Presentation on theme: "1. What are nitrogen fixers, and why are they important? 2. __________ break dead organisms down into matter. This adds carbon and nitrogen back into the."— Presentation transcript:
1. What are nitrogen fixers, and why are they important? 2. __________ break dead organisms down into matter. This adds carbon and nitrogen back into the ecosystem. 3. Giant panda bears have a very low birth rate. Before they became a protected species, they were frequently poached, and lost much of their old habitats. Did they have a positive or negative growth rate?
What determines our climate?
Climate refers to the average yearly conditions of temperature and precipitation. ◦ Contrast with weather, the day-to-day conditions. The biggest difference between climate and weather? Weather changes frequently each day, but climate rarely changes from year to year.
Climate is determined by several factors. 1. How well heat is trapped by the atmosphere. 2. The latitude (north-south position) of each region. 3. The presence of wind and ocean currents. 4. The amount of precipitation present.
Our atmosphere contains trace amounts of important greenhouse gases – gases that are capable of trapping heat energy. ◦ Greenhouse gases include carbon dioxide, methane and water vapor. Greenhouse gases trap heat energy, which keeps our atmosphere warm. ◦ Without them, Earth would be 30 degrees Celsius cooler. That amounts to 86 degrees Fahrenheit! However, too many greenhouse gases is not a good thing, either!
Due to Earth’s shape and its tilted axis, the Earth does NOT receive sunlight evenly. Sunlight is the primary means of heating up the atmosphere. Therefore, certain parts of Earth get a lot of direct sunlight, and are quite warm. Other parts of Earth get little direct sunlight, and are quite cold.
The polar zones are at the very top and bottom of Earth. They get very little direct sunlight; the sun’s rays are at very low angles. These regions are cold year-round.
The tropical zone is located around the equator. This region gets direct sunlight almost all year round. As such, this region is quite warm year- round.
The temperate zones are located in between the polar and tropical zones. The angle of sunlight varies greatly during the year. As such, climate changes from hot to cold, based on the seasons.
Throughout Earth, warm air and water rises, and cool air and water sinks. This principle is known as convection. Convection causes air currents, better known as wind. Convection also causes many ocean currents. Wind also produces ocean currents. Currents transport heat all over Earth. Warm currents keep climate moderate, and cool currents make climate cold.
Areas close to large bodies of water are likely to see a lot of precipitation. ◦ Why? Mountain ranges create rain shadows. Basically, clouds are forced upward due to the mountain range, which cools them down. This makes precipitation much more likely, and the cloud disappears. As a result, the other side of the mountain is a lot less likely to get precipitation, creating a dry climate behind the mountain range.
1. What is the difference between climate and weather? 2. ___________ gases trap heat in the atmosphere, which keeps Earth warm. 3. The [polar, temperate, tropical] zone(s) have the largest range of possible climates. 4. The [polar, temperate, tropical] zone(s) receive little direct sunlight. 5. True or false: In convection, cool air rises, and warm air sinks.