Before anyone comes for me, I grew up southern baptist – went to a private christian school & was homeschooled for a few years. The extent of my “science” education when it came to evolution & the origin of the universe was “if we came from monkeys why do monkeys still exist?” and “look at this galaxy that’s shaped like a cross, isn’t god amazing!!” I’m an atheist now and would like to have some sort of understanding of how our world came to be, but trying to figure it out as an adult with no real foundation has been incredibly difficult, and none of it’s making sense. I also know I’m asking a lot as all 3 of those subjects are pretty extensive, so if you know any good videos or books I’d love some recommendations!
In: Biology
Evolution is simply things changing over time, that’s all. Some animal is randomly born with a slightly longer neck -> it gets to eat a few more leaves than others around it -> it’s slightly more likely to survive long enough to breed -> fast forward a million years and we have giraffes.
No one knows how the big bang happened; we just have a pretty good idea that it *did* happen. The “why” will result in someone winning a Nobel Prize someday.
Kinda the same with abiogenesis; we mostly have a good idea that it *did* happen but the specific “how” is still being figured out.
I’m sure you’ll get a better answer but since it’s ELI5, I think it’s important to take a second and really accept the knowledge that we humans don’t know everything. In the education you got in childhood God had all the answers and everything was made by a creator with and for a purpose. Really though there are things we might never know with as much certainty as the education you were raised with. That can be a really tough concept after leaving religion- that the world isn’t just black and white and there might not be a Right Answer to every question.
Richard Dawkins wrote a book for people in exactly this situation. It’s called “The Blind Watchmaker.” It doesn’t cover cosmology, but it will cleanly address your first and third questions. It pays special attention to dispelling the myths that are sometimes confusing to people with a religious background.
He is on a short list of the most impactful biologists in the second half of the 20th century, so you’re really in good hands learning from him.
How abiogenesis happened is something we don’t know for certain. There are various hypotheses about it but nothing proven as far as im aware.
And for evolution the simplest way to look at it is that random changes in genes can happen, some beneficial some not. Creatures with changes that help them survive and reproduce in their environment obviously reproduce more often than those with negative changes.
And so over time as nature itself selects those that are best adapted to their surroundings. Species change over time in a sort of arms race against other species or creatures and against nature itself.
As for more material. There are entire college courses on these subjects available for free on youtube.
I’m trying to be really clear about what we actually *know*, and what we’re just assuming that means. A good scientist will never tell you this is definitely how it all happened. They’ll simply say this is the best idea we have right now, and if they see something that contradicts this idea and can’t be explained, they will change their mind and think of a better idea. That’s science: think of an idea, come up with a test that would tell you if the idea is right or not, and see if it’s right. If the idea passes the test, test it another way. If the idea is wrong, come up with a new idea that does explain all the tests.
—
Evolution: creatures have genes that determine what they are. They get most of them from their parents, but sometimes various factors make something change.
If you’ve got 10 animals of some kind, and one of them happens to grow up with a mutation that helps it find food more easily, it will have more kids than the other animals. Maybe next generation she’ll have 3 kids that live when her fellow animals have 1 or sometimes zero kids. Now 30% of them are hers and have that adaptation. Next generation they all do well, too, and so on. Eventually all the animals like that have this adaptation. All the others eventually had no kids one generation and they’re all gone now. This concept is “natural selection”, that the animals that do better, *do better*. There’s really nothing more to it than that.
Evolution (its full name is “evolution by natural selection”) is just the idea that this is how **all** the life ended up how it is, which seems to check out as far as we can tell. Everything has this genetic code and it makes sense that the ones that survive better do so.
—
Big Bang: we don’t know how it happened. What we truly know is that everywhere we look with telescopes, far-away stuff is getting further away. The light from it is getting stretched, and it stretches more the further away it is. It’s moving away from us, everywhere. That means in a year it will be further away… so a year ago it was closer, right? Carry that to its naive conclusion, and at one point, everything was really close. This discovery (cosmic expansion or Hubble expansion, they call it) is what led us to think: maybe this whole universe started with a big… bang of everything blasting out into a universe. It was a fun idea.
What led us to **really** think we were on to something with this big bang idea is the discovery that no matter where you aim a radio telescope into the sky, a good telescope picks up this background noise in the microwave range. It’s almost the same everywhere, any “blank spot” in the sky has this noise. What’s more, if we calculate the amount of light stretching because of expansion that would lead to that microwave noise, it matches our other estimates for how old the universe is.
What we think happened was: when the universe was first banging (heh…), all the matter was so crowded up and soupy that light couldn’t just fly around like light does now. At one magic point, stuff spread out enough that electromagnetism could draw elections into orbit around protons (and make hydrogen!), and there was *empty space* for the first time. Right then all the light of the universe that was caught up in the soup was able to blast out for the first time, everywhere in every direction. And stretched out over billions of years, *that is the noise that we pick up everywhere*. It’s still here: it’s already everywhere so there’s nowhere else for it to go. We call that the CMB, the Cosmic Microwave Background. When we discovered that, this bang bang idea really caught on as the most reasonable explanation we have for this.
—
Abiogenesis. My friend, we have no clue. We don’t know how it happened… we just don’t. There have been experiments that showed that if you just blast electricity (like lightning) at rocks in water through methane gas you can get it to create amino acids and stuff, and some of them created weird spherical structures that accumulated and “grew”… but as to how the first real living thing started living, we just don’t have the data to work with right now. All we know is that somehow, really simple life that grew based off a chemical inside (genes) that could change and grow formed, and from there on natural selection makes sense. But that initial starting point: we just don’t know yet.
So, here is why there are monkeys. Organisms are constantly evolving. Genetically, our closest ancestors are chimpanzees and bonobos, but we didn’t come from them. A couple million years ago there was a group of apes that wasn’t human or chimp or bonobo. At some point a population of this group split off, maybe food got scarce so some decided to head off in a different direction to look for more. Who knows really, but they split up and went their different ways and didn’t see each other much again. So now as millennia go by, the group that left has been isolated from the original population. During that time, small changes (evolution) have been happening in both groups. But the changes are different depending on the environment and resources that both groups are dealing with. Carry this on a few million more years and they’ve become completely different species. One group split off many more times, most of the split off groups eventually dying out, leaving humans. The other branch probably branched multiple times in that time (I’m less familiar), but two of the branches continue to survive, the chimps and bonobos. Since they split from each other after the human branch split, we’re equally related to both, but they are more closely related to each other. But all three species have continued evolving since they split from a common ancestor. When a species evolves, it isn’t a direct line where all of one species turns into another. It’s two or more populations of a species splitting up and those populations slowly becoming differentiated over time.
[removed]
Formation of life;
The formation of the first life is unknown. Experiment has shown that the elements of life can be created, but the exact way it started on its own is currently a mystery waiting to be solved.
Clearly it came about far earlier than thought, and likely took more primitive forms for many years. Well over a billion. In fact, all life you can think of existing from dinosaurs to modern animals are all within the last 580 million years only. Once complex life started, it took off and transformed the entire planet, Coming back again and again after major extinctions.
Evolution of life
How it works is evolution, which is genetic changes happening over time that are selected for by the environment. Nature is beautiful, but it is brutal. If those that have a trait that helps them survive, it is more likely to pass those genes on, which is the key. Poor traits would die off in the long run.
Three darwin finches are an example he used. Birds that diverged over time to look very different. Some with normal beaks to eat certain foods, and others that became much heavier, thicker beaks which allows them to access entirely different food sources.
They say the genetic changes are entirely random, but I have a feeling that environmental stress guides them to be more specific.
The beginning of time
The big bang is the idea that the universe started as a small point, which expanded unbelievably fast at first, then slowed, but never stopped. What expanded is everything. Space and time, and everything within it. Its the reason energy condensed into atoms, which made galaxies, stars, planets, and ultimately, life.
Sounds crazy, but the more we learned about our solar system, other stars, and other galaxies, it became clear that they were moving apart from one another. The universe is expanding. That means it must have been closer in the past. Moving backwards logically, it means everything must have been much closer.
The more we learned about matter and physics, the more the idea lined up. So far everything has lined up to say the big bang model is our most correct. As much as some religious scientists of the past wanted the universe to be eternal, the evidence didn’t go their way. I think one of the biggest proofs was the idea that light from the moment matter condensed would be still detected, and it was. The cosmic microwave background radiation is a map of the early universe.
Evolution is more or less a fancy way of saying that our method of reproducing is not perfect. Our DNA is a complicated and surprisingly fragile thing. Over time with life, random errors/damage happen, known as mutations. When we reproduce, some of those mutations may be passed along at random, which may result in the offspring having some differences. Over many generations this can result in some lineages changing their appearance or other traits, while others may not change that much. Further driving evolution is a process known as natural selection. Basically, with natural selection, organisms that have developed traits that help them in their environment are more likely to survive and reproduce, passing on these traits, while changes that are a hindrance are more likely to get the organism killed before it can reproduce.
The Big Bang is unfortunately still one of science’s greatest mysteries. Part of the issue is the Big Bang is thought to be the source of all the known matter in the universe, so we effectively have no way to really find out what was going on before. The closest we can get is the instant after the big bang when all the matter in the universe was suddenly rapidly expanding outwards. As pressure was released due to the expansion, matter started to take the form of protons, neutrons, and electrons, forming the first atoms. The universe to this day is still expanding even though locally matter has coalesced into asteroids, planets, stars, galaxies, nebula, black holes, etc
The origin of life is another tough one, because we have no real way to truly know or replicate the conditions. Wherever the first primitive origins of life formed on earth have long been destroyed due to the ocean crust subducting back into the mantle and our planet having vastly more oxygen in the air and water than it did when life first formed, as oxygen is toxic and destructive to cells that have not evolved defenses against the element’s reactivity, though its theorized hydrothermal vents may have been the key, the high heat and nutrient and mineral rich water providing the soup of materials needed for a self-replicating molecule to first form. But even then its very hard to try and study how this process might have turned into the first primitive cells, as the cells we all known have had 3 billion years of evolution behind them, and there’s no way to create a truly sterile environment anymore, microbes are everywhere now and would be happy to consume bits of organic matter or new primitive cells before we could even get a chance to known they exist.
Start with some high school level textbooks from non-conservative states in biology and basic science. This should give you enough to work from to explore free college level courses. You are starting 12+ years behind a lot of posters here. Also do not feel bad. Millions of thinkers and millenia of language were required to distill that knowledge into ordinary k-12 education.
Latest Answers