Transcript Succession, population growth and human impact

Ecology
Keep this in mind…
In California…
 LOS ANGELES, Oct. 31 — A 10-year-old boy
admitted that he accidentally started one of the
largest of last week’s Southern California
wildfires while playing with matches,
enforcement officials say.
 Fanned by high winds and hot, dry weather, it
spread quickly, driving 15,000 people from their
homes, destroying 21 houses and 22 other
buildings, injuring three people and blackening
more than 38,000 acres
In Iceland…
 Volcano in Iceland erupted twice in one month. The
volcano has erupted for the second time in less than
a month, melting ice, shooting smoke and steam into
the air and forcing hundreds of people to flee rising
floodwaters. The volcanic ash has forced the
cancellation of many flights and disrupted air traffic
across.
SUCCESSION
• What happens to an area after a disturbance?
 A predictable set of stages begins to change the area
 The changes are plant based; referred to as
ecological succession.
• What does it mean if you call someone a successor?
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EXAMPLE: The prince is the king’s successor.
Ecological Succession
 Natural, gradual changes in the types of plant species
that occupy an area
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You have studied pond succession!
Primary Succession
 occurs on an area of newly exposed rock, sand, lava
or any area that has not been occupied previously by
a living (biotic) community
Secondary Succession
 takes place where a community has been removed,
i.e. a plowed field, clearcut forest, forest fire
 Complete the Succession WS
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What is a pioneer species?
What is a climax community?
Do Now
 What type of succession would occur on this land?
 If a fire occurred 100 years into succession of this
land what type of succession would occur?
 HAND IN!
Population
 Populations are dynamic!
 3 important characteristics of populations:
geographic distribution, density and growth rate
What is density?
1.
2.
3.
4.
Nutrients can limit plant growth
 Plant life grows best when all nutrients are present
 Not present?
 Limited
nutrient
 Animals have limiting factors that affect growth as
well:
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Density-dependent factors
Density-independent factors
Factors that influence density…
 Other Limiting Factors
 environmental influences that prevent species from
obtaining a high population: generally populations
decrease in size
 Two categories:
 Density-dependent limited factors
 Density-independent limited factors
Density-dependent factor
 Density-dependent factors- affects populations due
to their size
 Example- predation
Density-independent factors
 Density-independent factors- affects all populations
in similar ways, regardless of population size
 Example- hurricane
Density-dependent or density-independent?
 Competition
 Earthquake
 Flood
 Parasitism
 Disease
 Seasonal cycles
 Available mates
Do Now
 Define population density.
 Label each factor as d.dependent or d.independent:
 Territory (available space)
 Food
 tornado
Population Growth
 Three factors affect population size
 Number of births
 Number of deaths
 Number of individuals that enter or leave the population
 Immigration: movement of individuals into an area
 Emigration: movement of individuals out of a population
Population
 Exponential Growth (J-shaped graph)
 Logistic Growth (S-shaped graph)
Exponential Growth
 Under ideal
conditions with
unlimited resources, a
population will grow
 Industrial revolution:
1820-1870
 Current population:
~6 billion
Exponential growth faces problems…
 Exponential growth does not continue in natural
populations for very long
 As resources become less available, the growth of a
population slows or stops
Logistic Growth
 Acceleration, high growth period, deceleration, fairly
steady state
Carrying capacity
 the number of individuals who can be supported in a
given area within natural resource limits
 Carrying capacity- K
Carrying capacity
Patterns of Population Growth
 Human population cannot keep growing
exponentially forever because Earth and its
resources are limited…
 Study of human population is demography
 Birthrate, death rates and the age structure of a population
help predict population increases and decreases of countries
 Age-structured diagrams
Population pyramid
 Birth vs death rate within a population
US population pyramid
Human limits?
World Resources
 Renewable
 Nonrenewable
Renewable Resources
 A resource that can be continually reproduced
 Capable of being replaced by
- natural ecological cycles or
- sound management practices
 humans need to think of "renewable" as
replenishable only in the right circumstances
and within the laws of the balance of nature
Do NOT Think…
 "Oh well, it's renewable so we can use as
much as we want"
 "It's OK to log these forests- trees grow back”
 "Industries can pull all the water they want
from the Great Lakes, without limitation.
After all, water is a renewable resource, like
air."
 Renewable" resources become non-
renewable due to mis-management by
humans and pollution of the environment by
humans.
 What are examples of renewable resources?
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trees, wildlife, oxygen, and fresh water
Nonrenewable Resources
 A resource that cannot reproduce
 Once the resource is used up- it is gone
 Humans are using up natural resources at a great rate
and at a great cost to the health of the natural environment
and life on Earth.
 What do humans use A LOT of? (think carbon cycle)
Nonrenewable Resources
 Fossil fuels- oil, natural gas, coal
 How do they form?
 How long does it take for these resources to form?
The world at night from space
Human Impact
 Acid Rain
 What it is, where does it come from and what
damage can it cause?
What is acid rain?
 Acid rain is rain that is lower on the pH scale than
normal rain water…
 Acid rain carries the chemicals sulphur dioxide and
nitrogen oxide
 pH may vary: 5.5 to 3.0 (normal water is ~7-5.6)
 (ocean water ~7-8)
Acid rain cycle
Damage from acid rain
 Lakes and streams are normally acidic, acid rain can
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make them so acidic that it damages animal and
plant life.
Acid rain can cause a mass killing to trees.
Area's can become very hazy and foggy due to acid
rain
linked to breathing and lung problems in children,
and people who have asthma.
Stone buildings and monuments are targets of
damage from acid rain.
Damage of acid rain
 Acid "rain" isn't just rain; acid snow, acid fog or mist,
acid gas, and acid dust all have the same effect as
acid rain.
So much pollution!!! (don’t write, just read)
 40% of America’s rivers and 46% of America’s lakes are too polluted for
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fishing, swimming, or aquatic life
1.2 trillion gallons of untreated sewage, storm water, and industrial
waste are discharged into US waters annually.
Polluted drinking waters are a problem for about half of the world’s
population. Each year there are about 250 million cases of water-based
diseases, resulting in roughly 5 to 10 million deaths.
Each year, U.S. factories spew 3 million tons of toxic chemicals into the
air, land, and water.
Every year, one American produces over 3,285 pounds of hazardous
waste.
Seventy-three different kinds of pesticides have been found in
groundwater, which is potential drinking water
Over 80% of items in landfills can be recycled, but they’re not.
What should be recycled?
 NOT GUM!!!
 Plastic bottles, cans, paper, card board
Pollution…
Biomagnification
 Humans use of DDT (Dichloro-diphenyl-trichloroethane)
 insecticide and pesticide (world-wide use)
 30 years prior to its cancellation, a total of
approximately 1,350,000,000 pounds of DDT was
used domestically
 DDT is a persistent, toxic chemical which easily
collects in the food chain posing a proven hazard to
non-target organisms such as fish and wildlife and
otherwise upsetting the natural ecological balance
Biomagnification
 Prime example of a non-target animal that was hurt
by the use of DDT
 The bald eagle-
What can be done to help?
 Recycle
 Turn off electronics
 Take shorter showers
 Educate yourself!
 ALTERNATIVE ENERGY 
Alternative Energy
 The Alternative Energy Institute (AEI) was formed
in 1977 at West Texas State University, Texas, USA
 Consequences are minimal
 renewable and are thought to be "free" energy
sources
 lower carbon emissions, compared to conventional
energy sources
Alternative Energy
 These include
 Biomass
Energy,
 Wind Energy,
 Solar Energy,
 Geothermal Energy,
 Hydroelectric Energy sources
Alternative energy
Human Impact
 What is the differences and similiarities between…
 Ozone layer depletion
 Greenhouse effect
 Global warming
Ozone layer
 Affects earths climate
 Gas that occurs naturally
 vital role by shielding
humans and other life
from harmful ultraviolet
light from the Sun
Ozone depletion
 chemicals, such as chlorofluorocarbons (CFCs) and
hydrochlorofluorocarbons (HCFCs)
 Depleted protective layer
 International agreement to limit emissions
Greenhouse effect
 Affects earths climate, especially temperature
 Positive and natural occurrence
 Greenhouse gases: such as water vapor, carbon
dioxide, ozone and methane
 Greenhouse gases slow down the rate at which heat
is released back into space
 Too much of these gases is a bad thing!
Greenhouse effect
Global warming
 Affects the earths climate
 Especially temperature! Not only in the air but on land
 Overabundance of greenhouse gases higher
temperature
 Burning of fossil fuel, deforestation
 Possible effects of global warming:
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Melting ice results in water level rising
Stronger hurricanes
Ice age
More drastic weather cycles