Chapter 18:
Accelerated Biology
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.
-
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)
Key theme of Ecology
• Interdependence:
• Species interact with each other & with abiotic
factors in the environment.
• Disturbances in one species affects other species.
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/ Fossil Fuels
6. Sustainability
1. Human Population Growth
Graph of Human Population Growth
Human population growth, notice birth & death rates
Notice in this Population Pyramid that developing
countries, with many young individuals, will soon
have exponential population growth, while developed
nations will have stable growth.
http://www.globalchange.umich.edu/globalchange2/current/lectures/human_pop/human_pop.html
How big can a population grow?
carrying capacity
• The
of a
biological species in an environment is
the maximum population size of the
species that the environment can
sustain indefinitely, given the food,
habitat, water and other necessities
available (growth limiting factors).
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
These things are “environmental resistance” to
population growth.
Is there a Carrying Capacity for
Homo sapiens?
• As we have seen, the human population growth
curve is currently following an exponential curve or
a "J-shape" (see graphs).
• Common sense tells us that such growth cannot
continue - otherwise within a few hundred years
every square foot of the Earth's surface would be
taken up by a human.
HUMAN POPULATION COUNTER:
http://www.worldometers.info/world-population/
Can carrying capacity be increased?
• Yes, TECHNOLOGY can increase how many
individuals the environment can support- for
example, agriculture, use of fuels, etc. can increase
resources for population growth.
• Many professors discard the notion of a human
carrying capacity altogether, claiming that the
additional people will provide sufficient creativity
and innovation to break through any possible
natural barriers to human population growth.
http://www.globalchange.umich.edu/globalchange2/current/lectures/human_pop/human_pop.html
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 & their sources
• H2O (water vapor) – evaporation, plant respiration.
• CO2 (Carbon dioxide)-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
NOTE- sources in red are
independent of human activities
3. 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
3. 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
. Use of
Resources/ Burning Fossil Fuels
What is a sustainable energy source for the future???
http://interestingenergyfacts.blogspot.com/2009/09/fossil-fuels-facts.html
5. Use of Resources/ Burning Fossil Fuels
Projected oil production:
http://www.almc.army.mil/alog/issues/JulAug99/MS406c2.jpg
Fossil Fuels- remains of ancient organisms, changed into coal, oil or natural
gas. 2 BIG Problems:
Supply is limited, Environmental Consequences
(Renewable) Alternative Energy Sources
•
•
•
•
•
•
•
•
•
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)
Sustainability
• means that we must meet the needs of the
present without compromising the ability of
future generations to meet their own needs.
•
• http://www.sarep.ucdavis.edu/Concept.htm
BIOSPHERE – the thin layer of LIFE
• includes:
– All plant and animal
life
– Atmosphere (air)
– Lithosphere (crust)
Hydrosphere(water)
– It includes a variety
of ecosystems that
are connected by
natural cycles.
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
•
•
•
•
single 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) & nonliving (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
Tolerance Curve- shows most individuals
can survive average conditions
• Abiotic Factors do not remain constant
• Organisms are able to survive in a range of conditions,
• At extremes, they die off.
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 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.
- An organism’s “PROFESSION”
- Includes both biotic and abiotic factors
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 energy- the food for the rest of the
organisms
• 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 levels because
a low rate of energy transfer to
levels, only 1/10th of the energy makes
it to the next level!
there is
Each tropic level depends completely
on the level below it.
http://worldslife-nisha.blogspot.com/2011/06/trophic-levels-food-chain.html