Why do rich and poor countries trade in different goods and why do rich countries trade in similar goods with other rich countries? I think that differences in climate is one key factor but I think it could be explained by David Ricardo's theory on international trade differences???
The key is production capabilities, not relative specialization. In words of Hausmann and Rodrik (2006):


  The idea that rich (poor) countries tend to export goods exported by other rich
  (poor) countries is quite obvious and is compatible with many possible theories. For
  example, in conventional trade theory a la Heckscher-Ohlin, countries export products
  that are more intensive in the factors of production that are relatively abundant at home.
  As development takes place, physical, human and institutional capital is accumulated and
  the products countries export become more intensive in these factors. ...
  
  Labor-abundant countries trade with land- or capital-abundant countries in order to
  acquire more efficiently the goods that are intensive in the factors they don’t have. The
  transition between goods is of little significance: they are the passive consequence of
  changing factor endowments.