Service and Sacrifice

Dear Teacher,

I am currently reading the article: Bhavachakra - Service and Sacrifice.

It is said:
Sacrifice generally to mean charity, to serve others, to help humanity, to give up our own interests and desires and longings in order to serve and aid others, to put others before ourselves, to emulate the great masters who did not seek to feed themselves, their desires, their name, their reputation, but only to serve others.

The emphasize of this service/sacrifice/generous action, is for other Human. But why is it Human? Why is it not for other creatures?

We, human, are very able to preserve ourselves. We were born with higher intelligence, which is a huge advantage over other creatures. In fact, we could, and we already did everything in our ability, to preserve our kind. For food, for health, for welfare, for amusement, or for prolonging-life reason, we explored and exploited Earth, to the extend of other creatures' extinction, leaving behind many damaged polluted areas. All of these, were done in the name of Human's life preservation. And we are, indeed, well preserved. Our population on this Earth, is going to reach 8 billions, and more of us, are coming with every second. With these many bodies to feed and to take care of, we will then further exploit more resources, or tamper with more genes/cells/atoms to create continuous food for our kind. And we will be populating this Earth to the fullest, and maybe other Earths in future, while other creatures' population will be reduced faster and faster, except for species we choose to let live to supply our food.

So, with our current intelligence-advantage and fast population growth, why is our service-sacrifice-generous action, still have to be aimed for other Human? To preserve more Human? How can this be considered good? Or right? Shouldn't we take into account the balance of things? Kindly enlighten.

Thanks, Noni