Transcript Notes Chapter18 Ecology

Chapter 18
Introduction to Ecology
Biology I
Mrs. Schalles
ECOLOGY?
- comes from the GREEK Words:
OIKOS (HOUSE where one lives)
LOGOS (STUDY)
Ecology is the Study of the
“House” in which We Live.
Ecology can be defined
more specifically as:
• The Study of the Interactions
between:
–Living Organisms
–Non-living Components of their
Environment.
Parts of the Environment:
• Biotic- Living Organisms
-Producers, Consumers, and Decomposer
• Abiotic- Non-living components
-sunlight, temperature, humidity, water
supply, soil type, mineral nutrients (Nitrogen,
Phosphorous, Sulfur, etc)
Interdependence
- Effects of Interactions between
organisms & their environment.
- Each organism Depends in some way
on other living and nonliving things in
its Environment.
Key theme of Ecology
• No Organism is isolated- Everything is
interconnected
• Species interact with each other & with
abiotic factors in the environment.
• Disturbances in one species can affect
other species.
Example of Interdependence:
• See diagram on page 360 in textbook
• Unexpected “chain reaction”
• In a year when more acorns are producedeventually see humans with more lyme
disease.
• Explain how this happens.
• Can you think of another example of
how a change in your environment can
indirectly affect living organisms?
Some examples of complex,
controversial interactions are
not completely understood :
Because they involve:
• dynamic ecosystems
• multiple governments
• differing interpretations of data in
an area of ever-changing science.
Some Environmental Problems
1. Human Population Growth
2. Mass Extinction
3. What is Climate Change/Global Warming?
4. Pollution
5. Use of Resources/ Burning Fossil Fuels
6. Sustainability
1. Human Population Growth
Graph of Human Population Growth
1. Human Population Growth
Growth-limiting factors
• the availability of food and water
• invasion of parasites, pathogens or
disease
• over-crowding (increasing competition
for food, water and space)
• severe or sudden climatic changes
• pollution of air, soil and water
2. Mass Extinction
• As human population has increased, many
other species decline in number or
become extinct.
• There have been at least 5 periods of
mass extinction, could we be causing # 6?
3. What is Climate Change/Global Warming?
What is the greenhouse effect?
3. What is Climate Change/Global Warming?
Greenhouse Earth
• The earth is naturally warmed by the
greenhouse effect.
• Without the greenhouse
effect the earth would be
too cold to maintain the
diversity of life that it
does now.
3. What is Climate Change/Global Warming?
Major Greenhouse gases
and their sources
• H2O (water vapor) – evaporation, plant respiration.
• CO2 (Carbon dioxide)- burning fossil fuels,
volcanic eruptions
• CH4 (Methane)
-animal waste, fossil fuels, landfills,
sewage, wetlands
• N2O (Nitrous Oxide) – deforestation, fossil fuels,
microbe activities (in soil)
• CFCs (Chlorofluorocarbons)- aerosols, propellants,
solvents, refrigerants
3. What is Climate Change/Global Warming?
Is Global Warming actually happening?
• Many scientists say NO!
• The Cooling World- Newsweek, April 28, 1975
– ( scientists warned in the 1970’s that the earth was dangerously cooling!
www.denisdutton.com/cooling_world.htm
• 1980’s-2006 Global Warming was the politically correct topic
– See Al Gore & many Hollywood actors opinions.
• In 2007, hundreds of people died, not from global warming, but from
cold weather hazards
http://www.washingtontimes.com/article/20071219/COMMENTARY/10575140
• 2008 – Independent study commissioned by congress
– Mr. Wegman& team from George Mason University concluded that the idea that
the planet is experiencing global warming "cannot be supported."
http://www.washingtontimes.com/apps/pbcs.dll/article?AID=/20080314/COMMEN
TARY/702895001/home.html
3. What is Climate Change/Global Warming?
Concerns if there were global warming:
• Ecosystem interactions between predator
& prey may change
• Change in breeding times
• Human health issues for increased
mosquito population.
• Rising sea levels
• Coral Reefs
3. What is Climate Change/Global Warming?
If Ice caps were to melt- Rising sea levels would be
a concern to islands like the Maldives.
3. What is Climate Change/Global Warming?
Coral reefs, the nurseries of many marine species,
would be killed by higher temperatures, or by a
lack of sunlight as sea level rises.
4. Pollution
Pollution Issues: An average person
may produce a ton of refuse in a year
• a volume that rapidly overflows local dumps.
4. Pollution
Types of Hazardous Wastes
• Dyes, Cleaners, Solvents
• PCB’s (Polychlorinated biphenyls- from
old electrical equipment)
• Plastics, Solvents, Lubricants, Sealants
• Toxic Heavy Metals ( Lead, Mercury,
Cadmium, Zinc)
• Pesticides
• Radioactive Wastes
4. Pollution
Effects of Toxins on Health
-Over 85,000 synthetic chemicals are in
use today, many now known to cause
cancer & damage to the brain, nervous,
reproductive & human hormonal systems.
-An estimated 3-4 million American
Children live within one mile of at
least one hazardous waste site.
Toxicology- The study of the harmful
effects of toxins on organisms
5. Use of Resources/ Burning Fossil Fuels
Non- Renewable Energy
Fossil Fuels- the remains of ancient organisms, changed
into coal, oil or natural gas. -central to modern lifestyle.
2 BIG Problems:
(1) Supply is limited
(2) Environmental Consequences
* March 2008over 100$/barrel
FUEL RESOURCES
What is a sustainable energy source for the future???
5. Use of Resources/ Burning Fossil Fuels
Projected oil production:
http://www.almc.army.mil/alog/issues/JulAug99/MS406c2.jpg
6. Sustainability
Alternative Energy Sources
(Renewable Energy)
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•
•
•
•
•
•
•
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Nuclear Energy
Solar Energy
Wind Power
Biomass (methane, ethanol)
Hydroelectricity-water power
Geothermal Power- from inside the earth
Hydrogen PowerTidal Power- using water power for turbines
OTEC (Ocean Thermal Energy Conversion)
In Ecosystems- all
things are connected
• To appreciate how an ecosystem worksthink about other things depend on
hundreds of individual parts.
• If one part is missing or breaks, the entire
thing does not work.
BIOSPHERE
• The biosphere is the thin layer of the
Earth’s crust with the atmosphere & ocean
layers that support LIFE that includes:
– All plant and animal life
– The things that sustain life: air, soil and water.
– It includes a variety of ecosystems that are
connected by natural cycles.
Biosphere- is composed of three parts:
• ATMOSPHERE – a light blanket of air
enveloping the earth, with more than half its
mass within 4 miles of the surface and 98%
within 16 miles
• HYDROSPHERE --- the surface and
subsurface waters in oceans, rivers, lakes,
glaciers, and groundwater,
• LITHOSPHERE --- the upper reaches of the
earth's crust containing the soils that support
plant life, the minerals that plants and animals
require for life and the fossil fuels and ores that
humans exploit.
Earth Age: About 4.5 Billion Years Old
Location: In the Solar System, on the outer
edge of the Milky Way, about 28,000 light
years from the galactic center
Some Earth Facts:
• Highest Point: 29,028 feet
above sea level, Mount Everest,
formed 60 million years ago,
located on the border of Tibet &
Nepal in the Himalayas (Asia).
• Lowest Point (on Land): 1,320 feet below sea
level, Dead Sea, (middle east) It is so salty -- the
saltiest on Earth -- that it is unable to support any
type of life.
• Deepest Point on Earth: 35,802 feet, Mariana
Trench in the Pacific Ocean. The water pressure
there is over eight tons per square inch.
Some Earth Facts:
• Surface Data: 70% covered by water, with the
remaining 30% composed of the
7continental land masses.
• Water Composition:
• 97% salt water,
3% fresh water
– (about 2% Is glaciers/ice & only.3% of all water is usable).
• Air Composition:
• 78% nitrogen,
• 21% oxygen,
• 1% other content
Hierarchical Levels of Organization-
Ecology
• Just like the hierarchy of levels of
organization in organisms, there are also
levels of increasing complexity in the
environment.
• Each level has unique properties that
cannot be identified just by studying a
lower level.
• Each level is influenced by the other
levels.
Levels of Organization
• ORGANISM -Simplest Level of Organization
•
•
•
•
(1 living thing)
POPULATION- Includes all the members of
the same species - that live in one place at a
given time & make-up a breeding group.
COMMUNITY- Includes all the interacting
populations in one area.
ECOSYSTEM- Includes all the living (biotic) &
non-living (abiotic) factors in the environment.
BIOSPHERE- Thin layer of life around the
earth.
Levels of Organization
• Examples of populations:
All the bacteria of one
kind on this agar plate
Example of community:
All the organisms living
Together in this pond
All the gorillas of 1
species on this mountain
A Changing Environment
• Abiotic Factors do not remain constant
• Organisms are able to survive in a range of
conditions.
• Most individuals can survive average conditions
Tolerance Curve
• A graph showing performance vs. values for a
specific variable such as temperature for a
species. (See page 364 textbook)
Example: Some bacteria can survive boiling water, some
plants can survive arctic cold.
But- Most organisms can not survive BOTH extremes.
Acclimation
• Some organisms can adjust their
tolerance to abiotic factors.
– Examples- YOU adapting to less oxygen in higher
altitudes
– Goldfish, adapting to new water temperature
• Conformers- organisms that do not
regulate their internal conditions
– Examples- Lizards, cold blooded organisms
• Regulators-
Organisms that use energy
to control some of their internal conditions to
optimum range in a variety of conditions.
Escape from unsuitable
conditions
Ways organisms cope with changes:
•
•
•
•
•
Dormancy
Hibernation
Estivating
Migration
Encysting
An Organism’s Relationship to
the Environment
Niche- The way of life of an organism
-the status of an organism in its environment &
community (affecting its survival as a species).
-a position particularly well suited to the
organism that occupies it.
- An organism’s “PROFESSION”
- Includes both biotic and abiotic factors
The Niche includes:
• the range of conditions that the species
can tolerate,
• the methods by which it obtains needed
resources,
• the number of offspring it has,
• its time of reproduction
• and all its other interaction with its
environment.
Earthworm Niche
Generalists & Specialist Niches
GENERALIST are species with Broad
Niches; they can tolerate a range of conditions
and use a variety of resources.
example: opossum- eats a lot of different things
SPECIALIST. Species that have narrow
Niches, such as the koala, who only eats 1
kind of leaf.
Energy Transfer: from producers to consumers
• Producers- are Autotrophs that manufacture
their own food. (grass, plants, phytoplankton)
• Creates Biomass(all the organic material in an ecosystem)
• Biomass is the stored
rest of the organisms
energy- the food for the
• Consumershave to eat
something
(deer, bear)
http://www.ftexploring.com/ftimages2/dr_br1.gif
Net Productivity
• Measuring Productivity
–Gross primary productivity is the rate at
which producers in an ecosystem capture the
energy of sunlight & organic compounds.
– The rate at which biomass accumulates is called
net primary productivity.
– different BIOMES (Places w/ a distinct climate
like the tropical rain forest or the desert)
produce different amounts of biomass.
Food Chains and Food Webs
– A single pathway of energy transfer is a
food chain.
– A network showing all paths of energy
transfer is a food web.
-Trophic level- an organism’s relative
position in the sequence of energy transfer
in a food chain or web (who eats what)
•
•
•
•
Producers
…………………… very many in #
Primary Consumers …………….many
Secondary Consumers …………..fewer
Tertiary Consumers…………fewest # organisms
Food Chain & Food web in an
Antarctic Ecosystem
Energy Transfer
– Ecosystems contain only a few trophic
because there is a low
levels
rate of energy
transfer between each level.
Trophic levels
10s
100s
1000s
millions
Biochemical cycles:
• Matter must be recycled & reused.
• Water • Carbon- photosynthesis, cellular respiration, role of
evaporation, transpiration,& precipitation
autotrophs, consumers, decomposers
• Nitrogen-note role of Nitrogen-fixing bacteria & plants
• Calcium & Phosphorousmoves from rocks to soil to organisms to the oceans.
Your Assignments:
• Draw each of the 4 cycles.
• Label all parts of each drawing (40
points)
• Questions: Write in complete & legible
sentences or I will not grade them:
• Answer 8 questions in sect. 4 (p 374)
• Chapter review questions # 7-20 on
page 376 ( 20 points)
Water cycle
Nitrogen cycle
Carbon cycle