Search results
Results from the WOW.Com Content Network
Macroevolution comprises the evolutionary processes and patterns which occur at and above the species level. [ 1 ] [ 2 ] [ 3 ] In contrast, microevolution is evolution occurring within the population(s) of a single species.
Macroevolution refers to evolution that occurs at or above the level of species, in particular speciation and extinction, whereas microevolution refers to smaller evolutionary changes within a species or population, in particular shifts in allele frequency and adaptation. [135] Macroevolution is the outcome of long periods of microevolution. [136]
For example, the brain of a human embryo looked first like that of a fish, then in turn like that of a reptile, bird, and mammal before becoming clearly human. The embryologist Karl Ernst von Baer opposed this, arguing in 1828 that there was no linear sequence as in the great chain of being, based on a single body plan , but a process of ...
Another example (if memory serves me) is a new polyploid Spartina which originated and spread in Europe in the mid-20th century. I suppose the wheat example is the best one, but there is a nice example in the Triangle of U article. Guettarda 04:41, 3 Jun 2005 (UTC)
Macroevolution is guided by sorting of interspecific variation ("species selection" [2]), as opposed to sorting of intraspecific variation in microevolution. [3] Species selection may occur as (a) effect-macroevolution, where organism-level traits (aggregate traits) affect speciation and extinction rates, and (b) strict-sense species selection, where species-level traits (e.g. geographical ...
Human evolution (origins of society and culture) – Transition of human species to anthropologically modern behavior; Inversion (evolutionary biology) – Hypothesis in developmental biology; Mosaic evolution – Evolution of characters at various rates both within and between species
We humans like to think of ourselves as masters of the planet, bending nature to suit our needs. We build roads, carve out neighborhoods, and raise cities from the ground up. But in reality, our ...
For example, neutral human DNA sequences are approximately 1.2% divergent (based on substitutions) from those of their nearest genetic relative, the chimpanzee, 1.6% from gorillas, and 6.6% from baboons. [10] [11] Genetic sequence evidence thus allows inference and quantification of genetic relatedness between humans and other apes.