This document provides an overview of key principles of ecology, including matter, energy and biochemical cycles. It discusses the basic building blocks of life, like cells, organisms, and populations. It covers concepts like energy transformations, conservation of matter, and the laws of thermodynamics. It also summarizes important biogeochemical cycles like carbon, nitrogen, water and others that are essential to life.

1. Principles of Ecology: Matter, Energy and Life

3. Part 1: Principles of Matter and Energy To understand how ecosystems function, it is important to first know something about how energy and matter behave - in the universe and in living things. It is also important to understand the basic building blocks of life, starting with cells and organisms, and proceeding to communities and populations.

9. Properties of Energy Energy cannot be recycled. Energy is reused, but it is constantly degraded or lost from the system. Most energy used in ecosystems originates as solar energy. Green plants convert some of this energy to chemical energy, which is then converted to heat or kinetic energy by the animal that eats the plant.

10. Laws of Thermodynamics First Law of Thermodynamics Energy cannot be created or destroyed, only changed Second Law of Thermodynamics With each successive energy transfer or transformation in a system, less energy is available to do work. Even though the the total amount of energy remains the same, the energy's intensity and usefulness deteriorate. The second law recognizes the principle of entropy , the tendency of all natural systems to move towards a state of increasing disorder.

11. The Building Blocks of Earth and Life The basic units of matter are called “elements”, which can’t be subdivided chemically into smaller units. Elements make up molecules and compounds. It is important to understand basic chemistry in order to understand the critical role of chemistry in Environmental Science.

13. Fig. 2.3

14. Periodic Table of the Elements

15. Elements and Environmental Science Just four elements - carbon, hydrogen, oxygen, and nitrogen - make up over 96% of the mass of most organisms.

17. Fig. 2.4

19. Fig. 2.5

20. Water Molecule

24. The Electromagnetic Spectrum The wavelengths of visible light drive photosynthesis.

25. Photosynthesis

26. Light and Dark Reactions of Photosynthesis

27. Energy Exchange in an Ecosystem

29. Food Web: Cross-connected Food Chains

31. Energy Pyramid Most energy in most ecosystems is stored in the bodies of primary producers . Only about 10 percent of the energy at one energy level passes to the next highest trophic level.

32. The Water Cycle

33. The Carbon Cycle

34. The Nitrogen Cycle

35. Nitrogen Fixation The nodules on the roots of this plant contain bacteria that help convert nitrogen in the soil to a form the plant can utilize.

36. The Phosphorous Cycle

37. The Sulfur Cycle