Regents Biology
Ecology
Chapters 3 through 6
Use this Ecology packet to supplement the information in the textbook and our notes. Read the indicated
pages, make notes & diagrams, and define vocabulary terms.
Ecology – The study of interactions between organisms and their interactions with their
environment. p. 62 to 68. What are the different levels of the biosphere? What is the
difference between the biotic and abiotic parts of the ecosystem?
1. Energy – p. 69 – 78 – Just like living organisms, energy is needed to sustain ecosystems.
a. Where does the energy come from? In what form is it usable to organisms in the
ecosystem? What is a food chain? food web?
b. What are producers, consumers (herbivores, omnivores, carnivores, scavengers,
decomposers, detritivores, saprophytes).
c. How do they all interact? (trophic levels, 10% rule, energy pyramid, biomass/numbers
pyramids)
2. Material Cycles in Ecosystems – Page 79-87.
a. Define Biogeochemical cycles. How do nutrient/material cycles differ from energy flow in
an ecosystem?
b. The Water Cycle: Define different processes involved in the water cycle. List possible
sources of water. Outline the water cycle, using arrows to show how water moves through
the ecosystem.
c. The Carbon Cycle: Identify sources of carbon in the ecosystem. Define the processes
that transform the carbon from one form to another. Outline the carbon cycle, using
arrows to show how carbon moves through the ecosystem. Include organisms that carry
out the processes.
d. The Nitrogen Cycle: Identify sources of nitrogen in the ecosystem. Define the processes
that transform the nitrogen from one form to another. Outline the nitrogen cycle, using
arrows to show how nitrogen moves through the ecosystem. Include organisms that carry
out the processes.
e. Why is phosphorus necessary for living organisms?
f. What is a limiting factor/nutrient? What happens if an excess of a limiting
factor/nutrient gets into an ecosystem? How can this negatively impact an ecosystem
(especially and aquatic ecosystem)?
3. Niche and Community Interactions – Read pages 94 – 104.
a. What is a niche? Why does each organism have its own niche within an ecosystem?
b. Community Interactions – How do different populations interact with each other within
ecosystems? List and define the types of relationships (competition, predation,
symbiosis).
c. List three types of symbiotic relationships. Define each and provide an example for each.
4. Ecological Succession – Read pages 106 to 109.
a. How do ecosystems change over periods of time? What is succession? What causes
succession?
b. What is the difference between primary and secondary succession? Provide an example
for each.
5. Biomes and Climax Communities – Read p. 110 - 123.
a. How does climate affect the biome of an area? (temperature, latitude (or altitude) and
precipitation)
b. What is a biome? Read about the major biomes. You should identify the abiotic factors
that shape each of the major biomes listed below, the typical vegetation of the biome and
the typical animals found there. You should also know where these biomes are found. The
Biomes with which you should be familiar are: polar regions (ice caps), tundra, taiga
(Boreal Forest), temperate forest (deciduous forest), grasslands (savanna, prairie,
steppe), tropical rainforest, tropical forest, desert, and aquatic biomes: fresh water
ecosystems, estuaries, and salt water ecosystems.
6. Populations – Population size and stability in ecosystems p. 128 – 147
a. Define a population. What do researchers study about populations? Does population size in
a stable ecosystem remain relatively constant or does it change? How do populations
grow, and which factors change the population size? What is exponential growth? What
logistical growth and carrying capacity?
b. What are limiting factors? How do they determine the population size and carrying
capacity of a species in an ecosystem? List and describe different Limiting Factors
(Competition, predation/ herbivory, disease and parasitism, overcrowding, natural
disasters, weather extremes, invasive species.
c. Human population – How has human population size increased? Why did human population
size grow slowly before the year 1000? What kinds of limiting factors kept the human
population size in check? What has happened to the human population size since then?
Why? What kind of stresses does an increasing human population put on our environment
and the balance of ecosystems?
Human Impact on the Environment – Chapter 5 to 6.
We only have one Earth.
We should take care of it!
Humans and the Biosphere
Everything humans do have an impact on the environment. Sometimes it may be a negative
impact, but we can make choices to reduce the negative impact or even have a positive impact on
the environment too. Humans have a great impact on the environment because of the increasing
human population and use of technology. Humans consume resources.
Negative Aspects
A) Human Population Growth: Human population has exploded in the since the 1800's. The
world's population was under one billion people before the 1800's. In 1950 it was
about 2.5 billion. Today it is about 6.8 billion and rising. More people means:
more food, more cities, more homes, more roads, more resources being used,
more pollution, more garbage, more destruction of habitat, more trees cut, more
consumption……..
B) Overhunting & Overfishing: Due to increasing demand for food and other resources
animals provide, animals are being overhunted. The population sizes of animals is
decreasing, and getting too small to sustain the species. This can lead to extinction of
the species. Ex. Fur trade almost wiped out sea otters. Tuna, Pollack, cod, and other
fish populations are on the decline, but commercial fishing continues.
C) Poor Land Use/ Management:
Loss of habitat /habitat destruction
fragmentation of habitat (separates ecosystems/forms isolated chunks)
mining for resources (coal/metals) clear cutting (lumber industry)
agriculture: slash & burn, monoculture (reduces biodiversity of an area), over-use
of land (reduces nutrients in soil leads to decreased productivity), increased use
of chemical fertilizers & biocides (pesticides/herbicides)
D) Importation of non-native organisms (invasive species): People transport species from
one ecosystem to another. The imported species may out-compete native species since
it lacks natural predators and other population controls that existed in it’s native
environment. The invasive (non-native) species can replace native species, reducing
biodiversity and even destroy the ecosystem. Why would people move species from
one place to another? How could it happen with out us knowing?
E) Exploitation of wildlife – People want rare/unique species or want parts of those
species for their own. Ex. Tiger rugs, ivory, rhino horns, shark fin soup, orchids.
F) Adverse Effects of Technology: Humans develop and use technology that increases
our impact on the environment. Most technology is based on using energy – primarily
fossil fuels. Increased use of fossil fuels adds CO2 to the atmosphere and may
contribute to global climate change (global warming). CO2 is a greenhouse gas. Mining
for coal and drilling for oil/natural gas destroys the environment.
a. Air pollution: Burning fossil fuels adds particulates to the atmosphere.
Industry creates airborne chemicals that are harmful to the environment.
Acid Rain - sulfates and nitrites emitted from industry mix with water in
clouds, makes rain acidic. The acid rain reduces the pH of aquatic
ecosystems, killing plants and animals.
CFC’s (chlorofluorocarbons) - Chemicals used in air conditioners and aerosol
sprays have depleted the ozone layer in the atmosphere. The ozone layer
absorbs harmful UV rays from the sun, so they do not reach the surface of
the planet.
b. Water Pollution – Chemicals disrupt the stability of aquatic ecosystems.
Sometimes chemical are dumped by industry, chemicals are carried by surface
run-off water, or through the sewer/ water treatment systems. Harmful
chemicals include but are not limited to…pesticides, herbicides, biocides,
fertilizers, animal/human waste, fossil fuels, industrial chemicals, plastics,
antibiotics, cleaning products, dry cleaning/photography chemicals, acid rain,
runoff from landfills, tainted ground water, PCB’s, Dioxins,…..
c. Land Pollution – GARBAGE, landfills, chemicals in the soil, nuclear waste
disposal, heavy metals (mercury, lead), plastics, styrofoam, batteries…
Biomagnification - Harmful/toxic chemicals are stored in organisms and move
through the food chain. Organisms high up on the food chain will have high
concentrations of the chemical in their tissues. Harmful chemicals include
PCB's, Dioxins, DEPH, DDT, heavy metals such as mercury and lead.
What can we do to make things better?
Conservation of Resources – use less, use things again, recycle things to be made into
something else, instead of just throwing everything away. Here is a list of things you can do to
help save the environment. Turn off water when brushing teeth. Take shorter showers. Reuse
containers. Buy bulk and divide into portions, using a reusable container. Drink tap water instead
of bottled water; refill bottles/cups. Bring your own re-useable bags when shopping. Use energy
efficient light bulbs. Turn off lights in rooms that aren’t occupied. Walk. Ride your bike or take
public transportation. Buy energy efficient cars. Keep thermostat below 65° in winter, above
75° in summer. Try not to buy something unless you NEED it. Send unused clothes to a charity.
Make a compost heap and put fruit and vegetable scraps in the compost instead of in the
garbage. Reuse white papers for scrap paper. Don’t take more food than you will eat. Buy locally
grown produce. Grow your own produce. The list continues……….. Reduce, Reuse, Recycle…
Pollution Controls: Laws, regulations and consumer demand can reduce pollution. Demand
cleaner cars, that factories release less pollution into the environment and dispose of polluting
and toxic waste appropriately. Use natural fertilizers (compost) instead of chemical fertilizers.
Avoid using pesticides, use natural repelling agents instead.
Species Preservation – efforts to protect species that are threatened or endangered. Some
programs will breed in captivity and re-introduce species into the wild (ex. California Condor).
There are laws to protect endangered species and restrict the use of the land where the
species live. Natural preserves are set aside to allow the species to live in a protected habitat.
Reforestation – Replanting of native trees and vegetation. In areas where there is development
and deforestation, people are replanting trees and natural vegetation to restore the ecosystem
and to help control erosion.
Biological Controls – Using organisms to control pest populations rather than using chemical
pesticides. Using a natural predator or parasite to control the pest population is less harmful to
the ecosystem than adding poisons to kill the pest. Example: put ladybugs on plants to eat
aphids, a pest that destroys the plant. Ladybugs can be purchased at a nursery. Grow marigolds
to reduce mosquitoes in your yard.
Legislation, Environmental Laws and Regulation – Government reinforced laws and regulations
that reduce negative impact on the environment. These laws protect natural areas, endangered
and threatened species, reduce carbon emissions, reduce pollution from industry, reduce illegal
dumping of wastes, instate recycling regulations, and limit development to protect ecosystems.
Water Cycle:
Carbon Cycle:
Nitrogen Cycle: