2012-11-22

South American men are APES!

Yes, you read that correctly. All men born in South America are apes. Just consider their posture, their limbs, their hips and their heads, clearly the posture, limbs, hips and heads we see in all apes. How could anyone not see the resemblance?

OK, let's be clear: the title is just a pun to grab your attention. I myself am male and born in South America and I too am an ape. And besides the South American males, so are all other human males and females in the world, and that includes you. We humans are just as much apes as all ducks are birds. Not all apes are humans but all humans are apes, just like not all birds are ducks but all ducks are birds. Ape is a more encompassing group that includes chimpanzees, gorillas, orangutans and humans. Now many people might argue that humans do not belong in this category since "apes" are hairier and have smaller brains than humans. These however are quantitative differences and not qualitative. Humans do have hairs all over their body with the exception of the palms and soles, but the hairs are thinner than that of other apes and our brains are bigger but their make-up is similar to that of other apes. Furthermore, biological taxonomy groups together organisms based on their similarities, not their difference.  The following is an elaboration that is based on a 2003 post to the Usenet group "talk.origins" by L. Aron Nelson (a.k.a "AronRa" from YouTube fame).

Humans are metabolic organisms.

That means that we can harvest and utilize our own energy that is needed for living. We share this trait with all animals, plants, fungi, bacteria, etc. Viruses don't have their own metabolism but depend on the cellular mechanism of host cells to multiply. For this reason many biologists do not consider viruses to be alive.

Humans are eucaryotes.

All the cells in our bodies contain a nucleus (which contains the nuclear DNA) and a number of organelles which have specific cellular functions (like the mitochodria which are essential for the cellular energy utilization and which contain their own DNA). The eucaryotes comprise one of the three domains of the tree of life, and the procaryotes (cells without a nucleus) comprise the other two domains, namely bacteria and archea. The latter were formerly mistaken to be bacteria but molecular biology has determined that they are a domain of their own.

Humans are animals.

Unlike the former two categories, some people have issues accepting this. Their idea of taxonomy is usually "plants, animals and humans", but as stated before, biological taxonomy is driven by similarities, not differences. Humans contain all traits that the animals have in common and that makes us an animal. All animals are heterotroph, which means that we have no means of producing our own energy and depend on killing other live to harvest it. Animals are multicellular (at least in their adult stage) and the cells consist of thin membranes, unlike the other multicellular organisms (plants, fungi and algae) which contain rigid cell walls. Animal cells are contained in collagen and glycoproteins. Not all animals are motile - sponges (porifera) are not - but all multicellular motile organisms are animals. That includes us.

Humans are craniates.

This simply means that we have a skull and a spinal cord. Having a spinal cord also makes us a chordate but unlike us, not all chordates are craniates.

Humans are vertebrates.

This means that our spinal cord is contained in a spine. All animals with a spine contain a skull and a spinal cord, but hagfishes contain a skull and spinal cord without a spine. That includes them in the craniates but not in the vertebrates. The fact that we have a skull with a jaw makes us part of the gnathostomata. There are vertebrates without a jaw (like lampreys) but all craniates with a jaw are vertebrates and thus contain a spine, as do we.

Humans are tetrapods.

We are jawed vertebrates with four limbs. Some tetrapods like snakes and whales have lost some or all of their limbs but these may still be present as vestigial organs and are also visible during part of the embryonic stage. The earliest lobe-finned fishes which seem ancestral to the amphibians (like tiktaalik rosea) were tetrapods as well. Since we are vertebrates with four limbs we qualify as well.

Humans are mammals.

Our females have mammary glands which produce milk to feed the young.We also have three middle-ear bones and our brains contain a neocortex. Most of the mammals give birth to live young except for the momotremes (like the platypus) which lay eggs, and some mammals carry their young in a pouch to complete the fetal stage (the marsupials). Placental mammals have a placenta where the fetus is kept until the end of the fetal stage when the young is born. Humans qualify in the latter category and are thus placental mammals.

Humans are primates.

We have two mammary glands on the chest i.o. on the abdomen, males have a pendulous penis, all limbs have five distinctive digits, the thumbs and big toes have flat nails, we have color vision and an enlarged cerebral cortex and we lack the ability to produce our own vitamin C. It's noteworthy that Carolus Linnaeus, the inventor of the biological taxonomy that is still in use today included humans in the group of primates even though he was a Christian creationist.

Humans are apes.

And here we complete the list with our starting statement. We have shoulder joints that allow for much movement of the arms, we have a bony stub instead of a tail, we have a dentition that includes incisors, canines, premolars and molars. We share these traits with all other apes along with all other traits that they have in common. That makes us an ape.

Note that both morphologically and genetically chimpanzees and humans have more in common with each other than each has in common to the gorilla. So if it makes sense to qualify both the chimpanzee and the gorilla as apes, it makes no sense to exclude humans from that group.

Next time someone makes you out to be an ape, confirm it and hit back by making him or her out to be a fungi, or next time someone claims not to be descendent to an ape, specify that you are and respectfully question if they happen to be descendent from a turtle instead.

Sources used:

AronRa's 2003 posting:
http://www.talkorigins.org/origins/postmonth/may03.html
and his superb page on taxonomy:
http://locolobo.org/Taxonomy.html

Tree of Life web project:
http://tolweb.org/tree/phylogeny.html

The source of all knowledge:
http://www.wikipedia.org/

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