Ecosystems

1. Biomes

  - Desert Biome
    - Characterized as the driest biome out of all biomes.
    - Receives very little precipitation.

  - Cold Biome
    - Consistently cold year-round.
    - May experience slightly milder temperatures in summer.
    - Ground is permanently frozen, referred to as permafrost.
    - Features very low biodiversity and lacks trees.

2. Climatic Patterns

  - Equatorial Characteristics
    - Tropical rainforests located along the Equator.
    - Temperature decreases as one moves away from the Equator, both north and south.
    - Dewiness and Precipitation Patterns
      - It’s very wet at the Equator where tropical rainforests exist, contrasted with dry conditions at approximately 30 degrees north and south of the Equator.
      - Warm, moist air rises at the equator and loses moisture as it moves north or south, resulting in deserts at these latitudinal points.

  - Temperature Exceptions
    - Elevation can lead to surprising temperature drops; for instance, at 10,000 feet above sea level, it can be much colder even at the Equator.

3. Rain Shadow Effect

  - Definition: A phenomenon that results in one side of the mountain being lush and wet while the other side is dry due to the topography.
  - California Example
    - Air from the Pacific Ocean moves inland, rises as it meets the Sierra Nevada Mountains, cools, and drops precipitation on the western side.
    - The eastern side becomes dry as the air loses moisture.
    
  - South American Example
    - The Andes Mountains cause similar effects; the eastern slope experiences heavy rainfall while the western side remains arid.
    - This area is known for being the driest place on Earth, in stark contrast to the lush Amazon Rainforest on the opposite side.

4. Coastal Climate Factors

  - Lima, Peru: An example of extreme dryness despite proximity to the equator due to the cold Humboldt Current from the South Pole, leading to a cold climate.
    - Little to no rain; average yearly precipitation is extremely low, mere millimeters.
    - The phenomenon referred to as ocean moisture can occur at night, resembling rain without actual precipitation.

5. Heat Island Effect

  - Definition: The increased temperature in urban areas compared to surrounding rural areas due to human activity, buildings, and roads.

6. Ecosystem Energy Flow

  - Energy Transfer in Ecosystems
    - Energy flow in ecosystems is unidirectional; energy from the sun is captured by plants (autotrophs) via photosynthesis, converting it into glucose (C6H12O6).
    - Primary consumers (herbivores) eat producers and transfer energy, but the flow is highly inefficient—generally, only 10% of energy is transferred to each subsequent trophic level.
    - Trophic Levels
      - Producers (plants) > Primary Consumers (herbivores) > Secondary Consumers (carnivores) > Tertiary Consumers (top predators).

7. Food Chains and Food Webs

  - Food Chain: A linear representation of energy transfer from one organism to another.
  - Food Web: A complex network illustrating multiple connections between different organisms, showcasing more realism than a food chain.
    - Examples of consumers include:
      - Squirrel: A secondary consumer since it can consume both plants and primary consumers (grasshoppers).

8. Biological Magnification

  - Definition: The increasing concentration of toxins up the food chain.
    - Example with DDT: Initially used as a pesticide, it caused eggs of birds to become soft and resulted in population decline.
    - Rachel Carson documented this phenomenon, showing how DDT concentrations increased significantly from primary consumers to quaternary consumers, posing serious ecological threats.
    

9. Environmental Impact of Mercury

  - Sources of Mercury Pollution: Often originates from burning coal in power plants, which releases mercury into the atmosphere and subsequently into waterways.

10. Energy Loss in Trophic Levels

  - Only 10% of energy is passed to the next higher trophic level, meaning that with each transfer, a majority of energy (90%) is lost, leading to fewer organisms at higher trophic levels.

11. Carbon Cycle

  - Carbon Cycle Mechanics: Carbon is cycled through photosynthesis (plants convert CO2 into glucose) and cellular respiration (organisms metabolize glucose, releasing CO2 back into the atmosphere).

  - Human Contributions: The extraction and burning of fossil fuels release stored carbon back into the atmosphere, contributing to atmospheric CO2 levels, hence exacerbating climate change.

WATER CYCLE

The water cycle is a continuous process through which water moves in various forms from one part of the Earth to another. It involves several key stages:

  1. Evaporation: Water from oceans, rivers, and lakes is heated by the sun and transforms into water vapor, rising into the atmosphere.

  2. Condensation: As the water vapor rises, it cools and condenses to form clouds. This stage is influenced by temperature and pressure changes in the atmosphere.

  3. Precipitation: When the clouds become heavy with water droplets, they release the moisture in the form of rain, snow, sleet, or hail, depending on atmospheric conditions.

  4. Collection: The precipitation gathers in bodies of water like rivers, lakes, and oceans. Some water also infiltrates into the ground replenishing groundwater supplies.

  5. Transpiration: Plants also contribute to the water cycle by absorbing water through their roots and releasing water vapor through their leaves, a process called transpiration.

This cycle is vital for maintaining ecosystems and supports life on Earth by distributing fresh water, regulating climate, and nourishing plants and animals.