Transcript Ecology Notes

Ecology
Chapters 3, 4, 5, and 6
Ecology – definition:
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Ecology is the study
of the interactions of
living organisms with
one another and with
their physical
environment.
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Living things and
Soil, air, water….
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Hierarchy of Ecology:
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Species
Population
Community
Ecosystem
Ecosphere
Energy in Ecosystems
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The sun is the primary
source of energy on
Earth.
Producers (Autotrophs) –
harness the sun’s energy
in chemical bonds of
organic molecules.
Example: plants making
sugar, algae.
Energy in Ecosystems continued..
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Consumers (Heterotrophs) – consume the organic
molecules created by producers to obtain energy.
Primary consumers – eat only producers. Rabbit.
Secondary consumers – eat other consumers. Fox.
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An example of energy flowing through a food chain
Energy flow through ecosystems:
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Energy flows from one trophic level to another.
Not all energy is transferred to the next level.
Some goes to the environment (body heat).
This is why the food chain cannot go on
forever!
Decomposers – final level. Eat wastes and dead
matter.
Can a food chain begin without the sun?
Yes! Chemoautotrophs (bacterial species) can
use chemical energy to produce carbohydrates.
Ocean vents, hot springs…
Food
web –
shows
multiple
ways
energy
can flow.
Source: Zoology, 2nd edition, by
Stephen A. Miller and John P.
Harley, Wm. C. Brown
Publishers, 1994, p. 209
Ecological
Pyramid –
shows relative
amount of
energy,
biomass, or
numbers of
organisms at
each trophic
(feeding)
level
Biogeochemical Cycles
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Matter is not created or destroyed, it just
changes forms!
All matter cycles through the environment
and takes many forms as it cycles
Including: Water, nutrients, carbon,
nitrogen, and phosphorus (see diagrams in
your book, pages 75-79)
Nutrient Limitations:
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Limiting nutrient – a substance that is
scarce or cycles slowly. It will limit an
organism’s growth.
Example: High crop yields need extra
nitrogen, phosphorus, and potassium
Algal bloom – when excess fertilizers
cause algae to rapidly grow in a lake or
pond. Can lead to dead zones
Algal Bloom in Lake Erie
Abiotic Factors of Ecosystems:
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Climate is determined by:
Physical features:
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Soils
Mountains
Lakes etc.
Solar energy (greenhouse
effect) and lattitude
Atmospheric and oceanic
circulation
Abiotic/Biotic Factors in the
Ecosystem
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Biotic – living
Abiotic – non-living
Habitat – Area in which an organism lives
Niche – what it eats (what eats it), where it
lives, and how it goes about its everyday
life
Interactions – See “Good Buddies” activity
Cuckoo egg Cuckoo brother
Niches..Same habitat, different
roles…
Limiting Factors:
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Limiting factors: Any factor that causes
population growth to decrease
Density-dependent factors – are limiting
when a population is large. Competition,
parasitism, disease…
Density-independent factors – limit the
population growth no matter what the
population size. Weather, human
activities…
Ecological Succession – The
progression of species replacement.
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Primary
Succession –
Succession on a
newly formed
habitat.
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Example: Volcanic
islands. Begins with
only barren rock.
Succession continued:
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Secondary succession
– when succession
occurs in an area that
previously supported
growth.
Example: A cleared
field, recently
unglaciated land.
Mt. St. Helens
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Climax community- The final community
of organisms after years and years of
succession. Example: Oak/Hickory forest
Biomes of the World
Populations
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Controlled by birth and death rates, and
immigration (move into an area) and
emigration (move out of an area)
Exponential Growth – in ideal conditions
with unlimited resources, a population
grow at a rapid rate. J-curve
Logistic Growth – rate slows down and
reaches its carrying capacity (the largest
number of individuals an environment can
support
Exponential Growth
Logistic Growth
Population Graphs
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Tribble Graph A
Reindeer Graph B
Graph C
Hare/Lynx Graph D
Human Population
Graph E
Population Pyramids
Graphs F G H I J K
Human Activity
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Hunting
Gathering
Farming
Industry
Urban development (houses,
cities)
Almost always negatively
impacts the biosphere
Resources – any necessity of life
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Renewable resource –
can recycle or
regenerate. Ex: trees,
water, sun, biomass
Non-renewable resource
– cannot be replenished
by natural processes
(anytime soon..) Ex:
Fossil fuels, uranium
Sustainable Development
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Humans should promote sustainability-using the planet’s resources in such a way
to ensure they can last longer or cycle back
without being entirely depleted.
If this is not done, environmental damage
is done
Also, humans will run out of the resources
they need to survive
WHEN??
Human
activity
can
cause…
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Soil erosion – improper farming,
overgrazing, or deforestation can lead to
valuable topsoil lost to wind and water.
Ex: Rainforest used for grazing lands, then
becomes desert-like
Oldfishingreels.com
Overfishing
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Harvesting fish faster
than they can be
replenished by
reproduction. Example:
Bluefin Tuna
Much of the world’s
population rely on the
ocean’s catch
How can this be
regulated? Endangered?
Air Pollution
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Mostly due to the burning of fossil fuels
Smog – Smoke and fog
Acid Rain – Sulfur and nitrogen
compounds from fossil fuels combining
with water reduce the pH of precipitation
Ozone depletion – from the release of
CFCs (Chlorofluorocarbons) deplete
atmospheric ozone which protects us from
ultraviolet radiation
Global Climate Change
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Greenhouse gases – trap the sun’s energy
in our atmosphere. GOOD – they help
regulate our Earth’s temperature. Concern
– Too much and the atmosphere traps too
much heat. Examples: Water vapor,
carbon dioxide, and methane
Concern: Burning fossil fuels releases
trapped CO2 at a rate much faster than
naturally could be released.
Climate Change
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Scientific evidence points to increasing
levels of CO2 and increasing global
temperature (ice cores, Mauna Loa)
Can humans really cause climate change?
(think of the lights from space image)
Yes, the climate naturally cycles and we
are in a warming trend…how much more
does fossil fuel use contribute?
Difficult because it takes DECADES to see
the results
When temperature increases…
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More rain/less rain
Higher overall temperatures
Ecosystem changes (can organisms adapt?)
Droughts
Sea level rises, flooding in low areas
Possibly stronger storms..Why? More heat
= more evaporation, more moisture in the
atmosphere. Even more snow!
So what should you do?
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Try not to worry about the politics
involved!
Energy conservation is good for
everyone*! It saves money for the
consumer and helps our non-renewable
resources last longer (follow the 3 Rs)
Less fossil fuel use = less pollution (smoke,
heavy metals, dioxins, smog)
Biodiversity – needed for a
healthy planet!
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Biodiversity – the sum of the genetically
based variety of all organisms in the
biosphere
Ecosystem diversity – many different
ecosystems
Species diversity – number of species in
the biosphere
Genetic diversity – sum total of all genes
carried by all living things
Threats to biodiversity
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Extinction – when a species no longer
exists in all or part of its range
Endangered – decreasing populations at
risk for extinction. Small gene pool
Why? Habitat loss, hunting, pollution
(biological magnification of pollutants, Ex.
DDT), and invasive species – species
which humans have transported around the
world and threaten native species(see
activity) The World’s Loneliest Animals
Conservation
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Conservation – the wise management of
natural resources, including the
preservation of habitats and wildlife.
(Sustainability!)
Wildlife preserves, breeding programs,
laws to protect living things and
environments…
Challenges? Monetary value of land and
products, economies.. Blood Ivory