Thomas Henry Huxley in the context of "Metatheria"

John Maler Collier OBE ROI RP (/ˈkɒliər/; 27 January 1850 – 11 April 1934) was an English painter and writer. He painted in the Pre-Raphaelite style, and was one of the most prominent portrait painters of his generation. Both of his marriages were to daughters of Thomas Henry Huxley. He was educated at Eton College, and he studied painting in Paris with Jean-Paul Laurens and at the Munich Academy starting in 1875.

Agnosticism is the view or belief that the existence of God, the divine, or the supernatural is either unknowable in principle or unknown in fact. It can also mean an apathy towards such religious belief and refer to personal limitations rather than a worldview. Another definition is the view that "human reason is incapable of providing sufficient rational grounds to justify either the belief that God exists or the belief that God does not exist."

The English biologist Thomas Henry Huxley said that he originally coined the word agnostic in 1869 "to denote people who, like [himself], confess themselves to be hopelessly ignorant concerning a variety of matters [including the matter of God's existence], about which metaphysicians and theologians, both orthodox and heterodox, dogmatise with the utmost confidence." Earlier thinkers had written works that promoted agnostic points of view, such as Sanjaya Belatthiputta, a 5th-century BCE Indian philosopher who expressed agnosticism about any afterlife; and Protagoras, a 5th-century BCE Greek philosopher who expressed agnosticism about the existence of "the gods".

The Wallace Line or Wallace's Line is a faunal boundary line drawn in 1859 by the British naturalist Alfred Russel Wallace and named by the English biologist Thomas Henry Huxley.

It separates the biogeographic realms of Asia and 'Wallacea', a transitional zone between Asia and Australia formerly also called the Malay Archipelago and the Indo-Australian Archipelago (present day Indonesia). To the west of the line are found organisms related to Asiatic species; to the east, a mixture of species of Asian and Australian origins is present. Wallace noticed this clear division in both land mammals and birds during his travels through the East Indies in the 19th century.

The Huxley family is an English family; several of its members have excelled in science, medicine, arts and literature. The family also includes members who occupied senior positions in the public service of the United Kingdom.

The patriarch of the family was the zoologist and comparative anatomist Thomas Henry Huxley (1825–1895). His grandsons include:

Eutheria (from Ancient Greek εὐ- (eú-), meaning "true, well", and θηρίον (thēríon), meaning "beast", and thus, "true beasts"), also called Pan-Placentalia, is the clade consisting of placental mammals and all therian mammals that are more closely related to placentals than to marsupials.

Eutherians are distinguished from non-eutherians 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 (marsupials and monotremes). This allows for expansion of the abdomen during pregnancy, though epipubic bones are present in a number of primitive eutherians. Eutheria was named in 1872 by Theodore Gill; in 1880, Thomas Henry Huxley defined it to encompass a more broadly defined group than Placentalia.

Darwinism is a term used to describe a theory of biological evolution developed by the English naturalist Charles Darwin (1809–1882) and his contemporaries. The theory states that all species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual's ability to compete, survive, and reproduce. Also called Darwinian theory, it originally included the broad concepts of transmutation of species or of evolution which gained general scientific acceptance after Darwin published On the Origin of Species in 1859, including concepts which predated Darwin's theories. English biologist Thomas Henry Huxley coined the term Darwinism in April 1860.

Darwinism stricto sensu lacks a clear theory of inheritance, in contrast with later neo-Darwinian theories such as the modern synthesis (which integrates mendelian inheritance).

Sauropsida (Greek for "lizard faces") is a clade of amniotes, broadly equivalent to the class Reptilia, though typically used in a broader sense to also include extinct stem-group relatives of modern reptiles and birds (which, as theropod dinosaurs, are nested within reptiles as more closely related to crocodilians than to lizards or turtles). The most popular definition states that Sauropsida is the sibling taxon to Synapsida, the other clade of amniotes which includes mammals as its only modern representatives. Although early synapsids have historically been referred to as "mammal-like reptiles", all synapsids are more closely related to mammals than to any modern reptile. Sauropsids, on the other hand, include all amniotes more closely related to modern reptiles than to mammals. This includes Aves (birds), which are a group of theropod dinosaurs despite originally being named as a separate class in Linnaean taxonomy.

The base of Sauropsida is traditionally divided into main groups of "reptiles": Eureptilia ("true reptiles") and Parareptilia ("next to reptiles"). Eureptilia encompasses all living reptiles (including birds), as well as various extinct groups. Parareptilia is typically considered to be an entirely extinct group, though a few hypotheses for the origin of turtles have suggested that they belong to the parareptiles. The clades Recumbirostra and Varanopidae, traditionally thought to be lepospondyls and synapsids respectively, may also be basal sauropsids. The term "Sauropsida" originated in 1864 with Thomas Henry Huxley, who grouped birds with reptiles based on fossil evidence. The divisions of "Eureptilia" and "Parareptilia" have been challenged in a number of recent studies, who find that they do not represent monophyletic groups.