I think that the fundamental difference between both types of discrimination relates to where the exclusion takes place. In the world of racism, there is a definite division of racial identity amongst humans. The follower of racism believes in some type of hierarchy of races. There is a definite "higher" and "lower" distinction between races and superiority is based on racial identity. Those who advocate racism do so in the established glorification of one race over another or in the destruction of a particular race, seeing it as a potential threat. The division point is drawn within human beings because the racist does not see a particular race as being human.
In this, one can see how species-ism bears some similarity. In this form of discrimination, animals and other organisms are seen as secondary to human beings. Essentially, the speciest believes that as a human being, they are able to do exert control and dominion over other members of different species because those creatures are not human. Ruder defines it in this manner:
the belief that we are entitled to treat members of other species in a way in which it would be wrong to treat members of our own.
In this conception of discrimination, humanity is seen as representing power over another species. Both terms refer to a form of discrimination and exclusion of another entity, both within the human race and outside of it.