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[15] Darwin's tree is not a tree of life, but rather a small portion created to show the principle of evolution. Because it shows relationships (phylogeny) and time (generations), it is a timetree. In contrast, Ernst Haeckel illustrated a phylogenetic tree (branching only) in 1866, not scaled to time, and of real species and higher taxa. In his ...
The idea of a tree of life arose from ancient notions of a ladder-like progression from lower into higher forms of life (such as in the Great Chain of Being).Early representations of "branching" phylogenetic trees include a "paleontological chart" showing the geological relationships among plants and animals in the book Elementary Geology, by Edward Hitchcock (first edition: 1840).
The results are a phylogenetic tree—a diagram setting the hypothetical relationships between organisms and their evolutionary history. [4] The tips of a phylogenetic tree can be living taxa or fossils, which represent the present time or "end" of an evolutionary lineage, respectively. A phylogenetic diagram can be rooted or unrooted.
This schema constitutes a basic framework of the overlapping behavioural fields of ethology, behavioural ecology, comparative psychology, sociobiology, evolutionary psychology, and anthropology. Julian Huxley identified the first three questions. Niko Tinbergen gave only the fourth question, as Huxley's questions failed to distinguish between ...
The theory of recapitulation, also called the biogenetic law or embryological parallelism—often expressed using Ernst Haeckel's phrase "ontogeny recapitulates phylogeny"—is a historical hypothesis that the development of the embryo of an animal, from fertilization to gestation or hatching (), goes through stages resembling or representing successive adult stages in the evolution of the ...
Phylogenetic comparative methods (PCMs) use information on the historical relationships of lineages (phylogenies) to test evolutionary hypotheses.The comparative method has a long history in evolutionary biology; indeed, Charles Darwin used differences and similarities between species as a major source of evidence in The Origin of Species.
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The phylogenetic lineage leading back from Neornithes to the point where it merges with the crocodilian lineage, along with all side branches, constitutes pan-birds. In addition to non-crown group primitive birds like Archaeopteryx , Hesperornis and Confuciusornis , therefore, pan-group birds would include all dinosaurs and pterosaurs as well ...