Cenozoic Era Environment
During the Paleogene Period, the climate cooled and dried. Sea surface temperatures rose between 9 and 14 degrees Fahrenheit over a few thousand years which killed many single-celled marine organisms called foraminifera and it also killed some other invertebrates. This event affect northern forests and land mammals diversed into many different forms. During the Neogene Period, mountains rose and sea levels fell and the climate cooled and dried. The continents started to crash together. India crashed into Asia which made the Himalaya mountains. Italy crashed into Europe which made the Alps. Spain crashed into France and made the Pyrenees. These high mountains changed the air circulation and weather which made the climate drier and cooler. The Arctic ice cap grew and thickened and snow and ice gathered on high mountains. Later, South America and North America merged which made the Isthmus of Panama. During the Quaternary Period, there were ice ages that lasted about 100,000 years and after that there were warmer interglacial periods that lasted about 10,000 to 15,000 years each. About 10,000 years ago is when the last ice age ended. The sea levels also rose rapidly. When the temperatures drop and the ice sheets spread, they freeze so much water that sea levels fall. Land bridges form between continents that allow animals and humans to move from one landmass to another landmass. When the weather becomes warm, the ice melts and shows that reshaped mountains that have rivers. The rivers flow down to great basins and make many lakes. During the warm periods, the plants and animals that went to the equator for warmth, move back to higher places.