So you would choose the life of the cow. No, actually you will claim that is not what you are saying at all, although clearly that is what you are implying. I know that game.
So the human is destructive to the environment and therefore his life has less value than that of the cow. Now, that implies that the condition of the environment matters. There has to be a reason why the condition of the environment matters. What is it? Is it because life in general has to be preserved? I hardly think over the scope of millions of years that anything we do is going to snuff out life. It's fairly likely that Earth has experienced both its crust being seared by asteroid impact so that rock was vaporized into the atmosphere, and its being totally enveloped in ice. Yet life perseveres.
So then the condition of the environment right now or at least in the short to medium term matters, then? Well, why would that be? Is it because we must place supreme value on plant and animal life currently in existence, so much so that the value of a cow exceeds that of a human being?
Did your professor really mean that the environment must be protected in order to preserve humanity in general, which would imply that human beings have some inherent value that we should care about?
And you just take that for granted like it is a given. There is such a thing as being so open-minded that one's brains fall out. This is one of those cases.
In the past, Westerners took it for granted that theirs was the greatest, most advanced, most civilized culture and everyone less was either in some lesser form of civilization or outright savage. Repudiating this kind of chauvinism seems now to an obvious requirement for dispassionate study of people groups. Starting off with the assumption that civilization X is a bunch of barbaric godless heathens tends to color one's conclusions.
But to take that kind of scientific discipline and generalize it like it is some kind of moral axiom is ridiculous. Everyone has values and beliefs and evaluates the world around them in terms of those values and beliefs. For example, if a person believes in human rights, it would be ridiculous to say that he could not evaluate this society or that one in terms of its respect for human rights. If one person looks and says, "Hey, the Sudan commits mass slaughter against its minority groups and Sweden doesn't, so in terms of treatment of minorities Sudan is worse," and you respond, "You can't say that because that is being ethnocentric" that doesn't make you a enlightened bright -- it makes you an incoherent moron.
It doesn't make much sense to measure something like a Human Development Index if one cannot go so far as to say that a higher number is better, much less that trying to raise the number is a worthwhile goal.
And see, here's what happens when you start off with a stupid assumption. You took for granted that it is an indisputable moral axiom that no culture is better or worse than another, and now extend that to claim that is an indisputable moral axiom that no species has greater or lesser value than another. Non sequitur.
So if animal life is the same as human life, then if I see a cheetah run down an impala in order to eat it, has the cheetah committed a crime? Of course not, you'll say, that's part of the natural order. OK, so if humans should avoid being species-centric, then shouldn't we consider ourselves part of the natural order? Well, no, you'll say, we're different because we're sentient beings, accountable to morals and ethics, whose rational faculties have allowed us such technology as to have moved beyond the natural order. Oh, so then are we fundamentally different or are we not?
You might want to give a few more details about your flood story, for it is tremendously misleading. People might tend to think you are talking about residents who placed their poor helpless pets in the basement to die while they fled from the flood, which of course is absolutely not what happened. But I see your simplistic thinking -- animals put someplace by humans died, therefore humans bad.
Really? There are no prehistoric people who were hunters? When the term "hunter-gatherers" was coined, was it referring to how early humans "hunted" for berries before they gathered them?
How exactly did human beings come to be omnivrous if they didn't evolve that way? Can I really eat anything I want? Can I eat leaves off a tree like a giraffe? Can I eat a 2x4 like a termite? Hey, why is it that Europeans can drink cow's milk while most other people groups are lactose-intolerant? Is it because Europeans through the sheer force of will chose to drink cow's milk?
You are doing a great job of convincing me of the enormous difference between the pure sciences like biology, chemistry, physics, and the like and studies like anthropology, history, economics, which have a teensy bit of evidentiary science mixed together with large helpings of groundless conjecture and untethered ideology masquerading as "science."
Please tell me you did not just use the storyline from a prime-time science-fiction drama to make a serious point about the end of civilization. The Valenzetti equation is not, um, real.