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5/1/2013 AUTHOR-GURU IB/ESS 1
• 2.1 Structure of Eco System
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2
Organism :
• An organism is a fundamental functional
unit in ecology because it interacts
directly with the environment as well as
with other organism
e.g., Rabbits
What is Organism ?
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What is Population?
• It refers to the organism of the same
species that are in proximity to one
another
• e.g., A group of rabbit
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What is Community? • This includes all the populations occupying a
given area.
• The size of the community depends on our
scale of reference
• The community and the non-living
environment together are referred to as an
ECOLOGICAL SYSTEM or ECOSYSTEM
• e.g., pond fish and plants
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• A species is often defined as a group
of organisms capable of interbreeding and
producing fertile offspring.
What is species?
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• A habitat is an ecological or environmental area that
is inhabited by particular species of animal, plant or
other type of organism.
• It is the natural environment in which an organism
lives, or the physical environment that surrounds a
species population.
What is habitat?
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Biosphere
Ecosystems
Communities
Populations
Organisms
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• In biology, a species is one of the basic
units of biological classification .
• A species is often defined as a group
of organisms capable of interbreeding and
producing fertile offspring.
What is species?
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• A habitat is an ecological or environmental area that is
inhabited by particular species of animal, plant or other
type of organism.
• It is the natural environment in which an organism lives,
or the physical environment that surrounds a
species population.
What is habitat?
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Experts release list of world's 100 most threatened
species
• Seoul, Sept. 11 : International conservation
group has identified a list of the earth's most
threatened 100 animals, plants and fungi and have
called for an urgent need to protect them.
• The species have been identified by more than
8,000 scientists from the IUCN Species Survival
Commission (IUCN SSC), but they fear they will
be allowed to die because none of these species
provide humans with any benefits.
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• An ecosystem has two basic components
• ABIOTIC COMPONENTS
• BIOTIC COMPONENTS
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• Biotic components is classified into
three categories:
• PRODUCERS-Autotrophic
• CONSUMERS -Heterotrophic
• DECOMPOSERS OR
SAPTROTROPHS
Biotic Components
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• Producers are things such as plants that are fed
off of but do not eat other producers or
organisms.
• Consumers are organisms (including us
humans) that get their energy from producers,
regarding the flow of energy through an
ecosystem
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CONSUMERS
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• A decomposer is an organism of decay.
• These are also called saprobes.
• They break down the remains of dead animals
and plants, releasing the substances that can be
used by other members of the ecosystem
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DECONSUMERS
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PRODUCERS
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• The non living ,physical and chemical
components of an ecosystem are called the
abiotic factors and include:
• Light
• Temperature,
• Water,
• Soil
• The atmosphere
• Climate –Light intensity, temperature range,
precipitation
What is Abiotic components?
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• In ecology, a niche is a term describing the way
of life of a species.
• Each species is thought to have a separate,
unique niche.
• The ecological niche describes how an organism
or population responds to the distribution of
resources and competitors
What is NICHE?
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• One example is squirrels that collect acorns and bury them for winter.
• Another is honeybees that gather nectar from flowers to make honey.
• Other organisms that may exist in the same environment don't do this.
• For instance, a bird may live in the same tree as a beehive, but the bird does not make honey the way the bees do. That is not its niche.
Example for NICHE
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What is Eco System?
• A dynamic complex of plants, animals and
micro organisms inhabiting a particular area
with their non living environment interacting
as a functional unit
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Sir Arthur George Tansley (15 August 1871 - 25 November 1955) was
an English botanist who was a pioneer in the science of ecology
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2.1.3 Identify and explain trophic levels in food chains and food webs selected from the local environment.
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• Trophic levels are the feeding position in a food
chain such as primary producers, herbivore,
primary carnivore, etc.
• Green plants form the first trophic level, the
producers.
• Herbivores form the second trophic level, while
carnivores form the third and even the fourth
trophic levels.
What is Trophic levels?
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• The feeding of one organism upon another in a
sequence of food transfers is known as a food
chain.
• Food chain is the chain of transfer of energy
from one organism to another. A simple food
chain is like the following:
• rose plant -- aphids -- beetle -- chameleon --
hawk.
What is Food chain?
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• In an ecosystem there are many different food
chains and many of these are cross-linked to
form a food web.
• Ultimately all plants and animals in an
ecosystem are part of this complex food web.
What is food web?
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Grazing type food chains
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phytoplankton
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"Zooplankton" refers to small aquatic animals.
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2.1.4 Explain the principles of pyramids of numbers, pyramids of biomass, and pyramids of productivity, and construct such pyramids from given data.
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Trophic levels and the energy flow from one
level to the next, can be graphically depicted
using an ecological pyramid.
Three types of ecological pyramids can
usually be distinguished namely:
1. Pyramids of numbers
2. Pyramid of biomass
3. Pyramids of productivity
What is Ecological Pyramids?
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Pyramids of numbers • A pyramid of numbers is a graphical
representation of the numbers of
individuals in each population in a food
chain.
• A pyramid of numbers can be used to
examine how the population of a certain
species affects another
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PYRAMID OF NUMBERS represents storages
found at each trophic level.
Units vary
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Grassland (summer)
Temperate Forest (summer)
Producers
Primary consumers
Secondary consumers
Tertiary consumers
A few large producers (the trees) support a much larger number of
Small primary consumers (insects) that feed on the trees.
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Pyramids of Numbers
Advantages
• Overcomes the problems of pyramids of
number.
Disadvantages
• Only uses samples from populations, so it is
impossible to measure biomass exactly. also
the time of the year that biomass is measured
affects the result.
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Jayanthi Natarajan Minister for Environment and Forests
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Pyramid of biomass
• The total amount of living or organic matter
in an ecosystem at any time is called
'Biomass’.
• Pyramid of biomass is the graphic
representation of biomass present per unit
area of different tropic levels, with producers
at the base and top carnivores at the tip".
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• Represents the standing stock of each trophic
level (in grams of biomass per unit area g / m2)
• Represent storages along with pyramids of
numbers
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PYRAMID OF BIOMASS represent the
standing stock at each trophic level.
Units:
J m-2
or
g m-2
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Abandoned Field Ocean
Tertiary consumers
Secondary consumers
Primary consumers
Producers
In open waters of aquatic ecosystems, the biomass primary consumers
(zooplankton) can exceed that of producers. The zooplankton eat the
Producers (phytoplankton) as fast as they reproduce, so their population
is never very large. 5/1/2013 AUTHOR-GURU IB/ESS 73
How do we get the biomass of a trophic level to
make these pyramids?
• Take quantitative samples – known area or volume
• Measure the whole habitat size
• Dry samples to remove water weight
• Take Dry mass for sample then extrapolate to entire trophic
level
• Evaluation It is an estimate based on assumption that
– all individuals at that trophic level are the same
– The sample accurately represents the whole habitat
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• Analysis of various ecosystems indicates that
those with squat biomass pyramids are less
likely to be disrupted by physical or biotic
changes than those with tall, skinny pyramids
(having conversion efficiencies less than 10%).
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Measurement of biomass of different
trophic levels in an ecosystem.
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Describe one method for the measurement of biomass of different trophic levels in an ecosytem.
• Representative samples of all living organisms
in the ecosystem are collected, for example
from randomly positioned quadrats.
• The organisms are dried, by being placed in an
oven at 60-80
C.
• The mass of organisms in each trophic level is
measured using an electronic balance.
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Multiply the mean height by the stem density 5/1/2013 AUTHOR-GURU IB/ESS 80
• Biomass can be assessed indirectly and
completely non destructively by
• Counting the number of individuals of the target
speices
• Randomly selecting a sample of individuals
• Determining mean height within the sample
(height will be an indirect measure of biomass)
• Multiply the mean height by the stem density
(number of individuals)
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• A more destructive method involves taking a
sample of individuals of the target species and
cutting them at soil level.
• Tag each individual with a label, dry it to a
stable weight and weigh it.
• Determine the mean mass of the plants in the
area and multiply by the stem density in the
area.
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Think this one………
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IDENTIFY THE ENDANGERED ANIMAL
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Lion Tailed Macaque
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Pyramids of Productivity
• A graphical representation in the shape of
a pyramid showing the distribution of
productivity or flow of energy through
the tropic levels.
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producers
10 J m-2 yr-1
100 J m-2 yr-1
1,000 J m-2 yr-1
10,000 J m-2 yr-1
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PYRAMID OF PRODUCTIVITY represents
the flow of energy through each trophic level.
Units:
J m-2 yr-1
or
g m-2 yr-1
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Pyramids of productivity
• Flow of energy through trophic levels
• Energy decreases along the food chain – Lost as heat
• Productivity pyramids ALWAYS decrease as they go higher – 1st and 2nd laws of thermodynamics
• Shows rate at which stock is generated at each level
• Productivity measured in units of flow (J / m2 yr or g / m2 yr ) Joule per square metre in year/
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• As you move up each trophic level, only
10% of the energy is transferred.
• The other 90% is used for everyday life
functions, metabolism.
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Pyramid structure
affects
the functioning of
an
ecosystem.
Bioaccumulation
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Pyramids of productivity
• Advantages
• Most accurate system shows the actual energy
transferred and allows for rate of production.
• Disadvantages
• It is very difficult and complex to collect
energy data.
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PYRAMID OF STANDING CROP
• Pyramid diagrams may show the fixed quantity
of number, biomass or energy that exists at a
particular time in a given area or averaged
from many of these measurements.
• This is termed STANDING CROP.
• The unit would be number,dry biomass or
energy kg/m2 or J/m3.
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Figure 54.14 Food energy available to the human population at different trophic levels
Efficiency of trophic levels in relation to the total energy
available decreases with higher numbers But efficiency of transfer always remains around that 10% rule
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• ENERGY FLOW THROUGH
• PRODUCERS
• CONSUMERS
• DECOMPOSERS
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Energy Flow through Producers
• Producers convert light energy into chemical
energy of organic molecules
• Energy lost as cell respiration in producers
then as heat elsewhere
• When consumers eat producers energy passes
on to them
• In death organic matter passes to saprophytes
& detritivores
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Energy Flow through Consumers
• Obtain energy by eating producers or other
consumers
• Energy transfer never above 20% efficient,
usually between 10 – 20%
• Food ingested has multiple fates
1. Large portion used in cell respiration for meeting
energy requirements (LOSS)
2. Smaller portion is assimilated used for growth,
repair, reproduction
3. Smallest portion, undigested material excreted as
waste (LOSS) 5/1/2013 AUTHOR-GURU IB/ESS 100
Figure 54.10 Energy partitioning within a link of the food chain
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Energy flow through Decomposers
• Some food is not digested by consumers so
lost as feces to detritivores & saprophytes
• Energy eventually released by process of cell
respiration or lost as heat
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2.1.5 Discuss how the pyramid structure affects the functioning of an ecosystem.
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How does pyramid structure effect
ecosystem function?
1. Limited length of food chains • Rarely more than 4 or 5 trophic levels
• Not enough energy left after 4-5 transfers to support organisms feeding high up
• Possible exception marine/aquatic systems b/c first few levels small and little structure
2. Vulnerability of top carnivores • Effected by changes at all lower levels
• Small numbers to begin with
• Effected by pollutants & toxins passed through system
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What is Biomagnification?
• Biomagnification is the sequence of processes
in an ecosystem by which higher
concentrations of a particular chemical, such
as the pesticide DDT, are reached in organisms
higher up the food chain, generally through a
series of prey-predator relationships.
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What is bioaccumulation? • Bioaccumulation refers to the accumulation of
substances, such as pesticides, or other organic
chemicals in an organism.
• Bioaccumulation occurs when an organism
absorbs a toxic substance at a rate greater than
that at which the substance is lost.
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Think this one………
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IDENTIFY THE ENDANGERED ANIMAL
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Blackbuck
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• According to the Hindu
mythology blackbuck
or Krishna Jinka is
considered as the
vehicle (vahana) of the
Moon-god Chandrama.
Akbar Hunting Black Buck-Akbarnama
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• In ecology, predation describes a biological
interaction where a predator feeds on its prey.
• Examples :Lion killing buffalo, Eagle killing
Rabbit, Mantis eating a bee.
Predation
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• Herbivores are organisms that are adapted to
eat plants.
• Herbivory is a form of predation in which an
organism consumes principally autotrophs
such as plants, algae and photosynthesizing
bacteria.
Herbivore
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• Parasitism is a type of symbiotic relationship
between organisms of different species where
one organism, the parasite, benefits at the
expense of the host.
Example :
• Mosquito: Females ingest blood for the
protein. Male mosquitos ingest plant juices.
• Heartworm of dogs, whose adults reside in the
right side of the heart
Parasitism
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Mosquito: Females ingest blood for the protein. Male
mosquitos ingest plant juices
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Heartworm of dogs, whose adults reside in the right side of the heart
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• Mutualism is a biological interaction that is beneficial to both parties.
• Mutualism is the way two organisms biologically interact where each individual derives a fitness benefit (i.e. increased survivorship).
• Examples :Clownfish and sea anemones, langur monkey curing cow's ear
Mutualism
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2.3.5 APPLY SIMPSON’S DIVERSITY INDEX
AND OUTLINE ITS SIGNIFICANCE
Simpson’s Diversity Index
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1) Simpson's diversity index (also known as species diversity index) is one of a number of diversity indices, used to measure diversity.
2) In ecology, it is often used to quantify the biodiversity of a habitat.
3) It takes into account the number of species present, as well as the relative abundance of each species.
4) The Simpson index represents the probability that two randomly selected individuals in the habitat will not belong to the same species.
Simpson’s Diversity Index
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• For plant species the percentage cover in a
square is usually used;
• For animal species, for example in a river, the
number of organisms of a species is used.
• The reason percentage cover is used is because
it is usually very difficult to count all the
individual plants
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• Where:
• D = diversity index N = total number of organisms of all species found n = number of individuals of a particular species
Simpson’s Diversity Index
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Species Number of individuals in
Ecosystem 1
Number of individuals in
Ecosystem 2
A 23 2
B 28 2
C 22 1
D 27 93
Total individuals in
ecosystem
100 98
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Simpson’s Diversity Index =
100 x (100 – 1)
[23x(23-1)] + [28x(28-1)] + [22x(22-1)] + [27x(27-1)]
= 4.08
For Ecosystem 2:
Simpson’s Diversity Index =
98 x (98 – 1)
[2x(2-1)] + [2x(2-1)] + [1x(1-1)] + [93x(93-1)]
= 1.11
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RESULT
• From this it can be seen that ecosystem 1 has
the highest index of diversity.
• The larger then Simpson’s index the more
diverse.
• Increasing diversity tends to suggest more
stable ecosystems with more connections
within them.
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2.2.2 Abiotic factors in Marine
Ecosystems
Describe and evaluate methods for measuring at least three abiotic (physical) factors within an ecosystem.
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Marine Ecosystems
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What are Limiting Factors of an
ecosystem? • Limiting factors are physical or
biological necessities whose presence or absence in inappropriate amounts limits the normal action of the organism.
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Limiting factor fro Marine Ecosytem
• Light
• Temperature
• Salinity
• Dissolved Gases
• Pressure
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Light is needed for photosynthesis and
vision.
• Blue light penetrates deepest.
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Temperature
influences the
metabolic rate,
the rate at which
reactions proceed
within an
organism.
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What is the Deepest Part of the Ocean?
• The ocean's deepest area is
the CHALLENGER DEEP (also called the
Marianas Trench), which is about 11 km
(almost 7 miles, or almost 36,000 feet) deep.
• The trench is 1,554 miles long and 44 miles
wide,
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• Most marine organisms are ECTOTHERMIC having an internal temperature that stays very close to that of their surroundings.
• A few complex animals (mammals & birds) are ENDOTHERMIC, meaning they maintain a stable internal temperature.
• Ocean temperature varies in both depth and latitude.
• Ocean temperatures vary less than on land.
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Salinity greatly affect cell membranes and
protein structure.
• Disrupts cells osmotic pressure.
• Varies because of rainfall, evaporation and
runoff from land.
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How deep is the ocean?
The average depth of the ocean is about 4,267 meters (14,000 feet).
The deepest part of the ocean is called the Challenger Deep and is located beneath the western Pacific Ocean in the southern end of the Mariana Trench, which runs several hundred kilometers southwest of the U.S. territorial island of Guam.
Challenger Deep is approximately 11,030 meters (36,200 feet) deep.
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GASES
Dissolved Gases are necessary for photosynthesis and respiration.
• CO2 dissolves more easily in water than O2.
• CO2 is more abundant in deep waters than surface water.
• O2 decrease dramatically where light penetration decreases.
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How deep can humans go
underwater?
• Breathing air, humans can go down around
350 feet without any sort of protection from
pressure
• Utilizing mixed gases, a diver can reach a little
over 300 meters
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Pressure from the layers of water above.
• Increases with increasing depth.
• To counteract the mass of heavy muscles and bone, many swimming fishes have gas-filled bladders.
• Deep-sea fish don’t have gas bladders, but light bones and oily watery flesh.
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Marine Zones • Areas of homogeneous physical
features.
• Usually based on light, temperature,
salinity, depth, latitude, behavior
and/or water density.
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By light • Upper zone is called the Euphotic
zone and is where the rate of photosynthesis is high.
• Lower zone is called Disphotic zone and is where organisms can see, but there is sufficient light for photosynthesis.
Aphotic zone where no light penetrates.
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By Location Pelagic zone between water and ocean
bottom.
a. Neritic zone = near shore over the continental shelf
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b. Oceanic zone = deep-water beyond the
continental shelf.
i. Epipelagic = photic zone of the ocean.
ii. Mesopelagic = middle ocean waters.
iii. Bathypelagic = ocean floor.
iv. Abyssopelagic = deep-ocean trenches.
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Classification of
Organisms
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MEASURING THE ABIOTIC
FACTORS
You should be able to describe & evaluate three methods in details with references to a named
ecosystem
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1.TEMPERATURE:-Normally measured using
thermometers or temperature probes attached
to data logger.
Seasonal & diurnal variations important ,as is
the influence of aspect
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2.LIGHT INTENSITY:
• This measured using a light meter in lux.
• Seasonal,latitide influence incident the radiation
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3.SOIL: • Soil organic matter is assessed by baking in the
oven at over 100 degrees to evaporate off the water and given as percentage of original soil mass
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4.WIND SPEED:
• This is measured using an anemometer; an
instrument with cuts that spin in the wind
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5.SALINITY:
• This measured using refractometer by placing
a droplet of sample water on a lens and
allowing light to enter through the water
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6.PH:
• This measured using universal indicator or a pH
probe
7.Turbidity
• Measured in depth(m) using a sechi
disc(black& white decorated disc) lowered on a
measuring rope until it is no longer visible
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The Secchi disk measures the transparency of the water. Transparency can be
affected by the color of the water, algae, and suspended sediments. Transparency
decreases as color, suspended sediments, or algal abundance increases.
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SPECIES IDENTIFICATION
• This is usually done with a published
identification key.
• The key asks a question and the answer
determines what step to go to next, either the
name of the species or another question
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(presence/absence of legs; number of legs; presence/absence of tentacles; number of tentacles; shape; visible eyes; bristles
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DIRECT METHODS OF ESTIMATING
OF ABUNDANCE IN ANIMALS
• Animals that don’t move quickly, such as
rocky shore limpets or grassland snails, can be
counted in quadrats giving a direct measure of
population density.
• This only suitable for species that don’t run
away
• A variety of direct sampling techniques can be
used to collect invertebrates using nets and
traps 5/1/2013 AUTHOR-GURU IB/ESS 172
2.3.2 Abundance of organisms.
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Methods for Estimating Population Size
1. Quadrats
2. Capture/Mark/Release/Recapture (Lincoln
Index)
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• Knowing population size is important in making environmental decisions that would affect the population.
• Making a decision on an estimate that is too high extinction.
• Making a decision on an estimate that is too low unnecessarily hurt people that depend on the animals for food & income.
Why we should know the population size of
an ecosystem?
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• ESTIMATING THE
POPULATION USING THE
NETS
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1.Freshwater nets for lake and stream
invertebrates
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2.Sweep nets for grassland and scrub
Sweep nets are sturdy nets used to collect insects from long grass.
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4.Pit trapping and baited traps for terrestrial
invertebrates
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5.Beating trays for invertebrates in trees
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• When estimating population size it is
important to collect RANDOM
SAMPLES.
• A sample is a part of a population, part of
an area or part of some other whole thing,
chosen to illustrate what the whole
population, area or other thing is like.
• In a random sample every individual in a
population has an equal chance of being
selected.
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•Quadrats METHOD
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Using Quadrats
1. Mark out area to be sampled.
2. Place quadrates ( 1 m2, 10 m2) randomly within the area.
3. Count how many individuals are inside each of the quadrates.
4. Calculate the mean number of individuals per quadrate.
5. Pop. Size = mean x total area
area of each Quadrat 5/1/2013 AUTHOR-GURU IB/ESS 197
RANDOM
QUDRATS
SYSTEMATIC
QUDRATS
Quadrat sampling is suitable for
plants that do not move around and
are easy to find. 5/1/2013 AUTHOR-GURU IB/ESS 198
Quadrat method can be used to determine:
POPULATION DENSITY = number of
individuals of each species per area.
PERCENTAGE FREQUENCY =
percent of each species found within an
area.
PERCENTAGE COVER = percent of
plant covering a given area.
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Capture/Mark/
Release/Recapture
Lincoln index
1. Capture as many individuals as possible in the area occupied by the animal population, using netting, trapping or careful searching.
2. Mark each individual, without making them more visible to predators and without harming them.
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3. Release all the marked individuals and allow
them to settle back into their habitat.
4. Recapture as many individuals as possible
and count how many are marked and how
many are unmarked.
10 marked
14 unmarked
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Capture and Marking
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Assumptions: 1. The population of organisms must be closed, with
no immigration or emigration.
2. The time between samples must be very small compared to the life span of the organism being sampled.
3. The marked organisms must mix completely with the rest of the population during the time between the two samples.
4. Organisms are not hurt or disadvantaged by being caught and marked and therefore all organisms have an equal opportunity of being recaptured
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5. Calculate the estimated population size by using the Lincoln Index:
population size = N1 X N2
N3
N1 = number caught and marked initially
N2 = total number caught in 2nd sample
N3 = number of marked individuals recaptured
Most suitable for animals that move around and are difficult to find.
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• Next unit is continuing in the another
PowerPoint presentation
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