The difference in terms of services and functions comes from the distribution you are using.
Let me know what you exactly meant by 'Linux we use in embedded systems'.

To understand this thing first of all we must know what is an Embedded System. It is a particular task based system having specific storage space,specific instructions to follow and the limited number of tasks to do.The Linux operating system which we use in Embedded Systems is very particular about the space it consumes as well as the modules it has in its kernel space,being more understandable if we compare the linux kernel which we have in our PC,MAC etc. does have so many modules for the functions which everyone don't use but the manufacturer doesn't know the user's usage domain hence it provides a general purpose operating system kernel with all the functionalities associated with it which may be used my the user(but not always),while in an embedded system, the task is specified as well as the developer knows the task or the domain for which the operating system is to be used sometimes along with the development board upon which it is to be installed. So the developer just includes the functionalities(modules) according to the usage so as to remain specific about the less storage available on that development board. Hope you'll get my answer. Still confused??reply back and i'll make u understand it.