1. Ecosystems: What Are They and How Do They Work?
G. Tyler Miller’s
Living in the Environment
14th Edition
Chapter 4

2. Key Concepts
Basic ecological principles
Major components of ecosystems
Matter cycles and energy flow
Ecosystem studies
Principles of Sustainability

3. The Nature of Ecology
Oilos “place to live” and logos “study of” The study of how organisms interact with each other and their environment.
Organism: any form of life.
Cell types: Eukaryotic = membrane bound nucleus, Prokaryotic = first cell no membrane bound nucleus.

4. Microbes: invisible rulers of the earth
Mostly Prokaryotes but some Eukaryotes.
Microbes are ubiquitous… that means EVERYWHERE.
Billions in your body, on your skin, in the soil… EVERYWHERE.
Bacteria (prokaryotes), protozoan, fungi, etc. Most are too small for us to see.
Bad things microbes are usually known for: infectious disease, fungal infections, malaria.
Good things: vital role in producing many foods: bread,cheese, yogurt, vinegar, sauerkraut, beer.

5. Microbes: invisible rulers of the earth
Bacteria the “fix” nitrogen needed for protein production.
Decompose waste… think of all of the dead things that would still be around without decomposition.
Digest your food, provide nutrients, some antibiotics are microbes.
Control disease… take care of “bad” bacteria.

6. Ecosystem organization
The Nature of Ecology
Ecosystem organization
Organisms
Populations
Communities
Ecosystems
Biosphere
Fig. 4-2 p. 57

7. Organism Organism: any form of life.. Cell is basic unit of life
Eukaryotic Cell: membrane bound organelles w/ nucleus. Protists, fungi, plants, animals,
Prokaryotic Cell: no distinct nucleus. Bacteria
Species: group of organisms with similar appearance, behavior, chemistry and genetic makeup. Produce fertile offspring.
Asexual reproduction: binary fission, budding
Sexual: combine haploid gametes to produce offspring.

8. Population Group of interacting individuals of the same species.
Populations respond to changes in environment: 1. Size. 2. Age distribution. 3. Density. 4. Genetic composition.

9. Ecosystem: all biotic and abiotic components are interacting
Communities: Complex interacting populations.. Including plants, animals, fungi, protists, and bacteria.
Ecosystem: all biotic and abiotic components are interacting
Communities of different species interacting with one another and their non-living environment.
Range in size from a puddle to entire forest. Define the “system.”
Biosphere: all of the earth’s interacting ecosystems.

10. The Earth’s Life-Support Systems
Troposphere
Stratosphere
Hydrosphere
Lithosphere
Biosphere
Fig. 4-7 p. 60

11. Major Parts of Earth’s Life Support
Atmosphere: thin envelope of air around the planet.
Troposphere: inner layer about 17 kilometers above sea level.
Stratosphere: kilometers. Lower portion contains enough ozone O3 to filter most of the Sun’s harmful Ultraviolet radiation.
Hydrosphere: Earth’s liquid water (surface and underground), ice (polar, icebergs), and ice frozen in the soil, and water vapor in the atmosphere.

12. Major Parts of Earth’s Life Support
Lithosphere: Earth’s crust and upper mantle
Contains nonrenewable fossil fuels and minerals
Contains renewable soil nutrients needed for plant life.
Biosphere: portion of Earth where living (biotic) organisms exist and interact with one another.
Includes most of the hydrosphere, lower parts of the atmosphere, and the upper lithosphere.
Reaches from the deepest ocean floor to the tops of the highest mountains.

13. Goal of Ecology is to understand the interactions in this thin, life-supporting global skin or membrane of air, water, soil, and organisms.

14. Natural Capital: Sustaining Life of Earth
One-way flow of energy from Sun
Through livingorganisms
Cycling of Crucial Elements
Atoms, ions, molecules through the biosphere.
Gravity allows the Earth to hold on to the atomosphere and causes downward movement of chemicals in matter cycles.
Fig. 4-8 p. 60

15. Solar Capital: Flow of Energy to and from the Earth
Lights and warms the planet
Supports photosynthesis
Powers the cycling of matter
Drive the climate and weather systems that distribute heat and freshwater.
Gigantic fireball of hydrogen and helium.
Temperatures and pressures in its inner core cause fusion of hydrogen releasing enormous amounts of energy.
Fig. 4-9 p. 61

16. Giant Thermonuclear Reactor
Radiates in all directions
Radiation moves at the speed of light (EMS) and makes the 150 million kilometer (93 million miles) trip in slightly more than 8 minutes.
What happens to the solar radiation?
1 billionth received by Earth.
Most energy reflected or absorbed by chemicals in the atmosphere.

17. Natural Capital: Major Biomes
Role of climate
Aquatic life zones
Fig p. 62

18. Components of Ecosystems
Abiotic chemicals
Photosynthesis:removes CO and water and adds Oxygen and glucose 6H2O + 6CO2 + energy C6H12O6 + 6O2
Producers (autotrophs)
Consumers (heterotrophs)
Aerobic cellular respiration
C6H12O6 + 6O2 6H2O + 6CO2 + energy
Decomposers
Fig p. 67

19. Ecosystem Factors Abiotic factors Range of tolerance Biotic factors
Limiting factors
Fig p. 64

20. Range of Tolerance
Law of Tolerance: The distribution of a species in an ecosystem is determined by the levels of one or more physical or chemical factors.
Tolerance Limits: too much or too little of any abiotic factor can limit or prevent growth of a populations, even if all other factors are at or near an optimum range of tolerance.

21. Respiration: Getting Energy
Producers & Consumers use chemical energy stored in glucose and other organic compounds to fuel life processes.
Aerobic Respiration: uses oxygen to convert organic nutrients back into carbon dioxide and water.
C6H12O6+ O2  CO2 + H2O + energy
Anaerobic respiration (fermentation): releasing of energy w/out oxygen.

22. Biodiversity: the amazing variety of earth’s genes, species, ecosystems, and ecosystem processes.
Genetic diversity: variety in genetic make-up among individuals in a species
Species diversity: Variety among species or distinct types of living organisms.
Ecological diversity: Variety of forests, deserts, grasslands, streams, lakes, oceans, coral reefs, wetlands, and other biological communities.
Functional diversity: Biological and chemical processes or functions such as energy flow and matter cycling needed for the survival of species and biological communities.

23. Connections: Energy Flow in Ecosystems
Food chains: sequence of organisms each of which is a food source for the next.
Trophic Levels: feeding step.. Producers are the first level always.
Food webs: complex network of interconnected food chains … most species participate in several different food chains.

24. Trophic Levels Autotroph (producer): first trophic level
Primary consumer (herbivore): second trophic level
Secondary consumer (carnivore): third trophic level
Tertiary consumer: fourth trophic level
Omnivore eats producers and consumers.
Detritivores and scavengers: all trophic levels… they do not care.
Decomposers

25. Connections: Food Webs and Energy Flow in Ecosystems
Food chains
Food webs
Fig p. 77; Refer to Fig p. 78

26. Figure 4-19 Page 78 Human Blue whale Sperm whale Killer whale Elephant
seal
Crabeater seal
Leopard
seal
Emperor
penguin
Adélie
penguins
Petrel
Squid
Fish
Carnivorous plankton
Herbivorous
zooplankton
Figure 4-19 Page 78
Krill
Phytoplankton

27. Ecological Pyramids Pyramid of energy flow Ecological efficiency
Fig p. 70
Ecological efficiency
Pyramid of biomass
Pyramid of numbers

28. Primary Productivity of Ecosystems
Gross primary productivity (GPP): rate at which an ecosystem’s producers convert solar energy into chemical energy.
Net primary productivity (NPP): Producers need energy to survive. What is left or available for use as food b other organisms in an ecosystem.
Fig p. 81

29. 73%
Not used by humans
It is estimated that humans use, waste, or destroy about 1. 27% of the earth’s total NPP and about 2. 40% of the earth’s NPP of terrestrial systems. What will happen when population doubles in the next years? 3%
Used directly
16%
Altered by human activity
Figure 4-26 Page 82 8%
Lost or degraded land

30. Soil Profiles in Different Biomes
Fig. 4-27, p. 75

31. Soils Origins Importance Maturity and Horizons
Variations with Climate and Biomes
Variations in Texture and Porosity

32. Connections: Matter Cycling in Ecosystems
Biogeochemical cycles
Hydrologic cycle (H2O)
Carbon cycle
Nitrogen cycle
Phosphorus cycle
Sulfur cycle

33. Hydrologic (Water) Cycle
Fig p. 76

34. Hydrological Cycle Condensation Rain clouds Transpiration Evaporation
Precipitation to
land
Transpiration
from plants
Precipitation
Precipitation
Evaporation
from land
Evaporation
from ocean
Runoff
Surface runoff
(rapid)
Precipitation to
ocean
Infiltration and
Percolation
Surface
runoff
(rapid)
Groundwater movement (slow)
Ocean storage
Hydrological Cycle

35. The Carbon Cycle (Marine)
Fig. 4-29, p. 78

36. The Carbon Cycle (Terrestrial)
Fig. 4-29, p. 79

37. The Nitrogen Cycle
Fig p. 80

38. The Phosphorus Cycle
Fig p. 82

39. The Sulfur Cycle
Fig p. 83

40. How Do Ecologists Learn About Ecosystems?
Field research
Remote sensing
Geographic information systems (GIS)
Laboratory research
Systems analysis

41. Geographic Information System (GIS)
Fig p. 84

42. Systems Analysis
Fig p. 85