Animals are ruled by the laws of nature and experience evolutionary changes through the guidance of natural selection and adaption. This is what Darwin came to understand in his Theory of Evolution. I can accept that based on a number of details contained with in the Bible.
On the other hand modern man does not fall into this category because he was created in the likeness of God. A God who does not change.
Let's look at the scriptures below: Green needs to be paid special attention to. Blue is God talking.
Genesis 1:11-13 (New International Version)
Then God said, "Let the land produce vegetation: seed-bearing plants and trees on the land that bear fruit with seed in it, according to their various kinds." And it was so. The land produced vegetation: plants bearing seed according to their kinds and trees bearing fruit with seed in it according to their kinds. And God saw that it was good. And there was evening, and there was morning—the third day.
Genesis 1:20-23
And God said, "Let the water teem with living creatures, and let birds fly above the earth across the expanse of the sky." So God created the great creatures of the sea and every living and moving thing with which the water teems, according to their kinds, and every winged bird according to its kind. And God saw that it was good. God blessed them and said, "Be fruitful and increase in number and fill the water in the seas, and let the birds increase on the earth." And there was evening, and there was morning—the fifth day.
Genesis 1:24-25
And God said, "Let the land produce living creatures according to their kinds: livestock, creatures that move along the ground, and wild animals, each according to its kind." And it was so. God made the wild animals according to their kinds, the livestock according to their kinds, and all the creatures that move along the ground according to their kinds. And God saw that it was good.
God had established the rules by which everything was to be played out. Plants on dry land, plants in the oceans. Birds, fish, and animals both sea and land. Then God created man.
Genesis 1:26-27
Then God said, "Let us make man in our image, in our likeness, and let them rule over the fish of the sea and the birds of the air, over the livestock, over all the earth, and over all the creatures that move along the ground."
So God created man in his own image, in the image of God he created him; male and female he created them.
There we can see a big difference "according to their kinds" and "in his own image" that difference shows a divide in the design of animal and man. This scripture also uses man in a plural form sense when the scripture reads "and let them rule..." which tells me multiple humans are existing.
Now simply speaking time is only relevant to the place you are standing and how you measure it. According to Einstein it was. His theory of time slowing down or speeding up is based on the amount of gravity and several other things that are present in his General Theory of Relativity. God was there before the creation, so time was based on his "God clock" not the Earth's 24 hour day that we use. So anyone that lays claim that the Earth was created 6000 Earth years ago is pretty much wrong, even in the eyes of the Bible. Read this:
Psalm 90:4
For a thousand years in your sight are like a day that has just gone by, or like a watch in the night.
2 Peter 3:8 (New International Version)
But do not forget this one thing, dear friends: With the Lord a day is like a thousand years, and a thousand years are like a day.
God is not bound by time like we are. If you look at this link below it show evidence of humanoid creatures that date back before the Bible indicates. The God Clock solves this problem of carbon dating.
http://www.pbs.org/wgbh/evolution/humans/humankind/o.html
I'm not sure if Moses was trying to do some back dating or fine tuning because the eraser wasn't invented yet but we see some additional information being added here in Genesis Chapter 2.
Genesis 2:4
This is the account of the heavens and the earth when they were created. When the LORD God made the earth and the heavens-
Genesis 1:26-27 talk about the creation of man as a species. Then we have the creation of Adam in Genesis 2:7. But why? My guess would be this creation was special.
Genesis 2:7
The LORD God formed the man from the dust of the ground and breathed into his nostrils the breath of life, and the man became a living being
"the man" and "his nostrils" implies one man was made. A single person, a special person. But just previously we seen in Genesis 1:26-28 man was already formed. Again we're on God time so understand the Bible shows man already existed in form when Adam was specially created. I wasn't there 5000 years ago when the Bible was being written and later assembled. But to me, if Genesis reads in chronological order, it shows that the human race already existed when the perfect Adam was created. Cain, who is Adam's son, after he kills his brother says...
Genesis 4:14
"Today you are driving me from the land, and I will be hidden from your presence; I will be a restless wanderer on the earth, and whoever finds me will kill me."
He feared others might kill him because other humans had already been on the land.
Genesis 4:17
Cain lay with his wife, and she became pregnant and gave birth to Enoch. Cain was then building a city, and he named it after his son Enoch
Again, I'm no expert but to read the Bible with the understanding of God's clock and Genesis being in chronological order. We can say Cain's wife was already on planet Earth.
With this understanding that there was TWO lines of humans, One created with a divine purpose and another already living under the laws of nature.
My theory is, God wanted to create another human race one that had direct contact with their creator. Because the first humans were not doing well with the guidance of nature. I imagine God seen a greater potential in humans so he created Adam. Otherwise they were basically just another animal in the great circle of life. (Que the lion king music.) Not long after the creation of second humans God destroyed the entire world in the great flood. To wipe the humans and early creations away who failed to come to God through Adam and Eve. The creations who knew God personally.
This leaves lots of open questions on God's will and power. I've got theories on those that fit into this scenario. More to come, but not in this post.