Makingof the Fittest Analysis
Fossilshave been used over the years to provide a glimpse of historical lifethat once existed. Genes on the other hand, are used to prove theprocess of evolution indeed occurs. This book gives significant newevidence of evolution provided in the DNA. It reviews new examplesfrom a sequence of DNA that one time coded for genes that seized tobe used. It focuses on the remains of ancestral lives to bring forthevolutionary changes. It further uses forensic evidences of evolutionto reveal new evidence of characteristics and capabilities that wereabandoned as species embraced new lifestyles. This book refutes thecontemporary understanding that evolution is a completely randomprocess. It reveals that there exist order and complexity of naturethat compels this process to occur outside the context of randomprocess.
Thefirst theme that is evident is that some genes are immortal whileothers are not. Any living organism has a set of genes adapted to thedomain of life. These living organisms could be fungi or bacteria.These set of genes usually encode functions dedicated to the decodingof the genetic material. These functions have been in existence for abillion years before (Carrol 27). It is thus clear that they arepreserved by the natural selection processes. The codes noted inthese organisms are shared. The main reason for preservation isessential for the function that these organisms would not survivewithout them. They are thus protected from any major changes a rolethat is not guaranteed in other types of genes. These genes are veryuseful in assisting to trace the past history of the organisms.
Thesecond theme is the fossil genes that reveal they were functional forthe ancestral species at one time. These genes over the years seizedto be functional and as a result decayed and only created DNArecords. It is important to note that there are evidences that showthat such genes were very essential to the lives of the hostancestor. While mutations happen, some are known to leave negativeimpacts to the host. When they have no negative impact to the host,they tend to continue existing and are tolerated. This pushes thehost specie to begin changing their lifestyles (Carrol 34). A perfectexample given in the book is an animal that starts living in caves asopposed to the host ancestor that lived in the open air. This changesthe selective conditions and certain traits have started developing.Example of traits that change is the body pigmentation and thevision. Such traits are no longer preserved because there is noevident pressure to preserve them. As a result the genes which areresponsible for encoding such traits decay and are thus the fossilgenes.
Thethird major theme is that all genes are generally vulnerable tomutations. It is clear that some mutations are not successful togenes that are specifically responsible in carrying out somefunctions. This is because they may compromise those functions andmake the host species difficult to survive. If mutations happen tosome species and there are no evident negative effects, mutationtends to pile up (Carrol 57). An example given in the book is thefact that genes in host species who have shifted their lifestyles andabandoned their former life, results to many broken pieces of DNA.
Comparisonof DNA across different species has expanded knowledge aboutevolution. It is a common assumption when species share the sametraits and same genetic sequence tend to share common ancestors.However, it has always emerged that there is also convergentevolution. In this the same traits and same genetic sequence areobserved in species that existed in many millions of years apart(Carrol 89). This book concludes that the current species cannot bedeemed better than the ancestral species. This is solely because ofthe natural selection process that is forced by many existingdynamics of life and it happens at that time that is essential forthe species. In this regard it is clear that the process did notforesee the future, rather it happened in the present to help thespecies exist. There are many dynamics that force this naturalselection process occurs. These may be changes in climate, earth ordrifting of continents. The making of the fittest reveals thatnaturally species have to keep up with these changes over time.
Carrol,Sean. Makingof the fittest. London:W.W. Norton and Company publishers. 2007, Print