1. Ecology, ecosystems and food webs
Chapter 3
Ecology, ecosystems and food webs

2. Ecology Groupings Organism – single living thing
Species – several of same type of organism
Population – several of same species interacting
Community – several populations interacting in a certain area
Ecosystem – community interacting with each other and the environment

3. Biosphere Biosphere Ecosystems Communities Populations Organisms
Fig. 4.2, p. 72

4. Parts of the planet
Planet as a solid – inner/outer core, mantle, crust
Lithosphere is the crust and asthenosphere
Hydrosphere is the water regions
Atmosphere is the 5 layers of air
Troposphere (11 miles) 78% N2, 21% O2, 1% Ar
Stratosphere (11 – 30 mi) O3, blocks UV

5. core Mantle Crust Biosphere Atmosphere Hydrosphere Lithosphere
Vegetation and animals
Soil
Crust
Rock
core
Lithosphere
Mantle
Crust
(soil and rock)
Crust
Biosphere
(Living and dead
organisms)
Atmosphere
(air)
Hydrosphere
(water)
Lithosphere
(crust, top of upper mantle)
Fig. 4.6, p. 74

6. Incoming solar energy 34% reflected by clouds
42% heats earth and atmosphere
23% evaporates water
1% creates wind
<1% photosynthesis

7. Solar radiation Energy in = Energy out Earth
Reflected by
atmosphere (34%)
UV radiation
Radiated by
atmosphere
as heat (66%)
Lower Stratosphere
(ozone layer)
Visible
light
Greenhouse
effect
Absorbed
by ozone
Troposphere
Heat
Absorbed
by the earth
Heat radiated
by the earth
Earth
Fig. 4.8, p. 75

8. Greenhouse effect
Solar energy (light) that reaches the earth is converted into short wave radiation (heat) infrared.
This infrared radiation has a hard time passing through the gasses in our atmosphere thereby trapping heat and keep the planet about 30 degrees (Celsius) warmer
Important gasses – H2O, CO2, CH4, N2O, O3

9. Biomes
Large regions characterized by a distinct climate and adapted vegetation
Remember climate is weather patterns over a long period of time, usually several decades
Because certain plants are adapted to a particular biome, so too are certain animals which depend on those plants for food

10. Biomes
There are not distinct boundaries between biomes, rather there are ecotones.
An ecotone is a blending of biomes and generally carries a greater quantity and variety of species

11. Components of Ecosystems
Abiotic – nonliving
Sunlight
Temperature
Precipitation
Wind
Latitude
Soil
Salinity (aquatic)

12. Terrestrial Ecosystems
Aquatic Life Zones
• Sunlight
• Temperature
• Precipitation
• Wind
• Latitude (distance from equator)
• Altitude (distance above sea level)
• Fire frequency
• Soil
• Light penetration
• Water currents
• Dissolved nutrient concentrations (especially N and P)
• Suspended solids
Fig. 4.13, p. 79

13. Components of Ecosystems
Range of tolerance – how much of an abiotic factor can an organism withstand
Limiting factor – the one factor that is holding back a population from reaching its biotic potential (max growth)
Important limiting factors in aquatic systems
Dissolved oxygen, salinity, temperature, light, nutrients, etc.

14. Abundance of organisms
Population size
Low
High
Temperature
Zone of
intolerance
physiological stress
Optimum range No
organisms
Few
Lower limit
of tolerance
Abundance of organisms
Upper limit
Fig. 4.14, p. 79

15. Food webs (chains) Producers (autotrophs) plants
Using chemosynthesis (some bacteria)
Using photosynthesis (plants)
6 CO2 + 6 H2O + sun (yields) C6H12O6 + 6 O2
Plants convert only about 1-5% of the light they absorb into chemical energy, and absorb only about half the light that strikes them

16. Herbivores Primary consumers – eat producers (oh the humanity)
Teeth designed for grinding

17. Carnivores Secondary consumers – meat eaters only
Feed on primary consumers (herbivores)
Teeth designed for tearing (large canines and sharp molars) cats for example

18. Omnivore
Tertiary consumer – eat anything, feeding on other carnivores makes them tertiary
We are omnivores, just look at our teeth,
but we really should eat more veggies and less meat (in my opinion)

19. The other consumers
Scavengers – feed on dead organism they did not kill, but found dead
Detritivores – feed on parts of dead organisms
Decomposers – bacteria and fungi, break down small detritus into raw nutrients
Biodegradable means can be broken down by decomposers

20. Aerobic respiration Normal cellular process for most organisms
Convert sugar and oxygen into energy leaving water and carbon dioxide as products
C6H12O6 + 6O2 yields 6 CO2 + 6 H2O + energy

21. Anaerobic Respiration
Also called fermentation
The breakdown of glucose without oxygen present
Produces: methane, ethyl alcohol, acetic acid, and hydrogen sulfide

22. Food chains Trophic level – feeding level First trophic level – plants
Second trophic level – primary consumers
Third trophic level – secondary consumers
Fourth trophic level – tertiary consumers
Remember heat is lost in every transfer between trophic levels

23. Pyramid of energy flow
Only about 10% of the usable energy transfers between trophic levels (5-20%)
For this reason we must rely on the transfer of solar energy from producers to consumers
This is why it is so important to care for the plants of this planet

24. Biomass Organic matter produced by producers (photosynthesis)
Total dry weight of organic matter in plants and animals in an ecosystem

25. Biomass Productivity
Highest net biomass productivity per square meter is in wetlands, estuaries, and rain forests
Highest gross (but lowest per sq. meter) is the open ocean. Because of its size it has a lot of algae that add up to high productivity

26. Nutrient cycles Atmospheric – Carbon and Nitrogen
Sedimentary – Phosphorus and Sulfur
Hydrologic cycle – water cycle helps to transport many nutrients

27. Hydrologic cycle Evaporation/transpiration Condensation Precipitation
Infiltration
Percolation
Runoff
Powered by the Sun and gravity

28. Carbon cycle Atmosphere Photosynthesis/respiration Fossil fuels
Limestone
Dissolved in the ocean

29. Nitrogen cycle (very important)
Nitrogen in the air
Nitrogen fixation by bacteria to ammonia
Nitrification by bacteria to nitrite NO2-
Nitrification by bacteria to nitrate NO3-
Assimilation by plants
Ammonification of dead organic material by bacteria and fungi
Denitrification of nitrate by bacteria back to atmosphere

30. Phosphorus cycle Very slow Limited amount found in the soil
Limiting factor for plant growth
Excess causes prolific plant growth (algal blooms in water)
We add phosphates to detergents/fertilizers

31. Sulfur cycle Passed as sulfates (salts) mostly
Hydrogen sulfide (swamps/volcanoes)
Sulfur dioxide (volcanoes)
Ammonium sulfate (sea spray)
Reacts in atmosphere to create hydrogen sulfate (H2SO4) sulfuric acid (acid rain)

32. Ecosystem services Waste removal pest control
Soil formation biodiversity
Water purification matter resources
Air purification aesthetic pleasure
Climate control
Recycling vital chemicals
Renewable energy

33. Achieve sustainability
Use renewable energy (especially solar)
Recycle chemical matter
REALIZE WE LIVE IN A CLOSED SYSTEM!
The END!!!