Week 4 Archaeology
Weekly Topics and subtopics
Evolutionary lines, trees, bushes, and species
Trees, Lines, and Grades
The best way to approach the human fossil record is to avoid getting into the essentially unresolvable debates about how to subdivide species or where gene flow barriers exist between fossil groups. True, there are some parts of the human fossil record where there is significant consensus on species diversity, but there are many more areas where the evidence for gene flow (or not) is lacking but the arguments continue. So what is a student to do?
It is best to start with what we know. We can see changes over time in the fossil record, and these changes don't happen all at once. Although the process of evolution is dynamic and largely gradual, thinking of the human fossil record as a series of stages is very useful. The three hominid genera are Ardipithecus, Australopithecus, and Homo. Within each of the se genera many species have been recognized, and will be looking at many of them, but start with the genera. Read the text in the figure below to understand the key features of each stage. GLCA refers to the gorilla last common ancestor. CLCA refers to the chimpanzee last common ancestor.
That said, during the late Miocene, when humans slipt from chimps, the world was a warmer, moister place. Coming to the present, we have become, on average, cooler and drier over time, but the fluctuations have become more intense.
It is best to start with what we know. We can see changes over time in the fossil record, and these changes don't happen all at once. Although the process of evolution is dynamic and largely gradual, thinking of the human fossil record as a series of stages is very useful. The three hominid genera are Ardipithecus, Australopithecus, and Homo. Within each of the se genera many species have been recognized, and will be looking at many of them, but start with the genera. Read the text in the figure below to understand the key features of each stage. GLCA refers to the gorilla last common ancestor. CLCA refers to the chimpanzee last common ancestor.
That said, during the late Miocene, when humans slipt from chimps, the world was a warmer, moister place. Coming to the present, we have become, on average, cooler and drier over time, but the fluctuations have become more intense.
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