The other is an acceleration of birth to counteract the anomalously large birth weight produced by retardation. There is also a corresponding delayed closure of sutures of skull. A phyletic change in the onset or timing of development, so that the appearance or rate of development of a feature in a descendant's ontogeny is either accelerated or retarded relative to the appearance or rate of development of the same feature in an ancestor's ontogeny. Occurs by slowing somatic development. Two extremes are K and r selection strategies.
Examples are primates and fruit flies, respectively.
5 phylogeny the evolutionary history of a lineage, conventionally depicted as a sequence of adult stages. 6 allometry change of shape correlated with increase or decrease in size 7 convergence or analogy a similarity between organisms due to independent evolution of the similar feature by each, e.g. fins, wings in various unrelated species Compare homology and parallel evolution. A similarity between organisms due to recent developments in parallel lines of descent due to continued similiarity of evolutionary factors operating on similar individuals, e.g. larger size of apes. Correlations are no more immutable than species themselves. Upright posture freed the hand for tool use and set selection pressures for an expanded brain.