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Chapter Two Glossary
Organic, inorganic, pesticide, pest, bioamplification,
photosynthesis, cellular respiration, nitrogen fixation,
denitrification, nutrients, fertilizer, natality, mortality, open
population, closed population, biotic potential, carrying
capacity,
Chapter Three
Litter, topsoil, humus, subsoil, bedrock, surface water,
ground water, percolation, water table, acid deposition,
The Carbon Cycle
Carbon is an essential element to organic
compounds and therefore life itself. Carbon
is found in sugars, fats, DNA, RNA, vitamins
etc. Carbon passes through a few different
forms on Earth, together these forms make
up the Carbon Cycle. see p. 62 figure1.
Carbon does not move very quickly through
its different forms and is said to be held in
different reservoirs.
Inorganic Reservoirs
-CO2 in the atmosphere
-CO2, CO3-2, HCO3-, CaCO3 in the oceans
-by far the largest reservoir
-CO2, CO3-2, HCO3-, CaCO3 in the soil
see figure 2 p. 63
Organic Reservoirs
-living things
-peat (due to low oxygen conditions in bogs
decomposition is very slow and the organic
material becomes trapped)
-fossil fuels (similar to peat but over much
longer times and great pressure fossil fuels
are formed)
CHANGES IN POPULATIONS
Population is affected by four factors,
natality (births), mortality (deaths),
immigration and emigration.
Population growth is the sum of births
and immigration minus deaths and
emigration.
Growth rate is the population growth
expressed as a percentage of the old
population.
b  i  ( d  e)
growth rate 
100%
pop.
Open populations are influenced by all
four factors while a closed population
is only affected by natality and
mortality.
LIMITS ON POPULATIONS
p. 77-79
Biotic potential is the maximum
number of offspring that a species
could produce , if resources were
unlimited.
Factors Affecting Biotic Potential
1. Birth potential is the maximum
number of offspring per birth.
2. Capacity for survival is the number
of offspring that reach reproductive
age.
3. Procreation is the number of times
that a species reproduces each year.
4. Length of reproductive life depends
on the age of sexual maturity and the
number of years the individual can
reproduce.
LIMITING FACTORS
The environment prevents populations
from attaining their biotic potential.
Food, water, territory, pollutants,
competition, disease, sunlight, wind,
temperature and many more can all be
considered limiting factors.
Without limiting factors populations
would experience uncontrolled growth.
Populations fluctuate due to the
influence of these biotic and abiotic
limiting factors (which change as well).
Stability is achieved when an ecosystem is in equilibrium. The largest
population an ecosystem can support
indefinitely is called the carrying
capacity.
A population can exceed the carrying
capacity of the ecosystem but not for
long.
LIMITS OF TOLERANCE
Law of the minimum states that the
nutrient in least supply is the one that
limits growth. (Liebig)
Law of tolerance states that an
organism can survive within a certain
range of an abiotic factor.
DENSITY DEPENDENT FACTORS
The density of a species depends on the
population and the area it habitates.
Density dependent factors affect a
population because of the density of the
population. Food supply, water quality
and disease are some examples.
Density independent factors affect a population regardless of
population density. Fire and flood are two examples of this
type of factor.
homework: p. 80 2, 3a-c, 4, 5 (only ponder)
Readings: 52-57, 70-73, 97-99, 106-110
Notes: 52-55, 97-98, 108-110
The Caterpillar Debate is Coming!!