BIOLOGY 1M03 Lecture : Bio 1M03 ch 1
10 Dec 2012
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Document Summary
At the end of the triassic, most therapsid groups disappeared and dinosaurs radiated to fill all of the niches for large, terrestrial animals. These early mammals were probably mouse-sized, nocturnal creatures that fed mainly on seeds and insects. They had internal fertilization, but still laid eggs. By the end of the mesozoic era, placental and marsupial mammals that bore live young had evolved. With extinction of dinosaurs at the beginning of the next era (cenozoic) came the radiation of mammals. According to darwin"s theory, complex adaptations are assembled gradually, each step favoured by natural selection. Modern humans have many complex adaptations, like grasping hands, bipedal locomotion, toolmaking abilities, language and large-scale cooperation. To understand the evolution of our species, it is important to understand the geological, climatic and biological conditions under which these evolutionary changes occurred. Evolution produces adaptation, but what is adaptive in one environment may not be adaptive in another environment.
