Common descent, an idea central to Darwin's theory of evolution, is well supported by multiple chains of evidence from the fields of genetics, biogeography and comparative anatomy. The fossil record also provides both direct and indirect evidence of descent with modification from common ancestors, though this line of evidence was generally unavailable to Darwin in the mid-19th century.Know More
Closely related plants and animals tend to be grouped geographically. Most of the birds in the Galapagos Islands, whatever their ecological niche, are recognizably finches. Honeycreepers occupy much the same position for the Hawaiian Islands. Penguins live exclusively in the southern hemisphere. The simplest explanation for this kind of distribution is that the modern species all derive from a recent common ancestor that migrated into the area they now occupy.
Direct comparison of genes contributes to the picture of common descent. Analysis of gene-influenced protein structure done by researchers at Brandeis University found that the cleanest explanation for the variance between modern eukaryotes, bacteria and archaea is that they are all descended from a universal common ancestor that lived several billion years ago.
The common descent model is also supported by its utility as a predictive tool. The close kinship between humans and other primates is the presupposition that underlies much animal testing. The more distant, but still relatively recent, common ancestry between all mammals is the reason experiments on rats can be loosely extrapolated to human physiology.Learn more about Anthropology
According to the University of Portsmouth, Albert Cohen's delinquent subcultural theory posits that delinquency often emerges as a subculture from a shared sense of economic and social disadvantage within a society. This idea attempts to explain why delinquency occurs so often in gangs and among lower working-class males.Full Answer >
The theory of evolution is supported by biochemical evidence; many of the same molecules and biochemical processes occur within all living organisms, from single-cell bacteria to humans. Originally, scientists couldn't understand how the process of evolution began, but they later discovered that RNA possesses catalytic properties.Full Answer >
The dynamo theory, which attempts to explain the origin of planets' magnetic fields, is supported by three lines of evidence: theoretical evidence from models, positive evidence from observations of planets with magnetic fields, and negative evidence from worlds without such a field. Some anomalous examples, such as Mercury, are exceptions.Full Answer >
Plate tectonics theory, formerly known as the theory of continental drift, is well supported in geology, geography and biology. It has the power to explain many phenomena, such as volcanoes and earthquakes. The theory provides a working model for analyses of phenomena that scientists observe. This explanatory power is, itself, strong evidence that the theory is correct.Full Answer >