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APES: Learning Objectives
Chapter 3: Ecosystems and How They Work
Objectives:
1. Be familiar with all previous material from earlier chapters.
2. Be able to give four examples of abiotic factors.
3. Explain what it means to say energy flows one-way through an ecosystem.
4. Name and briefly describe the four interacting spheres upon which life depends.
5. What three factors sustain life on earth?
6. Draw and label an energy pyramid with the terms: producers, consumers, top
predators, herbivores, trophic levels.
7. Draw and label simple diagrams of both photosynthesis and aerobic respiration.
8. Briefly explain why energy pyramids are limited to 5-6 trophic levels.
9. Explain the difference between gross and net primary productivity.
10. Know, in detail, the Water, carbon, and nitrogen cycles.
11. Explain the ecological concept known as Limiting Factors.
12. Perform math calculations using unit conversions and dimensional analysis.
13. Compare and contrast field research with laboratory research. What are the
advantages and disadvantages of each.
Video’s
Food chains and webs http://www.youtube.com/watch?v=cWh-XKhh8xo
Limiting Factors https://www.youtube.com/watch?v=J1Qe5Ad3ap8
Nitrogen Cycles https://www.youtube.com/watch?v=oy8e2HrOh6Q
Carbon Cycles https://www.youtube.com/watch?v=nzImo8kSXiU
ENERGY Units
The Calorie
You may recall that one calorie is the amount of heat required to raise the temperature
of one gram of water by one Celsius degree. One kilocalorie would increase the
temperature of 1 kg of water by the same amount. The kilocalorie is sometimes
referred to as a "big" calorie and written with a capital C, namely, as Calorie. Food
calories are always "big" calories.
The Btu
Another popular unit of heat energy is the Btu (British thermal unit). One Btu is the
amount of heat required to raise the temperature of one pound of water by one degree
Fahrenheit.
Btus are commonly used in the United States to rate water heaters, furnaces, and air
conditioners.
See handout for additional energy units.
Vocabulary
1. biotic
2. Abiotic
3. Organism
4. Species
5. Population
6. Community
7. Ecosystem
8. Biosphere
9. asexual reproduction
10. sexual reproduction
11. lithosphere
12. hydrosphere
13. photosynthesis
14. producer (autotroph)
15. consumer (heterotroph)
16. herbivore
17. omnivore
18. scavenger
19. decomposer
20. aerobic respiration
21. food chain
22. food web
23. ecological efficiency
24. trophic level
25. biomass
26. gross primary productivity
27. net primary productivity.
APES: Homework Assignment
Chapter 3
Name:_________________________________
Due Date:
___________
Directions: complete each of the following questions by the due date. Your answer must be
hand written. You will be held responsible for them in class on the due date and on future
tests and quizzes.
Section 3-1
1. What layer contains the majority of the atmosphere’s mass?
2. In which layer of the atmosphere filters out most of the harmful ultraviolet radiation?
3. Give two examples of interactions that occur between the various “spheres” of earth’s life
support system.
3-2
4. Explain how detritivores are different than other decomposers.
5. Answer the Critical Thinking question in the Science Focus side bar on page 46.
6. In what fundamental way is the flow of matter different than the flow of energy through an
ecosystem?
3-3 Ecosystem Concepts and Components
7. What is biomass?
8. What is a trophic level?
What organisms occupy the first trophic level?
9. Critical Thinking: Why can the earth support more people if human ate at a lower trophic
level?
10. Why do food chains/webs rarely have more than 4-5 trophic levels?
3-4
11. In the context of biogeochemical cycles, what are reservoirs (sinks)?
12. Science Focus (page 52): make a list of the unique properties of water. Briefly explain
why each is important to life on earth.
13. For each biogeochemical cycle describe one way humans have altered the cycle.
a. carbon
b. water
c. nitrogen
d. sulfur
e. phosphorus
Carbon Cycle (page 52).
15. What two biological processes circulate carbon through the atmosphere?
Nitrogen Cycle (page 54).
16. Briefly describe two ways atmospheric nitrogen is made available to multicellular animals
and plants.
17. What organisms are essential to the process of nitrogen fixation?
---------------------------------------------------------------------------------------------------------------18. Why is the cycling of phosphorus so much slower than the cycling of carbon?
What are the three big ideas from this Chapter (page 58).
Chapter 3: Ecosystems: Components, Energy Flow, Matter Cycling
3-1 Earth’s Life-Support Systems
EQ’s: 1- How do tolerances levels and limiting factors help structure ecosystems?
The Earth has several layers or spheres upon which life depends:
______________________________: layer of air
___________________________________: layer of water
Lithosphere: layer of __________
Biosphere: layer of _________
http://study.com/academy/lesson/the-four-spheres-of-earth-geosphere-hydrospherebiosphere-and-atmosphere.html
Three factors Sustain life on Earth:
1. The one-way flow of _________________________________flows through the Earth’s systems
from the sun.
2. The cyclying of _________________________(Matter). Carbon, nitrogen, water. Oxygen,
phosphorus, etc..
3. ____________________________-which allows the planet to keep its atmosphere and aids in the
recycling of nutrients.
3-2 The Nature of Ecology
EQ’s: What language (vocabulary) is used by ecologists to classify the various aspects of
the ecosystems they study?
Definitions:
Ecology is the study of how organisms (_________________) _________________with each other
and their environment (__________________).
Organisms are individual living things. Organisms that ___________________with each other
under natural conditions are called____________________.
A population consists of all the individuals of the same __________________that occupy a
specific area of the _____________________________(habitat).
A community consists of all the ________________________populations in a given location.
All the communities interacting communities along with the abiotic components in a given
area constitute an _____________________________and all the ecosystems together make up the
biosphere (see Fig:3-4; page 43).
Abiotic factors include: sunlight, temperature, precipitation, wind, fire, soil, etc.).
http://www.youtube.com/watch?v=woSO0D94VGA students only
Living things are can be organized into feeding (trophic) levels (how many __________________
transformations away from the sun).
Producers (________________________) make their own nutrients through a process called
photosynthesis.
Photosynthesis is the process by which plants capture solar energy and use it to transform
water and carbon dioxide into a ___________________________________.
light
6CO2 + 6H2O --------------- C6H12O6 + 6O2
The sun’s energy also powers the cycling of _________________________that drives
__________________and ____________________systems across the planet.
Heterotrophs are dependent upon autotrophs for their organic molecules.
They are further classified as herbivores (_________________eaters), carnivores
(__________eaters), ____________________________(eat both), scavengers (feed on dead
organisms), and decomposers (fungi and bacteria).
Both autotrophs and heterotrophs breakdown the carbohydrates produced during
photosynthesis in a process known as _____________________respiration.
C6H12O6+6O2---6CO2+6H2O+energy (ATP)
As energy flows through an ecosystem much of it is lost. Most ecosystems have an
ecological efficiency of ______________________________.
This loss of energy between trophic (feeding) levels is often illustrated using a
_______________________ of energy (See Figs. 3-12; page 49).
As a result of this loss of energy most energy pyramids are limited to _____ or ______ trophic
levels.
ADDITIONAL TERMS
______________________________________organisms have a membrane bound nucleus and
complex organelles. Almost all organisms have eukaryotic cells.
Prokaryotic: no distinct ________________________and lack most ___________________-(bacteria
and the blue-green algae.
http://www.youtube.com/watch?v=WRO-DPyB9Bk students only
_________________________reproduction: no exchange of _________________information and
therefore little genetic variation.
___________________________reproduction: combine sex cells to exchange genetic information
and create ______________________diversity in the offspring.
3-3: Energy Flow in Ecosystems
EQ: 1- How does the flow of energy contribute to the structure of ecosystems?
Energy flows through an ecosystem only in one-way. The sequence of organisms through
which energy flows is called a ______________chain.
What information do food chains fail to convey? (2 things).
Food ________________show a more realistic view of energy flow because organisms typically
do not feed on a single species (Fig. 3-11; pg. 48).
Use the information provided below to perform the following calculations.
How much of the Sun’s energy do the producers capture? _______ cal
As a %? :_______
1. What percentage of that is transferred to the herbivore level (energy efficiency)?
Energy out
Energy In
X 100
2. What percentage is lost as metabolic heat?
3. What percentage of what the herbivores capture is passed on to the carnivores?
4. Of the original amount of heat captured by the producers (20,810 kcal) what percentage is
passed on to the top carnivores?
5. So why are there typically so few top predators in a given ecosystem?
https://www.youtube.com/watch?v=wGfOoRrICto ecological pyramids
The rate an ecosystem’s primary producers convert solar energy into biomass is called
________________ primary productivity (GPP). (it’s a __________________so there must be a
time component).
Some of this biomass is used to stay alive, grow, and reproduce (etc.). What remains is
called _____________________primary productivity (NPP). The NPP ultimately limits the
number of consumers in a given ecosystem. It has been estimated that humans use or waste
approximately _____ % of the planet’s total NPP.
http://www.youtube.com/watch?v=0hAiaQGHOQI throughout the year
See Figure 3-13 on page 49 to answer the following questions
1. What three ecosystems have the greatest NPP?
2. How many times greater is the NPP of
a rain forest compared to a temperate Grassland?
A temperate forest compared to a savanna?
Agricultural land compared to the open ocean?
Estuaries compared to extreme desert?
3-4 Matter in Ecosystems
Matter is constantly __________________in nature through biogeochemical cycles.
a. The Water Cycle is the simplest and most familiar.
Terms to know:
Precipitation:
Run off:
Infiltration and percolation:
Aquifers (groundwater):
Evaporation and transpiration:
A very tiny percentage of the earth’s water is avalable to humans (0.024%), due mostly to
salinity, depth, and/or because its frozen.
b. Carbon Cycle
All life on earth is based upon the element___________________. It is cycled between two
processes: ______________________________and aerobic__________________________________.
Decomposers also release carbon stored in the bodies of ______________organisms. Fossil fuels
represent a huge carbon ________________(storage place) for carbon that humans have been
releasing in increasing large amounts during the Industrial Revolution.
c. Nitrogen Cycle
Although extremly common in the atmosphere (_______%), nitrogen (N2) is unreactive. It cannot
be absorbed and used by living things in this form.
Nitrogen can be “fixed” (put into a ___________________form) as a result of lightning strikes and
by nitrogen fixing_____________________________.
Know the Nitrogen Cycle in Detail including (nitrogen fixation):
1. N2 --Bacteria = NH3 (ammonia)
2. NH3-Bacteria =NO3 (nitrate ions)= __________________________3. In this form it can be ______________________________by plants.
4. Animals and plants (waste, die)-> bacteria = _________________________
5. Bacteria convert NH3 and NH4 back to N2 = ___________________________
The increased use of inorganic fertilizers in modern agriculture has greatly overburdened the
natural nitrogen cycle (_________________________Overload).
d. Phosphorus: a ______________________factor for many plants. Cycle is slow because there is
no _______________________________component (rocks and sediments serve as sinks).
e. Sulfur: releashed into the atmosphere when coal is burned, metals are removed from sulfur
containing rocks, and through natural processes like ____________________eruptions or the
breakdown of organic substances (decay).
3-5 How Do Ecologist’s Learn About Ecosystems
EQ: What advantages and disadvantages are associated with the methods scientists use
to study ecosystems?
_________________Research involves going into nature to observe and measure what is
going on in ecosystems. Disadvantages include _________ (travel, food, etc.) and the difficulty
associated with trying to control________________.
Laboratory research uses _______________that allow greater control of variables. The
major disadvantage is knowing if the model _________________like the real thing.
Systems analysis involves the use of complex _________________models and computer
simulations to mimic the natural world. Today most ecological research is done using a
combination of all three approaches.