1. Principles of Ecology
Chapter 2

2. Section 1 Vocabulary Ecology Biosphere Biotic Factor Abiotic Factor
Population
Biological Community
Ecosystem
Biome
Habitat
Niche
Predation
Symbiosis
Mutualism
Commensalism
Parasitism

3. Section 1 Organisms and Their Relationships
Ecology
Each organism depends on both living and nonliving factors in their environment for survival
Scientists who study ecology are called ecologists
Science models are a way of creating a visual representation of a hypothesis to test in a lab setting

4. The Biosphere Biotic Factors Abiotic Factors
All living things in an environment
Interactions among organisms are necessary for the health of all species in the same geographic location
Abiotic Factors
Nonliving factors in the environment
Factors may include temperature, air or water currents, sunlight, soil type, rainfall, or available nutrients
Organisms depend on both abiotic and biotic factors for survival
If an organism moves to another location with different abiotic factors, it must adapt or it dies

5. Levels of Organization
Organism, Population, Biological Community, Ecosystem, Biome, Biosphere
Organisms, populations, and biological communities
Lowest level is the organism
Individual organisms often compete for the same resources; if resources are plentiful, the population grows
Usually there are factors that prevent a population from becoming extremely large
Organisms may or may not compete for the same resources in a biological community

6. Ecosystems, biomes, and the biosphere
Ecosystem is similar to a biological community, except that it also includes abiotic factors
Ecosystem can be large or small and even overlap
Biome is a large group of ecosystems
The biosphere consists of all of the biomes; the highest level of organization on Earth

7. Ecosystem Interactions
Interactions between organisms are important to survival in an ecosystem (ex. Tree)
Habitat could be one tree or a grove of trees
An organism’s niche is it’s role or job
Community Interactions
Competition
Occurs when more than one organism uses a resource at the same time
Strong directly compete with the weak
Usually the strong survive; the weak could move to another location
If the resource is plentiful, them competition is not very fierce

8. Symbiotic Relationships
Predation
Many species get their food by eating (predator) other species (prey)
Ladybug and praying mantises are insect predators, but also called beneficial insects (used for garden control)
Symbiotic Relationships
Mutualism: both benefit (algae and fungi form lichens through a mutualistic behavior
Commensalism: one benefits and the other gets neither hurt or helped (clownfish and sea anemones; clownfish get protected)
Parasitism: one benefits at the expense of the other (ticks or fleas)
In parasitism if the host dies, so can the parasite

9. Section 2 Vocabulary Autotroph Heterotroph Herbivore Carnivore
Omnivore
Detritivore
Trophic Level
Food Chain
Food Web
Biomass

10. Section 2 Flow of Energy in an Ecosystem
Autotrophs
Green plants and other organisms that produce their own food (primary producers)
Are the foundations for all ecosystems because they make energy available for all organisms
Heterotrophs
Also called consumers
Gets energy from consuming other organisms
Decomposers break down dead organisms
Decomposers are the primary method used to make nutrients available for producers to reuse

11. Models of Energy Flow Food Chains Food Webs Ecological Pyramids
Arrows normally start with autotrophs and move to heterotrophs
Remaining energy is released into environment and not available to organisms
Food Webs
Usually more complex than a food chain
Food webs are the most common
Ecological Pyramids
Shows the relative amounts of energy, biomass, or numbers of organisms at each trophic level in an ecosystem
Only 10% of all energy is transferred to level above
Number of organisms at each level gets less, as you move up the energy pyramid

12. Food Web

13. Section 3 Vocabulary Matter Nutrient Biogeochemical cycle
Nitrogen fixation
Denitrification

14. Section 3 Cycling of Matter
Cycles in the Biosphere
Connection to Chemistry
In most ecosystems, plants obtain nutrients, in the form of elements and compounds, from the air, soil, or water
The Water Cycle
Constant recycling
Same water today that was here when Earth began
Approximately 90% of water vapor evaporates from oceans, lakes, and rivers, 10% from the surfaces of plants through transpiration
All living organisms rely on fresh water

15. Freshwater constitutes only about 3% of all water
Water available to living organisms is about 31%
The remaining 69% of freshwater is frozen
Processes in the water cycle are evaporation, condensation, precipitation, transpiration, and percolation (seepage)

16. The Carbon and Oxygen Cycle
All living things are composed of carbon molecules
Carbon and oxygen make up the molecules essential for life
Green plants convert carbon dioxide and water into carbohydrates and release oxygen back into the atmosphere (photosynthesis)
Carbon dioxide is recycled when autotrophs and heterotrophs release it back into the air during cellular respiration
Carbon enters a long cycle when organic matter is buried
Carbon is released from fossil fuels when they are burned
Carbon and oxygen can also combine with calcium to create calcium carbonate

17. The Carbon Cycle

18. The Nitrogen Cycle
Largest concentration of nitrogen is found in the atmosphere
Plants and animals can’t use nitrogen directly from the atmosphere; only from the soil
Nitrogen can be fixed (converted) during an electrical storm
Nitrogen is often a factor that limits the growth of producers
Nitrogen gets returned to the soil in several ways: animals urinate, organisms die, or denitrification

19. Nitrogen Cycle

20. The Phosphorus Cycle
Phosphorus is essential for the growth and development of organisms; limits the growth of producers
Short term and long term cycles
Producers obtain it from the soil and consumers by eating the producers
When organisms die or produce wastes, decomposers return the phosphorus to the soil where it can be used again
Moves from the short term to the long term through precipitation and sedimentation to form rocks
In the long term cycle, erosion and weathering of rocks that contain phosphorus, adds it back to the soil

21. Phosphorus Cycle