Can my early-2008 Macbook Pro run OS X Mavericks?
Yes, it can. According to Apple these are minimal system requirements:


  To install Mavericks, you need one of these Macs:
  
  Mac (Mid-2007 or later)
  
  MacBook (13-inch Aluminum, Late 2008), (13-inch, Early 2009 or later)
  
  MacBook Pro (13-inch, Mid-2009 or later),
  
  MacBook Pro (15-inch or 17-inch, Mid/Late 2007 or later)
  
  MacBook Air (Late 2008 or later)
  
  Mac mini (Early 2009 or later)
  
  Mac Pro (Early 2008 or later)
  
  Xserve (Early 2009)
  
  Your Mac also needs:
  
  OS X Mountain Lion, Lion, or Snow Leopard v10.6.8 already installed 2
  GB or more of memory 8 GB or more of available space