Ecosystem Ecology
• Ecology is the
study of how
organisms interact
with each other
and their
environment.
Levels of Biological Organization
Levels Important to Ecology
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Organisms
Populations
Communities
Ecosystems
Biosphere
Energy and Matter in
Ecosystems
Another definition of an ecosystem is a system
through which energy flows and matter cycles.
Local
Watersheds
• Watersheds are usually the smallest units
that can be considered ecosystems.
Welcome Passengers!
• Your attention please. Thank you for
choosing earth as your planetary vehicle.
We hope you enjoy the many wonderful
features of this wonderful planet, as you
hurtle through the cosmos...
• Please take a moment to locate this
planet's emergency exits. As you can see,
there aren't any!
(Courtesy Blue Man Group)
Mars has a physical
environment, but no
biological environment.
Atmosphere
Van Allen Belts
• Far above the surface are the Van Allen
radiation belts, which trap most cosmic rays.
Earth’s Unique Features
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oxygen atmosphere.
liquid water.
atmospheric pressure.
greenhouse effect.
ozone layer
atmosphere protecting
surface from meteorites.
• right size of planet and
distance from the Sun.
• gravity
• solar energy
Biomes
A biome is a region described
by a particular type of
vegetation and caused by a
particular climate (average
temperature and
precipitation).
--temperate deciduous
forest
-- northern coniferous
forest.
-- prairie.
-- desert.
-- chaparral
-- tundra
-- tropical rain forest.
Biomes of the World
Aquatic Life Zones
An aquatic life zone is
the equivalent of a
biome underwater,
but is determined by
the type of water
(fresh or salt), depth,
and presence of a
bottom or of sunlight.
Abiotic Factors
• Abiotic refers to all of the factors in the
environment that are nonliving—the physical
environment.
Dead Zone
• An example of abiotic factors
Biotic Factors
Biotic refers to all
the factors in the
environment
caused by living
things—the
biological
environment.
Limiting factors 1
• Some biotic and abiotic factors can be tolerated by a
species; some cannot.
• Beyond a certain salinity, goldfish die, while other fish
can still thrive.
Limiting factors 2
• There is also a range of factors—at extreme
high and low ends, these factors cannot be
tolerated, but moderate values promote the
growth of the organisms.
Limiting factors 3
• Finally, there are factors that limit a species
abundance in an area by scarcity.
Factors that limit population
size
Limited resources.
the most limiting resource, the one that if
increased could allow population to grow,
is called the limiting factor.
an example of a limiting factor is dissolved
oxygen (DO). (ex. Dead water zone) (water depth and sp.)
limiting factors are usually abiotic.
Food Webs
Soil Trophic Levels
Soil Terminology
• Soil is a thin covering over most land
- consists of a mixture of weathered rock, organic
matter, water, air, and organisms.
• Soils are arranged in horizons—layers of soil
characterized by 1) composition and 2) depth.
-- O horizon—leaf litter. (dead plant material)
-- A horizon—topsoil. (2-8 inchs thick, most organic matter, life)
-- B horizon—subsoil. (metals and minerals)
-- C horizon—bedrock. (large rocks)
• The soil profile consists of the 1)horizons present
and their 2)thicknesses.
Soil profiles
Tropical vs. Temperate
Leaching is the removal of
nutrients from soil by the action
of water.
Hydrologic Cycle
Nitrogen Cycle
Carbon Cycle
Sulfur Cycle
Phosphorus Cycle
Biodiversity as natural capital
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Biodiversity reflects
the variety of natural
resources available.
The greater the
variety, the more
possible “solutions”
there are.
The greater the
variety, the more
redundancy there is
in the system.
Decreased Biodiversity in
Crops
• Increased uniformity decreases diversity in
crops.
• Bananas and potatoes are examples.
Forest Products as Natural
Capital
• Forest products provide timber and energy.
Non-timber resources
Next up, Evolution
Species
• A species is a group of organisms that resemble
each other in terms of appearance, lifestyle,
behavior, chemistry, and genetics.
Cells
• The cell is the basic unit of life.
• All of the processes that make living
things alive happen in cells—
reproduction, growth, development,
metabolism, energy use, etc.