Author: Zach
LC11. Climate and Human Evolution
Chapter 11 { Life and Climate Contents } Paleoanthropologists—scientists who study the physical evolution of humans—call our species Homo sapiens. This means that we are part of a category of individuals who share common characteristics, the genus Homo, and that within that genus our group or species is called “sapiens.” Fossil evidence shows that there […]
LC10. The Ice Ages
Chapter 10 { Life and Climate Contents } I. The Climate Record During the Cretaceous period, the dinosaurs enjoyed a climate much warmer than we have today; however, other periods were much colder than it is now. In recent years paleoclimatologists (scientists who study past climates during the Earth’s history) have gathered evidence of ice […]
LC9. What Happened To the Dinosaurs?
Chapter 9 { Life and Climate Contents } For about 150 million years dinosaurs were the dominant animal life on our planet. Then, 65 million years ago, dinosaurs became extinct. That was bad news for the dinosaurs but good news for the small mammals that managed to survive. Since they no longer had to compete […]
LC8.1. Dissolving Rocks
{ Life and Climate Contents } { All GSS Books } In the laboratory, you can simulate the process of chemical weathering by setting up an arrangement as shown here. This apparatus will allow you to control drops of soda water (carbonic acid, H2CO3) to drip onto limestone (CaCO3) for a few days, and collect […]
LC8. Highs and Lows Over the Past 750 Million Years
Chapter 8 { Life and Climate Contents } Volcanoes that occur near the edges of continents are called strato or ash volcanoes. Volcanoes like Mount St. Helens were responsible for major changes in past climates because of the important role they played in the long-term carbon cycle. While they sometimes produce lava, they are more […]
LC7.1. Observing Convection Currents
{ Life and Climate Contents } { All GSS Books } (This activity also appears in GSS Energy Use chapter 3) Model 1: Adapted from GEMS Convection Activity This model uses water, food coloring as a marker of currents in the water, and a cup of very hot water as a heat source. Movie clips of […]
LC7. Earth’s Shifting Crust
Chapter 7 { Life and Climate Contents } I. Dinosaurs in Antarctica? In 1991, exploring just 400 miles from the present-day South Pole, geologists discovered the remains of dinosaurs! This discovery confirmed what many scientists had inferred—that 200 million years ago Antarctica had a warm climate, with forests and flowing rivers, giant fern trees, dinosaurs, […]
LC6. How and When Did Complex Life Begin?
Chapter 6 { Life and Climate Contents } I. Discovery of the Earliest Complex Life Forms For a long time it was thought that complex life forms, which can be seen without the aid of a microscope, started to evolve during the Cambrian period, which lasted from about 570 million years ago to about 505 […]
LC5. The Origin of Our Oxygen-Rich Atmosphere
Chapter 5 { Life and Climate Contents } Today our atmosphere consists mostly of nitrogen (about 78%) and oxygen (21%) plus carbon dioxide and other trace gases (about 1%). The nitrogen is injected into the atmosphere during volcanic eruptions. The reason nitrogen is so plentiful in the atmosphere is that it does not easily combine […]
LC4. The Beginning of Life on Earth
Chapter 4 { Life and Climate Contents } One fundamental question that scientists have asked is: how did life on Earth begin? Many theories have been suggested in answer to this important question; we will present two of them. First, however, we’ll describe the most ancient fossils discovered so far, and significant laboratory experiments that […]