“Surprisingly, attempting to define man in simple terms is not an easy task. There are many things that could be included in the definition and a line has to be drawn somewhere. I’ve chosen to define man according the very first use of the term in the Bible.
In Genesis 1 we find at least four defining characteristics that teach us whatman is:
1) As most English Bibles make clear in their footnotes, the term man in Hebrew (adam) is very closely related to the Hebrew word for earth or ground (adama). This is an intentional and ongoing reminder that God formed man “from the dust of the ground” (Genesis 2:7), which teaches us that man is an integrated, natural member of God’s created world.
2) Man is created “in the image of God” (Genesis 1:27); which means that, along with being a natural member of God’s creation, he is also a supernatural being. Having been made in the image of God, he carries the imprint of the supernatural Creator, the God who exists and operates in ways that exceed the natural order he has created. James 3:9 affirms that this divine image has not been removed even after man’s fall from his original state of sinlessness.
3) Man has dominion over creation. God makes this clear in his original mandate to man: “let them have dominion over [everything else I’ve created]” (Genesis 1:26). One of the main implications of being created in God’s image is that we share in his dominion over other created things. But note how our first point affects this: since we are also a member of creation, we serve ourselves best when we steward the rest of creation well.
4) Man is male and female. “In the image of God he created him; male and female he created them” (Genesis 1:27). This verse teaches us that a central component of what God intended when he made man is that we would exist as two intentionally distinct sexes.
In summary, then, Genesis 1 teaches us that man is the one creature made male and female, from the earth, in the image of God, with dominion over the rest of creation.”
-Tim Challies, http://www.challies.com/resources/the-essential-man