AP Environmental Science: Global Warming, Atmosphere, and Ecosystems

Population Equations and Crude Rates Update

• Alternate Population Equation: An alternate version of the population equation exists, though it is less common on the Advanced Placement (AP) Environmental Science exam.

• Rate Conversion: To calculate growth using crude rates, values are converted to "per thousand."     * $1\%$ is equivalent to $10$ per thousand.     * $0.5\%$ is equivalent to $5$ per thousand.

• Net Growth Calculation: The formula used is $\text{In} - \text{Out}$. Specifically:     * $(\text{CBR} + \text{Immigration}) - (\text{CDR} + \text{Emigration})$.     * In the example provided, converting the percentages to crude rates (e.g., $10 \text{ per } 1,000$ and $5 \text{ per } 1,000$) resulted in a calculated growth rate of $3\%$.

Consequences of Global Warming

• Surface-Level Consequences: These are the immediate, visible impacts of rising global temperatures:     * Ice Melting: Reduction in glacial and polar ice caps.     * Rising Sea Levels: Thermal expansion of water and meltwater contributing to higher oceans.     * Increased Global Temperature: Direct warming of the Earth's atmosphere and oceans.

• Deep-Level / Ecological Consequences: These are secondary but equally critical effects:     * Decrease in Biodiversity: Loss of various species due to habitat changes.     * Limiting Habitat Range: Restricting the geographic areas where specific organisms can survive.     * Increase in Diseases: Warming temperatures can expand the range of disease-carrying vectors (e.g., mosquitoes).

Greenhouse Gases and the Atmosphere

• The Big Four Greenhouse Gases:     1. Carbon Dioxide ($CO_2$): Primary driver of human-induced climate change.     2. Methane ($CH_4$): A potent greenhouse gas with a high heat-trapping capability.     3. Water Vapor: Often forgotten, but it is a major greenhouse gas because it is abundant and retains heat.     4. Ozone ($O_3$): Found in the atmosphere; there is a notable "hole" over Antarctica.

• Atmospheric Layers (Bottom to Top):     * Mnemonic: "Truly Stealthy Monkeys Thump"     1. Troposphere ($TR$): The lowest layer closest to Earth's surface. This is where weather occurs and where greenhouse gases are concentrated.     2. Stratosphere ($S$): The second layer. The Ozone Layer is located at the base of the stratosphere, between the troposphere and the stratosphere.     3. Mesosphere ($M$): The third layer.     4. Thermosphere ($TH$): The highest layer.

• Ozone Depletion and Legislation:     * CFCs (Chlorofluorocarbons): The primary chemicals responsible for depleting the ozone layer.     * The Montreal Protocol: Considered one of the most successful pieces of environmental legislation worldwide. It was passed to phase out and ban the use of CFCs globally to protect the atmosphere.

Ecosystem Components and Biological Cycles

• Biotic Components: Living parts of an ecosystem. Examples include animals, plants, and bacteria.

• Abiotic Components: Non-living, physical, and chemical elements of an ecosystem. Examples include air, water, and soil. These are essential for the survival of biotic components.

• Photosynthesis Reaction: The process by which plants convert light energy into chemical energy.     * Equation: $6CO_2 + 6H_2O \xrightarrow{\text{sunlight}} C_6H_{12}O_6 + 6O_2$     * Inputs: Carbon dioxide and water. Outputs: Glucose and oxygen.

• Cellular Respiration: The process performed by animals (humans included). It is the exact opposite of photosynthesis.     * Equation: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{Energy}$

• Age of the Earth: Approximately $4.5 \times 10^9$ years (4.5 billion years).

Species Classifications and Biodiversity

• Species Roles and Examples:     * Invasive Species: Zebra mussel (spreads and disrupts local ecosystems).     * Endemic Species: Species found in only one specific geographic location. Examples include the Galapagos Tortoise (Galapagos Islands) and Lemurs (Madagascar).     * Keystone Species: A species that has a disproportionately large effect on its environment relative to its abundance. They keep the ecosystem in balance and are often top predators. Examples include the American Alligator, Sea Otters (controlling sea urchins), and the Gray Wolf (Yellowstone).     * Indicator Species: Species that are very sensitive to environmental changes (pollution, temperature). Their health or presence indicates the state of the ecosystem. Examples include the Tiger Salamander (amphibians have thin skin and are vulnerable in both water and land).     * Generalist Species: Species that can live in various habitats and eat various foods. Example: Rat.     * Specialist Species: Species with a narrow niche and specific requirements. Example: Giant Panda (primarily eats bamboo).

• Biodiversity Definition: The variety of all living things on Earth.

• Agriculture History: Humans have engaged in agriculture for approximately $12,000$ years, beginning in areas like the Fertile Crescent (Mesopotamia).

• Synthetic: A term used for man-made products, such as synthetic fertilizers.

Global Geography and Environmental Phenomena

• The Equator: The line of latitude dividing the Earth into Northern and Southern hemispheres.

• Mid-Atlantic Ridge: The longest mountain range on the planet. Curiously, it is located underwater in the middle of the Atlantic Ocean between South America/North America and Africa.

• El Niño and La Niña:     * These phenomena involve the switching of cold and warm water currents off the western coast of South America (particularly impacting Chile).     * The reversal of upwelling affects fish production, as fish move further out to sea when water temperatures change.

• Regional Identifications:     * Ethiopia: Located in Central-Northern Africa.     * Brazil: Contains the Amazon Rainforest in South America.     * Bangladesh: Located in Asia, near India.

World Biomes: Characteristics and Adaptations

• Tropical Rainforest:     * Location: Along the Equator (e.g., South America).     * Climate: Hot and wet.     * Adaptations: Homeostasis/sweating (mammals), nocturnal behavior (to avoid heat), camouflage, and mimicry (to reduce competition and avoid predators).

• Temperate Deciduous Forest:     * Location: USA (Midwest).     * Climate: Moderate temperature and rain. It is one of the only biomes with four distinct seasons.     * Adaptations: Hibernation, seasonal flexibility (withstanding cold and hot).

• Taiga (Boreal/Coniferous Forest):     * Location: Russia, Canada, Alaska.     * Climate: Cold with low precipitation.     * Adaptations: Hibernation, thick insulating fur, seasonal coat color changes. Husky eyes (blue) are an evolutionary adaptation to better reflect the bright sunlight bouncing off white snow.

• Tropical Grassland (Savannah):     * Location: Central Africa.     * Climate: Dry and warm. Frequent fires occur.     * Adaptations: Long necks (Giraffes) to reach high leaves, water-storing trees (the Baobab tree), fire-resistant thick bark, and shedding leaves during dry seasons.

• Temperate Grassland (Prairie):     * Location: US Midwest (e.g., Illinois, Kansas). Known as the "Bread basket" or "Wheat belt."     * Climate: Moderate temperature and rain; also features four seasons.     * Adaptations: Deep root systems, flexible stems (grasses).     * Note: The Markham Prairie in Markham is a famous example of an original, primary prairie fragment used for research by universities like the University of Illinois at Urbana-Champaign.

Questions & Discussion

• Question: Could you post the finished worksheets online?

• Response: Yes, that was the intention.

• Question: What makes the lemurs in Madagascar and the tortoise in the Galapagos similar?

• Response: They both only live in one place, which means they are endemic species.

• Question: What is the difference between specialist and endemic?

• Response: Specialist refers to a species having very specific needs (like food), whereas endemic refers to a species being found in only one geographic location.

• Question: Is the alligator an indicator?

• Response: No, the alligator is a keystone species. It is a top predator that keeps the populations of other species in check.

• Question: Why do huskies have blue eyes?

• Response: It is an evolutionary adaptation. Since snow is white and reflects all colors of light, it can be very bright. Blue eyes help the husky reflect some of that light to see better.