Introduction

• Quotation of Galileo highlights the vastness of the universe and yet the singular focus of the sun in ripening grapes.

Basic Inputs for Life

Matter

• Definition: Any physical substance that has mass and occupies space (volume).

Energy

• Definition: The ability to perform work.

Composition of Matter

Atoms

• Definition: The smallest particle that retains the properties of an element.

• The Periodic Table lists all known elements (types of atoms).

Discovery of Oxygen

Joseph Priestley

• Proposed air was a composition of gases.

• Discovered oxygen through experiments with a candle and a mouse in sealed jars.

Structure of Atoms

Subatomic Particles

• Protons: Positively charged, within the nucleus.

• Neutrons: Neutral, within the nucleus.

• Electrons: Negatively charged, orbit the nucleus.

Chemical Bonds

• Atoms can bond to form molecules (e.g., oxygen gas as O2 molecules).

Composition of Air

• Primarily consists of:

  • Nitrogen: 78%

  • Oxygen: 21%

  • Trace gases: 0.02% Carbon Dioxide, 0.03% other gases.

Photosynthesis

Jan Ingenhousz

• Repeated Priestley's experiment, demonstrating that plants produce oxygen when exposed to sunlight.

Forms of Energy

Types

• Potential Energy: Stored energy, based on position or chemical arrangement.

• Kinetic Energy: Energy of motion.

Electromagnetic Spectrum

• Energy travels in waves with various wavelengths.

  • Types include: Radio, Microwave, Infrared, Visible Light, Ultraviolet, X-ray, Gamma Ray.

Sources of Energy for Life on Earth

• The sun is the primary energy source, providing energy in three forms:

  • Ultraviolet: Penetrates living tissue, may cause damage.

  • Visible: Detected by human eyesight.

  • Infrared: Represents heat energy.

Plant Growth and Photosynthesis

• Plants absorb visible light energy (except green) for growth.

• Nicolas de Saussure: Demonstrated mass gain in plants comes from water and carbon.

• Overall process: 6 H2O + 6 CO2 + solar energy → C6H12O6 + 6 O2 (photosynthesis).

Cellular Respiration

• Other organisms (animals, fungi) utilize cellular respiration to extract energy by breaking down consumed organisms:C6H12O6 + 6 O2 → 6 H2O + 6 CO2 + energy.

• Photosynthesis and cellular respiration are complementary processes in ecosystems.

Thermodynamics in Ecosystems

Laws of Thermodynamics

1. Energy cannot be created or destroyed, only transformed (Law of Conservation).

2. Some energy is lost as heat in transformations; this energy is unavailable for work.

Ecological Structures

Atmosphere Layers

• Troposphere: 0 - 11 miles, contains weather.

• Stratosphere: 11 - 30 miles, contains ozone for UV protection.

Major Spheres of Earth

• Lithosphere: Earth's crust.

• Hydrosphere: All water on Earth.

• Biosphere: Regions of Earth that support life.

Levels of Ecology

• Organisms: Individual species.

• Populations: Groups of the same species.

• Communities: Interactions among populations.

• Ecosystems: Communities plus nonliving factors.

• Biosphere: Global sum of all ecosystems.

Energy Flow in Ecosystems

Food Chains

• Illustrate energy movement among organisms.

• Trophic levels:

  • Producers: Convert sunlight into energy.

  • Consumers: Ingest plants/animals.

  • Decomposers: Break down dead matter.

Ten Percent Rule

• 10% of energy transfers to the next trophic level, while 90% is lost as heat.

Biogeochemical Cycles

Matter Flow

• The Earth is a closed system for matter; essential elements are recycled through biogeochemical cycles (e.g., carbon, nitrogen cycles).

Water Cycle

• Water continuously recycled through the hydrologic cycle:

  • Processes include evaporation, transpiration, precipitation, and infiltration.

Nitrogen Cycle

Nitrogen Transformation

• Nitrogen fixation and decomposition ensure nitrogen returns to the ecosystem.

Conclusion

• All water on Earth is ancient, with historical significance from prehistoric times.

• Charles Fishman: Water's timeline highlights its cyclical nature throughout Earth's history and evolution.