PNB 2250 Lecture Notes - Lecture 3: Oviparity, Notochord, Tunicate
10 Nov 2016
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Document Summary
Retrotransposons: self-amplifying genetic elements, chunks of dna floating around, make up almost 90% of plant genome, make up about 50% of mammalian genome. 15% of our genome is retroviral: powerful mutation force. Far more invertebrates on earth than vertebrates: vertebrates are more complex, requires more energy. Jelly-like layer sandwiched between 2 layers of cells. No nervous system, gi, or circulatory systems: heterotrophs, no cell walls, produce sperm cells. Internal calcium or silicon dioxide skeletons: consume bacteria, genomic analysis. 1,300 genes essential for formation of body structure. 2 layers of cells surrounding a jelly-like interior. Unique type of neuron not seen in other animals. Fossils for ctenophores are 515 million years old. + reptile eggs surrounded by membranes for protection and transport. + feathers, beak, no teeth, hard-shelled eggs, high metabolic rate, four- chambered heat, lightweight, but strong skeleton. + pterosaurs are largest animal ever to fly. + hair, three middle ear bones, mammary glands, neocortex, four-chambered heart, high metabolic rates.
