Re: Why doesn't all meat taste the same?

Well Fiona meats do not all taste the same because they are all diiferent 
animals and each animal has its own unique genetic makeup giving it 
different proportions of muscle, fat and body composition.  It even 
depends upon its exercise and feed.  The ratios of salt, water, acids, 
oils, sugars, proteins and fat and the way they're combined all break down 
and combine in a different way upon cooking.  The breakdown process of 
proteins is called denaturation.  These then combine with sugars in the 
meat and begin to brown upon heating.  Meat's flavor largely depends upon 
this crossreaction of sugars and proteins in the browning process called 
the 'Maillard reaction.'  Also different meats have their unique flavor 
proteins known as 'meaty peptides'.
The amount of fat will also determine flavor because aroma and flavor 
molecules dissolve in fat.  This is why beef cuts are more tasty than 
chicken or turkey breast. 
Muscle proportion is another factor for flavor.  Muscle contains compounds 
known as extractives which carry flavor molecules.  That's why chicken 
legs are tastier than chicken breast which gets much less exercise, and 
why brisket is a tasty cut of beef.  
Of course cooking techniques are an important part of flavor.  Those 
methods that preserve the juices of the meat will be the most flavorful.  
Marinating and seasoning will also enhance the flavors and smoking and 
charring add distinctive flavors to meats as well.  However, well done 
meats may be less tasty due to the juices that are lost.
Animals also lend their unique aromas to the makeup of the meat which 
contributes significantly to flavor and taste perception.  The best 
example of this is that unique 'fishy' smell of fish.
For more info read the excellent book by H. McGee called "On Food & 
Cooking".  Hope that helps.