The Judeo-Christian responses are clear: Nature has been created for man's use; and on its own, without man, it has no meaning. Dolphins are adorable because human beings find them adorable. Without people to appreciate them or the role they play in the earth's ecosystem to enable human life, they are no more adorable or meaningful than a rock on Pluto.Yeah there's all that about dominion over the earth and whatnot, but the Bible really does go past Genesis.
If you'll turn to Job, you'll find this lovely passage of Chapter 38:
25: "Who has cleft a channel for the torrents of rain, and a way for the thunderbolt,and read through Chapter 39:
26: to bring rain on a land where no man is, on the desert in which there is no man;
27: to satisfy the waste and desolate land, and to make the ground put forth grass?
28: "Has the rain a father, or who has begotten the drops of dew?
29: From whose womb did the ice come forth, and who has given birth to the hoarfrost of heaven?
30: The waters become hard like stone, and the face of the deep is frozen.
31: "Can you bind the chains of the Plei'ades, or loose the cords of Orion?
32: Can you lead forth the Maz'zaroth in their season, or can you guide the Bear with its children?
33: Do you know the ordinances of the heavens? Can you establish their rule on the earth?
34: "Can you lift up your voice to the clouds, that a flood of waters may cover you?
35: Can you send forth lightnings, that they may go and say to you, `Here we are'?
36: Who has put wisdom in the clouds, or given understanding to the mists?
37: Who can number the clouds by wisdom? Or who can tilt the waterskins of the heavens,
38: when the dust runs into a mass and the clods cleave fast together?
39: "Can you hunt the prey for the lion, or satisfy the appetite of the young lions,
40: when they crouch in their dens, or lie in wait in their covert?
41: Who provides for the raven its prey, when its young ones cry to God, and wander about for lack of food?
1: "Do you know when the mountain goats bring forth? Do you observe the calving of the hinds?This is God telling Job to shut up and think seriously about the world around him. This world wasn't made for man, it was made for God. The majesty of these things isn't for the benefit of our puny and incomplete understanding.
2: Can you number the months that they fulfil, and do you know the time when they bring forth,
3: when they crouch, bring forth their offspring, and are delivered of their young?
4: Their young ones become strong, they grow up in the open; they go forth, and do not return to them.
5: "Who has let the wild ass go free? Who has loosed the bonds of the swift ass,
6: to whom I have given the steppe for his home, and the salt land for his dwelling place?
7: He scorns the tumult of the city; he hears not the shouts of the driver.
8: He ranges the mountains as his pasture, and he searches after every green thing.
9: "Is the wild ox willing to serve you? Will he spend the night at your crib?
10: Can you bind him in the furrow with ropes, or will he harrow the valleys after you?
11: Will you depend on him because his strength is great, and will you leave to him your labor?
12: Do you have faith in him that he will return, and bring your grain to your threshing floor?
13: "The wings of the ostrich wave proudly; but are they the pinions and plumage of love?
14: For she leaves her eggs to the earth, and lets them be warmed on the ground,
15: forgetting that a foot may crush them, and that the wild beast may trample them.
16: She deals cruelly with her young, as if they were not hers; though her labor be in vain, yet she has no fear;
17: because God has made her forget wisdom, and given her no share in understanding.
18: When she rouses herself to flee, she laughs at the horse and his rider.
19: "Do you give the horse his might? Do you clothe his neck with strength?
20: Do you make him leap like the locust? His majestic snorting is terrible.
21: He paws in the valley, and exults in his strength; he goes out to meet the weapons.
22: He laughs at fear, and is not dismayed; he does not turn back from the sword.
23: Upon him rattle the quiver, the flashing spear and the javelin.
24: With fierceness and rage he swallows the ground; he cannot stand still at the sound of the trumpet.
25: When the trumpet sounds, he says `Aha!' He smells the battle from afar, the thunder of the captains, and the shouting.
26: "Is it by your wisdom that the hawk soars, and spreads his wings toward the south?
27: Is it at your command that the eagle mounts up and makes his nest on high?
28: On the rock he dwells and makes his home in the fastness of the rocky crag.
29: Thence he spies out the prey; his eyes behold it afar off.
30: His young ones suck up blood; and where the slain are, there is he."
If it were all for man, why the hell would God "bring rain on a land where no man is, on the desert in which there is no man"?
Because it isn't all for us, you petty, trite, stuckup, half-literate putz.
I'll let Dr. Myers and Jesse handle the rest.
FYI, a great (if dated) treatment of Job from an environmentalist perspective is The Comforting Whirlwind of Creation: God, Job, and the Scale of Creation by Bill McKibben. It isn't a religious book, but it does lean heavily on the Bible for intuition into the human mind.