This is an old essay from Talk.Origins:
A giraffe has never given birth to a horse, as far as we know it. An ape has never given birth to a man. I will give a million bucks to anyone who can observe an ape giving birth to a human. Even your mother, if such were true.
You are a metabolic organism.
As such, you are basically a collection of replicative proteins that function according to metabolic chemical reactions and processes. A virus is similar, in that it too is a replicative protein complete with mutable DNA and RNA, just as you have. But viruses lack metabolism, and so may not be considered to be alive in the same manner that you definitely are.
You are a eukaryote.
All remaining organic life is distinguished by structural differences at the cellular level between different groups of prokaryotes (which are essentially bacteria) and the eukaryotes (us). Unlike bacterial or viral cells, our cells have a nucleus. Hence, all non-viral / bacterial lifeforms are as we are; eukaryotes.
You are an animal.
Now I've heard a few creationists argue that there are plants and there are animals and then there are human beings. And that none of them are actually related to one another other than through a common creator. They adamantly argue that we are not animals, as if there is some insult in that association. But you are one of only about a half-dozen kingdoms of eukaryotic life forms. Unlike those of most other biological kingdoms, you are incapable of manufacturing your own food and must compensate for that by ingesting other organisms. In other words, your most basic structure requires that you cause death to other living things. Otherwise, you wouldn't have a means of digestion. This, along with some very specific anatomical differences in the chemical composition of our metazoic cells, are the factors that define and distinguish an animal like yourself from all other kingdoms of life. Given the alternative choice between plants, molds, or fungus, animalia should seem reasonable even to the most adamant fundamentalist.
You are a chordate.
You have a spinal chord and every other minute physical distinction of that classification. You also have a skull, which classifies you as a craniate. Note: Not all chordates have skulls, or even bones of any kind. Once one of the chordates has enough calcium deposited around the brain to count as a skull, all of its descendants will share that. This is why absolutely all animals with skulls have spinal chords. And that is yet another commonality that implies common ancestry as opposed to common design.
You are a vertebrate.
Like all mammals, birds, dinosaurs, reptiles, amphibians, and most fish, you have a spine. Not everything with a spinal cord has a spine to put it in, but everything with a spine has a spinal cord in it, implying common descent.
Every animal that has a jaw and teeth (Gnathostomata) also has a backbone. And of course, you have both as well, again implying common descent.
You are a tetrapod.
You have only four limbs. So you are like all other terrestrial vertebrates including frogs. Even snakes and whales are tetrapods in that both still retain vestigial or fetal evidence of all four limbs. This is yet another consistent commonality implying a genetic relationship. There certainly is no creationist explanation for it.
You are synapsid.
Unlike turtles (which are anapsid) and "true" reptiles, dinosaurs and birds (which are all diapsid), your skull has only one temporal fenestra, a commonality between all of the vast collection of "mammal-like reptiles", which are now all extinct without any Biblical recognition or scriptural explanation either for their departure or their presence in the first place.
You are a mammal.
You are homeothermic (warm-blooded), follicle-bearing and have lactal nipples. And of course, not all synapsids are or were mammals, but all mammals are synapsid, implying common descent.
You are eutherian.
Or more specifically, you are a placental mammal, like most other lactal animals from shrews to whales. All eutherians are mammals, but not all mammals are eutherian. There are six major divisions in mammalia, only three of which still exist; those that hatch out of eggs like reptiles (monotremes), marsupials, that are born in the fetal stage and complete their development inside the mother's pouch, and those that developed in a shell-like placenta and were born in the infant stage, as you were. Your own fetal development seems to reveal a similar track of development from a single cell to a tadpole-looking creature, then growing limbs and digits out of your finlike appendages, and finally outgrowing your own tail. Some would consider this an indication of ancestry. Especially since fetal snakes, for example, actually have legs, feet, and cute little toes, which are reabsorbed into the body before hatching, implying common descent.
You are a primate.
You have five fully-developed fingers and five fully-developed toes. Your toes are still prehensile and your hands can grasp with dexterity. You have only two lactal nipples and they are on your chest as opposed to your abdomen. These are pointless in males, which also have a pendulous penis and a well-developed ceacum or appendix, unlike all other mammals. Although your fangs are reduced in size, you do still have them along with some varied dentition indicative of primates exclusively. Your fur is thin and relatively sparse over most of your body. And your claws have been reduced to flat chitinous fingernails. Your fingers themselves have distinctive print patterns. You are also susceptible to AIDS and are mortally allergic to the toxin of the male funnel web spider of Australia (which is deadly to all primates, but only dangerous to primates, which is why you'd better beware of these spiders). And unlike all but one unrelated animal in all the world, your body cannot produce vitamin-C naturally and must have it supplemented in your diet, just as all other primates do. Nearly every one of these individual traits are unique only to primates exclusively. There is almost no other organism on Earth that matches any one of these descriptions separately, but absolutely all of the lemurs, tarsiers, monkeys, apes, you, and I match all of them at once perfectly, implying common descent.
You are an ape.
Your tail is merely a stub of bones that don't even protrude outside the skin. Your dentition includes not only vestigial canines, but incisors, cuspids, bicuspids, and distinctive molars that come to five points interrupted by a "Y" shaped crevasse. This in addition to all of your other traits, like the dramatically increased range of motion in your shoulder, as well as a profound increase in cranial capacity and disposition toward a bipedal gait, indicates that you are not merely a vertebrate cranial chordate and a tetrapoidal placental mammalian primate, but you are more specifically an ape, and so was your mother before you.
Genetic similarity confirms morphological similarity rather conclusively, just as Charles Darwin himself predicted more than 140 years ago. While he knew nothing of DNA of course, he postulated that inheritable units of information must be contributed by either parent. He rather accurately predicted the discovery of DNA by illustrating the need for it. Our 98.4% to 99.4% identical genetic similarity explains why you have such social, behavioral, sexual, developmental, intellectual, and physical resemblance to a bonobo chimpanzee. Similarities that are not shared with any other organism on the planet. Hence you are both different species of the same literal family. In every respect, you are nearly identical.