Populations and Ecosystems
Plants in Relationship to Their Habitats
Habitat
Organisms
Complete its life cycle
operational habitat
habitat
plant
constitute
effect or not, are its habitat.
two type of component #
Abiotic
Biotic
Abiotic Components of the Habitat
Climate 
Solar factor
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Climate is critically important to all organisms; most species are restricted to certain
regions primarily because they cannot live in climatic conditions outside those region
Climate itself has many components—temperature, rainfall, relative
humidity, and winds being just a few
Latitude and Altitude
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The areas may have varying day lengths,
depending on their latitude. An additional stress present in high-altitude habitats is
High altitudes are above much of Earth’s atmosphere
ozone, oxygen, carbon dioxide, and water vapor.
Disturbance 
Disturbances are phenomena such as fires, landslides, snow avalanches, and floods
they produce a significant, often radical change in an ecosystem quickly
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Soils are formed by breakdown of rock. Initially, the resulting soil is thin and
virtually identical to the parent rock in its chemical composition; consequently,
young soils are variable in the amounts of macronutrients and micronutrients they
Biotic Components of the Habitat
The Plant Itself
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Habitat modification may be beneficial, detrimental, or neutral to the continued
success of that species in its own habitat. In beech/oak forests of the northern United
Other Plant Species
If the interaction is basically beneficial for both
organisms,
mutualism,
competition
competitive exclusion:
The species that
get sunlight and other resources win
those that do not lose and are eliminated
Organisms Other Than Plants
Commensal relationships, 
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one species benefits and the other is
unaffected,
are also common between plants and animals
The Structure of Populations
Geographic Distribution
Boundaries of the Geographic Range
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This factor, whatever it may be, is the limiting factor.
photosynthesis, at a medium level of carbon dioxide, increasing the amount of light.
causes an increase in photosynthesis, whereas increasing the concentration of carbon.
dioxide does not; light is the limiting factor.
Local Geographic Distribution
random distribution
Clumped distributions 
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has no predictive value; knowing the position of one plant does not let you estimate
the position of another plant
are those in which the spacing between plants is either
small or large
BUT mostly in average size
Age Distribution: Demography
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a population responds to various factors in its habitat is
affected partly
the relative proportions of
young, middle-aged.
and old individuals.
r- and K-Selection
r-Selection
the biotic potential is the limiting factor,
and as a result
mutations that increase r are selectively advantageous
K-Selection
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Conditions in a crowded habitat
where a population is close to its carrying capacity,
The Structure of Ecosystems
Physiognomic Structure
Temporal Structure
Species Composition
Trophic Levels
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criterion for classification was the means by which the plant survives stressful
seasons, such as by placing buds below growth
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The changes that an ecosystem undergoes with time constitute its temporal
structure; the time span can be as short as a day or can encompass seasons or death 
diversity of species that coexist in an
ecosystem, and it depends on whether the climate is mild or stressful, the soil is rich
or poor, and the species’ tolerance ranges are broad or narrow
Each ecosystem contains some
members, autotrophs, that bring energy into the system
feeding levels