of Grandmother Fish & Clades

September 7, 2016
by Jonathan Tweet
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Order Grandmother Fish 2nd Ed

Get the groundbreaking book that teaches evolution to preschoolers!

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Grandmother Fish is also available in digital format.

On iPad (see iTunes)

On Android tablet

On Kindle

Grandmother Fish is available in the UK.

From Amazon


December 6, 2016
by Jonathan Tweet
Comments Off on Birds: Four Lines of Dinosaurs that Survived

Birds: Four Lines of Dinosaurs that Survived

blusrep3In Clades, sauropsids of the air are represented by birds. Today’s birds all descend from a species of flying theropod dinosaur that lived before the Cretaceous-Tertiary extinction event of 66 million years ago. Unlike today’s common birds, these early birds did not perch in trees. Four bird lineages survived the extinction event that wiped out the other dinosaurs. One surviving lineage led to today’s ostriches and their close relatives (Paleognatha, or “old jaws”). The other lineage, the Neognatha or “new jaws”, survived in three separate lines, one leading to ducks and fowl, another to sea gulls and their relatives, and the third to “earth birds” (Telluraves). Telluraves predominate today, and they mostly perch and nest in trees. Telluraves split into Afroaves (or “African birds”) and Australaves (or “southern birds”), represented in Clades by a bald eagle and an American robin, respectively. The common ancestor of all eagles and robins was evidently a carnivorous bird that perched on tree branches. “Old-jaw” birds and “new-jaw” birds together form the clade Aves, or birds. If one includes the many birdlike dinosaurs that didn’t survive the last extinction event, this larger clade is called Avialae (“bird wings”). Archaeopteryx are in the clade Avialae, but they are a separate branch from Aves.

December 5, 2016
by Jonathan Tweet
Comments Off on Dinosaurs: From Little Runners to Ponderous Plodders

Dinosaurs: From Little Runners to Ponderous Plodders

In Clades: Prehistoric, the sauropsids of the land are dinosaurs, represented by a theropod (like Tyrannosaurus), a sauropod (like Diplodocus), and an ornithischian (like Triceratops). The earliest dinosaur precursors were, small, two-legged relatives of crocodiles, as were the first theropods, sauropods, and ornithischians. Walking efficiently on two legs gave them an advantage over crocodiles, lizards, and early mammal relatives. Dinosaurs first appeared about 230 million years ago (MYA), after the Permian–Triassic extinction event of 250 MYA. The plant-eating ”bird-hipped” dinosaurs (Ornithischia) evolved greater size, and several lines evolved a four-legged gait, especially the frilled and armored dinosaurs. The “lizard-hipped” dinosaurs (Saurischia) split into two major clades. The sauropods evolved long necks to eat tree foliage and large size to protect themselves against theropod predators. Their large size necessitated a four-legged gait. Theropods ate meat, and they, too, became larger over time. Theropods evolved feathers, and some developed flight. The only dinosaurs to survive the Cretaceous-Tertiary extinction event of 66 million years ago were some of these flying dinosaurs, known today as birds.

December 2, 2016
by Jonathan Tweet
Comments Off on Malacostraca: From the Sea Floor to Under a Log

Malacostraca: From the Sea Floor to Under a Log

water arthropodsThe arthropods of the water are a crab, a lobster, and a woodlouse, together representing the most recognizable branch of crustaceans, the malacostracans. Lobsters and their relatives are distinct from other crustaceans in that mothers incubate their eggs, which are attached to the mother’s swimming legs. Many other clades are successful because of adaptations that help them take better care of their offspring, mammals included. While lobsters live in crevices or burrows on the sea floor, crabs often live in shallower waters. Many sorts of crabs have evolved some degree of air-breathing, allowing them to take advantage of air’s higher oxygen content. Woodlice still breathe through gills like their water-breathing ancestors, but their gills are adapted for life on land. A woodlouse’s gills stop working if they dry out, and that’s also true for your lungs. Like other crustaceans, malacostracans eat with side-by-side mandibles, quite different from arachnids’ fangs. Other crustaceans tend to be tiny, such as copepods, which often resemble shrimp but are smaller than a grain of rice. Another successful branch of the crustacean clade is the insects. They were originally classified as a sister group to crustaceans when in fact they’re a daughter. The clade of all crustaceans and insects is Pancrustacea (“all shelled ones”).

November 29, 2016
by Jonathan Tweet
Comments Off on Clades and Clades: Prehistoric Both Funded!

Clades and Clades: Prehistoric Both Funded!

Karen and I have raised enough money on Kickstarter to fund not only Clades but a second version of the game with all prehistoric animals—Clades: Prehistoric. For the real dinosaur lover, we’ve added a pledge level that lets you tell us which dinosaur to include in the game. The Kickstarter continues until December 6th.



November 15, 2016
by Jonathan Tweet
Comments Off on Supraprimates: Climbers, Chewers, and Walkers

Supraprimates: Climbers, Chewers, and Walkers


Supraprimates, AKA Euarchontaglires

In the Clades game, the mammals of the land are represented by suprapimates, also known as Euarchontoglires. A squirrel represents rodents, a rabbit represents lagomorphs, and a child represents primates. Like most sorts of mammals, these animals diversified soon after the non-bird dinosaurs went extinct 66 million years ago. Rodents and lagomorphs are together in a clade called Glires, which is distinguished by front teeth that keep growing and growing. This adaptation allows these animals to chew through seed shells and wood without wearing out their teeth. More than any other order of mammals, rodents have diversified into many species, including unusual types such as flying squirrels, beavers, porcupines, capybaras, and naked mole rats. The sister clade to Glires is Euarchonta, which includes three tree-dwelling clades: tree shrews, colugos, and primates. Some primates live exclusively in the trees, while others climb trees to avoid predators. Two million years ago, however, our lineage lost its apelike shoulders, suggesting a shift away from tree-climbing to a life fully on the ground. Those Homo erectus ancestors gave rise to several species of human that spread out across the continents, including our species, which appeared in Africa 200 thousand years ago. We are the most successful primate on Earth, at least for now.

October 24, 2016
by Jonathan Tweet
Comments Off on Whippomorphs: Big, Swimming Mammals

Whippomorphs: Big, Swimming Mammals



The mammals of the water are whippomorphs, represented by a blue whale, a dolphin, and a hippopotamus. The term “whippomorph” means “whale-hippo shape”, and it proves that scientists have a sense of humor. As with many sorts of modern mammal, the earliest whippomorphs appeared shortly after the non-bird dinosaurs were wiped out 66 million years ago. These ancestors were apparently large, semiaquatic mammals. The clade soon split into two clades, one clade including today’s hippos, and the other including today’s whales and dolphins. The whale-dolphin clade is Cetacea, meaning “whales”. Blue whales and other baleen whales have no teeth, and instead they have baleen bristles that filter plankton as a food source. Dolphins are technically toothed whales, like sperm whales are. They prey on fish, like the earliest whales probably did. Air-breathing gives toothed whales an advantage over their water-breathing prey because air has much more oxygen in it than water does.

October 19, 2016
by Jonathan Tweet
Comments Off on Lizards and Snakes Form a Scaly Clade: Squamata

Lizards and Snakes Form a Scaly Clade: Squamata

blueliz3In Clades, the sauropsids of the earth are squamates, comprising all lizards and snakes. “Squamate” means scaly, and their scales distinguish them from turtles, birds, and crocodiles. These other sauropsids have scutes, which are made of bone and horn, but they don’t have scales. The earliest modern lizards lived almost 200 million years ago and resembled geckos. That was about 50 million years after the earliest dinosaurs appeared. The common ancestor of all lizards and snakes could unhinge its jaw to swallow large prey, as can today’s squamates, especially snakes. In Clades, the three squamates are a gecko, a snake, and a chameleon. Scientists propose that snakes and chameleons are together in a “venom clade” called Toxicofera. This clade also includes iguanas, gila monsters, and related lizards.

October 19, 2016
by Jonathan Tweet
Comments Off on Clades Kickstarter Launched and Funded!

Clades Kickstarter Launched and Funded!

Karen and I have a new game on Kickstarter. It’s Clades, the Evolutionary Card Game. Clades is an animal-matching game based on evolutionary relationships, for kids and adults. Please take a look at the Kickstarter page. We funded on the second day, and now we’re trying to raise enough money to create a second version of the game, Clades: Prehistoric, with all prehistoric animals.




Thanks for your interest in sharing the wonderful story of evolution with children (and grownups).


August 13, 2016
by Jonathan Tweet
Comments Off on Clades on Kickstarter in October

Clades on Kickstarter in October

This October, Karen and I are going to launch a Kickstarter campaign to fund our new game, Clades. Click on the card back for a quick description.

early draft of card back

In biology, a clade is an evolutionary family. In Clades players match animal cards according to their features, including which clades the animals belong to.

cladesCard3BlueAirReptileEvery card features one, two, or three of Karen’s spirited animal drawings. The animals are arranged according to their evolutionary history.


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