Ecosystem powerpoint 3

Biotic and Abiotic Factors

Biotic 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.

Abiotic 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.

5/1/2013 Author-Guru IB /ESS

Ecosystem 1

2.2 Measuring Abiotic Components of the System

2.3 Measuring Biotic Components of the System


Ecosystem 2

Setting up stage quadrats of 100m2 in the meadow area of the ecological gradient


Ecosystem 3

Setting up group quadrats of 1m2


Ecosystem 4

Setting up sampling quadrats of 0.1m2 in the meadow


Ecosystem 5

Using the light meter in the forest group quadrat of 1m2


Ecosystem 6

Soil Temperature


Ecosystem 7

Taking a soil sample with a soil borer (auger) in the forest section of the

gradient


Ecosystem 8

Results of soil borer sample, Chemical analysis of the soil can be seen

in the background


Ecosystem 9

Testing the meadow area for pH, phosphates, nitrates and potassium


Ecosystem 10

Collecting samples in Ziploc bags for analysis back in the lab


Ecosystem 11

Taking observations in the forest Notice the absence of plant growth on the

forest floor


Ecosystem 12

Chemical testing in the forest


Ecosystem 13

Insect sampling with net in the meadow


Ecosystem 14

Setting up 0.1m2 sampling quadrats for biomass analysis


Ecosystem 15

Next Chapter…..


Ecosystem 16

Chapter : 2.5.2

Topic : Photosynthesis & Respiration

in Energy Transformation


Ecosystem 17

Figure 10.1 Photoautotrophs


Ecosystem 18

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


Ecosystem 19

Figure 10.2 Focusing in on the location of photosynthesis in a plant


Ecosystem 20


Ecosystem 21

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


Ecosystem 22

Producers • Make their own food - photoautotrophs,

chemoautotrophs

• Convert inorganic materials into organic

compounds

• Transform energy into a form usable by living

organisms


Ecosystem 23


Ecosystem 24

Photosynthesis

• Inputs – sunlight, carbon dioxide, water

• Outputs – sugars, oxygen

• Transformations – radiant energy into chemical

energy, inorganic carbon into organic carbon


Ecosystem 25

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


Ecosystem 26

• 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.

5/1/2013

Author-Guru IB /ESS Ecosystem

27


Ecosystem 28

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


Ecosystem 29

• carbon dioxide + water chlorophyll →→→→→→→→ light energy sugar (glucose) + oxygen


Ecosystem 30


Ecosystem 31


Ecosystem 32


Ecosystem 33

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.


Ecosystem 34


Ecosystem 35

RECAP

• What is photosynthesis?

• What is RESPIRATION?

• Output of Photosynthesis

• Output of Respiration


Ecosystem 36

2.5.5-- Define the terms gross productivity, net

productivity, primary productivity and

secondary productivity.


Ecosystem 37

2.5.5-.7 Productivity


Ecosystem 38

• Gross productivity (GP)

• Gross Primary Productivity (GPP)

• Gross Secondary Productivity (GSP)

• Net productivity

• Net Primary Productivity (NPP)

• Net Secondary Productivity (NSP)

• Primary productivity

• Secondary productivity


Ecosystem 39

What is Productivity?

• The rate at which producers convert light energy into chemical energy is called primary productivity.


Ecosystem 40

• 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)


Ecosystem 41

The energy entering ecosystems is

fixed by producers in photosynthesis.

Gross primary production (GPP)

is the total energy fixed by a plant

through photosynthesis.

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.

Primary Production

Grassland: high productivity

Grass biomass available to consumers


Ecosystem 42

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


Ecosystem 43

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.

Measuring Plant Productivity


Ecosystem 44

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.

Ecosystem Productivity

kcal m-2y-1

kJ m-2y-1

Although the open ocean’s

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.


Ecosystem 45

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 100.0% 5/1/2013


46


Ecosystem 47


Ecosystem 48

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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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


Ecosystem 50

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.


Ecosystem 51

• 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.


Ecosystem 52

Ocean Area vs Productivity


Ecosystem 53

Effects of Depth


Ecosystem 54


Ecosystem 55

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.


Ecosystem 56


Ecosystem 57


Ecosystem 58

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


Ecosystem 59

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.


Ecosystem 60

NP = GP – respiration (for both producers and consumers)

When energy is released from ATP it is lost

as heat. (2nd Law of Thermodynamics)


Ecosystem 61

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


Ecosystem 62

JANUARY-FEBRAURY SUMMATIVE

• Date : 6th February, Wednesday

• Syllabus-The Ecosystem-

• Unit 2.5-Function

• Marks-45

• Time :1 hour

• Paper 1

• Formative:

• Holiday homework

• Worksheet

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63


Ecosystem 64

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


Ecosystem 65


Ecosystem 66


Ecosystem 67

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?


Ecosystem 68

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.


Ecosystem 69


Ecosystem 70

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 5/1/2013


71

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.


Ecosystem 72

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 inefficient.

Secondary Production

Herbivores (1

consumers)...

Eaten by 2

consumers 5/1/2013 Author-Guru IB /ESS

Ecosystem 73

Plant material

consumed by

caterpillar

200 J

The percentage of energy transferred from one trophic level to the next varies between 5% and 20% and is called the ecological efficiency.

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.

Ecological Efficiency

100 J

Feces

33 J

Growth

67 J

Cellular

respiration


Ecosystem 74

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.


Ecosystem 75

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.


Ecosystem 76

What affects productivity?

1. Solar radiation

2. Temperature

3. CO2

4. H2O

5. Nutrients

6. Herbivory


Ecosystem 77

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.


Ecosystem 78

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)


Ecosystem 79

Three years of satellite data on the earth’s GP.

LAND: high = dark green low = yellow

OCEAN: high = red low = blue 5/1/2013


80

73% Not used by humans

8% Lost or degraded land

16% Altered by human activity

3% Used directly

Human use of biomass

produced by photosynthesis

(NPP).


Ecosystem 81


Ecosystem 82

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


Ecosystem 83

Producers

• NPP = GPP – R

Consumers

• GSP = Food eaten – fecal losses

• NSP = change in mass over time

• NSP = GSP – R


Ecosystem 84

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


Ecosystem 85

• Measuring Aquatic Primary Production using

the Light and Dark Bottle Method


Ecosystem 86

TRANSPARENT BOTTLE(LIGHT BOTTLE)

OPAQUE BOTTLE(DARK BOTTLE)


Ecosystem 87

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


Ecosystem 88

• 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


Ecosystem 89

Sample Data


Ecosystem 90

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


Ecosystem 91

Can use satellite imaging: Nutrient rich waters of the north Atlantic


Ecosystem 92

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 5/1/2013


93

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


Ecosystem 94

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


Ecosystem 95

Other parameters to change

• Terrestrial vs. aquatic

• Oxygen, carbon dioxide

• Biomass

• B.O.D. bottles


Ecosystem 96

GPP estimates


Ecosystem 97

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


Ecosystem 98

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


Ecosystem 99

March summative

• Date :15 March,2013

• Format: Paper 2

• Total Marks-65

• Syallabus:Ecosystem

• Time :3:30pm -5:30pm


Ecosystem 100

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


Ecosystem 101

2.6.1-.2 Populations


Ecosystem 102

Topic -2.6

CHANGES


Ecosystem 103

What is POPULATION CURVE?

• The curve which is use to describe the

population of an particular animals in an

ecosystem is called POPULATION

CURVE


Ecosystem 104

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)


Ecosystem 105

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


Ecosystem 106

• Two types of population curve

• S Population Curve

• J Population Curve


Ecosystem 107

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.


Ecosystem 108

• S-Shape curve is also known as - Logistic

curve shows the effect of a limiting factor

• S-Sigmoid


Ecosystem 109


Ecosystem 110

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.


Ecosystem 111

• In population of an ecosystem which

factors determining the S shape curve?


Ecosystem 112

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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113

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:

I. 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.


Ecosystem 114

• 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

forms. 5/1/2013


115


Ecosystem 116

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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117

• Area: 430 square kilometers

• Population :2500 rhinoceros

• It can hold up to 4000 Rhinoceros


Ecosystem 118


Ecosystem 119

CARRYING CAPACITY

• The population that can be supported

indefinitely by an ecosystem without

destroying that ecosystem


Ecosystem 120


Ecosystem 121


Ecosystem 122

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.


Ecosystem 123

‘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).


Ecosystem 124

‘J’ Curves


Ecosystem 125

‘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.


Ecosystem 126

‘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.

• .


Ecosystem 127

March summative

• Date :15 March,2013

• Format: Paper 2

• Total Marks-65


• Time :3:30pm -5:30pm


Ecosystem 128

March Formative


name it.


• Presentation

• Naming the bird




Ecosystem 129

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?


Ecosystem 130

Population Growth

Change in the size of a population over time.


Ecosystem 131

• 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 . . .

• resources pop. size

• resources pop. size


Ecosystem 132

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

Clumped (elephants)

Uniform (creosote bush)

Random (dandelions) 5/1/2013


133

No population can grow indefinitely!

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

1.5

1.0

.5

Nu

mb

er

of

she

ep

(m

illio

ns)

1800 1825 1850 1875 1900 1925

Year 5/1/2013


134

Factors that affect carrying capacity:

1. Competition with/in and between species.

2. Natural and human caused catastrophes.

3. Immigration and emigration.

4. Seasonal fluctuations in food, water, shelter,

and nesting sites.


Ecosystem 135

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.

Time (t)

Po

pu

lati

on

siz

e (

N) “J” population

growth curve


Ecosystem 136

Bacteria population

8 1024

24 hours

later


Ecosystem 137


Ecosystem 138

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

Time (t)

Po

pu

lati

on

siz

e (

N)

K


Ecosystem 139

Time (t)

Po

pu

lati

on

siz

e (

N)

K

Exponential phase

Transitional phase

Plateau phase


Ecosystem 140

Kaibab Plateau


Ecosystem 141

2,000

1,500

Nu

mb

er

of

rein

de

er

1910 1920 1930 1940 1950

Year

1,000

500


Ecosystem 142

Kaibab Plateau


Ecosystem 143


Ecosystem 144

March summative

• Date :4th April,2013

• Format: Paper 2

• Total Marks-40


• Two Essay Type Questions


Ecosystem 145

March Formative


name it.


• Presentation

• Naming the bird




Ecosystem 146

2.6.1- Population Dynamics


Ecosystem 147

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


Ecosystem 148

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


Ecosystem 149


Ecosystem 150


Ecosystem 151

Examples of K-selected species

• Examples of K-selected species

include birds, larger mammals (such

as elephants, horses, and primates), and

larger plants.


Ecosystem 152

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.


Ecosystem 153

• What is Density-Dependent Factors?

• A limiting factor that depends on population size is called a density-dependent limiting factor.


Ecosystem 154

What is Density Dependent Factors

• Increasing population size reduces available resources limiting population growth.

• In restricting population growth, a density-dependent 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.


Ecosystem 155

• Density-dependent limiting factors include:

1. Competition

2. Predation

3. Parasitism

4. Disease


Ecosystem 156

• Examples of density-

dependent limiting factors include:

1. Unusual weather

2. Natural disasters

3. Seasonal cycles

4. Certain human activities—such as

damming rivers and clear-cutting forests


Ecosystem 157

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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158

Robert MacArthur

E. O. Wilson


Ecosystem 159

http://upload.wikimedia.org/wikipedia/en/c/c3/Robert_MacArthur.jpg

http://upload.wikimedia.org/wikipedia/commons/9/9d/Plos_wilson.jpg


Ecosystem 160


Ecosystem 161


Ecosystem 162


Ecosystem 163


Ecosystem 164

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.


Ecosystem 165

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.


Ecosystem 166

• 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.


Ecosystem 167

• 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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• 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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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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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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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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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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March summative

• Date :4th April,2013

• Format: Paper 2

• Total Marks-40


• Two Essay Type Questions


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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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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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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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• 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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Population Dynamics

Factors that tend to increase or decrease the size of a population.


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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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POPULATION SIZE

Growth factors (biotic potential)

Favorable light Favorable temperature Favorable chemical environment (optimal level of critical nutrients)

Abiotic

Biotic High reproductive rate

Generalized niche

Adequate food supply

Suitable habitat

Ability to compete for resources

Ability to hide from or defend against predators Ability to resist diseases and parasites

Ability to migrate and live in other habitats Ability to adapt to environmental change

Decrease factors (environmental resistance)

Too much or too little light Temperature too high or too low Unfavorable chemical environment (too much or too little of critical nutrients)

Abiotic

Biotic Low reproductive rate

Specialized niche

Inadequate food supply

Unsuitable or destroyed habitat

Too many competitors

Insufficient ability to hide from or defend against predators Inability to resist diseases and parasites

Inability to migrate and live in other habitats Inability to adapt to environmental change


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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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Nu

mb

er

of

ind

ivid

ual

s

Time

Carrying capacity

K species; experience K selection

r species; experience r selection

K

REPRODUCTIVE STRATEGIES


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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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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

elephant saguaro

Competitor or K-Selected Species


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SURVIVORSHIP CURVES


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Population density affects population growth.


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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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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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INTERNAL FACTORS = might include density-

dependent fertility or size of breeding territory.

EXTERNAL FACTORS = might include predation and

disease.


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Species interactions influence population growth and carrying

capacity = SYMBIOSIS

Competition for resources.

High

Low

Re

lati

ve p

op

ula

tio

n d

en

sity

0 2 4 6 8 10 12 14 16 18

Days

Each species grown alone

Paramecium aurelia

Paramecium caudatum

High

Low

Re

lati

ve p

op

ula

tio

n d

en

sity

0 2 4 6 8 10 12 14 16 18

Days

Both species grown together

Paramecium aurelia

Paramecium caudatum


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Resource Portioning


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PREDATION

PREY

POPULATION

PREDATOR

POPULATION


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Span worm Bombardier beetle

Viceroy butterfly mimics monarch butterfly

Foul-tasting monarch butterfly

Poison dart frog When touched, the snake caterpillar changes shape to look like the head of a snake

Wandering leaf insect

Hind wings of io moth resemble eyes of a much larger animal

Avoiding predators


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Parasitism


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Mutualism

Oxpeckers and black rhinoceros Clown fish and sea anemone


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Shark and ramora


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Cleaning station

Sabertooth blenny

Cleaner blenny


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Commensalism


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Herbivory


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Chapter : 2.5.4

Topic : Transfer and Transformation

of Materials in Cycle in Eco system


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• 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.

What is Biogeochemical cycle?


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• 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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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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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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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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• 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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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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Ammonium Nitrate

Nitrogen dioxide

Nitrite bacteria (present in the soil)

Nitrate bacteria

Nitrate Directly-

Bacteria present

in plant roots

starts active on

lightening

Convert into

gas with help

of bacteria

Nitrogen

fixation Denitrification


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• 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.

What is Nitrogen fixation?


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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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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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Nitrate

Nitrogen dioxide

Ammonium Nitrate

Nitrogen


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actinomycetes


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cyanobacteria


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• 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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• 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.

What is Water Cycle ?


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• The four stages in this process are:

Evaporation

Condensation

Precipitation

Collection

.


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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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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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• 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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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.


Ecosystem 248

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.


Ecosystem 249

School Director

Principal

Coordinator

Teacher


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Heating of solids, sunlight and shade in different altitudinal zones

(North hemisphere)


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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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Changes in the distribution of animals with

elevation on a typical mountain in Kenya. Another

example of Zonation


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• In population of an ecosystem which factors

determining the J shape curve?


Ecosystem 259

Estimated Net Productivity of Certain Ecosystems (in

kilocalories/m2/year)

Temperate deciduous forest 5,000

Tropical rain forest 15,000

Tall-grass prairie 2,000

Desert 500

Coastal marsh 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. 6,800

Sugar cane, Hawaii 25,000 5/1/2013 Author-Guru IB /ESS

Ecosystem 260

2.6 CHANGES


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The series of changes in an ecological community


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• Lichens re composite organisms consisting of a fungus and a photosynthetic partner growing together in a symbiotic relationship.


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• 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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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


Ecosystem 275

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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Types of succession

Two types of Succession • Primary succession

• Secondary succession


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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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Coastal Sand Dunes An Example of Primary Succession


Ecosystem 282

• 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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the succession of a pond ecosystem to a meadow over 250 years.


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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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• Secondary succession can proceed much faster because the soil has already been prepared by the previous community


Ecosystem 289

• 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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• 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.


Ecosystem 293

Differences between pioneer and climax communities

Pioneer Community Climax Community

Unfavorable environment favorable environment

biomass increases quickly biomass is generally stable

energy consumption

inefficient

energy consumption

efficient

some nutrient loss Nutrient cycling and

recycling

r - strategists K - strategists

low species diversity, habitat

diversity, genetic diversity

high species diversity,

habitat diversity, genetic

diversity 5/1/2013 Author-Guru IB /ESS

Ecosystem 294

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-

living organic

matter)

Increasing

Species

diversity

Low diversity in the early stages, then increasing in

the intermediate stages and then stabilizing in the

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Productivity

Ecosystem characteristic Trends in ecological

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


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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


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1.World Environment Day is observed

on which date :


Ecosystem 299

2.In which year Project Tiger was

introduced in India


Ecosystem 300

3.Which State in India having the

highest percentage of forests?


Ecosystem 301

4.Earth day is observed on which

date


Ecosystem 302

5.Branch of Biology which is concerned

with the inter-relationship between plants

and animals is called :


Ecosystem 303

6.Which is the first state to implement the

path-breaking proposal that environment

should be included as a separate subject in

schools?


Ecosystem 304

7.Name the National Marine

animal of India?


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8.Which popular brand takes its name

from a particular species of deer native

to South Africa?


Ecosystem 306

9.Which comic character cannot

stand trees being cut down?


Ecosystem 307

• 10.Which ancient Indian text contains

rules and regulations on how to run a

protected forest or a ‘abhayaranya’?


Ecosystem 308


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1.World Environment Day is observed

on which date :

June 5


Ecosystem 310

2.In which year Project Tiger was

introduced in India

1973


Ecosystem 311

3.Which State in India having the

highest percentage of forests?

Mizoram


Ecosystem 312

4. Earth day is observed on which

date

April 22


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5.Branch of Biology which is concerned

with the inter-relationship between plants

and animals is called :

Ecology


Ecosystem 314

6.Which is the first state to implement the

path-breaking proposal that environment

should be included as a separate subject in

schools?

Maharashtra


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7.Name the National Marine

animal of India?

Gangetic Dolphin


Ecosystem 316

8.Which popular brand takes its name

from a particular species of deer native

to South Africa?

Reebok


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9.Which comic character cannot

stand trees being cut down?

Dogmatix of Asterix


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• 10.Which ancient Indian text contains

rules and regulations on how to run a

protected forest or a ‘abhayaranya’?

Kautilya’s Arthashastra


Ecosystem 319

• 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


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Education

Ecosystem powerpoint 3