Download Unit 10: Ecology Notes

Ecology Unit
Name ___________________________ Hour ____
I. The Basics of Ecology
A. Ecology – The study of the relationship between organisms and the adaptations to their environment.
B. Levels of Organization
Atoms- The smallest unit of matter, dead or alive
Molecules- Combinations of atoms (ex. Lipids, Carbohydrates, Proteins, Nucleic Acids)
Organelles- Cell structures that perform specific functions (groups of molecules)
Cells- Groups of organelles all working towards common functions
Tissues- Groups of cells all working towards common functions
Organs- Groups of tissues working towards common functions
Systems- Groups of organs working towards common functions
Organism- An individual that can carry out all life processes
Population/Species- _________________________________________________
Community- _________________________________________________
Ecosystem- All living organisms and nonliving features in an area
Biome- Large ecosystems
Biosphere- Where life exists (Earth – all biomes)
C. Ecosystem – All abiotic (___________)
and biotic (____________) factors in a given
area.
1. Habitat – The physical area where an
organism lives, which includes climate,
topography, soil and water chemistry, and plants
& animals (where it lives).
2. Niche – How an organism lives in its
habitat which includes feeding habits,
reproductive behavior (how it lives).
RAPS: Explain the relationship between the
variety of resources and the number of niches
in an ecosystem.
_________________________________________________________________________________________________
_________________________________________________________________________________________________
RAPS: Explain the relationship between the number of niches and biodiversity in an ecosystem. ______________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
II. Energy Flow
A. Trophic (eating/feeding) Levels – Determined by what an organism eats and what eats the organism.
1. Autotroph/Producer – _______________________________________________________________________
2. Heterotroph/Consumer – Organism that must obtain its food from other organisms.
a. primary consumer – Eats producers; known as an herbivore
b. secondary consumer – Eats primary consumers; known as an carnivore
c. tertiary consumer – Eats secondary consumers
d. omnivore – Eats both producers and consumers
e. scavenger – Eats newly killed animals
3. Saprotrophs/Decomposers/Detrivores – Organisms that obtain nutrients from dead organisms.
Q: What important role do the decomposers play in an ecosystem?_______________________________________
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B. Food Chain – Diagram showing the direction energy flows from one organism to the next due to feeding habits.
1. Most energy on Earth used by living organisms is derived from _______________________.
2. The sun’s energy is converted into stored chemical energy by producers through the process of ________________.
3. On average, an organism stores about 10% of the energy it receives from the organism upon which it feeds.
C. Food Web – Interrelated food chains. In an ecosystem, many animals may eat the same organism, and animals
can eat a wide variety of other organisms.
or
or
or
Sun’s Energy
or
or
ALL ORGANISMS IN A FOOD WEB HAVE AN EFFECT ON THE OTHER ORGANISMS IN THAT WEB!!!
What do the arrows in the food web represent?
___________________________________________
What would happen to the fox population if the
grasshoppers were to all die?
___________________________________________
___________________________________________
Write out a food chain that has a 4°consumer.
___________________________________________
___________________________________________
If there is a total of 20,000 kilocalories of energy
available in the grass, how much of that energy will
the owl receive?
___________________________________________
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D. Ecological Pyramids – A diagram showing the relative amounts of energy or matter contained within each trophic
level in a food chain or food web.
1. Energy Pyramid – represents the total amount of energy (kilocalories) in each trophic level.
a. Only about 10% of the total energy transfers from one level to the next. What happens to the rest?
________________________________________________________________________________________
b. Energy pyramids are never inverted (small bottom & big top); energy is always lost between trophic levels.
2. Biomass Pyramid – Compares the amount of biomass at each trophic level.
Numbers
Biomass
a. Biomass is the total dry weight (w/o water) of the organisms in an ecosystem.
b. Usually, producers have the greatest biomass.
c. An example of an inverted biomass pyramid would be one in savanna grasslands where the biomass of
herbivores such as zebra, gazelles, elephants and hippopotamuses is more than the biomass of the slender
grasses found in that food web.
3. Numbers Pyramid – compares the number of individual organisms at each trophic level.
a. Usually, producers are the greatest in number.
b. An example of an inverted numbers pyramid would be one tree that sustains a population of leaf-cutting ants.
III. Cycles of Matter
A. Water/Hydrologic Cycle
1. Evaporation – Radiant energy from the
sun moves water from
land to the atmosphere.
2. Transpiration – Radiant energy moves
water from plants to
the atmosphere.
3. Precipitation – Water returning to the
land in the form of rain,
snow, sleet, hail, or fog.
(the air is saturated with water).
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B. Carbon (and Oxygen) Cycle
1. What two processes cycle C and O in our
environment?
____________________________________
CO2 + H2O → C6H12O6 + 6O2 (Photosynthesis – Plants, Bacteria, Protists)
C6H12O6 + 6O2 → CO2 + H2O + Energy (Cell Respiration – all organisms)
____________________________________
____________________________________
2. What has increased the CO2 levels in our
atmosphere in the last century?
____________________________________
____________________________________
____________________________________
____________________________________
3. CO2 along with methane gas, water vapor,
and others cause the greenhouse effect.
C. Nitrogen Cycle
1. Nitrogen gas comprises 78% of our
atmosphere in the form of N2 gas, which
many organisms cannot use in this form.
2. What do organisms need Nitrogen to build?
________________________________________
_______________________________________
3. Bacteria convert N2 gas into usable forms
such as nitrate (NO3) and nitrite (NO2).
4. Denitrification – ______________________
____________________________________.
Nucleotide
D. Phosphorus Cycle
1. Living organism need Phosphorous for ________ and __________.
2. This cycle does not involve the atmosphere, but rather earths
lithosphere or its rock layer. Weathering of rock releases
phosphorus into the soil, usually as phosphate (PO 4), where it
is absorbed by plants and moved along the trophic levels.
3. Phosphorus is returned to the soil via animal wastes and the
decomposition of organisms by bacteria and fungi.
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IV. Climate - The average, year to year conditions of ___________________ and ___________________________.
A. Weather – The day to day condition of earth’s atmosphere at a particular time and place.
B. Climate Zones – Created due to the tilt of earth’s axis; causes different light
intensities for different regions or zones
a. Polar Zone – ____________ Temperature & ____________ Precipitation
b. Temperate Zone – __________ Temperature & __________ Precipitation
c. Tropical Zone – ___________Temperature & ___________ Precipitation
C. Ocean and Wind Currents – Created from the uneven heating of air and water.
List at least 3 factors that determine climate for a biome or ecosystem. ___________________________________,
____________________________________________, ____________________________________________________
RAPS: Explain how climate affects the biotic factors in an ecosystem. _____________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
V. Biomes
A. Terrestrial – Land areas whose climate determines plant types (flora), which in turn determines animal life (fauna).
Examples: ___________________________________________________________________________________________
B. Aquatic – Bodies of water whose temperature and salinity (salt content) determine flora & fauna (plants & animals).
1. Freshwater Biomes
a. Low salinity (.005% salt)
→ Freshwater that moves - ____________________ & ____________________.
→ Freshwater that does not move - ____________________ & ____________________.
2. Marine Biomes
a. High salinity (3.5% salt)
→ Ocean – ____________________________________________________________
→ Wetland – An ecosystem in which the roots of plants are submerged under water at least part of the year.
→ Estuaries –freshwater flows into saltwater; shallow enough for sunlight to reach the bottom plants.
Explain the importance of wetlands and estuaries for the wildlife of many biomes. __________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
VI. Other Driving Forces in an Ecosystem
A. Abiotic Factors – Nonliving components of an ecosystem.
Examples: ________________________________________
1. Rivers can flood changing soil composition of nearby banks.
2. Volcanoes can form mountains.
3. Lightning can cause forest fires.
B. Biotic Factors – Living organisms of an ecosystem.
Examples: _________________________________________________________
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1. Competition - Use or defense of a resource that reduces the availability of that resource to another individual.
 Intraspecific Competition – Occurs between organisms of the same species
 Interspecific Competition – Occurs between organisms of different species
Explain why intraspecific competition is more intense than interspecific competition. ________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
 Gauses' Competitive Exclusion Principle - ______________________________________________________
__________________________________________________________________________________________
2. Predation – When one organism (predator)
feeds on another (prey).
Describe the predator/prey relationship in the
graph showing moose and wolf population
numbers.
_____________________________________________
_____________________________________________
_____________________________________________
_____________________________________________
3. Symbiosis – a biological relationship between unlike organisms
 Parasitism – When one organism (parasite) obtains nutrition from another organism (host). One organism
benefits while the other is negatively affected.
Examples: ____________________________________________________________________________________
 Commensalism – When one organism benefits and the other is not affected in a positive or negative way.
Examples: ____________________________________________________________________________
 Mutualism – When both organisms benefit.
Examples: _____________________________________________________________________________)
C. Succession – The gradual, sequential replacement
of populations in an area.
1. Primary Succession – The sequential replacement
of populations in an area that has not previously
supported life.
a. Pioneer Species –first species to live in a new
habitat (algae, lichen, short grasses, mosses, insects,
worms).
b. Seral community will out-compete and replace the
pioneer community (tall grasses, bushes, larger
animals).
c. Climax community – usually the highest
biodiversity; will remain stable as long as the
area is left undisturbed.
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VII. Population Growth
A. Population Density – The # of individuals per unit area (this # can vary depending on the species and ecosystem).
B. Population Growth Rate –change in the # of individuals ipopulation over time. Calculated by:
Growth 
 # organisms
time
C. Factors that Affect Population Growth
1. _____________________________
2. _______________________
3. ___________________________
Immigration – ________________________________ Emigration – ________________________________
D. Types of Population Growth
1. Exponential Growth – Occurs when the individuals in a population reproduce at a constant rate, assuming
unlimited resources and no predators.
→ In a graph, this type of growth forms a J-shaped curve.
2. Logistical Growth – Occurs when a population’s growth slows or stops after a period of exponential growth.
→ In a graph, this type of growth forms an S-shaped curve.
Q: What causes exponential growth to slow or stop in a population? __________________________________
_____________________________________________________________________________________________
E. Growth Curve – Shows population growth over time; * Label the lag phase and exponential phase on the graph.
1. Carrying Capacity – Max # of individuals that an ecosystem’s
resources and space can support.
2. Lag Phase – A time of little to no growth.
3. Exponential Phase – A time of rapid growth (population doubles
over shorter and shorter periods of time).
F. Limiting Factors – A factor that causes population growth to decrease.
1. Density-Dependent – limiting factor dependent population size.
Examples: ______________________________________________
_________________________________________________________
2. Density-Independent - Limiting factors affecting populations in similar ways regardless of population size.
Examples: __________________________________________________________________________ _____
RAPS: Explain why the carrying capacity of deer in Weldon Springs Conservation Area is limited . _______________
___________________________________________________________________________________________________________
___________________________________________________________________________________________________________
__________________________________________________________________________________________________________
G. Human Population Growth
1. Demography – The study of human populations, looking at changes in birth and death rates and their causes.
2. Demographic Transition – Occurs when population shifts from a high birth and death rate to a low birth and
death rate. The result is that the population grows very slowly, if at all. Most
developed countries have experienced this.
3. The population of Earth continues to grow exponentially because most people live in countries that have not
completed demographic transition.
Examples of countries with exponential growth: __________________, ________________________, ________________________
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* Use the graph below right to answer the following questions.
Estimate the human population in
9,000 B.C.:
_________________
Estimate the human population in
6,000 B.C.:
_________________
What was the human population in
1,000 B.C.?
_________________
What was the human population in
1,500 A.D.?
_________________
What was the human population in
2,000 A.D.?
_________________
Extrapolate the population for 2,010 A.D.: ___________________
Label the lag and exponential phases of growth.
RAPS: Explain why exponential growth in the human population began in the 1900s. ________________________
________________________________________________________________________________________________
_________________________________________________________________________________________________
4. Demographers can use age-structure diagrams
to predict the future growth of populations.
Q: Is Rwanda a steady, growing, or shrinking population?
Explain.
_____ __________________________________________
________________________________________________
5. Current projections suggest that the world population will
be 7.8 billion by 2025 and up to 9 billion by 2050.
6. In the US and other developed nations, the growing
population lives in mostly urban and suburban areas.
Urban Sprawl – ___________________________________
_________________________________________________
_________________________________________________
RAPS: Explain the impact of urban sprawl on ecosystems. ______________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
VIII. Natural Resources – The biotic and abiotic materials that support life on Earth.
A. Renewable Natural Resources – The materials that can be replenished in a relatively short time span.
1. Forests – Communities dominated by trees and many different species of organisms.
a. Deforestation (fast process) – Clearing large areas of forested land for human use and consumption.
b. Reforestation (slow process) – Replanting or seeding to replace trees and reverse deforestation.
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2. Wildlife – All plants and animals in a community that are interdependent on one another.
a. Endangered Species – Those organisms that are at risk of extinction in their native habitats.
b. Threatened Species – Those organisms that are likely to become endangered in their near future.
c. Endangered Species Act (1973) – Passed by the U.S. government to define endangered species and
establish regulations for their protection.
3. Soil – A mixture of rock fragments, minerals, and organic matter.
a. Soil is renewed by erosion and decaying organisms. Plants and animals rely on soil for nutrients and
water, and soil relies on plants and animals to prevent destructive soil erosion.
b. Desertification – Formation of deserts by drought, overgrazing, and/or over farming (depletes nutrients).
Q: How can humans help prevent soil erosion and depletion?
 Crop Rotation – Reduces loss of nutrients.
 Treelines – Decrease wind erosion.
 Plant Grasses – Decrease soil erosion because roots hold
onto the soil.
 Irrigation Ditches – Allow run-off (from watering or rains)
to be stored near root level.
 Contour Plowing – Decreases water erosion
 Terracing – Decreases water erosion
 Fertilizers – Increases plant growth
4. Water (H2O) – Essential to all life, only 3% of the water on
Earth is usable by man and nearly 2% is in the ice caps.
Q: How does man get by on such little water?
_________________________, _________________________, & ______________________________
B. Nonrenewable Natural Resources – Those materials in nature that cannot be replenished by nature or man.
1. Fossil Fuels – Formed by incomplete decay of prehistoric plants and animals living in the Carboniferous
period about 300 million years ago. Fossil fuels are used for over 90% of our energy needs.
Examples:
____________________, ____________________, ____________________
Q: What are some alternative energy sources to fossil fuels?
→ _________________________
→ _________________________
→ _________________________
→ _________________________
→ _________________________
→ _________________________
2. Minerals – Inorganic solids formed in earth (Fe, Ag, Al, Cu, Zn…) - maintain normal body structure & function.
3. Air – composed of a mixture of gases, including N 2 (78%), O2 (21%), and CO2 (.03%)
a. Smog – _______________________________________________________________________________
b. Acid Rain – The release of Nitrogen and Sulfur compounds from burning fossil fuels (lowers H 2O pH).
c. Ozone Layer - __________________________________________________________________________
__________________________________________________________________________


There has been thinning of the ozone layer from excess CFCs in the atmosphere
CFC’s have been banned, so now the ozone layer can begin to slowly recover.
d. Greenhouse Effect– An excess of CO2 and other gases (like methane, water vapor) traps the sun’s heat in
Earth’s atmosphere, resulting in increased temperatures thus global warming.
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IX. Biodiversity
A. Ecosystem Diversity – Includes the variety of habitats, communities, and ecological processes in the living world.
B. Species Diversity – The number of different species in the biosphere.
C. Genetic Diversity – The sum total of all the different genomes carried by all living organisms on Earth.
Why is biodiversity important? ____________________________
____________________________________________________
____________________________________________________
D. Human Activities Affect Biodiversity
1. Humans reduce biodiversity by altering habitats, hunting
species to extinction, introducing toxic compounds into food
webs, and introducing foreign species to new environments.
2. Habitat fragmentation - breaking habitat up into smaller,
disconnected pieces (roads, dams, urban sprawl, deforestation,
agriculture, draining wetlands).
3. Pollution – undesirable change in the chemical, physical, or
biological characteristics of an ecosystem.
a. Biodegradable pollutants – can be broken down by
decomposers such as fungus and bacteria
Examples: _____________________________________________
_______________________________________________
b. Nonbiodegradable pollutants – cannot be broken down by living organisms
Examples: waste oils, CFC’s (chlorofluorocarbons), Styrofoam, Industrial cleaning chemicals
c.
Biological Magnification – Concentration of a harmful substance increases in organisms at
higher tropic levels in a food chain or food web.
d. Recycling – reusing materials so that they do not become waste or pollution.
4.
Non-native species - (Invasive, exotic, alien, nonindigenous) – species migrate
(naturally or by human introduction) into areas where they have not previously lived. This
disrupts the food web of that habitat.
 Crown vetch plant is used along roadsides to prevent erosion, but it takes over large
areas and native plants can’t compete, so native animals have less nutritious food.
 Zebra mussels, immigrants from E. Europe/W. Asia in shipping vessels, remove so
many nutrients from our fresh water lakes and rivers that native mussels and other
organisms cannot find enough food. They also clog water drains, cover boat docks
and bridge posts and are very expensive to remove.
 Feral Hogs – tear up soil causing erosion, killing native plants, and creating mud holes
where mosquitoes breed. In Hawaii, this has led to spread of diseases in native birds.
Explain the effect of non-native/invasive species on a food web. __________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
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Human Activity
Describe Specific Example
Negative Impacts
Ways to reduce or reverse
the negative impact
Pollution
Habitat
Fragmentation
Over Fishing
1. What organism in the food web above is the producer? __________________________________________________
2. Write the names of all the secondary consumers below. ________________________ ________________________
______________________________
______________________________
______________________________
3. Identify the highest order consumer in the food web above: ___________________________ = Level _________
4. List 2 food chains to which the Adélie penguins belong.
a) ____________________________________________________________________________________________
b) ____________________________________________________________________________________________
5. A toxic chemical has found its way into the ocean, nearly depleting the krill. This causes the number of squid to
decrease. Describe a chain of at least three events that will result in a change in the population of killer whale.
_______________________________________________________________________________________________
_______________________________________________________________________________________________
6. The Leopard Seal receives 300 Kilocalories of useable energy from the King Penguin it eats. The King Penguin in turn
feeds on krill. How much initial energy was there in the Phytoplankton eaten by the penguin?____________________
7. What is the ultimate source of energy in the ocean ecosystem pictured above? ____________________
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