DINOSAURS AND PLANTS

Horsetails were an important source of nutrition for plant-eating dinosaurs. These primitive vascular plants were fast-growing and resilient (they could propagate using underground runners which a grazing dinosaur wouldn't eat). This meant that a hungry dinosaur could eat the plant without killing it, since the plant would regrow from the rhizome (the underground stem).

Williamsonia sewardiana was a cycadeoidphyte (a bennettitalean). It had a woody stem and simple leaves. It lived from the Jurassic period through the late Cretaceous period. Williamsonia was a bennettitalean (a primitive gymnosperm that resembled cycads but was not a cycad). Williamsonia had a long, thin, branching, woody trunk covered with spirals of broken-off leaf scars.

There was a tremendous boom in both plants and animals caused by the advent of flowering plants and the decline of less adaptable species (like conifers and seed ferns). This reshuffling of species led to the heyday of dinosaurs during the late Cretaceous period.

Other Cretaceous period plants included: Podocarpus, Betulaceae (like Alnus), Araliaceae (like Aralia), conifers (like Araucarioxylon, Metasequoia, and Pinus), Corneaceae (like Cornus), Cycadeodias (like Cycadeoidea), Fagaceae (like Quercus - oak), Filincophyta (like Dryophyllum), Filincophyta (like Tetrastichia ), Ginkgophyta (like Ginkgo), Lauraceae (like Laurus and Sassafras), Magnoliaceae (like Magnolia), Moraceae (like Ficus), Palmae (Palmus), Pandanaceae (Pandanus), and Salicaceae (like Populus and Salicaceae).

The large predatory dinosaurs (like Tyrannosaurus rex) came into being after nutrient-rich flowering plants became available, fueling large numbers of plant-eating dinosaurs (like the hadrosaurs, duck-billed dinosaurs, lambeosaurs (like Lambeosaurus), ankylosaurs (like Euoplocephalus), homalocephalians (like Homalocephale), pachycephalosaurids (like Pachycephalosaurus), and ceratopsians (like Triceratops), which the predators ate.

Meat-eating animals (carnivores like Tyrannosaurus rex) get their energy by eating other animals, mostly plant-eating animals (herbivores like Triceratops). The herbivores get their energy by eating plants (like cycads). The plants (producers or autotrophs) get their energy from sunlight, converting the light into chemical energy using photosynthesis.

PANGAEA AND WEATHER DURING THE CRETACEOUS PERIOD
There was enormous tectonic activity during the Cretaceous period. Pangaea separated into the continents Laurasia and Gondwana.

During the first half of the Cretaceous period, temperatures were warm, seasonality was low, and global sea levels were high (there was no polar ice). Toward the end of the Cretaceous period, there were severe climate changes, lowered sea levels, and very high volcanic activity .

DINOSAURS AND PLANTS