22 Things That Will Teach You Earth's Entire History In One Day

The Earth formed 4.5 billion years ago. In this story, Fraser Cain takes you through the processes that formed our world, the long and contentious history that lead to the realization that our planet is hella old, and the science behind it all.

Just when the earliest crust formed on Earth is a hard question to answer, but it is super important because life probably would struggle on a molten surface. In this story, Dan Vergano (now a reporter for BuzzFeed) describes how microscopic grains are the only evidence left of this time and how, remarkably, we can still learn a lot from them.

Scientists generally consider something living if it can metabolize (break things down, build things up, create energy, use energy, etc) and replicate (make a copy of itself). Viruses are self-replicating genes that need to feed off of other things to metabolize, and as such many think they came onto the scene after life had formed. This excellent feature by Carrie Arnold unpacks the idea that viruses could have come first and therefore played a big role in creating the earliest life.

Things were cruisin' along just fine before some cyanobacteria arrived on the scene around 2.3 billion years ago and mucked everything up real bad by producing tons of free oxygen as a waste product. This story by Phill Plait provides an excellent overview of this prodigious disaster, the first of many that life would experience.

Life couldn't really do anything too exciting until it upgraded its cellular structure. This new type of cell, called a eukaryotic cell, was just the upgrade life needed. Here, Jennifer Frazen explores a controversial claim that a 3-billion-year-old fossil is that of a eukaryote. Though hard to prove, this story highlights the importance of eukaryotes, and the mysteries that may alway surround their origin.

Multicellular organisms got off to a super-weird start, as the super enigmatic group of multicellular organisms known as the Ediacuran Biota show us. Here, Richard Corfield describes the conditions that gave rise to these organisms and the traits that make them so hard to pin down.

Around 540 million years ago, animals figured out how to make hard shells and armor. Maya Wei-Haas describes the discovery of one super creepy worm-like critter from this time period and explains what it can — or cannot — tell us about life from this heady time in our planet's history.

The first animals that met the definition of a vertebrate were fish. In this piece Jane Hu describes the earliest fish known to the fossil record. It looked wicked un-fish like.

Insects were the first animals to invade the land and they were the first to develop flight. As best we can tell, their ancestors first came onto the scene around 470 million years ago and now make up over 80% of the species we have described. Despite these accolades, there is a lot left to learn about their history, as Gwen Pearson explains.

Plants seem to have invaded the land, at least timidly, around 475 million years ago, but really took off during the Devonian period of Earth's history. As friendly as we generally view plants, this massive migration of green onto land may have really made things hard for ocean-dwelling organisms, as Annalee Newitz explains.

Around 350 million years ago, a group of fish called lobed-finned fish started playing around with limbs, giving rise to the tetrapods. Later fossils showed that some of these limb-bearing fish, like Tiktaalik, started messing around on land. In this fascinating story, Ella Kelly explains how even the most ancient fish had the genetic information to create limbs, they just didn't use it.

The first tetrapods to investigate the land were early amphibians. Later on, a group of organisms called amniotes would make the water part of the life cycle unnecessary by allowing them to lay eggs without the presence of water. These amniotes comprise all reptiles, birds, and mammals. Here, Dustin Welbourne describes why the term reptile isn't really all that scientifically valid in the first place.

The earliest dinosaurs looked very little like what we picture when we think of the terrifyingly massive lizards popularized in movies and in museums. This raises an important question: What is a dinosaur and how can we tell when they first appeared? Here, Megan Garber tackles that question head on by interviewing the research team credited with finding the earliest dino/dino-ancestor.

The classical view of early mammals is that they were tiny nocturnal animals who, for the most part, lived in hiding during the reign of the dinosaurs. In this story, Brian Switek explains how an early mammal fossil recently found in China could change that picture.

The basic gist of the famous dinosaur extinction story goes like this: A massive asteroid struck Mexico's Yucatan Peninsula causing a fiery explosion followed by a near complete dimming of the skies due to ash and gas for up to 100 years, triggering a mass extinction that ended the reign of the dinosaurs and paved the way for mammals like us. As with many things in science, the reality is likely a bit more complicated than that, as Brian Switek explains.

For a while, researchers figured that primates's reliance on eyesight and their superior grasping ability came from them being insect-hunting critters. But some researchers think that this couldn't have been the case because the earliest primates fed on the nectar of flowering plants. Here, Erin Wayman describes how the evolution of flowering plants, instead, may well have led to many of the traits shared by primates.

Whales, dolphins, and porpoises all evolved from tiny, decidedly un-whale-like hoofed land mammals. Here, Brian Switek takes you on a deep dive into the discoveries that helped fill out our understanding of the evolution of some of the weirdest, most surreal animals nature has ever produced.

The earliest creatures that we consider part of our human family are the australopithecines, a group of creatures descended from the same ancestor that gave rise to chimpanzees. The homo genus that includes us humans most likely came from an ancestor in this group. In this long-but-totally-worth-it feature, Ann Gibbons takes you through the wild discoveries that helped us put this picture together.

This read is on the longer side, but it is totally worth it. Here, Guy Gugliotta takes the reader through the many steps and many questions surrounding the rise and ultimate dominance of humans as we know them today.

Anthropologists often make the distinction between "anatomically modern humans" that looked like us and "behaviorally modern humans" that looked and acted like us. The question of when the latter evolved is the subject of considerable debate. Here, Erin Wayman explains that science used to have a clear-cut answer for that question, but now it seems like the more we learn the less we know.

Humans have left a permanent mark on the planet. These changes are so dramatic that some scientists want to coin a name for the slice of time we currently inhabit called the anthropocene (the age of humans). Here, Richard Monastersky describes the various arguments for and against the antrhopocene. As it turns out, it's as much a philosophy question as it is a science one.

Anything in the future is obviously speculation, but using current trends and our understanding of both human behavior and history, one can make some educated guesses. Here, Alan Weisman, author of The World Without Us, provides three different theoretical stories about our world just 100 years from now in this terrifying piece.