1. Environmental Science Lecture 04
(Ecosystem)

2. Ecosystem
All the living and non-living things that interact in a particular area make up an ecosystem
A prairie is just one of the many different ecosystems found on Earth
Other ecosystems include: mountain streams, deep oceans, swamps and dense forests.

3. Simple ecosystem model
Key Attributes:
Biotic and abiotic processes
Pools and fluxes

4. Habitats
Organisms(living things)-live in a specific place within an ecosystem.
Organisms obtain food, water, shelter and other things it needs to live, grow and reproduce from its surroundings
The place where an organism lives and that provides the things the organism needs is called its habitat.

5. Biotic Factors
An organism interacts with and responds to both the living and nonliving things in its environment
The living parts of an ecosystem are called biotic factors
Examples: grass, plants, hawks, ferrets, eagles, worms, fungi, and bacteria.

6. Abiotic Factors The nonliving parts of an ecosystem. Remember –TWOSS
Temperature
Water
Oxygen
Sunlight
Soil

7. Temperature
The temperatures of an area determine if an organism can live there.
Ex: Warm areas you might see palm trees, but not in very cold areas.
Some animals respond to very hot or very cold temperatures by altering their environment.
Ex: Prairie dogs line their dens with grass to keep warm.

8. Water
All living things need water to carry out their life processes.
Plants and algae use water, along with sunlight and carbon dioxide, to make food in the process of photosynthesis.

9. Oxygen
Most living things require oxygen to carry out their life processes.
Some organisms obtain oxygen from the air, which is about 20% oxygen.
Fish and other water organisms obtain dissolved oxygen from the water around them.

10. Sunlight Necessary for photosynthesis.
Important for plants, algae and other living things.
Places that receive little to no sunlight-like caves-have only a few organisms that can live their.

11. Soil
A mixture of rock fragments, nutrients, air, water and the decaying remains of living things.
Types of soil influence the kinds of plants that can grow there.
Microscopic organisms such as bacteria live in soil and break down the remains of other living things.

12. Population All the members of one species in a particular area.
Populations can be as small as a blade of grass or as large as the whole planet.
Individual members in some populations do not interact very much.
Some populations are very structured and relate to one another in specific ways.

13. Society
A society is a closely related population of animals that work together for the benefit of the whole group.
Ex: Honeybees-every member has a specific function.

14. Community Most ecosystems contain more than one type of organism.
All the different populations that live together in an area make up a community.
To be considered a community, the different populations must live close enough together to interact.

15. Levels of Organization in an Ecosystem
OPCE
Organism-the smallest unit of organization, that belongs to a population.
Population-other members of its species that belong to a community.
Community-different species in an ecosystem.
Ecosystem-community and abiotic factors together.

16. Levels of Organization

17. Ecology
The study of how living things interact with one another and with their environment.
Ecologist are scientists who study ecology. They look at how all the biotic and abiotic factors in an ecosystem are related
Ecologist study how organisms respond to changes in their environment.

18. Natural Capital: General Structure of the Earth
Figure 3.2: Natural capital.
This diagram illustrates the general structure of the earth, showing that it consists of a land sphere (geosphere), an air sphere (atmosphere), a water sphere (hydrosphere), and a life sphere (biosphere) (Concept 3-1a).
Fig. 3-2, p. 56

19. Atmosphere Biosphere (living organisms) Soil Rock Crust Mantle
Geosphere
(crust, mantle, core)
Mantle
Figure 3.2: Natural capital.
This diagram illustrates the general structure of the earth, showing that it consists of a land sphere (geosphere), an air sphere (atmosphere), a water sphere (hydrosphere), and a life sphere (biosphere) (Concept 3-1a).
Core
Atmosphere (air)
Hydrosphere (water)
Fig. 3-2, p. 56

20. The Diversity of Life Figure 3.3: Natural capital.
Land, air, water, and a variety of plants and animals sustain the earth’s diversity of life and human economies.
(a) Land, air, water, and plants in Siberia
Fig. 3-3a, p. 56

21. Three Factors Sustain Life on Earth
One-way flow of high-quality energy:
Sun → plants → living things → environment as heat → radiation to space
Cycling of nutrients through parts of the biosphere
Gravity holds earths atmosphere

22. Sun, Earth, Life, and Climate
Sun: UV, visible, and IR energy
Radiation
Absorbed by ozone and other atmosphere gases
Absorbed by the earth
Reflected by the earth
Radiated by the atmosphere as heat
Natural greenhouse effect

23. Flow of Energy to and from the Earth
Figure 3.4: High-quality solar energy flows from the sun to the earth. As it interacts with the earth’s air, water, soil, and life, it is degraded into lower-quality energy (heat) that flows back into space.
Fig. 3-4, p. 57

24. Lower Stratosphere (ozone layer)
Solar radiation
Reflected by atmosphere
Radiated by atmosphere
as heat
UV radiation
Lower Stratosphere (ozone layer)
Most UV absorbed
by ozone
Heat radiated by the earth
Visible light
Troposphere
Heat added to troposphere
Greenhouse effect
Figure 3.4: High-quality solar energy flows from the sun to the earth. As it interacts with the earth’s air, water, soil, and life, it is degraded into lower-quality energy (heat) that flows back into space.
Absorbed
by the earth
Fig. 3-4, p. 57

25. 3-2 What Are the Major Components of an Ecosystem?
Concept 3-2 Some organisms produce the nutrients they need, others get their nutrients by consuming other organisms, and some recycle nutrients back to producers by decomposing the wastes and remains of organisms.

26. Ecologists Study Interactions in Nature
Ecology: how organisms interact with each other and their nonliving environment
Organisms
Populations
Communities
Ecosystems
Biosphere

27. Ecosystems Have Living and Nonliving Components
Abiotic
Water
Air
Nutrients
Rocks
Heat
Solar energy
Biotic
Living and once living

28. Major Biotic and Abiotic Components of an Ecosystem
Figure 3.6: Key living and nonliving components of an ecosystem in a field are shown in this diagram.
Fig. 3-6, p. 59

29. Producers and Consumers Are the Living Components of Ecosystems (1)
Producers, autotrophs
Photosynthesis:
CO2 + H2O + sunlight → glucose + oxygen
Chemosynthesis
Consumers, heterotrophs
Primary consumers = herbivores
Secondary consumers
Tertiary consumers
Carnivores, Omnivores

30. Producers
Figure 3.7: Some producers live on land, such as this large tree and other plants in an Amazon rain forest (Core Case study) in Brazil (left). Others, such as green algae (right), live in water.
Fig. 3-7a, p. 59

31. Consumers
Figure 3.8: The giraffe (left) feeding on the leaves of a tree is an herbivore. The lions (right) are carnivores feeding on the dead body of a giraffe that they have killed.
Fig. 3-8a, p. 60

32. Producers and Consumers Are the Living Components of Ecosystems (2)
Decomposers
Consumers that release nutrients
Bacteria
Fungi
Detritivores
Feed on dead bodies of other organisms
Earthworms
Vultures

33. Decomposer
Figure 3.9: This saddle fungus feeding on a dead tree (left) is a decomposer. Three vultures and two Marabou storks (right), classified as detritivores, are eating the carcass of an animal that was killed by other animals.
Fig. 3-9a, p. 61

34. Detritivores and Decomposers
Figure 3.10: Various detritivores and decomposers (mostly fungi and bacteria) can “feed on” or digest parts of a log and eventually convert its complex organic chemicals into simpler inorganic nutrients that can be taken up by producers.
Fig. 3-10, p. 61

35. Carpenter ant galleries Termite and
Detritus feeders
Decomposers
Carpenter
ant galleries
Termite and
Bark beetle engraving
carpenter ant work
Long-horned beetle holes
Dry rot
fungus
Wood reduced
to powder
Figure 3.10: Various detritivores and decomposers (mostly fungi and bacteria) can “feed on” or digest parts of a log and eventually convert its complex organic chemicals into simpler inorganic nutrients that can be taken up by producers.
Fungi
Powder broken down by decomposers into plant nutrients in soil
Time progression
Fig. 3-10, p. 61

36. Producers and Consumers Are the Living Components of Ecosystems (3)
Aerobic respiration
Using oxygen to turn glucose back to carbon dioxide and water
Anaerobic respiration = fermentation
End products are carbon compounds such as methane or acetic acid

37. Energy Flow and Nutrient Cycling
One-way energy flow from sun
Nutrient cycling of key materials

38. Ecosystem Components Figure 3.11: Natural capital.
This diagram shows the main structural components of an ecosystem (energy, chemicals, and organisms). Nutrient cycling and the flow of energy—first from the sun, then through organisms, and finally into the environment as low-quality heat—link these components.
Fig. 3-11, p. 62

39. Science Focus: Many of the World’s Most Important Species Are Invisible to Us
Microorganisms
Bacteria
Protozoa
Fungi

40. 3-3 What Happens to Energy in an Ecosystem?
Concept 3-3 As energy flows through ecosystems in food chains and webs, the amount of chemical energy available to organisms at each succeeding feeding level decreases.

41. Energy Flows Through Ecosystems in Food Chains and Food Webs
Movement of energy and nutrients from one trophic level to the next
Photosynthesis → feeding → decomposition
Food web
Network of interconnected food chains

42. A Food Chain
Figure 3.12: This diagram illustrates a food chain. The arrows show how the chemical energy in nutrients flows through various trophic levels in energy transfers; most of the energy is degraded to heat, in accordance with the second law of thermodynamics (see Chapter 2, p. 47). Question: Think about what you ate for breakfast. At what level or levels on a food chain were you eating?
Fig. 3-12, p. 63

43. A Food Web
Figure 3.13: This diagram illustrates a greatly simplified food web in the southern hemisphere. The shaded middle area shows a simple food chain. Its participants interact in feeding relationships to form the more complex food web shown here. Many more participants in the web, including an array of decomposer and detritus feeder organisms, are not shown here. Question: Can you imagine a food web of which you are a part? Try drawing a simple diagram of it.
Fig. 3-13, p. 64

44. Estimated Annual Average NPP in Major Life Zones and Ecosystems
Figure 3.15: The estimated annual average net primary productivity in major life zones and ecosystems is expressed in this graph as kilocalories of energy produced per square meter per year (kcal/m2/yr). Question: What are nature’s three most productive and three least productive systems? (Data from R. H. Whittaker, Communities and Ecosystems, 2nd ed., New York: Macmillan, 1975)
Fig. 3-15, p. 66

45. Science Focus: Water’s Unique Properties
Properties of water due to hydrogen bonds between water molecules:
Exists as a liquid over a large range of temperature
Changes temperature slowly
High boiling point: 100˚C
Adhesion and cohesion
Expands as it freezes
Solvent
Filters out harmful UV

46. Carbon Cycle Depends on Photosynthesis and Respiration
Link between photosynthesis in producers and respiration in producers, consumers, and decomposers
Additional CO2 added to the atmosphere
Tree clearing
Burning of fossil fuels
Warms the atmosphere

47. Natural Capital: Carbon Cycle with Major Harmful Impacts of Human Activities
Figure 3.19: Natural capital.
This simplified model illustrates the circulation of various chemical forms of carbon in the global carbon cycle, with major harmful impacts of human activities shown by the red arrows. Question: What are three ways in which you directly or indirectly affect the carbon cycle?
Fig. 3-19, p. 70

48. Carbon dioxide in atmosphere Respiration
Photosynthesis
Animals (consumers)
Burning fossil fuels
Diffusion
Forest fires
Plants (producers)
Deforestation
Transportation
Respiration
Carbon in plants (producers)
Carbon dioxide dissolved in ocean
Carbon in animals (consumers)
Decomposition
Carbon in fossil fuels
Marine food webs Producers, consumers, decomposers
Figure 3.19: Natural capital.
This simplified model illustrates the circulation of various chemical forms of carbon in the global carbon cycle, with major harmful impacts of human activities shown by the red arrows. Question: What are three ways in which you directly or indirectly affect the carbon cycle?
Carbon in limestone or dolomite sediments
Compaction
Process
Reservoir
Pathway affected by humans
Natural pathway
Fig. 3-19, p. 70