BIO120H1 Lecture Notes - Lecture 11: Homo Erectus, Lake Turkana, Karyotype
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BIO120H1 Full Course Notes
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Document Summary
The evolution of morphological body parts first arose during the cambrian explosion, in particular hard exoskeletons for protections, and sensory features such as antennae. They were relatively immobile; they sat, swam but did not move as quick as modern animals. The diversity of this period had animals completely different. Predation first arose during this period as well, found by the trilobite fragments in the stomache of the undiscovered terror of the trilobites . The causes of the cambrian explosion were explained by the environmental factors, but in addition the hox/hom genes which were regulatory genes that changed the structures of an organism"s body. The switch from sulfur-consuming anaerobic photosynthesis to aerobic photosynthesis allowed for the deposition of oxygen into the environmental atmosphere. A mass extinction of cyanobacteria, since oxygen was toxic to these protozoic organisms. Respiration of oxygen was considerably more efficient than anaeorobic respiration.
