BIO202H5 Lecture Notes - Lecture 1: Coevolution, Ator, Symbiosis
Document Summary
More dense, more viscous medium (but body supported by buoyancy) Dry all the time: need more water, danger of desiccation. Less dense, less viscous medium (no body support by buoyancy: less energy used to move thorugh medium. No suspended nutrients: nutrients must be acquired whether predator or not (2) earth"s geologic history. Environmental pressures on animal life change in each geologic period. Many transitions from aquatic to terrestrial and vice versa. Different physical pressures resulting from changes of environments. Animals must evolve to survive the environment (3) evolutionary relationships endosymbiosis. Symbiotic relationship between leaf-cutter ants and fungi. Symbiont success limited by co-evolution (50 million years) if symbiont removed, other not successful. Ants use fungal environment to grow the food they need cut leaves that feed fungi (4) hox genes. In development, segments of chromosomes called hox genes hox genes group of related genes that control the body plan of an embryo along the cranio-caudal axis.
