By Definition, A Human Is...


1. A Material Object.
Humans are made up of atoms and molecules arranged in simple to complex forms.

2. A Living Thing.
Humans can grow, reproduce, respond to stimuli and evolve.

3. A Eurkaryote.
Human cells contain a nucleus.

4. An Animal.
Humans are able to move and to take in a digest food. They do not contain chlorophyll or cellulose. Humans reproduce by the fertilization of an egg by a sperm cell.

5. A Metazoan.
Humans are made up of many different kinds of cells. They are highly dependent on one another and are arranged in definite tissue layers. After fertilization a blastula (hollow sphere of cells) develops.

6. A Bilateral.
Humans are largely the same on the left and the right halves of their bodies.

7. A Deuterostome.
As the human embryo is formed, the first opening to appear becomes the anus, and the mouth is formed far from it.

8. A Eucoelomate.
Humans have an outer cell layer (the skin), an inner cell layer (the digestive tract), and a coelom between them. This third layer produces the skeleton, the muscles and non-digestive organs.

9. A Chordate.
Humans have a nerve chord in their back. Embryos have a notochord and gill slits.

10. A Vertebrate.
Humans have a backbone of cartilage and bone.

11. A Gnathostome.
Humans have jaws.

12. A Choanate.
Humans have nasal passages that lead into their mouth.

13. A Tetrapod.
Humans have four limbs. Each limb has one bone close to the body, two farther out, and many more at the end, which form wrist/ankle elements and five (sometimes more) jointed digits.

14. A Reptile (formerly "Amniote").
Human embryos are protected by an amniotic membrane.

15. An Archosauromorph.
In humans more jugal area is anterior to the postorbital process than posterior to it. The squamosal descends to the ventral skull. The dentary contributes to the coronoid process.

16. A Synapsid.
Human skulls have a lateral temporal fenestra. The teeth show some variety in size and shape.

17. A Therapsid.
Humans enlarge the lateral temporal fenestra. Their limbs can raise them above a sprawl and all of the lateral four digits are nearly equal in length.

18. A Cynodont.
Humans have no skull roof bones over their jaw muscles. A secondary palate and wide cheekbones are present. The occipital condyle is double-headed. Incisors are chisel-shaped and posterior teeth have more than one cusp.

19. A Mammal.
Human females have mammary glands that produce milk to nourish the young. Humans have hair, three middle ear bones, a single bone comprising each mandible and only two sets of teeth erupt during a lifetime.

20. A Therian.
Human females give birth to live young.

21. A Eutherian.
Human females have a complex placenta and give birth to fully developed young.

22. A Primate.
Humans have grasping hands, elongated limbs, a shortened snout and forward-directed eyes.

23. An Anthropoid.
Humans have a rounded skull, an enlarged brain, a flattened face, well-developed facial muscles, an uncleft upper lip, close-set eyes, fixed external ears, a thumb that moves independently and a flattened nail on every digit.

24. A Hominoid.
Humans lack a tail and have the ability to brachiate (swing from overhead branches). The chest is wider than deep, the backbone is short and stiff, and the molars have five cusps.

25. A Hominid.
Humans stand erect and the big toe is aligned with the other toes for walking, not grasping. The canine tooth is not fanglike.

26. A Hominine (genus Homo).
Humans have greatly enlarged brains.

27. Of the species Homo sapiens.
Humans have reduced brow ridges and high foreheads.

28. Of the subspecies Homo sapiens sapiens.
Humans have a dome-shaped skull, a protruding nose, a chine and the ability to speak due to a lower larynx.


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