Charles Darwin (1809–1882) was the first to produce an evolutionary tree of life. He was very cautious about the possibility of reconstructing the history of life. In "On the Origin of Species" (1859) Chapter IV he presented an abstract diagram of a theoretical tree of life for species of an unnamed large genus (see figure).
In Darwin's own words: "Thus, the small differences distinguishing varieties of the same species, will steadily tend to increase till they come to equal the greater differences between species of the same genus, or even of distinct genera."
This is a branching pattern with no names given to species, unlike the more linear tree Ernst Haeckel made years later.
In his summary to the section as revised in the 6th edition of 1872, Darwin explains his views on the Tree of Life:
The model of a tree is still considered valid for eukaryotic life forms. Research into the earliest branches of the eukaryote tree suggests a tree with either four supergroups, or two supergroups. There does not yet appear to be a consensus; in a review article, Roger and Simpson conclude that "with the current pace of change in our understanding of the eukaryote tree of life, we should proceed with caution".
Biologists now recognize that the prokaryotes, the bacteria and archaea have the ability to transfer genetic information between unrelated organisms through horizontal gene transfer (HGT). Recombination, gene loss, duplication, and gene creation are a few of the processes by which genes can be transferred within and between bacterial and archaeal species, causing variation that is not due to vertical transfer.
There is emerging evidence of HGT occurring within the prokaryotes at the single and multicell level and the view is now emerging that the tree of life gives an incomplete picture of life's evolution. It was a useful tool in understanding the basic processes of evolution but cannot explain the full complexity of the situation.
Three's Company
Three's Company is an American situation comedy. It aired on the ABC network. It began in March 1977 and ended in September 1984.
The show is a remake of the British sitcom "Man About the House". Nowadays the domestic distribution rights are handled by creator Don L. Taffner's estate and the international rights are handled by FremantleMedia (whose company Thames originated the sitcom "Man About the House").
The show is set in Santa Monica, California. It is about a man pretending to be gay so his landlord won't evict him, it is also about financial struggling such as the roommates not being able to pay their rent. The sitcom heavily relies on innuendo and sexy misunderstandings. It is also a comedy of errors. The show had two spinoffs also based on Britcoms: "The Ropers" ("George & Mildred") & "Three's a Crowd" ("Robin's Nest").
The series was later the subject of the made-for-TV movie "". The movie showed how cast changes led to the show ending.
Filmation
Filmation Associates or Filmation Studios was an American production company that produced animated television series and live action programming during the late 20th century. Founded in 1963, the company was in Reseda, California.
Theriodont
Theriodonts are a major group of therapsids. They are a clade which include not only the traditional theriodonts, but also their descendants the mammals as well (in the same way that theropod dinosaurs include the birds as a sub-clade).
They can be defined in traditional terms as a suborder of Synapsida that lived from the Middle Permian to the Middle Cretaceous. Theriodonts appeared about 265 million years ago, in the Middle Permian. Even these early theriodonts were more mammal-like than their relatives.
Theriodonts fall into three main groups: Gorgonopsia, Therocephalia and Cynodontia. Early theriodonts may have been warm-blooded. Early forms were carnivorous, but several later groups became herbivorous during the Triassic.
Theriodont jaws were more mammal-like than was the case of other therapsids, because their dentary (lower jaw) was larger, which gave them more efficient chewing. Several other bones that were previously on the lower jaw, moved into the ears, allowing the theriodonts to hear better and their mouths to open wider. This made the theriodonts the most successful group of synapsids.
Eutheriodonts refer to all theriodonts except the gorgonopsians (the most primitive group). They included the therocephalians, cynodonts and their descendants – the mammals. The name means "true beast tooth". The eutheriodonts have larger skulls, accommodating larger brains and improved jaw muscles.
The theriodonts (eutheriodonts) are one of the two synapsid survivors of the great Permian–Triassic extinction event, the other being the dicynodonts. Therocephalians included both carnivorous and herbivorous forms; both died out after the Lower Triassic.
The remaining theriodonts, the cynodonts, also included carrnivores such as "Cynognathus", as well as newly evolved herbivorous Traversodonts. While Traversodonts for the most part remained medium-sized to reasonably large (length of largest species up to 2 meters), the carnivorous forms became progressively smaller as the Triassic progressed.
By the Upper Triassic the small cynodonts included the rodent-like tritylodonts (possibly related to or descended from travsersodonts), and the tiny, shrew-like, trithelodonts, which evolved into the first mammals. The trithelodonts died out during the Jurassic, and the tritylodonts survived in the Cretaceous, but the mammals continued to evolve. Many mammal groups managed to survive the Cretaceous–Tertiary extinction event, which wiped out the non-avian dinosaurs, allowing the mammals to diversify and dominate the Earth.
Laura Ingraham
Laura Ingraham (born 19 June 1964) is an American conservative political commentator, author and radio host. Her nationally syndicated talk show "The Laura Ingraham Show" was broadcast for nine years on the Talk Radio Network. She has been known for her controversial statements against the left wing party.
Peptide bond
A peptide bond is a special chemical bond that happens between two amino acids. In the reaction (called condensation), the two amino acids are combined into a "dipeptide".
Repenomamus
Repenomamus is the largest known mammal from the Cretaceous period. Its fossil was found in Manchuria.
There is good evidence that it fed on dinosaurs. It is not known whether "Repenomamus" was a hunter or a scavenger.
"Repenomamus" was carnivorous. A specimen of "R. robustus" has been discovered with the fragmentary skeleton of a juvenile "Psittacosaurus" preserved in its stomach.
This is the strongest evidence that Mesozoic mammals fed on dinosaurs, though there were earlier indications of this.
The larger species, "R. giganticus", is the largest mammal known from the Cretaceous. "R. giganticus" was more than 1 metre (39 inches) long and weighed about 12–14 kg (26–31 lb). Its skull measures 16 cm (6.25 in) long, its body 52 cm (20.5 in), and the preserved part of its tail 36 cm (14 in).
The fossils were recovered from the lagerstätte of the Yixian Formation in the Liaoning Province of China, renowned for its extraordinarily well-preserved fossils of feathered dinosaurs. They have been dated to 130 million years ago, during the Lower Cretaceous period.
"Repenomamus" is a genus of triconodonts, a group of mammaliaformes with no modern relatives.
Frederick William III of Prussia
Frederick William III () (3 August 1770 – 7 June 1840) was king of Prussia from 1797 to 1840.
Frederick William was born in Potsdam in 1770 as the son of Friedrich Wilhelm II of Prussia and Frederika Louisa of Hesse-Darmstadt. He was considered to be a shy and reserved boy,