AP Biology Activities - Ch. 25 & 26

AP Biology Activities - Ch. 25 & 26 - CHAPTER 25...

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CHAPTER 25 Activity: “Grand Canyon Video” The Colorado River, about 35 million years ago, changed its direction towards the southeast when the Kaibab Plateau rose. The river noew flows into the Gulf of Mexico instead of the pacific. 12 million years ago the river’s path was blocked, causing lake Bidahochi to form. But was later drained when the Colorado river was reconnected. The river flowing through the area which was the lake cut deep canyons, creating the Grand Canyons. There has been gradual erosion over the past nine million years, and the layers, or strata, of sedimentary rocks are clearly visible, with the oldest at the bottom. Analyzing fossils from each stratum has taught us about the diversity of life forms. The course of the river has led to specific land formations such as the bluffs. This theory was first proposed by Scottish geologist James Hutton near the beginning of the 19th century. He theorized that we could attribute the formation of various land forms, such as canyons, to mechanisms currently operating, such as erosion by rivers. Activity: A Scrolling Geological Time Scale Using fossil records, geologists have put together a geologic record that shows the large-scale extinctions and enormous radiation of many diverse new life forms Precambrian Time: (began at least 4,600 million years ago 542 million years ago) life began as the first prokaryotic cells and cyanobacteria appeared, and the first animals. Paleozoic Era: (542 million years ago 251 million years ago) origin of most modern animal phyla, first plants, jawless fish, bony fish, and amphibians evolved. Amphibians became the dominant vertebrate life
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AP Biology Activities - Ch. 25 & 26 - CHAPTER 25...

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