1. Ecology
Biosphere

2. What is ecology? Biosphere
The study of interactions that take place between organisms and their environment
Biosphere
The portion of earth that supports living things
Extends from high in the atmosphere to the bottom of oceans

3. Biotic vs abiotic Non living environment – abiotic factors
The non living parts of an organism’s environment are abiotic
Ex- air currents, temp, moisture, light, and soil
Living environment- biotic factors
All the living organisms that inhabit an environment are biotic factors
All organisms depend on others directly or indirectly for food, shelter, reproduction, or protection
Biotic vs abiotic

4. Levels of organization
Organism
Population- all members of one species in an area
Community- all populations in a given area
Ecosystem- community + abiotic factors
Biome- ecosystems with similar climate and communities
Biosphere- abiotic + biotic factors of the entire earth
Levels of organization

5. Energy flow All organisms need energy for life activities
Energy comes from food, and ultimately the sun
Consumption of food is an energy transfer
Energy flow

6. autotrophs Ultimate source of energy for life is the sun
An organism that uses light energy or energy stored in chemical compounds to make energy for itself is a producer, or autotroph
Plants use the sun’s light energy to make food in photosynthesis
Chemoautotrophs use chemical energy to produce food instead of light
Ex- certain bacteria
autotrophs

7. An organism that cannot make its own food and feed on others
A heterotroph that only feeds only plants is a herbivore
Heterotrophs that eat both plants and animals are omnivores
Detritivores eat dead plants and animals (detritus)
Some organisms such as bacteria and fungi are decomposers breaking down complex compounds of dead and decaying organisms that can be more easily absorbed
Heterotrophs

9. Flow of matter and energy
A food chain is a simple model used to show how matter and energy move through an ecosystem
Nutrients and energy move from autotrophs to heterotrophs, and eventually to decomposers
A food chain is drawn using arrows to indicate the direction in which energy is transferred from one organism to the next
The amount of energy remaining in the final transfer is only a portion of what was available at the first transfer, 10%
Most of the energy is given off as heat at each transfer, 90%
Flow of matter and energy

11. Each organism in a food chain represents a feeding step or trophic level, in the passage of energy and materials
Producers convert solar energy into organic compounds
Primary consumers eat producers
Secondary consumers eat primary consumers
Tertiary consumers eat secondary consumers
A food chain represents only one possible route for the transfer of matter and energy
Food webs show all possible feeding relationships at each trophic level
Trophic levels

14. An ecological pyramid shows the amount of energy or matter an ecosystem contains at each level
The base represents the producers, at the first trophic level
Higher levels are layered on top
3 different pyramids exist: energy, biomass, and numbers
Ecological pyramids

15. The amount of available energy decreases at each succeeding trophic level
The total energy transfer from one trophic level to the next is only 10% because
Organisms fail to capture and eat all the food energy available
Organisms use much of the energy for life processes
Energy gets released as heat
Energy pyramid

16. The total mass of living matter at each trophic level
Biomass Pyramid

17. Shows that population numbers decrease at each higher trophic level
Numbers pyramid

18. Cycles in nature Hydrologic Cycle
1. Precipitation- water vapor condensing
2. Evaporation- liquid water changing to gad
3. Transpiration- water evaporating from leaves
Water is constantly moving between the atmosphere and earth, driven by the heat from the sun
Cycles in nature

20. Cycles in nature Carbon Cycle Carbon and oxygen combine to form CO2
Plants use CO2 during photosynthesis to produce sugars
Plants use sugars for growth and cellular respiration
Herbivores eat plants, and incorporate sugar into their structures and for cell respiration
Cell respiration breaks down sugar releasing CO2 and water back into the atmosphere
Cycles in nature

21. CO2 is added to the atmosphere by cellular respiration, volcanic action, and burning fossil fuels
It’s removed by plants
Green house gases, like ozone, impede the escape of heat from earth’s surface
This can lead to global warming or the long-term increase in temperature of the earth’s lower atmosphere
Photosynthesis: sunlight + 6 H2O  C6H12O6 + 6 O2
Respiration: C6H12O6 + 6 O2  ~34ATP + 6 H2O
Cycles in nature

23. Cycles in nature Nitrogen Cycle Relies heavily on bacteria
Soil major reservoir 78% nitrogen
Nitrogen found in proteins and DNA, RNA
Plants need nitrogen in the form of nitrate NO3
Animals get nitrogen from proteins in food
Cycles in nature

24. Cycles in nature Nitrogen Fixation- plants cannot use nitrogen gas
Nitrogen fixing bacteria convert nitrogen gas into ammonia (NH3) and are found in the roots of legume plants
Ammonia can be take up by plants
Nitrification- nitrifying bacteria convert ammonia to nitrates and nitrites
Denitrification- nitrogen often a limiting factor in ecosystems
Nitrogen is lost from soils via leaching and runoff
Denitrifying bacteria convert nitrates and nitrites into nitrogen gas
Cycles in nature

26. Cycles in nature Phosphorous Cycle
Phosphorous moves between the living and nonliving parts of the environment
Main abiotic reservoir for phosphorous is rock
Weathering of rock adds phosphorous to soil
Plants absorb phosphates from soil and build organic compounds (ATP, DNA)
Animals eat plants and incorporate phosphorous into compounds
Cycles in nature

28. Nutrient limitation Primary Productivity
The amount of light energy converted to usable energy by autotrophs
Gross vs. Net primary productivity
GPP- amount of light energy converted to chemical energy by photosynthesis per unit time
NPP- GPP minus the energy used by primary producers for cellular respiration GPP-R = NPP
What limits primary production?
Aquatic ecosystems- light, nitrogen, phosphorous
Terrestrial – temperature, moisture, minerals (potassium)
Nutrient limitation