COMMON DESCENT Meaning and
Definition
-
Common descent is a concept in biology that refers to the belief that all living organisms are interconnected and have evolved from a shared ancestor. It is a fundamental principle of evolutionary theory that suggests that the diversity of life on Earth can be traced back to a single, common origin.
According to the theory of common descent, all organisms, from the smallest microbe to the largest mammal, are related by virtue of their evolutionary history. The principle suggests that the traits and characteristics exhibited by different species are the result of gradual changes over time through the process of natural selection.
This concept is supported by a wealth of evidence from various fields of study, including comparative anatomy, embryology, biochemistry, and genetics. Shared anatomical features, for example, provide evidence of the common ancestry of different species, as do similar developmental patterns observed in embryos.
Furthermore, the analysis of DNA and protein sequences across different organisms also reveals striking similarities that point to their evolutionary relationships. The degree of genetic similarity between different organisms can be used to construct the tree of life, which illustrates the evolutionary history and relatedness of all living organisms.
In summary, common descent is the idea that all living organisms on Earth, regardless of their complexity, are ultimately connected through a vast tree of evolutionary relationships, which can be traced back to a single common ancestor.
Etymology of COMMON DESCENT
The word "common" derives from the Middle English word "commune", which came from the Old French word "comun", meaning "common" or "shared". It ultimately traces back to the Latin word "communis", which also means "common" or "general".
The term "descent" comes from the Old French word "descendent", which originated from the Latin word "descendere", meaning "to go down" or "to descend". This Latin word is a compound of "de", meaning "down", and "scandere", meaning "to climb" or "to go".
So, the etymology of the word "common descent" suggests the shared ancestry or origin of living organisms, with the term "common" highlighting what is shared or general, and "descent" emphasizing the idea of going down or tracing back to a common source.
