Two excerpts from the Catechism of the Catholic Church, respectively on the visible world and on respect for the integrity of creation.
THE VISIBLE WORLD
337 God himself created the visible world in all its richness, diversity and order. Scripture presents the work of the Creator symbolically as a succession of six days of divine “work”, concluded by the “rest” of the seventh day.  On the subject of creation, the sacred text teaches the truths revealed by God for our salvation,  permitting us to “recognize the inner nature, the value and the ordering of the whole of creation to the praise of God.” 
338 Nothing exists that does not owe its existence to God the Creator. The world began when God’s word drew it out of nothingness; all existent beings, all of nature, and all human history are rooted in this primordial event, the very genesis by which the world was constituted and time begun. 
339 Each creature possesses its own particular goodness and perfection. For each one of the works of the “six days” it is said: “And God saw that it was good.” “By the very nature of creation, material being is endowed with its own stability, truth and excellence, its own order and laws.”  Each of the various creatures, willed in its own being, reflects in its own way a ray of God’s infinite wisdom and goodness. Man must therefore respect the particular goodness of every creature, to avoid any disordered use of things which would be in contempt of the Creator and would bring disastrous consequences for human beings and their environment.
340 God wills the interdependence of creatures. The sun and the moon, the cedar and the little flower, the eagle and the sparrow: the spectacle of their countless diversities and inequalities tells us that no creature is self-sufficient. Creatures exist only in dependence on each other, to complete each other, in the service of each other.
341 The beauty of the universe: The order and harmony of the created world results from the diversity of beings and from the relationships which exist among them. Man discovers them progressively as the laws of nature. They call forth the admiration of scholars. The beauty of creation reflects the infinite beauty of the Creator and ought to inspire the respect and submission of man’s intellect and will.
342 The hierarchy of creatures is expressed by the order of the “six days”, from the less perfect to the more perfect. God loves all his creatures  and takes care of each one, even the sparrow. Nevertheless, Jesus said: “You are of more value than many sparrows”, or again: “Of how much more value is a man than a sheep!” 
343 Man is the summit of the Creator’s work, as the inspired account expresses by clearly distinguishing the creation of man from that of the other creatures. 
344 There is a solidarity among all creatures arising from the fact that all have the same Creator and are all ordered to his glory:
May you be praised, O Lord, in all your creatures, especially brother sun, by whom you give us light for the day; he is beautiful, radiating great splendor, and offering us a symbol of you, the Most High. . .
May you be praised, my Lord, for sister water, who is very useful and humble, precious and chaste. . .
May you be praised, my Lord, for sister earth, our mother, who bears and feeds us, and produces the variety of fruits and dappled flowers and grasses. . .
Praise and bless my Lord, give thanks and serve him in all humility. 
345 The sabbath – the end of the work of the six days. The sacred text says that “on the seventh day God finished his work which he had done”, that the “heavens and the earth were finished”, and that God “rested” on this day and sanctified and blessed it.  These inspired words are rich in profitable instruction:
346 In creation God laid a foundation and established laws that remain firm, on which the believer can rely with confidence, for they are the sign and pledge of the unshakeable faithfulness of God’s covenant.  For his part man must remain faithful to this foundation, and respect the laws which the Creator has written into it.
347 Creation was fashioned with a view to the sabbath and therefore for the worship and adoration of God. Worship is inscribed in the order of creation.  As the rule of St. Benedict says, nothing should take precedence over “the work of God”, that is, solemn worship.  This indicates the right order of human concerns.
348 The sabbath is at the heart of Israel’s law. To keep the commandments is to correspond to the wisdom and the will of God as expressed in his work of creation.
349 The eighth day. But for us a new day has dawned: the day of Christ’s Resurrection. The seventh day completes the first creation. The eighth day begins the new creation. Thus, the work of creation culminates in the greater work of redemption. The first creation finds its meaning and its summit in the new creation in Christ, the splendor of which surpasses that of the first creation. 
RESPECT FOR THE INTEGRITY OF CREATION
2415 The seventh commandment enjoins respect for the integrity of creation. Animals, like plants and inanimate beings, are by nature destined for the common good of past, present, and future humanity.  Use of the mineral, vegetable, and animal resources of the universe cannot be divorced from respect for moral imperatives. Man’s dominion over inanimate and other living beings granted by the Creator is not absolute; it is limited by concern for the quality of life of his neighbor, including generations to come; it requires a religious respect for the integrity of creation. 
2416 Animals are God’s creatures. He surrounds them with his providential care. By their mere existence they bless him and give him glory.  Thus men owe them kindness. We should recall the gentleness with which saints like St. Francis of Assisi or St. Philip Neri treated animals.
2417 God entrusted animals to the stewardship of those whom he created in his own image.  Hence it is legitimate to use animals for food and clothing. They may be domesticated to help man in his work and leisure. Medical and scientific experimentation on animals is a morally acceptable practice if it remains within reasonable limits and contributes to caring for or saving human lives.
2418 It is contrary to human dignity to cause animals to suffer or die needlessly. It is likewise unworthy to spend money on them that should as a priority go to the relief of human misery. One can love animals; one should not direct to them the affection due only to persons.
- Gen 1:1-2:4.
- Cf. Dei Verbum 11.
- Lumen Gentium 36 § 2.
- Cf. St. Augustine, De Genesi adv. Man. 1,2,4: PL 34,175.
- Gaudium et Spes 36 § 1.
- Cf. Ps 145:9.
- Lk 12:6-7; Mt 12:12.
- Cf. Gen 1-26.
- St. Francis of Assisi, Canticle of the Creatures.
- Gen 2:1-3.
- Cf. Heb 4:3-4; Jer 31:35-37; 33:19-26.
- Cf. Gen 1:14.
- St. Benedict, Regula 43, 3: PL 66, 675-676.
- Cf. Roman Missal, Easter Vigil 24, prayer after the first reading.
- Cf. Gen 128-31.
- Cf. Centesimus Annus 37-38.
- Cf. Mt 6:26; Dan 3:79-81.
- Cf. Gen 2:19-20; 9:1-4.