I am not going to explain evolution in terms that a professor of evolutionary biology would find perfect. Instead, I am going to try once again to clear the air with regards to the people in my world who aren’t so sure about evolution being real. In other words, this isn’t going to be a tough bit of technical jargon, but it will get across the points that I regularly hear people say to me.

1. I just don’t see how we could have come from monkeys..
Well good, cuz the answer is that we didn’t. An evolutionary specialist would explain to you that we have a common ancestor with primates. We are most closely related to chimpanzees and bonobos, but we are more closely related to monkeys and great apes and orangutans than we are with horses, and we are more closely related to horses than we are to canaries.

It isn’t that one day a monkey had a human baby, or anything remotely like that. The idea is called the Most Recent Common Ancestor, and the most recent common ancestor of humans and bonobos wouldn’t have looked exactly like either one. In the next section, I’ll explain the basic mechanics of evolution, and that might help you understand this better.

2. So how does it work?
Okay, let me first  say that it doesn’t. Evolution isn’t an active process in the sense that someone or something is making it work. Evolution doesn’t have a consciousness, an end goal, or anything of the sort.

People often interchange evolution with the term natural selection. But natural selection is just one of the ways that evolution works. Wikipedia defines natural selection as “the process by which biologic traits become more or less common in a population due to consistent effects upon the survival or reproduction of their bearers.” This means that genes are passed on through surviving long enough to reproduce. If a gene makes you slower, it might just make you slower to the point of getting caught by a predator. If a gene makes your hair appear a vivid red and you live in a dark green forest, the chances of finding good camouflage are pretty remote, and that’s a fine way to wind up dead. If reproduction occurs, then there is a chance that the gene will make it to another generation, but if your red hair makes you dead before you can pass any of your genes on, then the gene dies with you too.

But there are other factors. I’m a big fan of sexual selection, the process by which a quality is determined to be attractive. Lots of animals (including people) have elaborate displays, calls, dances, plumage, or any number of features that are specifically meant to make them look more attractive to the opposite sex. The dating process in humans is all about sexual selection. That doesn’t mean that only physically attractive people get second dates; it means that we tend to be choosy in our mates, and we tend to look for certain characteristics.

This is all very well expressed in a cartoon I read today that talks about sexual behaviors of crickets. Well, it talks more about sneaky crickets who take advantage of the song of other crickets to get their mack on. But the song of the cricket is a mating call, and they aren’t all the same. The way that a cricket makes his song can attract a female. She chooses him based on that criteria, which means that a cricket with a better song is more likely to reproduce.

And then there’s genetic drift. When a baby is conceived (i.e. when sperm hits egg) you wind up with about half of the genes coming from mom and half from dad. Any given trait could be passed on, but it doesn’t have to be. Let’s say that the trait for dad’s blonde hair comes from a particular gene, and the sperm cell that dad fertilizes mom with doesn’t contain that gene. That means the fertilized egg won’t have the trait. That’s just how life goes, and each baby is made up of the contributions of both parents. Random chance is ultimately at play here as parents do not actively engage in the process of determining which genes they will be sending to junior. To understand this better, read the paint can example on the wiki page I linked to.

Now, that isn’t all of the factors involved in evolution. In truth, there is a hell of a lot more going on there. But those are, I think, the ones most notable in terms of selection and what gets selected. However, isolation is also important for what they call speciation, meaning when a new species arises.

Let’s travel back in time to the days of that most recent common ancestor between us and chimpanzees. If we had stayed together the whole time, our evolutionary paths would have continued to intermingle and mutations would spread uniformly in the population. But lets say that for some reason we split up. Maybe it’s that a mating pair wound up moving away from the pack and living in a different area. That area could have different environmental factors, different predators, different food sources, and any number of different conditions that helped shape our evolution.

For example, let’s say that the main population of are ancestor mostly ate fruit, but enjoyed the taste of meat, but fruit was easy to get and meat required a lot more hustle and bustle to get. A mating pair wound up leaving and setting up shop in a place where meat was a lot easier to come by, so the natural pressures on their evolution would result in their needing to be better hunters. As time went by, their bodies could evolve in a variety of ways that were different than their cousins. Perhaps their cousins wouldn’t need to run as quickly, to learn to use simple tools to aid in their hunting, or who knows what. Eventually, as they develop in isolation of one another, the natural pressures and other changes add up to the point where they simply aren’t genetically compatible anymore. That’s when we can easily say that these are different species, even though they came from the same stock.

3. If only the strong survive, how come there are weak animals?
That’s actually a really bad understanding of evolution. Evolution doesn’t say that the strongest survive, it says the most fit do. Physical strength has its advantages of course, but it also comes with disadvantages. Dinosaurs were stronger than subterranean rodents, but rodents were more able to withstand the conditions that led to the dinosaurs becoming extinct. A rabbit that was extremely physically strong would move slower than a leaner rabbit, and thus the leaner rabbit could outrun predators. A large and powerful frame also requires a larger quantity of food and water to maintain itself. Particular conditions are what determines fitness.

4. Why can’t we see evolution happening today?
We can. What we can’t see is so-called macroevolution, that process where new species just suddenly up and show themselves. This is the argument used by creationists when they say, “How come when two dogs have sex they don’t produce a cat?” Evolution is a process of the babiest of baby steps. There is no missing link because there is no one missing link. Every ancestor of ours from the dawn of time is a missing link in the chain.

What we can see are examples of creatures adapting, examples of how isolating a group of animals and changing their environments impacts them, and examples of random mutation spreading through a group. Good examples would be the domestication of dogs (and silver foxes in Russia), this article about minnows by Timothy H. Vines and Dolph Schluter, or the color variation of pocket mice. And there are plenty of other examples to draw from that verify the theory beautifully.

5. If evolution is true, why are there still monkeys?
Because there is an environment that suits monkeys that allows them to continue to thrive, silly. Monkeys are better suited to their environment than man would be. This just seems like a stupid question to me. Remembering back to my made up version of how a mating pair left our closest ancestor, the rest of the pack would have presumably continued to evolve to better suit their own environments.

6. Is evolution only a theory?
I hate this question. There’s a difference between theory in the way we use it in regular language, such as “my theory is that the butler killed her in the conservatory using the revolver” and a scientific theory. The terminology difference is extremely important.

7. So if a wolf turned into a chihuahua, why can’t we turn a chihuahua into a wolf?
Wolves didn’t turn into chihuahuas. Over ten thousand years of selection, both human and natural, we took an ancestor of the modern chihuahua and the wolf and slowly changed it into the modern chihuahua. We did so largely through human selection, breeding the smallest dogs to get to the irritating, pocket-sized mouthpieces we have today. We couldn’t reverse the process and come up with a wolf that was genetically identical to another wolf because we can’t move backwards. We could, however, spend ten thousand years breeding the biggest chihuahuas and other suitable dogs to create a large dog, but to pretend like we could find the right recipe to make a genetic counterpart of the wolf is just silly.

8. I heard that mathematically it is impossible for life to have originated randomly.
You heard wrong. First off, that’s not the same discussion. Evolution does not speculate on the origin of life, it talks strictly about the way that life changes. You’re talking about abiogenesis, which is a completely separate field of study. However, the calculation of odds is a simple way to make anything impossible. Grab a deck of cards. What are the odds that they are in exactly that order? Well, just for the top 5 cards it would be 1/52 * 1/51 * 1/50 * 1/49 * 1/48 which means one in 311,875,200. Add in a sixth card and you get one in 14,658,134,400. Obviously that number gets even bigger when we’re dealing with 52 cards all in exactly those positions. And yet, the cards are in that order, even if it’s statistically impossible. Do you know what the actual odds are that the cards are in that order? 1 in 1. Because they are.

Jim