Thursday November 29, 2012

1. ThursdayNovember 29, 2012 (The Phanerozoic Eon: The Cenozoic Era – The Rise of Mammals and Flowering Plants)

2. The Launch Pad Thursday, 11/29/12 What was happening to the continental land masses during the Mesozoic Era? Pangaea began its breakup into the northern Laurasia and southern Gondwana sub-supercontinents. Parts of North America became submerged under a shallow sea. Which type of animal was dominant during the Mesozoic Era? The reptiles took the place of the amphibians as dominant vertebrates. Birds began to evolve. Mammals hid in holes.

3. Announcements Happy Cute Dog Day!

5. Recent Events in Science For Some Feathered Dinosaurs, Bigger Not Always Better Read All About It! www.sciencedaily.com/releases/2012/11/121128093254.htm Giant plant-eating theropods (close relatives of both T. rex and today's birds) lived and thrived alongside their meat-eating cousins. Now researchers have started looking at why dinosaurs that abandoned meat in favor of vegetarian diets got so big, and their results may call conventional wisdom about plant-eaters and body size into question. Scientists have theorized that bigger was better when it came to plant eaters, because larger digestive tracts would allow dinosaurs to maximize the nutrition they could extract from high-fiber, low-calorie food. Therefore, natural selection may have favored increasing body sizes in groups of animals that went meatless.

7. The Phanerozoic Eon The Cenozoic Era The Cenozoic Era is the current and most recent of the three Phanerozoic eras, following the Mesozoic Era and covering the period from about 66 million years ago to the present. The era began in the wake of the Chicxulub extinction event at the end of the Cretaceous that saw the demise of the last non-avian dinosaurs, as well as other terrestrial and marine flora and fauna. The Cenozoic is also known as the Age of Mammals, because the extinction of many groups allowed mammals to greatly diversify. • The Cenozoic is divided into three periods: The Paleocene, Neocene, and Quaternary.

8. The Phanerozoic Eon Early in the Cenozoic, following the Chicxulub event, the planet was dominated by relatively small fauna, including small mammals, birds, reptiles, and amphibians. It did not take long for mammals and birds to greatly diversify in the absence of the large reptiles that had dominated during the Mesozoic.

9. The Phanerozoic Eon Some birds grew larger than the average human, and were known as the "terror birds," which were formidable predators. Mammals came to occupy almost every available niche (both marine and terrestrial), and some also grew very large, attaining sizes not seen in most of today's mammals.

10. The Phanerozoic Eon Climate-wise, the Earth had begun a drying and cooling trend, culminating in the glaciations of the Pleistocene Epoch. The continents also began looking roughly familiar at this time and moved into their current positions.

11. The Phanerozoic Eon During the Cenozoic, mammals proliferated from a few small, simple, generalized forms into a diverse collection of terrestrial, marine, and flying animals, giving this period its other name, the Age of Mammals, despite the fact that birds still outnumbered mammals two to one.

12. The Phanerozoic Eon The Cenozoic is just as much the age of savannas, the age of co-dependent flowering plants and insects, and the age of birds.

13. The Phanerozoic Eon Grass also played a very important role in this era, shaping the evolution of the birds and mammals that fed on it. One group that diversified significantly in the Cenozoic as well were the snakes. Evolving in the Cenozoic, the variety of snakes increased tremendously, resulting in many colubrids, following the evolution of their current primary prey source, the rodents.

14. The Phanerozoic Eon In the earlier part of the Cenozoic, the world was dominated by the gastornid birds, terrestrial crocodiles like Pristichampsus, and a handful of primitive large mammal groups like uintatheres, mesonychids, and pantodonts.

15. The Phanerozoic Eon In the earlier part of the Cenozoic, the world was dominated by the gastornid birds, terrestrial crocodiles like Pristichampsus, and a handful of primitive large mammal groups like uintatheres, mesonychids, and pantodonts.

16. The Phanerozoic Eon But as the forests began to recede and the climate began to cool, other mammals took over. The Cenozoic is full of mammals both strange and familiar, including halicotheres, creodonts, whales, primates, entelodonts, saber-toothed cats, mastodons and mammoths,  three-toed horses, giant rhinoceros like Indricotherium, and brontotheres.

17. The Phanerozoic Eon But as the forests began to recede and the climate began to cool, other mammals took over. The Cenozoic is full of mammals both strange and familiar, including halicotheres, creodonts, whales, primates, entelodonts, saber-toothed cats, mastodons and mammoths,  three-toed horses, giant rhinoceros like Indricotherium, and brontotheres.

18. The Phanerozoic Eon But as the forests began to recede and the climate began to cool, other mammals took over. The Cenozoic is full of mammals both strange and familiar, including halicotheres, creodonts, whales, primates, entelodonts, saber-toothed cats, mastodons and mammoths,  three-toed horses, giant rhinoceros like Indricotherium, and brontotheres.

19. The Phanerozoic Eon But as the forests began to recede and the climate began to cool, other mammals took over. The Cenozoic is full of mammals both strange and familiar, including halicotheres, creodonts, whales, primates, entelodonts, saber-toothed cats, mastodons and mammoths,  three-toed horses, giant rhinoceros like Indricotherium, and brontotheres.

20. The Phanerozoic Eon But as the forests began to recede and the climate began to cool, other mammals took over. The Cenozoic is full of mammals both strange and familiar, including halicotheres, creodonts, whales, primates, entelodonts, saber-toothed cats, mastodons and mammoths,  three-toed horses, giant rhinoceros like Indricotherium, and brontotheres.

21. Figure 12.35 The Cenozoic heralded the development of the marsupial family of mammals.

22. By contrast, this is a placental mammal.

23. The Phanerozoic Eon What is the difference between a placental mammal and a marsupial mammal?

24. The Phanerozoic Eon The Cenozoic could also be called the “Age of Flowering Plants.” Flowering plants (angiosperms) strongly influenced the evolution of both birds and herbivorous mammals throughout the Cenozoic.

25. Figure 12.34A

26. Worksheet The Phanerozoic Eon: The Cenozoic Era – The Rise of Mammals and Flowering Plants