How Phylogeny Proves Evolution (And How You Could Prove it Wrong)

When I encounter creationists on social media I find their objections to evolution to be rather simpleminded. To put it bluntly, anybody who doesn't *believe* in evolution simply doesn't doesn't understand it. I'll start this blog post with a few samples of silly rebukes, answering the questions ephemerally and pragmatically, and then I'll proceed to my post on phylogeny.

If evolution were true, where did life come from?
The theory of evolution does not stake a claim on how life started or from where it came, nor does it depend on any one answer being true. Therefore, even if God existed and created life, evolution would still be true. The theory of evolution describes how life changes over time, and never tries to explain how it started. This is in no way a chink in its armor--the evidence for evolution is bountiful.

Show me the evidence for evolution, then.
Anybody who needs to ask for the evidence has never tried to search for it, or, more likely, they've been shown it and ignored it. The theory of evolution is evinced in the fossil record, in DNA analysis, by comparing phenotypes of related species of organisms (including plants and animals), and can be observed easily today. Scientists discover dozens of new species of organisms every year, and whenever a speciation event is observed, THAT'S observation of evolution. Evolution can be proven using genealogy, bio-chemistry, geology, evolutionary psychology, zoology, anthropology, ecology, oceanography, taxonomy, embryology, herpetology, botany, mycology, and morphology. It is true that the number of fossils needed to prove evolution is zero, but in spite of that fact, there are hundreds of thousands of fossils showing gradual changes between extant and extinct clades of life.

What is evolution, anyway?
As mentioned above, the theory of evolution is meant to explain how life changes over time. In more scientific terms, evolution can be defined as a change in allele frequency over time. An allele is an inheritable trait--evolution could not work without the premise that lifeforms inherit traits from their parents with slight modifications. Some of these modifications are beneficial, most are not. Over a very long time, the slight modifications can add up to huge changes and new species being born.

You keep saying "the theory of evolution." That proves it isn't true. It's just a theory.
"Just a theory" is an incredibly ignorant complaint. In science, "theory" doesn't have the same definition it has colloquially--it isn't a guess. A scientific theory is a very well supported explanation of a fact. Theories never get promoted to facts or laws. A theory is the pinnacle of scientific achievement--it is a comprehensive explanation for a large set of related observations and facts, and scientific theories usually include laws and facts. For example, Mendel's Law is encompassed in the theory of evolution. You can think of a scientific theory as a bucket, and inside that bucket are bundles of facts, observations, laws, accurate predictions, evidence, and experiments that have been duplicated by many other scientists who fact-check the work of others during peer review.

So, give me an example of when a cow gave birth to a cat, genius (or one kind giving birth to another kind).
This is a blatant misunderstanding of biological evolution. Remember, organisms inherit traits from their parents with slight modification, so never would we expect to see a 600lb grass eating, hooved, bovine with horns give birth to a 12lb carnivorous feline with sharp claws. Think smaller. Think if I stood on the beach in San Diego and stepped one inch per day to the east. The change in my position would be hardly noticeable. You'd probably be able to tell that I moved several feet (ahem, microevolution), but I wouldn't make it out of the city in your lifetime. It would take me 63,360 days to move one mile. That's more than 173 years. Assuming I had eternal life, I'd eventually make it to Phoenix, and then Dallas, Atlanta, and finally end up in Charleston, South Carolina, 424,251.5 years later (Hello, macroevolution!). So, saying you accept microevolution but not macroevolution is like saying you believe I can walk one inch, or 10 inches or even 63,360 inches, but it's impossible to walk one mile. It's ridiculous.

One more thing before we get to phylogeny, and that's dealing with the word kind. That isn't a word in biology, so it won't be used here. Kind is creationist speak. Conveniently, they can't define it, and when they try, they can't stay consistent or agree with each other. Is "kind" at the Genus level, or Family? Or is it higher up than that? Evolutionary biologists use the word clade which is easily definable as any group of related species. For example, you, your siblings, and your parents are a clade, but you can make the clade even bigger if you include your cousins, aunts, uncles, and grandparents. In phylogeny, a clade can exist at any taxonomic level. Mice and palm trees form a very large clade of eukaryotes that would also include all other animals and plants. Cows and cats are in the Mammalian clade. That means they are both mammals. Almost every creationist would agree with the statement that cats and cows are both mammals, but they probably don't realize that by admitting it they are describing phylogeny, which proves that evolution is a fact. Of course, they don't understand this, because they neither understand evolution, phylogeny, or science. My hope is that this blog helps.

Phylogeny is a branch of phylogenesis, which Google defines as "the evolutionary development and diversification of a species or group of organisms, or of a particular feature of an organism." Phylogeny is a description of the "tree of life." I'll stick with cats, more generally, Felidae, for the rest of this blog post. Below is the phylogenetic tree for cats.

Phylogeny for the family Felidae

All these species of felines are related to each other, descended from a common ancestor in the same way that you are related to very distant cousins because you both descended from the same set of grandparents many generations ago. I've personally never encountered a creationist who would disagree with that. The above phylogeny tree shows how those relations came about, grouping the animals into clades. For example, cougars and cheetahs are more closely related to each other as Pumas, than they are to house cats (Felis), even though they are both in the genus Lynx, which includes bobcats. Ocelot split off from Lynx, but both are in the Leopardis clade. Leopards and Panthers are both in the family Felidae. Notice that Felidae and Canidae are both in the order of Carnivora. Canidae (Canines) include dogs and wolves. 

This doesn't mean there was a wolf who gave birth to a cat, but it does mean that wolves and house cats are related to each other, as Carnivora. Since wolves and housecats are both placental mammals with cone shaped "canine" teeth and claws for hunting prey, along with four or more toes (among other shared traits) they are classified as carnivores. 

One especially important point needs to be made here, because it's one that almost nobody who misunderstands evolution ever seems to notice or comprehend. Organisms can split off to form new clades, but they ALWAYS  remain in the clades they inherited from their parents. House cats are classified as such (image from Wikipedia):

What does this mean? Let's walk through it step-by-step. 

House cats (Felis catus) are animals belonging to the Animal Kingdom. There are many phylums of animals; chordates, arthropods, mollusks, plus more, and cats happen to be chordates, but they are still animals and chordates are still related to arthropods and mollusks. 

There are several classes of chordates; mammals, reptiles, amphibians, birds, plus more, and cats happen to be mammals, but they are still chordates, and mammals are still related to reptiles, amphibians, and birds.

There are several orders of mammals; carnivores, rodents, primates, plus more, and cats happen to be carnivores, but they are still mammals, and carnivores are still related to rodents and primates.

There are two suborders of carnivores; Feliforms and Caniforms, and cats happen to be felines, but they are still carnivores and felines are still related to canines.

There are several families of Feliformia, including Felidae and Hyaenidae (hyenas), plus more, and cats happen to belong in Felidae, but they are still carnivores, and Felidae are still related to hyenas.

There are two subfamilies of Felidae; felines, and panthers, and cats happen to be felines, but they are still Feliforms and panthers and felines are still related.

There are many genera (plural of genus) of Felinae; Felis, Catopuma, Leoparda, plus more, and cats happen to belong to Felis, but they are still Felidae and Felis are still related to pumas and leopards.

No matter how many generations of breeding we look into the future cats will always be animals, and chordates, and mammals, etc... I'm sorry if I seemed to rant, but I feel this level of extreme detail is needed to hammer home this point to creationists: Organisms always inherit their parent's clade, and never breed out of the clade they inherited. They can create new clades, but those clades are merely twigs belonging to larger branches. Evolution is not magic. This stuff is observable. Just study nature.

Phylogeny proves evolution is true, because we can prove that cats have all the traits required of them to be classified in the ways I classified them above. If you don't know what the definition of Chordate is, look it up. You'll find that house cats have all the traits to fit the definition and so do all the other animals in that clade. Look up the traits of any other clade you wish. Fish. Kangaroos. Apes. Conifers. Bovines. The organisms within those clades all share common traits, and all inherited those traits with slight modification from parent clades.

The subtitle of this blog indicates that it is possible to prove phylogeny, and thus, evolution, wrong. One of the requirements of a theory is that it must be falsifiable, that is, the presenting scientist must demonstrate how his or her theory could be proven wrong, and then other scientists would and should try. If they can't do it, the theory passes muster. How could a creationist disprove phylogeny?

If all biological life is not related, then at some point, this tree breaks down. There would have to be a clade that is magically created and not related to other clades. So, demonstrate that. Name a clade that is demonstrated to be related to other clades, yet somehow isn't, and show the evidence for how and why that could be.

Nobody sums it up better than Aron Ra. This video is 12:45 long but I've started it at the 8:30 mark where he details his "phylogeny challenge."



The phylogeny challenge asks creationists to give the evidence showing which clades are magically created and thus not related in any way to their alleged parent clades. Nobody can do it because phylogeny proves evolution, because evolution is a fact.

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