This group includes the ancestors of mammals and lived alongside reptiles for millions of years. They eventually died out, except for the lineage that led to mammals.
The Triassic–Jurassic extinction cleared ecological space for dinosaurs to become the dominant land animals of the Jurassic.
Triassic–Jurassic Extinction: Volcanoes Open the Age of Dinosaurs Read More »
Snowball Earth was a time when our planet may have frozen nearly from pole to pole, testing life and setting the stage for later biological change.
Snowball Earth: When Ice Reached the Equator Read More »
The significant idea of the bilaterian body plan is directionality. By moving from a radial (circle) to a bilateral (line) symmetry, life transitioned from a passive state of “being” to an active state of “doing.”
Bilaterian Split: The Origin of Agency Read More »
Before, during, and after the K–Pg extinction: a thriving Late Cretaceous world of dinosaurs, pterosaurs, birds, and flowering plants gives way to the asteroid strike and global collapse that ended the age of non-avian dinosaurs.
The K-Pg Extinction Read More »
The Permian-Triassic extinction was not just the end of many species. It was a planetary reset that destroyed the old synapsid-dominated world and opened the door for the archosaur line that would later give rise to dinosaurs.
The P-T Extinction Read More »
About 255 million years ago, during the late Permian, our mammalian ancestory, the synapsids ruled the land.
The Synapsid World of the Late Permian Read More »
The Cenozoic era starts with the K–Pg extinction 66 million years ago. That event marks the sudden end of the reign of dinosaurs and the rise of mammals and birds.
Cenozoic Era: Age of Mammals & Birds Read More »
The Mesozoic era starts with the end-Permian mass extinction 252 million years ago. Dinosaurs ruled over all, including us. It ends the reign of dinosaurs with the K–Pg extinction 66 million years ago.
Mesozoic Era: Age of Dinosaurs Read More »
The start of the Paleozoic era is marked by burrowing life 538.8 million years ago. The era includes the dominant rise of our ancestors. It ends 252 million years ago with the end-Permian mass extinction, a volcanic cascade global warming event.
Paleozoic Era: The Age of Synapsids Read More »
Not yet a “full” mammal, the last common ancestor between us and the platypus lived around 225 million years ago.
Platypus–Ape Common Ancestor Read More »
In more advanced forms, play becomes a complex tool for social bonding, emotional learning, and cognitive development. Carnivores like wolves and cats engage in cooperative games that refine group hunting skills, while elephants are known for their intricate, playful interactions that build emotional connections. Among primates, play takes on its most elaborate forms, fostering problem-solving,
Higher Play Evolves in Social Mammals Read More »
Play in its most basic form likely began as simple, physical interactions aimed at honing survival skills. Modern animals like squirrels, kangaroos, and hedgehogs still exhibit these foundational behaviors, engaging in chasing, pouncing, and wrestling. These actions help young animals develop coordination and reflexes while providing a safe way to practice life-essential tasks. Surprisingly, even
Early Play Evolves in Mammals Read More »
Our last tails! The last common ancestor with humans and old-world monkeys lived around 29 million years ago.
Baboons Branch Off: Old World Monkeys Read More »
The last surviving primate before the great apes! Gibbons are a “lesser ape” that branched off from our common ancestor with great apes. By this time, our ancestors had already lost their tails (like all apes) and were very agile in trees, using brachiation (arm-swinging) to move through the canopy. Gibbons are known for their
Gibbons Branch Off: Genus Hylobates Read More »
Around 240 million years ago, the XX/XY sex-determination system emerged in a common ancestor of mammals.
XX/XY Sex System Emerges: A Tale of Mammalian Evolution Read More »
By about 125 million years ago, mammals likely increased their vocabulary above a dozen and perhaps for some species at times into the hundreds. This vocabulary, or signaling, was a series of gestures, grunts, and screeches. Today, mammals from this lineage communicate with a range of signals and gestures, not unlike our abstract vocabulary. We
Animal Vocabulary: Dozens of Words Read More »
Around 60 million years ago, the early ancestors of primates began to develop a crucial adaptation: the opposable thumb. This evolutionary milestone marked the beginning of increased dexterity.
Opposable Thumb Emerges Read More »
Likely between 25 and 30 million years ago, the evolution of the apes brought about further refinement of the opposable thumb. This period saw the divergence of the lineages that would lead to modern “lesser” apes like gibbons as well as later “great” apes, including orangutans, gorillas, and chimpanzees. The ape thumb evolved to become
Our last comman ancestor of all known great apes lived about 16.5 mya. The orangatan branch split off about 12 mya. After that split the orangatan branch split several more tiimes. The modern orangatan species, the last split of this branch, emerged about 400,000 years ago.
True Primate: Within mammals, only primates have binocular vision, grasping hands, and flat nails–instead of claws.
Early Intelligence Emerges: Aegyptopithecus zeuxis Read More »
