Why do the leaves of plants change color and fall in the autumn? What is hibernation and why do some animals engage in it? What types of animals, generally, hibernate?

First image of earth from space. Taken by Jim Lovell aboard Apollo 8 on 12/24/68.

Weather is the daily condition of Earth’s atmosphere at a particular place and time. Climate is the average yearly conditions of temperature and precipitation in a region. Climate is caused by: Trapping of heat in the atmosphere Latitude Transport of heat by winds and ocean currents Amount of precipitation Shape and elevation of landmasses

The greenhouse gases are atmospheric gases that trap infrared radiation (heat energy) that has been reflected off the Earth’s surface thus maintaining Earth’s temperature range. The natural event in which heat is retained by this layer of greenhouse gases is called the greenhouse effect. Sunlight Earth’s Surface Atmosphere Some heat escapes into space Greenhouse gases trap some heat

Could we survive without the greenhouse effect? No, Earth would be too cold for many organisms to survive, including human beings. Can you name any greenhouse gases? Think about cycles of matter… Water Vapor – evaporation (water cycle) Carbon Dioxide (CO2) – burning fossil fuels, deforestation, volcanic eruptions Methane (CH4) – decomposition/decay, livestock waste Nitrous Oxide (N2O) – fertilizer, fossil fuels, denitrification Synthetic gases (e.g. CFCs) – industrial processes

Remember from our last class that carbon dioxide is released from a variety of sources. A major contributor to atmospheric CO2 is human activity. Levels of CO2 in the atmosphere have risen dramatically sense the advent of the industrial revolution. Why do you think this is the case? In 1850, just before the industrial revolution the [CO2] in the atmosphere is estimated at about 274 ppm. In August 2015, the [CO2] in the atmosphere was over ppm.

What do you think are some potential effects of increased CO2 in the atmosphere?

Some potential effects of increased [CO2] could be: Increased growth/productivity by vegetation (increased levels of photosynthesis). Why? C3 plants (rice, wheat, soybeans) are more limited by CO2 availability than C4 plants (sugarcane, corn) so C3 plants may spread into C4 areas. A link between increased CO2 and increased temperature exists. So when [CO2] rises, temperature rises. Why? What are some potential results, globally and locally, from rising temperatures?

The Holocene Extinction is the present, widespread, ongoing extinction during the current Holocene Epoch. This is the Sixth Great Extinction, the largest since the one that killed off the last of the terrestrial dinosaurs. The Holocene Extinction has been going on since about 11,000 BCE and has been attributed to anthropogenic causes by a majority of biologists. Human-induced climate change, overexploitation, deforestation, and the introduction of non-native species may have all played a role.

Because all species are interdependent upon one another, what is the potential impact of losing any one species? The brazil nut, the tree from which the name of the edible nut is derived, is one of the most massive and important trees in the Amazon. Only one creature, a rodent called the Agouti, can crack the shell, thus allowing the tree to reproduce. Video: tree/bertholletia-excelsa/video-11.htmlhttp:// tree/bertholletia-excelsa/video-11.html Video:

The polar bear is listed as threatened. It is considered a vulnerable species. Habitat loss is the main threat to polar bears. It was the first species to be listed as threatened due to global warming.

There are literally thousands of examples of species’ interdependence. Many flowers have evolved to be dependent upon insects for pollination. Can you think of an example? The Holocene Extinction is generally thought to have begun with the extinction of the megafauna at the end of the last Ice Age. Many of these species were hunted to extinction, while others lost their sources of food due to human overexploitation.

The Wooly mammoth (Mammuthus primigenius) The theory of its extinction is controversial. Most scientists believe it was due to climate change, overhunting, or a combination of the two.

The Saber- toothed Cat (Smilodon populator) Extinction causes thought to be similar to mammoth’s. Likely due to overhunting by humans.

Baiji (Lipotes vexillifer) Freshwater river dolphin from China ‘Effectively Extinct’ 2006 Caused by humans: pollution in rivers, habitat destruction (dams), fishing, collisions with boats.

Javan Tiger (Panthera tigris sondaica) Subspecies of tiger on Indonesian island of Java. Extinct in 1980s due to hunting and habitat destruction.

If trends continue, what species will most likely survive? Why? If trends continue, what species will most likely go extinct? Why? How is this related to global climate change?