Whats up with thumbs?

  Everyday we use our hands to do all sorts of task. One of the most important features of our hands is that thing we call a thumb. With the help of having thumbs it has helped humans develop better motor skills. Imagine without our thumbs the things we couldn’t do. Would have our ancestors even developed tools? Would we even be considered as advanced as we are now? Most likely no humans would be.  But how did this opposable thing become on our hand become and are there other creatures with similar appendages?

  When it comes to looking at the evolution of the thumb it is seen with in Homo erectus or Homo habilis. What cause the thumb to become advanced though in our ancestors? A possible idea is the advancement of walking up right as proposed by Suzanna Kemmer. It is thought that as our ancestors began to walk up right there was now new usage for their hands. From this they created tools and learned to use resources that were around. Another possibility is the development of a gene enhancer known as HACNS1 that was found by Yale scientist. The HACNS1 enhancer is thought of as being a “human-specific gene enhancers, which are switches near genes in the human genome.”
 
  Knowing the possibility of our thumb makes us wonder how certain other animals developed their own thumbs. Primates have four categories that divide them based upon their thumbs. There are non-opposable, pseudo-opposable, opposable and opposable long. What causes their classification of thumbs different from ours is the fact that their thumbs do not fully rotate along its axis like our own does. So categories are divided by the amount of independence the thumb has. Other animals with “thumbs” are Giant Pandas (not a actual thumb but a extra bone that functions as one to help them eat bamboo), certain marsupials (in order to climb and gather food) and most birds also have an opposable digit.
 
  Without the thumb or in the case of other animals with thumb like appendages where would they be? Where would we be? Better yet one should ponder with this special adaptation we have what could possible evolve next from it as an adaptation. Will our thumbs slowly change in shape, size or movement? Or will that happen to another species? Who is to actually say what will happen. All we can do is watch what will take place.


Sources:
http://www.primates.com/faq/index.html
http://books.google.com/books?id=5fttVRAHA4MC&pg=PR11&dq=Ankel-Simons,+Friderun+(2007).+Primate+Anatomy+(3rd+ed.).&hl=en&ei=F4zcTNuyKoL78Aaw9JjrCQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CDEQ6AEwAA#v=onepage&q=nonopposable%20thumb&f=false
http://www.molecularstation.com/science-news/2008/09/junk-dna-hacns1-discovery/
http://onlinelibrary.wiley.com/doi/10.1002/ajpa.1330150203/abstract
http://www.ruf.rice.edu/~kemmer/Evol/opposablethumb.html