scientific name. It is the common ancestor of both modern humans and all other great apes.

Pierolapithecus evolved from Proconsul. The primary feature linking Proconsul with extant apes is its lack of a tail; other "ape-like" features include its enhanced grasping capabilities, stabilized elbow joint and facial structure. Proconsul could not hang effortlessly from tree

Aegyptopithecus is an early fossil catarrhine that predates the divergence between hominoids and cercopithecids. It is known from a single species, Aegyptopithecus zeuxis, which lived around 38-29.5 million years ago and had it's tail.

The haplorrhines include the two living groups: prosimian tarsiers, and simian monkeys, including apes. One of the earliest haplorrhines is Teilhardina asiatica, a mouse-sized, diurnal creature with small eyes. The Haplorrhini metabolism lost the ability to produce vitamin C.

Plesiadapiformes contain the ancestor species of all primates. They first appeared in the fossil record around 66 million years ago, soon after the Cretaceous–Paleogene extinction event that eliminated about 3-quarters of plant and animal species on Earth, including dinosaurs.

The Primatomorpha are a mirorder of mammals containing two extant orders: the Dermoptera or colugos and the Primates (Plesiadapiformes, Strepsirrhini, Haplorhini).

The common ancestor of Boreoeutheria lived between 100 and 80 million years ago. The boreoeutherian ancestor gave rise to species as diverse as giraffes, dogs, mice, bats, whales, and humans.

True placental mammals (the crown group including all modern placentals) arose from stem-group members of the clade Eutheria, which had existed since at least the Middle Jurassic period, about 170 MYA. These early eutherians were small, nocturnal insect eaters, and tree dwellers.

Juramaia is an extinct genus of very basal eutherian mammal known from the Late Jurassic (Oxfordian stage) deposits of western Liaoning, China. It is a small shrew-like mammal with a body length of approximately 70–100 mm, making it similar in size to the modern De Winton's shrew

Eutherians are distinguished from noneutherians by various phenotypic traits of the feet, ankles, jaws and teeth. All extant eutherians lack epipubic bones, which are present in all other living mammals. This allows for expansion of the abdomen during pregnancy.

Adelobasileus is an extinct proto-mammal from the Upper Triassic, about 225 million years ago. There is only a partial skull from strata in western Texas. It may be close to the common ancestor of modern mammals. Their sleek body type suggests they moved very fast.

Mammals originated from cynodonts, an advanced group of therapsids, during the Late Triassic. The modern mammalian orders arose in the Paleogene and Neogene periods of the Cenozoic era, after the extinction of non-avian dinosaurs.

256 Million years ago: Shortly after the appearance of the first reptiles, two branches split off. One branch is the Sauropsids, from which come the modern reptiles and birds. The other branch is Synapsida (Synapsids), from which come modern mammals. Both had temporal fenestrae.

The earliest mammal-like reptiles are the pelycosaurs. The pelycosaurs were the first animals to have temporal fenestrae. Pelycosaurs are not therapsids but soon they gave rise to them. The Therapsida were the ancestor of mammals.

The pelycosaurs appear to have been a group of synapsids that have direct ancestral links with the mammals, having differentiated teeth and a developing hard palate. The pelycosaurs appeared during the Late Carboniferous and reached their apex in the early part of the Permian.

Amniotes are tetrapods (descendants of four-limbed and backboned animals) that are characterised by having an egg equipped with an amnion, an adaptation to lay eggs on land rather than in water. Amniotes include synapsids (mammals along with their extinct kin) and sauropsids.

The informal variant of the name, "reptiliomorphs", is also occasionally used to refer to stem-amniotes, i.e. a grade of reptile-like tetrapods that are more closely related to amniotes than they are to lissamphibians, but are not amniotes themselves.

Reptiliomorphs were the ancestors of amniotes and appeared about 340 million years ago. Most of them were usually large and heavy animals, which presented more advanced adaptations to live on land (laterally-placed eyes instead of dorsally-placed ones and a knobby skin).

The ancestor of reptiliomorphs were tetrapods. Tetrapods evolved from a group of animals known as the Tetrapodomorpha which, in turn, evolved from ancient sarcopterygian fish around 390 million years ago in the middle Devonian period.

400 million years ago in the Devonian Period the earliest tetrapods evolved from lobe-finned fishes. Tetrapods are categorized as animals in the biological superclass Tetrapoda, which includes all living and extinct amphibians, reptiles, birds, and mammals.

Rhipidistia, also known as Dipnotetrapodomorpha, is a clade of lobe-finned fishes which includes the tetrapods and lungfishes.

The first tetrapodomorphs, which included the gigantic rhizodonts, had the same general anatomy as the lungfish, who were their closest kin, but they appear not to have left their water habitat until the late Devonian epoch (385–359 Ma), with the appearance of tetrapods.

Our ancestor, Guiyu oneiros, the earliest known bony fish, lived during the Late Silurian, 419 million years ago). It has a combination of both ray-finned and lobe-finned features, although analysis of the totality of its features place it closer to lobe-finned fish.

Teleostomes constitute the clade Euteleostomi, which includes all osteichthyans and tetrapods. 462 years ago our ancestors jaws evolved from anterior gill support arches that had acquired a new role, being modified to pump water over the gills by opening and closing the mouth.

Gnathostomata evolved from ancestors that already possessed a pair of both pectoral and pelvic fins. In addition to this, some placoderms were shown to have a 3rd pair of paired appendages, that had been modified to claspers in males and basal plates in females

Vertebrates originated about 525 million years ago during the Cambrian explosion, which saw rise in organism diversity. They had the basic vertebrate body plan: a notochord, rudimentary vertebrae, and a well-defined head and tail. All of these early vertebrates lacked jaws.

Our earliest known vertebrate ancestor is believed to be Myllokunmingia.

More than a hundred fossils of the creature – known as Pikaia Gracilens – have now been analyzed and researchers say it’s the most primitive of the chordates, which evolved into humans.

Our ancestor Saccorhytus is an extinct genus of animal belonging to the superphylum Deuterostomia, which is represented by a single species, Saccorhytus coronarius. Having lived approximately 540 million years ago in the Fortunian stage of the Cambrian Period.

Ikaria wariootia lived 555 million years ago and is an early relative of animals including fish, amphibians, reptiles, birds and mammals. Ancestral colonial flagellate.

Ikaria evolved from placazoa. The Placozoa are a basal form of marine free-living multicellular organism. They are the simplest in structure of all animals.

Filodigits, absent from other protists, were presumably present in the immediate ancestors of the first stem choanoflagellates from which animals almost certainly evolved; they apparently evolved at the same time as cadherins that have been involved in holozoan biology.

Choanozoa is a clade of opisthokont eukaryotes consisting of the choanoflagellates (Choanoflagellatea) and the animals (Animalia, Metazoa). The sister-group relationship between the choanoflagellates and animals has important implications for the origin of the animals.

Choanazoa formed benthic colonies that competed for space amongst other mat-forming organisms known to have existed during the Ediacaran Period some 635–540 million years ago. As such they would form a link between the unicellular ancestors of animals and ediacaran organisms.

The Filozoa are a monophyletic grouping within the Opisthokonta. They include animals and their nearest unicellular relatives (those organisms which are more closely related to animals than to fungi or Mesomycetozoa).

Icthyosporea or Mesomycetozoea contains a number of mostly parasitic species. The Ministeria and Capsaspora may be united in a group called Filasterea by the structure of their thread-like pseudopods. Along with choanoflagellates, filastereans are close relatives to animals.

Many protists reproduce sexually, as do the multicellular plants, animals, and fungi. In the fossil record, sexual reproduction first appeared by 1.2 billion years ago in the Proterozoic Eon. All sexually reproducing eukaryotic organisms likely derive from a common ancestor.

The unikonts have a triple-gene fusion that is lacking in the bikonts. The three genes that are fused together in the unikonts, but not bacteria or bikonts, encode enzymes for synthesis of the pyrimidine nucleotides: carbamoyl phosphate synthase, dihydroorotase, aspartate...

...carbamoyltransferase. This must have involved a double fusion, a rare pair of events, supporting the shared ancestry of Opisthokonta and Amoebozoa.

Eukaryotes developed from Archaea, and acquired their bacterial characteristics through the endosymbiosis of a proto-mitochondrion of bacterial origin.

Lokiarchaeota and the eukaryotes share a common ancestor, and diverged roughly two billion years ago. This putative ancestor possessed crucial starter genes that enabled increased cellular complexity. This common ancestor, eventually led to the evolution of eukaryotes.