Chapter 3: Matter, Energy, and Life

1. Chapter 3: Matter, Energy, and Life Define matter, atoms, molecules Define energy and energy flow Define basic fundamentals of Ecology

2. I. From Atoms to Cells • A. General Information • 1. Ecology – The study of the relationships between organisms and their environment • Studies the life histories, distributions, and behaviors of individual species • Studies the structure and function of naturals systems at the level of populations, communities, ecosystems, and landscapes

3. I. From Atoms to Cells • A. General information • 2. Holistic approach to ecology • Uses systems to study interactions • Observe the interconnected nature of systems and organisms within • B. Atoms, Molecules, and Compounds • 1. Matter – everything that has mass and takes up space • It exists in 3 distinct states • Solid, liquid, and gas

4. I. From Atoms to Cells • B. Atoms, Molecules, and Compounds • Atoms have unique chemical forms called Elements • Cannot be broken down into simpler forms by ordinary chemical reactions • 4 elements make up 96% of the mass of all organisms • The elements are O, C, H, N • 2. Atoms - the smallest particles that exhibit the characteristics of the element • Composed of electrons, protons, and neutrons

5. I. From Atoms to Cells • Atomic number is the number of protons and is used to form the periodic table • The number of neutrons may differ creating isotopes • Atoms can join together to form molecules • Molecules are any two atoms joined together • Compounds are molecules created with different types of atoms • Chemical bonds hold atoms together • 2 major types of bonds are ionic and covalent

6. I. From Atoms to Cells • 3. Ions • Make up acids and bases • Unequal numbers of electrons and protons • Positive ions form acids (give up electrons readily, i.e. electron donors) • Negative ions form bases (can bond easily with hydrogen ions, i.e. electron acceptors) • The number of free hydrogen (hydronium) ions and hydroxide ions in solution is used to create the pH scale

7. I. From Atoms to Cells • 4. Organic Compounds • Some elements are used, by organisms, in abundance • Some elements are used, by organisms, in trace amounts • Any compound containing carbon is called an organic compound • 4 major categories of organic compounds • Carbohydrates • Sugars, instant energy

8. I. From Atoms to Cells • Lipids • Fats and oils • Also called hydrocarbons • Long chains of carbon with 2 Hydrogen atoms attached • Proteins • Made up of amino acids • Composed of amine group and carboxyl group

9. I. From Atoms to Cells • Nucleic acids • Made up of deoxyribose, phosphate group and a nitrogen base • DNA • 5. Cells • Fundamental units of life • Some are single-celled • Bacteria, algae, protozoa • Some are multi-celled • Plants, animals, fungi

10. I. From Atoms to Cells • 5. Cells (cont.) • Chemical reactions occur because of enzymes • Otherwise cells would burn up due to the combustion of metabolism • Energy transfer is called metabolism in cells • For example, sugar to ATP

11. II. Energy and Matter • 1. General Information • Essential constituents of all living organisms • Energy provides the force to hold structures, tear apart structures, and move materials • 2. Energy Types and Quantities • Energy is defined as the “ability to do work” • Kinetic Energy – is the energy of movement

12. II. Energy and Matter • Potential Energy – is stored energy, the energy of position • Chemical Energy – is the energy stored in the food you eat, energy of chemical bonds • Measured as Joules (physics), BTU’s (propane), and Calories (food) • Power is the rate of doing work • Heat describes the total energy not used in the movement of an object; lost energy

13. II. Energy and Matter • Temperature is the speed of motion of an atom • 3. Conservation of Matter • Matter, like energy, is neither created nor destroyed • Called the Conservation of Matter • Matter is transformed and combined

14. II. Energy and Matter • 4. Thermodynamics and Energy Transfers • Organisms use gases, water and nutrients • Metabolism – waste products are returned to the environment in a different form (by-products) • Energy is not recycled (in the biosphere) • Must provide energy from an external source

15. II. Energy and Matter • Energy has a one-way path that eventually ends up in a low-temperature sink • First Law of Thermodynamics • Energy is conserved • Cannot be created nor destroyed, only transferred from one form to another form • Second law of Thermodynamics • As energy is transferred or transformed, there is less energy to do work • Energy is ‘lost’ to the environment

16. II. Energy and Matter • Recognizes a tendency of all natural systems to go from a state of order toward a state of increasing disorder • Entropy – “Entropy Rules!” • Also called the ‘Chaos Theory’ • For example: Life to Death

17. III. Energy for Life • 1. Solar Energy: Warmth and Light • Organisms survive at different temperature ranges • Low temps affect metabolism negatively, not enough energy produced to survive • High temps break down molecules rendering them non-functional • Photosynthesis converts sunlight into organic compounds that can be used as energy

18. III. Energy for Life • 1. Solar Energy: Warmth and Light • Cellular respiration converts the organic compounds of photosynthesis into ATP

19. IV. From Species to Ecosystems • 1. Populations, Communities and Ecosystems • Species are all of the organisms that are genetically similar enough to reproduce viable offspring • Populations consist of all of the members of a species living in a given area at a given time • Extinctions can be large scale (complete) and small scale (local)

20. IV. From Species to Ecosystems • 1. Populations, Communities and Ecosystems • A community is all of the populations of organisms living and interacting in a particular area • An ecosystem is the biological community and its physical environment • Boundaries between communities and ecosystems may be difficult, but must occur • Ecosystems are separated based on communities, climate, and productivity of the communities

21. IV. From Species to Ecosystems • 2. Food Chains, Webs, and Trophic Levels • Primary Productivity is the amount of biomass produced in a given area • Higher productivity ecosystems – TRF, TSF, and Wetlands • Lower productivity ecosystems – Deserts, Tundra • Net Primary Productivity includes decomposition and can change the scale of productivity • TRF is no longer a high productivity ecosystem

22. IV. From Species to Ecosystems • 2. Food Chains, Webs, and Trophic Levels • Consumption of plants is considered Secondary productivity • Food Chains are a linking of feeding series between organisms • For example, Grass  Grasshopper  Frog • Or Grass  Cow  Man (steak, yeah baby!) • In communities, consumers have primary food sources • Will eat that food source first • Some consumers have secondary food sources • Don’t compete as well for this food source

23. Food Chain

24. Food Web

25. IV. From Species to Ecosystems • 2. Food Chains, Webs, and Trophic Levels • Some consumers are opportunistic • Stumble on food (not the norm) • Will eat primary food source, but will anything it happens across • Typically are called omnivore • Examples are bears, raccoons • A Trophic Level is an organisms ‘feeding’ status • Producers are the first trophic level (autotroph)

26. IV. From Species to Ecosystems • Primary consumers are the second trophic level (herbivore) • Secondary consumers are the third trophic level (carnivore) • There is energy ‘loss’ at each trophic level • Typically the consumer receives 1/10th of the energy… 9/10th is lost • Most food chains are 3 trophic levels, some are 4, very few are 5 • Due to the energy loss during each consumption

28. IV. From Species to Ecosystems • Tertiary consumers are either top carnivores or scavengers (third, fourth, or fifth trophic level) • Detritovores consume leaf litter, debris, and dung (third, fourth, or fifth trophic level) • Decomposers finish the break-down process of materials (third, fourth, or fifth trophic level) • Turns the material into very elemental forms

30. IV. From Species to Ecosystems • 3. Ecological Pyramids • Number of organisms (by percent) in each trophic level • Can be used to describe the available energy for habitats, communities, or ecosystems

32. V. Material Cycles and Life Processes • 1. The Carbon Cycle • Has 2 purposes for organisms • Structural component of organic molecules • Energy storage in the chemical bonds • Starts with CO2 intake by producers • Carbon is incorporated into sugar • Sugar is burned in all organisms through Cellular Respiration, releasing CO2 into the ecosystem

33. V. Material Cycles and Life Processes • 1. The Carbon Cycle (cont.) • Some carbon is lost to ‘carbon sinks’ • Ex. Coal, Oil, and Trees • Carbon is not released until combustion • Calcium Carbonate (CaCO3) is incorporated into shells of organisms • Very difficult to break down, especially in anoxic conditions at the bottom of lakes and oceans

35. V. Material Cycles and Life Processes • 2. The Nitrogen Cycle • Organisms can not exist without organic compounds comprised of Nitrogen • Ex. Proteins, nucleic acids, amino acids, etc. • Inorganic forms of Nitrogen are utilized by plants to form organic compounds • Nitrogen is the most abundant element in the atmosphere, but it is unusable as N2

36. V. Material Cycles and Life Processes • 2. The Nitrogen Cycle (cont.) • The nitrogen cycle provides usable N for plants • Nitrogen-fixing bacteria turn the N2 into usable N for plants (NH3 : ammonia) • Nitrite forming bacteria change NH3 into NO2 (nitrite) • Nitrate forming bacteria converts NO2 into NO3 (nitrate) • NO3 is used by the plants

37. V. Material Cycles and Life Processes • 2. The Nitrogen Cycle (cont.) • Plants convert NO3 into NH4 (ammonium) • NH4 is used to create amino acids • Nitrogen re-enters the system when organisms die through decomposition • Nitrogen, also, re-enters the system through metabolic waste (uric acid) • Urination dumps nitrogen (called pulses) into streams, rivers, and soil • Bacteria consume and turn the waste into NH3

39. Root Nodules containing N-fixing bacteria

40. N-fixing bacteria

41. V. Material Cycles and Life Processes • 3. The Phosphorus Cycle • Phosphorus is used by organisms for energy transfer processes • Major component of fertilizers • Begins with phosphorus leaching from rocks into groundwater • Inorganic phosphorus is absorbed by producers • Turned into organic compounds

42. V. Material Cycles and Life Processes • 3. The Phosphorus Cycle • Reintroduced to the environment through decomposition of organic material

44. V. Material Cycles and Life Processes • 4. The Sulfur (Sulphur) Cycle • Used in proteins • Determine acidity of rainfall, surface water, and soil • Most is in the form of rocks and minerals • Iron disulfide (FeS2), calcium sulfate (CaSO4) • Inorganic sulfur is released into the atmosphere as SO2 and SO4 (Sulfate)

45. V. Material Cycles and Life Processes • 4. The Sulfur (Sulphur) Cycle (cont.) • Sulfur has many oxidative states • Ex. Hydrogen Sulfide (H2S), Sulfur Dioxide (SO2), Sulfate ion (SO4-), and S (elemental) • Human activities release sulfur • Ex. Burning of fossil fuels • Phytoplankton release large quantities of sulfur to the atmosphere (especially during warming trends) • DMS  SO2  SO4 (DMS is Dimethylsulfide) • Increases the earth’s albedo