1. Science, Matter, Energy and Ecosystems
Chapter 2
Pages 16-45

2. Matter and Energy Read section 2-2 on Matter and Energy
Background to many ES issues and future chapters
We will discuss some but not all

3. Science and Critical Thinking

4. Constructing the Hypothesis
The goal of science is to discover facts about the natural world and the principles that explain these facts.
How does one “measure” the natural world?
Use senses, see, hear, feel, taste smell, as well as tools to extend these senses
Observations
Can quantify, through statistics can validate
Scientific Knowledge is ultimately traced to Observations

5. Constructing the Hypothesis
The scientific method can be best described as procedures used to learn about our world.
Science cannot prove or disprove non-quantifiable factors, such as ESP.

6. Constructing the Hypothesis
Must be stated in a way that allows them to be tested.
A testable hypothesis is one that at least potentially can be proved false.

7. Constructing the Hypothesis
For example:
There are no mermaids in the sea
This is testable and can be proven false by finding a mermaid
There are mermaids in the sea
This cannot be proven false, as the true believer would say “They are there, you just didn’t find them”

8. Constructing the Hypothesis
Variables are factors that might affect observations
Models with variables one can alter – Laboratory
Ecological models – difficult to alter the variables. Often only observations to determine differences based on variability.
In science, no absolute truths. No hypothesis can be absolutely proved true.
Make best decisions with available evidence.

9. Scientific hypotheses – an unconfirmed explanation of an observation that can be tested
Scientific method – used to test hypotheses – ways scientists gather data, formulate and test hypotheses.
Peer review and publication – widely accepted – leads the scientific theories and laws.
Scientific theories – description of what we find happening through repeated observations – verified and credible hypothesis
Scientific (natural) laws – description of what we find happening, and is proven over and over
Frontier science – preliminary results – often subject to news stories
Junk Science – no peer review

10. Levels of organization in nature
Levels of organization in nature. The shaded portion is the five levels that ecology is based upon.

11. What is Matter? Atoms, ions and molecules
Anything that has mass and takes up space.
Two forms:
Element – distinctive building blocks of matter that make up every material substance
Compound – two or more different elements held together by chemical bonds

12. What is Matter? Organic compounds Inorganic compounds
Compounds containing carbon atoms combined with each other and with atoms of one or more other elements such as hydrogen, oxygen, nitrogen, sulfur, phosphorus, chlorine, and fluorine.
Inorganic compounds
All compounds not classified as organic compounds.

13. The Law of Conservation of Matter
Matter is not destroyed
It only changes form
There is no “away” – atoms are not destroyed, just rearranged.
What are some examples of matter changing form?

14. First Law of Thermodynamics
Energy is neither created nor destroyed
Energy only changes form
You can’t get something for nothing
Or “There is no such thing as a free lunch!”
ENERGY IN = ENERGY OUT

15. Energy Kinetic Potential Wind Electicity Flowing water
Water behind a dam
Gasoline in your car
Unlit match

16. Second Law of Thermodynamics
In every transformation, some energy is converted to heat
You cannot break even in terms of energy quality
Waste energy is
low quality and
cannot be reused

17. Second Law of Thermodynamics
What are some other examples of the Second Law of Thermodynamics?

18. Water is heated due to energy loss from the flowing water and turbines

19. 20-25% of the chemical energy in gasoline is converted to mechanical energy. The rest is lost into the environment as low quality heat energy.

20. 5% of electricity is changed into useful light
5% of electricity is changed into useful light. 95% is lost as low-quality heat.

21. Photosynthesis is the process of converting solar energy into chemical energy stored in food
CO2 + H20 ---> C6H12O6 + O2

22. Respiration is the process of releasing chemical energy stored in food to be used by living things.
C6H12O6 + O2 ---> CO2 + H20

23. Ecological Concepts
Ecology: Study of how organisms interact with each other and with their non-living surroundings.
Eco - is from the Greek word “Oikos” for house

24. The Nature of Ecology Levels of study in Ecology:
Organisms – single animal
Populations – same species
Communities – pop’ns living
together
Ecosystems – community +
physical environment
Biosphere – all the earth’s
ecosystems

25. The Earth’s Life-Support Systems
Atmosphere
Thin membrane of air
Troposphere
11 miles
Stratosphere
12-30 miles
Lower portion (ozone)
filters out harmful sun rays
Allows life to exist on earth
Lithosphere
Earth’s crust
Hydrosphere
water
Biosphere
Living and dead
organisms

26. Natural Capital: Sustaining Life of Earth
One-way flow of energy from Sun
Cycling of crucial elements
Gravity

27. Solar Capital: Flow of Energy to and from the Earth
Greenhouse gasses
water vapor
CO2
Methane
Ozone
Increases kinetic energy,
Helps warm troposphere.
Allows life to exist
(as we know it) on earth.
As greenhouse gasses
increase, temperature of
troposphere increases.

28. Ecosystem Components Abiotic factors Biotic factors
Range of tolerance for each species
what factors are important for…

29. Ecosystem Components
Limiting factors determines distributions

30. Law of Tolerance
The existence, abundance and distribution of a species is determined by levels of one or more physical or chemical factors.

31. Common limiting factors
Limiting factors – more important in regulating population growth than other factors.
Terrestrial ecosystems (on land)
precipitation
temperature
soil nutrients
Aquatic ecosystems
sunlight
nutrients
dissolved oxygen
salinity

32. Biological Components of Ecosystems
Producers (autotrophs)
Consumers (heterotrophs)
Herbivores, carnivores, omnivores
Decomposers and detritivores
detritus = dead organic material

33. Biodiversity
Genetic diversity – variety of genetic material within a species or a population
Species diversity – the number of species present in different habitats
Ecological diversity – the variety of terrestrial and aquatic ecosystems found in an area or on earth
Functional diversity – biological and chemical processes needed for the survival of species, communities and ecosystems

34. Energy Flow in Ecosystems
Food chains – sequence of organisms which is a source of food for the next.
Food webs – most species participate in several food chains (they don’t just eat one thing!).
Trophic levels
each step in the flow of energy through an ecosystem (feeding level)

35. Food Chains and Energy Flow in Ecosystems

36. Ecological Pyramids Pyramid of energy flow Ecological efficiency
Pyramid of biomass
Pyramid of numbers

37. Food webs
reality tends to be more complex than a linear food chain

38. Primary Productivity of Ecosystems
Gross primary productivity (GPP)
The rate at which an ecosystem's producers capture and store a given amount of chemical energy as biomass in a given length of time.
Net primary productivity (NPP)
Rate at which all the plants in an ecosystem produce net useful chemical energy; equal to the difference between the rate at which the plants in an ecosystem produce useful chemical energy (gross primary productivity) and the rate at which they use some of that energy through cellular respiration.
(NPP = GPP – Respiration)

39. Net Primary Productivity comparison

40. Soils Importance Maturity and Horizons
Provides most of the nutrients for plant life
Cleans water
Decompose and recycle biodegradable wastes
Maturity and Horizons
Surface litter layer
Top soil layer (humus)
Sub soil
Parent material
Variations with Climate and Biomes
Variations in Texture and Porosity

41. Soil Profiles in Different Biomes

42. Matter Cycling in Ecosystems
Biogeochemical cycles – global cycles recycle nutrients through the air, land and water
Cycles are driven directly or indirectly by solar energy and gravity
Hydrologic cycle (H2O)
Carbon cycle
Nitrogen cycle
Phosphorus cycle

43. Hydrologic (Water) Cycle

44. Human Influence on the Water Cycle
Water withdraw from lakes and streams
Clear vegetation
Construct impervious surfaces
Fill wetlands
Modify water quality by adding nutrients

45. The Carbon Cycle (Marine)
Based on Carbon Dioxide
Terrestrial producers remove
CO2 from the air; aquatic
producers remove it from the
water.
Through photosynthesis,
Converts to carbohydrates.
O2 consuming producers
respire,breaking carbo-
hydrates back to CO2.
CO2 not released until burned.

46. The Carbon Cycle (Terrestrial)

47. Human Influence on the Carbon Cycle
Clear trees and other plants, often times permanently
Burning fossil fuels and wood
Increased CO2 in the troposphere enhance natural greenhouse effect
Results in global warming

48. The Nitrogen Cycle Atmosphere’s most abundant element.
Bacteria help recycle nitrogen.
Nitrogen cannot be used by plants
and animals without bacteria’s help.
Waterlogged
soil
Ammonia not taken up by plants
Toxic to plants
Usable by plants

49. Human Influence on the Nitrogen Cycle
Add large amounts of nitric oxide by burning fuel
Gas converted to nitrogen dioxide gas and nitric acid (acid rain)
Add nitrous oxide through anaerobic bacteria breaking down livestock wastes (global warming).
Release nitrogen stored in soils and plants by destroying forests, grasslands and wetlands.
Add excess nitrates for agriculture
Remove nitrogen from topsoils through harvesting various crops

50. The Phosphorus Cycle Slow Bacteria not a major player
Washes from the land into
streams, then the sea.
Can be deposited as sediment
and remain for millions of
years.
Often a limiting factor for
plant growth on land.
Also limits growth in lakes
And streams because
phosphate salts are only
slightly soluble in water.
Fig p. 82

51. Human Influence on the Phosphorus Cycle
We mine large quantities of phosphate rock to make inorganic fertilizers.
We reduce the available phosphate in tropical soils by clearing tropical forests.
We disrupt aquatic systems with phosphates from runoff of animal wastes and fertilizers, and sewage systems.