BIOL 111 Lecture Notes - Lecture 22: Amniote, Transitional Fossil, Theropoda

• School: McGill University
• Department: Biology
• Course: BIOL 111
• Professor: Andrew Hendry , Elena Melania Cristescu , Anna Lesley Hargreaves

Document Summary

How to occupy extreme environments? (like antarctic or desert) The ancestor to birds was probably a theropod dinosaur. Shared characteristics of birds and dinosaur ancestor: bipedal (2 legs), 3 hind toes, carnivorous, 4-chambered heart, similar lungs, feathered, hollow bones, parental care of eggs and juveniles. Most important primitive bird fossils: archaeopteryx ancient wing : ~150 mya (jurassic, 12 of these fossil specimens (in museums, crow-sized. Non-avian characters (modern birds do not have: teeth, bony tail. Transitional fossil (mix of avian and non-avian character) Aves (birds: about 9,600 species, amniotes (amniotic egg with calcium carbonate shell, prevent water from moving out, endothermic, 4-chambered heart (completely separate pulmonary and systemic circuits like our heart, feathers, most fly (not ostriches for e. g. , diverse beaks diverse diets (carnivores, herbivores, nectivores) Bird breaks evolved in different shapes (size, colors) for different feeding functions. Some define specially to pick up particular food, seeds (e. g. skimming to grab fishes, nectar feeding from plants, insect catching )