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This is provided and shown by Robin Dunbar's social brain hypothesis. In addition, it has been shown that an increase in social interactions corresponds to the evolution of human intelligence or in other words, an increase in brain size. Language is a mosaic composite of various elements working together for one specific attribute, and this is not a single trait an offspring can inherit directly. Lastly, Group 3 involves the presence of behavior such as the human vernacular. An example of this is the variability of bipedalism forming independently within all related species of hominin. Group 2 relies on the different environmental impacts on the changes of a species. Examples of this can be seen within comparisons of A. Group 1 includes related species developing independently, of which carry deep variability in their own morphological structure. To help further explain the meaning of mosaic evolution in hominin, mosaicism will get broken down into three subgroups. Īlthough mosaic evolution is usually seen in terms of animals such as Darwin's finches, it can also be seen in the evolutionary process of hominin. Mammalian evolution, especially during the Mesozoic provides a clear and well-understood example.Evolution of the horse, in which the major changes took place at different times, not all simultaneously.

modularis was the first known pterosaur to display features of both long-tailed ( rhamphorhynchoid) and short-tailed ( pterodactyloid) pterosaurs. Meadow voles during the last 500,000 years.The peculiarity here is that the rest of the skeleton had not changed. His interest was in the basic affinity of birds and reptiles, which he united as the clade Sauropsida. Huxley showed that the two were very similar, except for the front limbs and feathers of Archaeopteryx. Both fossils came from the Solnhofen Limestone in Bavaria. Nearly 150 years ago, Thomas Henry Huxley compared Archaeopteryx with a small theropod dinosaur, Compsognathus. Hominid evolution: the early evolution of bipedalism in Australopithecines, and its modification of the pelvic girdle took place well before there was any significant change in the skull, or brain size.It is not claimed that this pattern is universal, but there is now a wide range of examples from many different taxa, including: Most novel human features (compared to closely related apes) were of this nature, not implying major change in structural genes, as was classically considered. A creature may, for example, present some neotenic features and retarded development, resulting in new features derived from an original creature only by regulatory genes. Ī creature in its ontogeny may combine heterochronic features in six vectors, although Gould considers that there is some binding with growth and sexual maturation. These names are not very indicative, as past theories of development were very confusing. Size must be combined with shape, so a creature may retain paedomorphic features if advanced in shape or present recapitulatory appearance when retarded in shape. That is insufficient to understand heterochronic mechanism. Alternatively, it may maintain its original size or, if delayed, it may result in a larger sized creature. When a creature is advanced in size, it may develop at a smaller rate. Thus a " heterochronic clock" has three variants: 1) time, as a straight line 2) general size, as a curved line 3) shape, as another curved line. Organs develop at differing rhythms, as a creature grows and matures. In the neodarwinist theory of evolution, as postulated by Stephen Jay Gould, there is room for differing development, when a life form matures earlier or later, in shape and size. 408 Its place in evolutionary theory comes under long-term trends or macroevolution. Another definition is the "evolution of characters at various rates both within and between species". Mosaic evolution (or modular evolution) is the concept, mainly from palaeontology, that evolutionary change takes place in some body parts or systems without simultaneous changes in other parts.