Vascular Plants

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1.) Vascular plants sequestered large amounts of CO2 through photosynthesis when they first expanded across terrestrial environment, leading to glaciation. Evaluate the claim that a similar glaciation event occurred when the first plants colonized land. Be sure to consider weather or not photosynthesis by these new species alone caused glaciation.

The book states that the initial colonization of land by plants was followed by cooling and abrupt glaciation. The CO2 levels were 20 times higher than todays concentrations and would need to be reduced by 50% to cause glaciation. Though weathering could help contribute to a decrease in CO2 levels; not enough to cause glaciation. The book says that early plants lacked roots, but showed they still …show more content…

Effects that could be caused by the collision of two plates, one could be that previously isolated populations to connect with other previously isolated populations and allow interbreeding which could help contribute to evolution. Another effect could be that when two plates meet that there is less shore lines, meaning less wet land and a decrease in moisture; which could lead to a decrease in rock weathering. This decrease in rock weathering could also lead to a increase in CO2 concentration because CO2 is needed for weathering, this change in CO2 concentration could also result in climate change.

3.) Analyze the factors that may have contributed to the Cambrian explosion.
The book states that multicellularity arose independently, which could have helped contribute the explosion in diversity of organisms evolving. Also help contributing to diversity is sexual reproduction which allows greater genetic diversity through processes of meiosis and crossing over. Also, the book states that the Cambrian explosion was right after the third Snowball Earth event, so this means climates could have been better suitable and help contributed to the rapid expansion. These are a the few topics talked about leading up the Cambrian explosion which could of help play a factor in the rapid

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