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Hox Gene and Cambrian Explosion

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Session 1.3: The Evolution of Cellular Life

Exam review

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In this session we focus on the natural history of cells and the evolutionary timelines of their appearance. The modern phylogenetic classification of domains is used to categorize the different types of cells: bacteria, archea, and eukarya. The names of periods and organisms and certain dates are often helpful in remembering or understanding events that occur in the natural history of evolution. However, we do not expect you to know the names of all organisms mentioned nor all dates (you may find some of the sound attachments on complicated figures useful for review). Those names and dates mentioned below are the ones to key on. The focus in this session is macroevolution which looks broadly at the time lines and changes over long intervals of time. Remember that small changes over millions of years are the framework for evolving complexity from simplicity. Summary of concepts and idea An initial step in covering this material is an understanding of the different types of cells (prokaryotic, eukaryotic animal and plant), their differences, and their place in the phylogeny of life. 1. Information from pre-class reading, Bioflix animations and briefly summarized in class discusses the fundamental components of the prokaryotic and eukaryotic cells. You need to know the differences and understand the basic functions of the cellular components as cells as they are the fundamental units of life. 2. The 3 domain tree of life is a modern version of how we believe life to have arisen from a common ancestor(s) through branch points very early in the life history of the Earth into Bacteria (3.8 BYA) and Archea (3.7 BYA)- the prokaryotes. Single celled Eukaryotes may have appeared between 2.1-2.8 BYA and branched more recently from the Archea than from the...

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