1. Biotic and Abiotic Factors
Biotic
Abiotic
1. Food – both quantity and
quality of food are
important.
2. Predators – refer back to
predator prey
relationships.
3. Competitors – other
organisms may require the
same resources from an
environment.
4. Parasites – may cause
disease and slow down
the growth of an
organism.
1. Temperature – higher
temperatures speed up
enzyme-catalyzed
reactions and increase
growth.
2. Oxygen Availability – affect
the rate of energy
production by respiration.
3. Light Availability – for
photosynthesis and
breeding cycles in animals
and plants.
4. Toxins and pollutants –
tissue growth may be
reduced.
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2. 2.2 Measuring Abiotic Components of
the System
2.3 Measuring Biotic
Components of the System
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3. Setting up stage quadrats of 100m2 in the
meadow area of the ecological gradient
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4. Setting up group quadrats of 1m2
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5. Setting up sampling quadrats of 0.1m2 in
the meadow
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6. Using the light meter in the forest group
quadrat of 1m2
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19. Photosynthesis in Plants
• Chloroplasts are the location of photosynthesis in
plants
• Green color from chlorophyll (photosynthetic
pigment)
• Found in cells of mesophyll – interior tissue of
leaves
• Gases exchanges through the stomata
• Water enters through xylem of roots
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20. Figure 10.2 Focusing in on the location of photosynthesis in a plant
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22. Energy Processes
• Photosynthesis (Green Plants)
sunlight +water + carbon dioxide oxygen + sugars
• Respiration (All living things)
oxygen + sugars ATP +water + carbon dioxide
• ATP is molecular energy storage
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23. Producers
• Make their own food - photoautotrophs,
chemoautotrophs
• Convert inorganic materials into organic
compounds
• Transform energy into a form usable by living
organisms
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25. Photosynthesis
• Inputs – sunlight, carbon dioxide, water
• Outputs – sugars, oxygen
• Transformations – radiant energy into chemical
energy, inorganic carbon into organic carbon
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26. Respiration
• Inputs - sugars, oxygen
• Outputs - ATP, carbon dioxide, water
• Transformations – chemical energy in carbon
compounds into chemical energy as ATP,
organic carbon compounds into inorganic
carbon compounds
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27. • The fundamental energy source for most of the environment
is the sun.
• Photoautotrophs capture the sun’s energy and use it to make
organic compounds through photosynthesis.
• Photoautotrophs are often also called primary producers
because they establish the basis for most other production;
they create organic material from inorganic, or non-living,
sources.
• The process of photosynthesis transforms carbon dioxide
and water into simple carbohydrates.
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29. What is Photosynthesis?
• Conversion by plants of light energy into chemical
energy, which is then used to support the plants'
biological processes.
• Process by which cells containing chlorophyll in
green plants convert incident light to chemical energy
and synthesize organic compounds from inorganic
compounds, especially carbohydrates from carbon
dioxide and water, accompanied by the simultaneous
release of oxygen
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30. • carbon dioxide + water chlorophyll
→→→→→→→→
light energy sugar (glucose) + oxygen
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34. What is Respiration ?
• The process by which oxygen is taken in and
used by tissues in the body and carbon dioxide
is released.
• The energy producing process of breathing, by
which an organism supplies its cells with
oxygen and relieves itself of carbon dioxide.
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36. RECAP
• What is photosynthesis?
• What is RESPIRATION?
• Output of Photosynthesis
• Output of Respiration
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37. 2.5.5-- Define the terms gross productivity, net
productivity, primary productivity and
secondary productivity.
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40. What is Productivity?
• The rate at which producers convert light
energy into chemical energy is called primary
productivity.
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41. • PRODUCTIVITY is production per unit time.
Energy per unit area per unit time (J m-2 yr-1)
Or
Biomass added per unit area per unit time (g m-2 yr-1)
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42. Primary Production
The energy entering ecosystems is
fixed by producers in photosynthesis.
Gross primary production (GPP)
is the total energy fixed by a plant
through photosynthesis.
Grassland: high productivity
Net primary production (NPP) is
theGPP minus the energy required
by the plant for respiration.
It represents the amount of stored
chemical energy that will be
available to consumers in an
ecosystem.
Grass biomass available to consumers
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43. Primary Productivity
The term used to describe the amount of
organic matter an ecosystem produces from
solar energy within a given area during a given
period of time.
Primary productivity simply defined is the
production of new plant material. In the oceans
this new plant material is phytoplankton
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44. Measuring Plant Productivity
The primary productivity
of an ecosystem depends
on a number of
interrelated
factors, such as light
intensity, temperature,
nutrient availability,
water, and
mineral supply.
The most productive
ecosystems are
systems with high
temperatures, plenty of
water, and non-limiting
supplies of soil nitrogen.
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45. Ecosystem Productivity
The primary productivity of oceans is lower than that of terrestrial
ecosystems because the water reflects (or absorbs) much of the
light energy before it reaches and is utilized by the plant.
kcal m-2y-1
Although the open ocean’s
kJ m-2y-1
productivity is low, the ocean
contributes a lot to the Earth’s total
production because of its large size.
Tropical rainforest also contributes a
lot because of its high productivity.
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46. Gross Productivity
Gross productivity is the total gain energy per unit time in
plants.
It is the biomass that could be gained by an organism
before any deduction.
But all organism have to respire to stay alive so some of
this energy is used up in staying alive instead of being
used to grow
Photosynthesis
2.2%
Reflection
3.0
Evaporation
(including transpiration and
heating of the surroundings
94.8
Total
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100.0%
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49. What is Gross Productivity?
• Gross Productivity (GP) – is the total gain in energy or
biomass per unit time.
• This is sometimes shown as GPP – Gross Primary Productivity
• It is related to the total amount of chemical energy
incorporated into the producers.
• The producers use some of this energy during respiration and
energy needs which is eventually lost to the environment as
heat.
• The remaining energy is available to the herbivores and is
known as net primary productivity (NPP)
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50. Gross Productivity
• Varies across the surface of the earth
• Generally greatest productivity
– In shallow waters near continents
– Along coral reefs – abundant light, heat, nutrients
– Where upwelling currents bring nitrogen & phosphorous to the
surface
• Generally lowest
– In deserts & arid regions with lack of water but high
temperatures
– Open ocean lacking nutrients and sun only near the surface
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51. GROSS PRIMARY PRODUCTIVITY (GPP)
• GPP is the quantity of matter produced, or solar
energy fixed, by photosynthesis in green plants
• It is measured per unit area per unit time.
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52. • Energy enters an ecosystem through
sunlight.
• Only 2% of the light energy falling on a tree
is captured and turned into chemical
energy (glucose) by photosynthesis.
• The rest is reflected, or just warms up the
tree as it is absorbed.
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53. Ocean Area vs Productivity
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56. Net Productivity
• Net productivity is the gain in energy per unit time that
remains after deductions due to respiration
• Net productivity is the amount of energy trapped in organic
matter during a specified interval at a given tropic level less
that lost by the respiration of the organisms at that level.
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59. Net Primary Productivity (NPP)
• The quantity of biomass potentially
available to consumers in an ecosystem.
• It is measured in unit of mass or energy per
unit area per unit time.
• Plants have to use some of the energy they
capture to keep themselves growing and
alive (metabolism).
NPP = GPP - respiration
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60. NET PRODUCTIVITY (NP)
• is the gain in energy or biomass per
unit time remaining after allowing for
respiratory loss.
• Organisms use some of the energy they
capture to keep themselves growing
and alive (metabolism).
• The energy used by organisms for
essential tasks is called RESPIRATORY
ENERGY, and eventually it is released
to the environment as heat.
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61. NP = GP – respiration
(for both producers and consumers)
When energy is released from ATP it is lost
as heat. (2nd Law of Thermodynamics)
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62. What is Net Productivity?
• Some of GPP used to stay alive, grow and
reproduce
• NPP is what’s left
• Most NPP
– Estuaries, swamps, tropical rainforests
• Least NPP
– Open ocean, tundra, desert
• Open ocean has low NPP but its large area
gives it more NPP total than anywhere else
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65. Agricultural Land
• Highly modified, maintained ecosystems
• Goal is increasing NPP and biomass of crop
plants
• Add in water (irrigation), nutrients (fertilizer)
• Nitrogen and phosphorous are most often
limiting to crop growth
• Despite modification NPP in agricultural land
is less than many other ecosystems
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68. RECAP
•
•
•
•
What is Productivity?
What is GPP?
What is NPP?
How to measure the GROSS PRIMARY
PRODUCTIVITY
• How to measure the primary productivity
• What is Net Productivity?
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69. Secondary Productivity
The rate at which herbivores produce new
biomass through growth and reproduction.
As a rule of thumb, only 10 percent of plant
matter is converted to herbivore tissue.
The remainder is either not ingested, not
digested (and thus passed through an animal to
be eliminated as feces) or released as heat.
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71. SECONDARY PRODUCTIVITY (SP)
• biomass gained by
heterotrophic
organisms through
feeding and
absorption.
• Not all food eaten is
absorbed (assimilated)
into an animals body.
• Unassimilated food =
feces or droppings
SP = food eaten – fecal loss
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72. In a food web you can
usually assume that:
• The energy input into
an organism = GP.
• The energy output to
the next trophic level =
NP.
• The difference between
GP and NP = R and/or
loss to decomposers.
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73. Secondary Production
Secondary production is the
amount of biomass at higher
trophic levels (the consumer
production).
It represents the amount of
chemical energy in
consumers’ food that is
converted to their own new
biomass.
Energy transfers between
producers and herbivores, and
between herbivores and
higher level consumers is
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inefficient.
Ecosystem
Herbivores (1 consumers)...
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Eaten by 2 consumers
73
74. Ecological Efficiency
The percentage of energy
transferred from one trophic
level to the next varies
between 5% and 20% and is
called the ecological
Plant material
consumed by
caterpillar
efficiency.
200 J
An average figure of 10%
is often used. This ten
percent law states that the
total energy content of a
trophic level in an
ecosystem is only about
one-tenth that of the
preceding level.
100 J
Feces
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Growth
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67 J
Cellular
respiration
74
75. Measuring Primary Productivity
1. Harvest method - measure biomass and
express as biomass per unit area per unit
time.
2. CO2 assimilation - measure CO2 uptake
in photosynthesis and release by
respiration.
3. O2 production - Measure O2 production
and consumption.
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76. Measuring Primary Productivity
4.
Radioisotope method - use C14 tracer in
photosynthesis.
5. Chlorophyll measurement - assumes a
correlation between amount of chlorophyll and
rate of photosynthesis.
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78. Therefore…
• The least productive ecosystems are
those with limited heat and light
energy, limited water and limited
nutrients.
• The most productive ecosystems are
those with high temperatures, lots of
water, light and nutrients.
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79. Biome Productivity
Estuaries
Swamps and marshes
Tropical rain forest
Temperate forest
Northern coniferous forest (taiga)
Savanna
Agricultural land
Woodland and shrubland
Temperate grassland
Lakes and streams
Continental shelf
Open ocean
Tundra (arctic and alpine)
Desert scrub
Extreme desert
800 1,600 2,400 3,200 4,000 4,800 5,600 6,400 7,200 8,000 8,800 9,600
Average net primary productivity (kcal/m2/yr)
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80. Three years of satellite data on the earth’s GP.
LAND: high = dark green low = yellow
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OCEAN: high = red low/ESSblue
=
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81. 73%
Not used by humans
Human use of
biomass
produced by
photosynthesis
(NPP).
3%
Used directly
8%
Lost or degraded land
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16%
Altered /ESShuman activity
IB by
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83. Productivity Calculations
Total Primary Production =
(NPP)
Gross Primary Production
• Amount of light energy converted into chemical energy
by photosynthesis per unit time
– Joules / Meter2 / year
• Net Primary Production GPP – R, or GPP – some
energy used for cell respiration in the primary producers.
• Represents the energy storage available for the whole
community of consumers
• Standing crop = Total living material at a trophic level
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84. Producers
• NPP = GPP – R
Consumers
• GSP = Food eaten – fecal losses
• NSP = change in mass over time
• NSP = GSP – R
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85. Measuring Primary Production
– Measure aspects of photosynthesis
– In closed container measure O2 production, CO2
uptake over time
– Must measure starting amount in environment then
amount added by producers
– Use dissolved oxygen probe or carbon dioxide
sensor
– Measure indirectly as biomass of plant material
produced over time (only accurate over long timer
periods) this gives NPP
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86. • Measuring Aquatic Primary Production using
the Light and Dark Bottle Method
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88. Light and Dark Bottle Method – for
Aquatic Primary Production
• Changes in dissolved oxygen used to measure
GPP and NPP
• Measures respiration and photosynthesis
• Measure oxygen change in light and opaque
bottles
• Incubation period should range from 30
minutes to 24 hours
• Use B.O.D. bottles
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89. • Take two sets of samples measure the initial
oxygen content in each (I)
• Light (L) and Dark (D) bottles are incubated in
sunlight for desired time period
• NPP = L – I
• GPP = L – D
• R= D–I
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91. Method evaluation
• Tough in unproductive waters or for short
incubation times
• Accuracy in these cases can be increased by
using radioactive isotopes C14 of carbon
• Radioactivity measured with scintillation
counter
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92. Can use satellite imaging: Nutrient rich
waters of the north Atlantic
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93. Measuring Secondary Productivity
• Gross Secondary Production
– Measure the mass of food intake (I) by an organism
(best if controlled diet in lab)
– Measure mass of waste (W) (excrement, shedding,
etc.) produced
– GSP = I – W
• Net Secondary Production
– Measure organism’s starting mass (S) and ending
mass (E) for experiment duration
– NSP = E-S
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94. Method evaluation
• GSP method difficult in natural conditions
• Even in lab hard to get exact masses for waste
• NSP method hard to document mass change in
organism unless it is over a long time period
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95. What types of things effect productivity?
• What can we measure for an experiment?
– Effects of light exposure – strength, time, color, …
– Effects of temperature
– Differences between types of plants
– Differences between types of producers
– Effects of nutrient additions
– Effects of salinity
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96. Other parameters to change
•
•
•
•
Terrestrial vs. aquatic
Oxygen, carbon dioxide
Biomass
B.O.D. bottles
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98. How to Calculate GPP &NPP
• Calculate the values of both gross primary
• Productivity (GPP) and net primary
• Productivity (NPP) from given data.
NPP = GPP – R
where R = respiratory loss
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99. How to Calculate GSP &NSP
•
•
•
•
•
•
Calculate the values of both gross secondary
Productivity (GSP) and net secondary
Productivity (NSP) from given data.
NSP = GSP – R
GSP = food eaten – fecal loss
where R = respiratory loss
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100. March summative
•
•
•
•
•
Date :15 March,2013
Format: Paper 2
Total Marks-65
Syallabus:Ecosystem
Time :3:30pm -5:30pm
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101. March Formative
• Collect four different types of feather and
name it.
Marks will be given based on
• Presentation
• Naming the bird
• Decoration of the chart
• Submission on Date
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104. What is POPULATION CURVE?
• The curve which is use to describe the
population of an particular animals in an
ecosystem is called POPULATION
CURVE
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105. What are the main factors that affect
the growth of a population?
The main factors that make
populations grow are births and
immigration.(The action of coming to
live permanently)
The main factors that make
populations decrease are deaths and
emigration.(moving from one place)
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106. What is Exponential growth?
• Exponential population growth is when
the birth rate is constant over a period of
time and isn't limited by food or disease
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107. • Two types of population curve
• S Population Curve
• J Population Curve
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108. TYPES OF POPULATION CURVE
• Two modes of population growth.
• J-Shape curve is also known as- Exponential
curve occurs when there is no limit to
population size.
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109. • S-Shape curve is also known as - Logistic
curve shows the effect of a limiting factor
• S-Sigmoid
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111. What is S-Shaped Curve?
• In S - shaped or sigmoid growth the population
show an initial gradual increase in population
size in an ecosystem, followed by an
exponential increase and then a gradual decline
to near constant level.
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112. • In population of an ecosystem which
factors determining the S shape curve?
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113. The curve obtained by plotting growth and
time is called a growth curve. It is a typical
sigmoid or S- shaped curve.
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114. •
•
I.
What is J shaped?
A curve on a graph that records the situation in which, in a new environment, the population density of an organism increases rapidly but then stops abruptly as environmental resistance
It may be summarized mathematically as:
dN/dt = rN (with a definite limit on N)
II. where N is the number of individuals in the population,
t is time, and
III. r is a constant representing the rate of increase for the
organism concerned.
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115. • The growth of population is measured as increase in
its size over a period of time and populations show
characteristic patterns of growth with time.
• These patterns are known as population growth
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115
117. RECAP
• What is POPULATION CURVE?
• What are the main factors that affect
the growth of a population?
• What are the types of population curve?
• What is S shaped?
• What is J shaped?
• What are the different stages of S shaped
curve?
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118. • Area: 430 square kilometers
• Population :2500 rhinoceros
• It can hold up to 4000 Rhinoceros
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120. CARRYING CAPACITY
• The population that can be supported
indefinitely by an ecosystem without
destroying that ecosystem
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123. What is Carrying Capacity?
• The carrying capacity (K) is the maximum
number of a species that the habitat can hold.
• Once the carrying capacity is reached, unless the
environmental resistance is changed, e.g. by a new
disease, the size of the population will only fluctuate
slightly.
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124. ‘S’ Curves
• This is the type of graph that is almost always
seen in nature.
• As the energy resources become more scarce
the population size levels off at the carrying
capacity (K).
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126. ‘J’ Curves
• ‘J’ curve example, a population establishing
themselves in a new area will undergo rapid
exponential growth.
• This type of growth produces a J shaped growth
curve.
• If the resources of the new habitat were endless then
the population would continue to increase at this rate.
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127. ‘J’ Curves
• This type of population growth is rarely seen in
nature.
• Initially exponential growth will occur but eventually
the increase in numbers will not be supported by the
environment.
• .
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128. March summative
•
•
•
•
•
Date :15 March,2013
Format: Paper 2
Total Marks-65
Syallabus:Ecosystem
Time :3:30pm -5:30pm
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129. March Formative
• Collect four different types of feather and
name it.
Marks will be given based on
• Presentation
• Naming the bird
• Decoration of the chart
• Submission on Date
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130. RECAP
• What is CARRYING CAPACITY?
• Example of Carrying capacity
• Which type of curve is common in nature?
Why?
• Why J curve is not common in the nature?
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132. • POPULATION = a group of interbreeding
organisms (same species) that live in the same
place at the same time and compete for the same
resources.
• Resources = food, water, shelter, mates, and so on .
..
•
pop. size
•
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resources
resources
pop. size
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133. Populations change in response to environmental stress
or changes in environmental conditions.
1. In size = # of individuals
2. Density = # of individual / specific space
3. Age distribution = proportions / age group
4. Dispersion
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(elephants)
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(creosote bush)
Ecosystem
Random
(dandelions)
133
134. No population can grow indefinitely!
Number of sheep (millions)
Every environment has a CARRYING
CAPACITY = the maximum number of
individuals of a given species that
can be sustained indefinitely in
a given space.
2.0
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1.5
1.0
.5
Author-Guru
1800
Ecosystem
IB /ESS
1825
1850
1875
Year
1900
1925134
135. Factors that affect carrying capacity:
1.
2.
3.
4.
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Competition with/in and between species.
Natural and human caused catastrophes.
Immigration and emigration.
Seasonal fluctuations in food, water, shelter,
and nesting sites.
Author-Guru
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135
136. “J” population
growth curve
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Population size (N)
A population that has few if any resource
limitations grows exponentially.
EXPONENTIAL GROWTH starts out slowly and
then proceeds faster and faster as the
population increases.
Author-Guru
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Time (t)
136
139. LOGISTIC GROWTH involves initial exponential
growth and then there is a steady decrease in
growth as the population encounters environmental
resistance and approaches carrying capacity and
levels off.
“S or sigmoid”
population growth
curve
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Population size (N)
K
Author-Guru
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Time (t)
139
140. Plateau phase
K
Population size (N)
Transitional phase
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Exponential phase
Time (t)IB /ESS
Author-Guru
Ecosystem
140
145. March summative
•
•
•
•
•
Date :4th April,2013
Format: Paper 2
Total Marks-40
Syallabus:Ecosystem
Two Essay Type Questions
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145
146. March Formative
• Collect four different types of feather and
name it.
Marks will be given based on
• Presentation
• Naming the bird
• Decoration of the chart
• Submission on Date
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146
148. TWO TYPES OF SPECIES
• r-selected species
• K-selected species
• r-selected species live in variable or
unpredictable environments
• K-selected species live in fairly constant or
predictable environment
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149. Examples of r-selected species
• Examples of r-selected species include pest organisms,
such as rodents, insects, Mosquitoes and Weeds.
• r-selected species thrive in disturbed habitats, such as
freshly burned grasslands or forests characterized by
canopies that open abruptly, such as when a forest’s
tallest trees have been knocked down by a windstorm
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152. Examples of K-selected species
• Examples of K-selected species
include birds, larger mammals (such
as elephants, horses, and primates), and
larger plants.
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153. K & R STRAEGIST
• Species of organism that uses a survival and
reproductive 'strategy' characterised by low
mortality, longer life and with populations
approaching the carrying capacity of the
environment, controlled by density-dependent
factors.
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154. • What is Density-Dependent Factors?
• A limiting factor that depends on population
size is called a density-dependent limiting
factor.
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155. What is Density Dependent Factors
• Increasing population size reduces available
resources limiting population growth.
• In restricting population growth, a densitydependent factor intensifies as the population
size increases, affecting each individual more
strongly.
• Population growth declines because of death
rate increase, birth rate decrease or both.
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157. • Examples of densitydependent limiting factors include:
1. Unusual weather
2. Natural disasters
3. Seasonal cycles
4. Certain human activities—such as
damming rivers and clear-cutting forests
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158. How this related to Ecology?
In ecology, r/K selection theory relates to the
selection of combinations of traits that trade
off the quantity and quality of offspring to
promote success in particular environments.
The terminology of r/K-selection was coined
by the ecologists Robert MacArthur and E. O.
Wilson based on their work on island
biogeography.
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165. STABLE & UNSTABLE ENVIRONMENTS
• Organisms that live in stable environments
tend to make few, "expensive" offspring.
• Organisms that live in unstable
environments tend to make many, "cheap"
offspring.
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166. EXAMPLE
• Imagine that you are one of the many invertebrate
organisms which existed during the Cambrian or
one of their descendents living today.
• Maybe you live in a tide pool which is washed by
waves.
• A storm appears on the horizon.
• The waves increase in height.
• You feel yourself being dashed upon the rocks or
into the mouth of a much larger and predatory
animal.
• Finally, you begin to see your brothers and sisters
die, one by one, as the forces of nature change
your unpredictable environment.
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167. • If you could design a "strategy" to overcome
the problems created by an unpredictable
environment, you would have two choices - go
with the flow or cut and run to a more
stable environment.
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168. • Suppose you stayed. Then, one thing you could do
would be to increase the number of offspring.
• Make lots of cheap (requiring little energy investment)
offspring instead of a few expensive, complicated ones
(requiring a lot of energy investment).
• If you lose a lot of offspring to the unpredictable forces
of nature, you still have some left to live to reproductive
age and pass on your genes to future generations.
• Many invertebrates follow this strategy - lots of eggs are
produced and larvae are formed but only a few survive
to produce mature, reproductive adults. Many insects
and spiders also follow this strategy.
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169. • Alternatively, you could adapt to a more stable
environment.
• If you could do that, you would find that it
would be worthwhile to make fewer, more
expensive offspring.
• These offspring would have all the bells and
whistles necessary to ensure a comfortable,
maximally productive life.
• Since the environment is relatively stable, your
risk of losing offspring to random
environmental factors is small. Large animals,
such as ourselves, follow this strategy.
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170. Mortality, Survivorship, &
Competition
• In r-selected species mortality is often catastrophic
and subject to density independent limiting factors.
• Survivorship is low early in life but increases for
those individuals surviving (Type III). Competition
lax.
• In K-selected species mortality is subject to density
dependent limiting factors Survivorship is high
throughout life until late in life (Type I). Competition
keen.
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171. Population Size
• In r-selected species, population size tends to
vary in time and recolonization occur into
unpopulated area frequently (pioneer species)
• In K-selected species, population size is
usually at or near the carrying capacity and
colonization is infrequent (keystone species in
climax communities)
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172. r Species Selection Factors
•
•
•
•
•
•
•
Rapid Development
High r = or net reproductive rate
Early Reproduction
Small Body Size
Single Reproduction
Many Small Offspring
Short Life Span
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173. K Species Selection Factors
•
•
•
•
•
•
•
Slow Development
Competitive Ability
Delayed Reproduction
Large Body Size
Repeated Reproduction
Few Large Offspring
Long Life Span
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174. March summative
•
•
•
•
•
Date :4th April,2013
Format: Paper 2
Total Marks-40
Syallabus:Ecosystem
Two Essay Type Questions
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174
175. RECAP
•
•
•
•
•
•
•
•
What is r selected species? Example
What is K selected species? Example
What is Density-Dependent Factors?
Factors which includes Density-dependent
limiting are…
How r/K species related to Ecology?
What is Stable &unstable Environment
r Species Selection Factors
K Species Selection Factors
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176. What is difference between r &K?
K
1.
Growth Pattern - large body, long juvenile period; Population grows
exponentially and then stabilizes around a max value
2.
Population Size - smaller, but stable
3.
Environment - stable, diverse ecology
4.
Reproductive strategy - mate choice, pair bonds, large investment,
parental care, few offspring
5.
Characteristics of offspring -They're born more dependent on the
parents and stay that way longer; later onset of repro maturity
• Examples - Elephants, humans, oak trees.
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177. 1.
r
Growth Pattern - small body, rapid maturation;
population grows exponentially then crashes
2.
Population Size - large, but rapid fluctuation
3.
Environment - unstable, recently disrupted, low
diversity, low resources
4.
Reproductive strategy - maximize number of
offspring, low parental investment, random mating
5.
Characteristics of offspring - independent right
away, early reproductive maturity, large numbers
6. Examples - weeds, mosquitoes, mice
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178. • In the scientific literature, r-selected species
are occasionally referred to as "opportunistic",
while K-selected species are described as
"equilibrium
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179. Population Dynamics
Factors that tend to increase or decrease the
size of a population.
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180. The population size of a species in a given space at a
given time is determined by the interplay between
BIOTIC POTENTIAL and ENVIRONMENTAL
RESISTANCE.
Biotic potential = growth rate with unlimited resources.
Environmental resistance = all the factors acting jointly
to limit population growth.
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181. POPULATION SIZE
Growth factors
(biotic potential)
Abiotic
Favorable light
Favorable temperature
Favorable chemical environment
(optimal level of critical nutrients)
Biotic
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Decrease factors
(environmental resistance)
Abiotic
Too much or too little light
Temperature too high or too low
Unfavorable chemical environment
(too much or too little of critical
nutrients)
Biotic
High reproductive rate
Low reproductive rate
Generalized niche
Specialized niche
Adequate food supply
Inadequate food supply
Suitable habitat
Unsuitable or destroyed habitat
Ability to compete for resources
Too many competitors
Insufficient ability to hide from or defend
Ability to hide from or defend
against predators
against predators
Ability to resist diseases and parasites
Inability to resist diseases and parasites
Ability to migrate and live in other
Inability to migrate and live in other
habitats
habitats
IB /ESS
Ability to adapt to environmental Author-Guru
Inability to adapt to environmental
Ecosystem
change
change
181
182. Four variables change population size:
1. NATALITY = birth rate
2. MORTALITY = death rate
3. IMMIGRATION = rate of organisms moving in
4. EMIGRATION = rate of organisms moving out
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184. Opportunistic or r-Selected Species
cockroach
dandelion
Many small offspring
Little or no parental care and protection of offspring
Early reproductive age
Most offspring die before reaching reproductive age
Small adults
Adapted to unstable climate and environmental
conditions
High population growth rate (r)
Population size fluctuates wildly above and below
carrying capacity (K)
Generalist niche
Low ability to compete
Early successional species
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185. Competitor or K-Selected Species
elephant
saguaro
Fewer, larger offspring
High parental care and protection of offspring
Later reproductive age
Most offspring survive to reproductive age
Larger adults
Adapted to stable climate and environmental
conditions
Lower population growth rate (r)
Population size fairly stable and usually close
to carrying capacity (K)
Specialist niche
High ability to compete
Late successional species
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188. DENSITY INDEPENDENT FACTORS = affect a populations’
size regardless of its population density.
1. Weather
2. Earthquakes
3. Floods
4. Fires
. . . Natural disasters
R-strategists populations are most affected by these.
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188
189. DENSITY DEPENDENT FACTORS = affect a populations’ size
depending on its population density.
1. Predation
2. Disease
3. Availability of food and water
4. Space
Negative Feedback!!
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190. INTERNAL FACTORS = might include densitydependent fertility or size of breeding territory.
EXTERNAL FACTORS = might include predation and
disease.
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191. Species interactions influence population growth and carrying
capacity = SYMBIOSIS
Competition for resources.
High
High
Relative population density
Relative population density
Paramecium
aurelia
Paramecium
caudatum
Low
0
2
4
6
8
10
12
14
16
18
Paramecium
aurelia
Paramecium
caudatum
Low
0
2
Days
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Each species grown alone
IB /ESS
4
6
8
10
Days
12
14
Both species grown together
16
191
18
194. Avoiding predators
Span worm
Wandering leaf insect
Poison dart frog
Viceroy butterfly mimics
monarch butterfly
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Ecosystem
Bombardier beetle
Hind wings of io moth
resemble eyes of a
much larger animal
IB /ESS
Foul-tasting monarch
butterfly
When touched, the
snake caterpillar
changes shape to look
like the head of a snake
194
201. Chapter : 2.5.4
Topic : Transfer and Transformation
of Materials in Cycle in Eco system
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202. What is Biogeochemical cycle?
• The cyclic transformation of chemicals through
interacting biological, geological and chemical
processes.
• Natural processes that recycle nutrients in
various chemical forms from the environment,
to organisms, and then back to the environment
• Ex: carbon, oxygen, nitrogen, phosphorus, and
hydrologic cycles.
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203. • The biogeochemical cycles of all elements
used by life have both an organic and an
inorganic phase.
• This cycling involves the decomposition of
organic matter back into inorganic nutrients
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203
205. What is Carbon Cycle?
• The process by which carbon is taken up by
plants and animals and returned to the
environment in a continuous cycle.
• The carbon cycle is the biogeochemical cycle
by which carbon is exchanged among the
biosphere, geosphere, hydrosphere, and
atmosphere of the Earth.
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207. Carbon is stored on our planet in the following
major sinks
1. As organic molecules in living and dead
organisms found in the biosphere;
2. As the gas carbon dioxide in the atmosphere;
3. As organic matter in soils;
4. In the lithosphere as fossil fuels and
sedimentary rock deposits such as limestone,
5. In the oceans as dissolved atmospheric carbon
dioxide and as calcium carbonate shells in
marine organisms.
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213. What is Nitrogen cycle ?
• A process in which atmospheric nitrogen enters
the soil and becomes part of living organisms,
and then returns to the atmosphere.
• Cyclic movement of nitrogen in different
chemical forms from the environment, to
organisms, and then back to the environment.
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215. • Earth's atmosphere is approximately 78-80%
nitrogen making it the largest pool of nitrogen.
• Most plants can only take up nitrogen in two
solid forms: ammonium ion and the nitrate
ion .
• Most plants obtain the nitrogen they need as
inorganic nitrate from the soil solution.
• Animals receive the required nitrogen they
need for metabolism, growth, and
reproduction
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215
216. 3 PROCESS OF NITROGEN IN THE
EARTH
• Nitrogen fixation----nitorgen+O2+CO2+H2
• Nitrification---- conversion of ammonia to nitrate
• Denitrification-- nitrate becomes molecular(GAS)
nitrogen
Bacteria
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217. Nitrogen
fixation
Denitrification
Ammonium Nitrate
Nitrite bacteria (present in the soil)
Nitrogen dioxide
Nitrate bacteria
Convert into
gas with help
of bacteria
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DirectlyBacteria present
in plant roots
starts active on
lightening
IB /ESS
Nitrate
217
218. What is Nitrogen fixation?
• Conversion of nitrogen into compounds is essential
by combining with carbon, hydrogen and oxygen
before it can be absorbed by the plants. This is known
as nitrogen fixation
• Some fixation occurs in lightning strikes, but most
fixation is done by free-living or symbiotic bacteria.
• These bacteria have the nitrogenase enzyme that
combines gaseous nitrogen with hydrogen to produce
ammonia.
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220. What is Nitrification?
• The conversion of ammonia (NH3) to nitrate
(NO3-) is called NITRIFICATION
• Degradation of ammonia to nitrite is usually the
rate limiting step of nitrification.
• Nitrification is an important step in the nitrogen
cycle in soil
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220
223. What is Denitrification?
• The process by which a nitrate becomes
molecular nitrogen, especially by the action of
bacteria.
• The process by which nitrogen, is converted to
a gaseous form and lost from the soil or water
column.
• The reduction of nitrate nitrogen to nitrogen
gas.
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223
232. • Almost all of the nitrogen found in any
terrestrial ecosystem originally came from the
atmosphere.
• Significant amounts enter the soil in rainfall or
through the effects of lightning.
• The majority, however, is biochemically fixed
within the soil by specialized micro-organisms
like
bacteria,
actinomycetes,
and
cyanobacteria.
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238. What is Water Cycle ?
• The cycle of water movement from the atmosphere to the earth
and back to the atmosphere through condensation, precipitation,
evaporation, and transpiration is called WATER CYCLE
• The continual cycle of water between the land, the ocean and
the atmosphere.
• The water cycle, also known as the hydrologic cycle, describes
the continuous movement of water on, above and below the
surface of the Earth.
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242. Evaporation
• This is the first stage of the water cycle.
• The Sun's rays heat the water on the surface of
the earth in rivers, oceans and lakes.
• This makes the water change into water vapour.
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244. Condensation :
After evaporation, condensation occurs.
Water vapor in the air gets cold and changes
back into liquid, forming clouds
The process that causes these changes is called
condensation.
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245. • Precipitation :
Precipitation occurs when so much water has condensed that
the air cannot hold it anymore. The clouds get heavy and
water falls back to the earth in the form of rain
• Collection
After precipitation comes the stage of collection. The
raindrops fall back into the lakes, rivers and oceans or are
absorbed by the land. This process by which rainwater
gathers on earth is called collection.
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248. Change in the relative abundance of a
species over an area or a distance is
referred to as an ECOLOGIAL GRADIENT
Also known as Zonation.
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248
249. What is ZONATION?
• Zonation – The arrangement or patterning of plant
communities or ecosystems into bands in response to
change, over a distance, in some environmental
factor.
• The main biomes display zonation in relation to
latitude and climate. Plant communities may also
display zonation with altitude on a mountain, or
around the edge of a pond in relation to soil moisture.
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255. What is Environmental gradient?
• An environmental gradient is a gradual
change in abiotic factors through space (or
time). Environmental gradients can be related
to factors such as altitude, temperature, depth,
ocean proximity and soil humidity.
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255
257. Changes in the distribution of animals with
elevation on a typical mountain in Kenya. Another
example of Zonation
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257
259. • In population of an ecosystem which factors
determining the J shape curve?
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259
260. Estimated Net Productivity of Certain Ecosystems (in
kilocalories/m2/year)
Temperate deciduous forest
Tropical rain forest
15,000
Tall-grass prairie
Desert
Coastal marsh
2,000
500
12,000
Ocean close to shore
2,500
Open ocean
800
Clear (oligotrophic) lake
800
Lake in advanced state of
eutrophication
2,400
Silver Springs, Florida
8,800
Field of alfalfa (lucerne)
15,000
Corn (maize) field, U.S.
4,500
Rice paddies, Japan
5,500
Lawn, Washington, D.C.
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5,000
6,800
Sugar cane, Hawaii Author-Guru
IB
25,000 /ESS
Ecosystem
260
267. • Lichens re composite organisms consisting of
a fungus and a photosynthetic partner
growing together in a symbiotic relationship.
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270. • Mosses are a botanical division (phylum) of
small, soft plants that are typically 1–10 cm
(0.4–4 in) tall
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275. In ecology what is succession?
• Succession is the process by which a habitat
changes over time as different plants get
established.
• This process can occur from bare rock up to an
old-growth forest, and can get reset by a
disturbance such as fire.
• The path of succession varies from one habitat
type to another, but the general idea goes like this:
Bare rock ---> Lichens --> Mosses --> Grasses &
Forbs --> Brush --> Deciduous hardwood forest -> Mixed deciduous-coniferous forest -->
Coniferous forest --> Old growth coniferous forest
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276. What is Ecological succession?
• Ecological succession, a fundamental concept
in ecology, refers to more or less predictable
and orderly changes in the composition or
structure of an ecological community.
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281. Primary Succession
• Primary succession is the series of community
changes which occur on an entirely new
habitat which has never been colonized before.
• Examples of such habitats would include
newly exposed or deposited surfaces, such as
landslips, volcanic lava and debris, elevated
sand banks and dunes, quarried rock faces.
• Stages will take place in which an initial or
'pioneer' community will gradually develop
through a number of different communities
into a 'climax' community, which is the final
stage
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282. Coastal Sand Dunes
An Example of Primary Succession
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283. • Primary succession is the gradual growth of
organisms in an area that was previously bare,
such as rock.
• For example lichens, mosses, and ferns will
first appear on bare rock.
• In primary succession pioneer species like
mosses, lichen, algae and fungus as well as
other abiotic factors like wind and water start
to "normalize" the habitat.
• This creating conditions nearer optimum for
vascular plant growth
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283
284. the succession of a pond ecosystem to a meadow over 250
years.
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286. What is Secondary succession?
• Secondary succession is the series of
community changes which take place on a
previously colonized, but disturbed or damaged
habitat. Examples include areas which have
been cleared of existing vegetation (such as
after tree-felling in a woodland) and destructive
events such as fires.
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289. • Secondary succession can proceed much
faster because the soil has already been
prepared by the previous community
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289
290. • Secondary succession is usually much quicker
than primary succession for the following
reasons:
• There is already an existing seed bank of
suitable plants in the soil.
• Root systems undisturbed in the soil, stumps
and other plant parts from previously existing
plants can rapidly regenerate.
• The fertility and structure of the soil has also
already been substantially modified by
previous organisms to make it more suitable
for growth and colonization.
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293. • The mature stage of succession in a particular area, in
which all organisms and non living factors are in
balance.
• Terrestrial communities of organisms move through a
series of stages from bare earth or rock to forests of
mature trees.
• This last stage is described as the "climax" because it is
thought that, if left undisturbed, communities can
remain in this stage in perpetuity.
• However, more recent studies suggest that climax may
be only one part of a continuous cycle of successional
stages in these communities.
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294. Differences between pioneer and climax
communities
Pioneer Community
Climax Community
Unfavorable environment
favorable environment
biomass increases quickly
biomass is generally stable
energy consumption
inefficient
some nutrient loss
energy consumption
efficient
Nutrient cycling and
recycling
r - strategists
K - strategists
low species diversity, habitat high species diversity,
diversity, genetic diversity
habitat diversity, genetic
Author-Guru
IB /ESS
diversity
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294
295. The following charts summarize the major
trends as the ecosystem undergoes
succession.
Ecosystem
characteristic
Trends in ecological succession
Food chains
Simple food chains becoming more complex food
webs
Relative
Species
abundance
Changes rapidly first, changes slower in the later
stages.
Total biomass
Increasing
Humus (non- Increasing
living organic
matter)
Species
diversity
5/1/2013
Low diversity in the early stages, then increasing in
the intermediate stages /ESS
and then stabilizing in the
Author-Guru
IB
295
Ecosystem
final stages as an equilibrium is approached
296. Productivity
Ecosystem characteristic
Trends
in
succession
Gross productivity (GP)
Increasing
during
early
stages
of
primary
succession then little or no
increase during final stages
of secondary succession
Net productivity (NP)
Decreasing
Respiration (R)
Increasing
5/1/2013
Author-Guru
Ecosystem
IB /ESS
ecological
296
297. Mineral and Nutrient cycles
Ecosystem characteristic
Trends in ecological succession
Mineral cycles
Becomes more self-contained
in later stages
Nutrient recycling
Increases in later stages
5/1/2013
Author-Guru
Ecosystem
IB /ESS
297
299. 1.World Environment Day is observed
on which date :
5/1/2013
Author-Guru
Ecosystem
IB /ESS
299
300. 2.In which year Project Tiger was
introduced in India
5/1/2013
Author-Guru
Ecosystem
IB /ESS
300
301. 3.Which State in India having the
highest percentage of forests?
5/1/2013
Author-Guru
Ecosystem
IB /ESS
301
302. 4.Earth day is observed on which
date
5/1/2013
Author-Guru
Ecosystem
IB /ESS
302
303. 5.Branch of Biology which is concerned
with the inter-relationship between plants
and animals is called :
5/1/2013
Author-Guru
Ecosystem
IB /ESS
303
304. 6.Which is the first state to implement the
path-breaking proposal that environment
should be included as a separate subject in
schools?
5/1/2013
Author-Guru
Ecosystem
IB /ESS
304
305. 7.Name the National Marine
animal of India?
5/1/2013
Author-Guru
Ecosystem
IB /ESS
305
306. 8.Which popular brand takes its name
from a particular species of deer native
to South Africa?
5/1/2013
Author-Guru
Ecosystem
IB /ESS
306
307. 9.Which comic character cannot
stand trees being cut down?
5/1/2013
Author-Guru
Ecosystem
IB /ESS
307
308. • 10.Which ancient Indian text contains
rules and regulations on how to run a
protected forest or a ‘abhayaranya’?
5/1/2013
Author-Guru
Ecosystem
IB /ESS
308
310. 1.World Environment Day is observed
on which date :
June 5
5/1/2013
Author-Guru
Ecosystem
IB /ESS
310
311. 2.In which year Project Tiger was
introduced in India
1973
5/1/2013
Author-Guru
Ecosystem
IB /ESS
311
312. 3.Which State in India having the
highest percentage of forests?
Mizoram
5/1/2013
Author-Guru
Ecosystem
IB /ESS
312
313. 4. Earth day is observed on which
date
April 22
5/1/2013
Author-Guru
Ecosystem
IB /ESS
313
314. 5.Branch of Biology which is concerned
with the inter-relationship between plants
and animals is called :
Ecology
5/1/2013
Author-Guru
Ecosystem
IB /ESS
314
315. 6.Which is the first state to implement the
path-breaking proposal that environment
should be included as a separate subject in
schools?
Maharashtra
5/1/2013
Author-Guru
Ecosystem
IB /ESS
315
316. 7.Name the National Marine
animal of India?
Gangetic Dolphin
5/1/2013
Author-Guru
Ecosystem
IB /ESS
316
317. 8.Which popular brand takes its name
from a particular species of deer native
to South Africa?
Reebok
5/1/2013
Author-Guru
Ecosystem
IB /ESS
317
318. 9.Which comic character cannot
stand trees being cut down?
Dogmatix of Asterix
5/1/2013
Author-Guru
Ecosystem
IB /ESS
318
319. • 10.Which ancient Indian text contains
rules and regulations on how to run a
protected forest or a ‘abhayaranya’?
Kautilya’s Arthashastra
5/1/2013
Author-Guru
Ecosystem
IB /ESS
319
320. • This tree was supposedly brought to India
from Sri Lanka by Hanuman when he was
carrying messages from Sita. He felt so
delighted by it that he threw the seeds on
what is presently Maharashtra. Which tree?
• The Mango
5/1/2013
Author-Guru
Ecosystem
IB /ESS
320
