Mr. Ramos
Ecology Study Guide
Students, here is a study guide for the Ecology Test. Read it and study it carefully in conjunction with
your class & book notes. Remember the Ecology test is 50 Multiple Choice questions worth 50% of your
total class grade. The test is curved. Take advantage of this test. Ecology is the EASIEST biology test you
will take all year. Also, take advantage of this generous study guide. I will NOT always do these nice
things for you all.
General Ecology
Energy Transfer
The sun is our planets main source of energy. The sun provides food to producers like plants, and the
sun powers the biogeochemical cycles, such as the water cycle.
Energy is transferred from the prey to the predator: grass  cow
(This type of predation with a producer is called herbivory)
The arrow represents where the energy is transferred to
There is more biomass and energy at the bottom of a pyramid than at the top.
The first organism in a food chain, is the same as the “bottom of the pyramid”
grass  cow  lion (the grass has the greatest biomass & energy)
10% of the energy is passed from the bottom trophic level to the level right above it.
90% of the energy is lost as heat to the environment. (This is why you need to talk less in class…because
then it gets hot)
1st Law of Thermodynamics states that ENERGY cannot be created or destroyed. Energy is transferred
(examples: solar energy  chemical energy  mechanical energy)
Law of conservation of matter states that MATTER cannot be created or destroyed. Unlike energy, which
flows in one direction, matter cycles. We call it the biogeochemical cycle: water cycle, carbon cycle,
nitrogen cycle.
Phytoplankton is “plant-like” plankton (it is a producer)
Zooplankton is “animal-like” plankton (it is a type of consumer)
Decomposers break down organic matter through a process of absorption.
Fungi and Bacteria are decomposers.
Producers and consumers will all eventually be decomposed
Producers
Plants, Algae, and bacteria are producers. They can “produce” their own food through sunlight or
chemicals.
Plants, Algae, and Cyanobacteria convert the sunlight into energy. This process is called photosynthesis.
Producers, such as plants, algae, and bacteria are also known as autotrophs.
Because plants, algae, and cyanobacteria use the energy from the sun, they are specifically called
photoautotrophs.
The rest of the bacteria use chemicals to produce their own food. They are then called
chemoautotrophs.
Remember that Fungi are not plants! Fungi are not producers! They do not perform photosynthesis.
Consumers
A consumer is an organism that cannot make its own food; it needs to feed off of other organisms to
obtain energy. Another word for consumer is heterotroph.
A herbivore is a consumer that eats plants (example: cow)
A carnivore is a consumer that eats meat (example: lion)
An omnivore is a consumer that eats plants and meat (example: humans)
A decomposer absorbs decaying matter (example: fungi and bacteria)
A detritivore actually eats dead matter (example: worms)
Photosynthesis and Cellular Respiration
Photosynthesis (to make/synthesize food with light) is a process used by producers, such as plants to
make their own food.
Plants absorb the carbon dioxide in the atmosphere (which causes global warming) and release oxygen
in the process.
If plants do not capture the carbon dioxide, excess heat is trapped in the Earth, and the Earth gets
hotter. Then the ice caps melt, the sea level rises, and we all DIE….
(because carbon dioxide is a greenhouse gas, and the greenhouse effect causes HEAT)
Photosynthesis Equation (what do we give them / what do they give us):
6CO2 + 6H2O + Sunlight  C6H12O6 + 6O2 (FYI: C6H12O6 is the sugar glucose)
The opposite of photosynthesis is cellular respiration. Who does cellular respiration? Hmmm…All living
things because they all have CELLS. So, yes, plants also do cellular respiration in addition to
photosynthesis.
Cellular Respiration Equation:
C6H12O6 + 6O2  6CO2 + 6H2O + ATP
(FYI: ATP is a high energy molecule)
Symbiotic Relationships
Mutualism: both organisms benefit from their relationship (+/+)
(example: bumble bee helps pollinate the flower, and the flower provides food for the bee)
Commensalism: one organism benefits, but the other organism neither benefits nor is harmed (+/0)
(example: a small fish swims next to a shark for protection from other fish, but the fish does not provide
anything in return to the shark) “Wouldn’t you like to have a big brother by your side to protect you
from bullies?”
Parasitism: one organism benefits while harming the other organism, called its host (+/-)
(example: A tapeworm in your intestines will eat all your food. Eventually you begin to get skinny and
notice something is wrong)
Succession
A succession is followed by some type of disturbance in nature.
Primary succession begins with bare rock and eventually forms into a forest. Lichens are the pioneer
species in primary succession. They can survive in these extreme conditions…Would you eat rock?
Lichens will.
Hawaii was probably a result of primary succession. Lava from volcano cools and becomes rock.
Eventually the rock becomes soil and is fertilized over hundreds of years.
Secondary succession results when a previous environment with SOIL has been partially or completely
destroyed. Secondary succession occurs quicker than primary. The Florida Everglades are constantly
being burned down and re-grow. The Everglades experience secondary succession.
Biotic and Abiotic Factors
A biotic factor is a living factor within an ecosystem (example: plants, birds, trees)
An abiotic factor is a nonliving factor within an ecosystem (example: soil, sunlight, water, wind)
Population Ecology
Denisty
Population Density is defined as the number of individuals per area.
Group A: 5 individuals in an area of 50 square feet
Group B: 30 individuals in an area of 50 square feet
Which group (A or B) has the greatest density? Group B has the greatest density because it has more
individuals than A, which has the same area.
Group C: 5 individuals in an area of 50 square feet
Group D: 20 individuals in an area of 500 square feet
Which group (C or D) has the greatest density? Group C has the greatest density of 0.1 (5 individuals
divided by 50 square feet) compared to group D with a density of 0.04 (20 individuals divided by 100
square feet)
Limiting Factors
A density-dependent limiting factor is something that “LIMITS” the population from growing based on
the density of that population. (examples: competition, predation, parasitism and diseases)
The more people in Miami, the less jobs. Jobs are examples of density-dependent limiting factors.
A density-independent limiting factor is something that “LIMITS” the population from growing but does
not depend on the density of that population. (examples: tornadoes, hurricanes, lightning storms,
earthquakes). A tornado doesn’t care how big or small a population is. A tornado will destroy anything in
its way.
Population growth depends on four factors: birth rate, death rate, immigration, and emmigration.
Populations grow exponentially at first but eventually reach a carrying capacity. Once the carrying
capacity for that population is met, the growth becomes “S-shapes” (logistic growth)
Environmental Ecology
Environmental Problems
Chlorofluorocarbons (CFCs) are chemicals that were once in aerosol products. They have caused a huge
hole in our ozone layer. (Please do not confuse CFCs with carbon dioxide. CO2 is a greenhouse gas)
Carbon dioxide is a greenhouse gas. Greenhouse gases cause global warming (hot, hot, caliente)
Acid rain is literally acid in the rain. It destroys statues, forests, etc…
Acid rain forms when nitrogen and sulfur gases mix with water vapor to form nitric acid rain and sulfuric
acid rain. Factories and pollution are responsible for acid rain.
pH is a scale used to determine whether something is acidic or basic. Less than 7 is acidic and greater
than 7 is basic. So what is 7? Water. Acid rain has a pH way below 7. Probably a pH of 3 or 4.