Ecosystem powerpoint 1

5/1/2013 AUTHOR-GURU IB/ESS 1

• 2.1 Structure of Eco System

5/1/2013 AUTHOR-GURU IB/ESS

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 ?



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



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




• A species is often defined as a group

of organisms capable of interbreeding and

producing fertile offspring.

What is species?


• 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?


Biosphere

Ecosystems

Communities

Populations

Organisms


• 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?


• 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?



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.



• An ecosystem has two basic components

• ABIOTIC COMPONENTS

• BIOTIC COMPONENTS


• Biotic components is classified into

three categories:

• PRODUCERS-Autotrophic

• CONSUMERS -Heterotrophic

• DECOMPOSERS OR

SAPTROTROPHS

Biotic Components



• 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


CONSUMERS


• 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


DECONSUMERS


PRODUCERS



• 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?



• 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?


• 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


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


Sir Arthur George Tansley (15 August 1871 - 25 November 1955) was

an English botanist who was a pioneer in the science of ecology


http://upload.wikimedia.org/wikipedia/ro/d/d1/Arthur_Tansley.png

2.1.3 Identify and explain trophic levels in food chains and food webs selected from the local environment.


• 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?




• 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?










• 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?



Grazing type food chains





phytoplankton



"Zooplankton" refers to small aquatic animals.




2.1.4 Explain the principles of pyramids of numbers, pyramids of biomass, and pyramids of productivity, and construct such pyramids from given data.


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?


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



PYRAMID OF NUMBERS represents storages

found at each trophic level.

Units vary





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.


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.


Jayanthi Natarajan Minister for Environment and Forests


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".


• Represents the standing stock of each trophic

level (in grams of biomass per unit area g / m2)

• Represent storages along with pyramids of

numbers


PYRAMID OF BIOMASS represent the

standing stock at each trophic level.

Units:

J m-2

or

g m-2




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




• 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%).


Measurement of biomass of different

trophic levels in an ecosystem.


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.


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)


• 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.


Think this one………


IDENTIFY THE ENDANGERED ANIMAL


Lion Tailed Macaque


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.


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



PYRAMID OF PRODUCTIVITY represents

the flow of energy through each trophic level.

Units:

J m-2 yr-1

or

g m-2 yr-1


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/


• As you move up each trophic level, only

10% of the energy is transferred.

• The other 90% is used for everyday life

functions, metabolism.



Pyramid structure

affects

the functioning of

an

ecosystem.

Bioaccumulation



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.


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.


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


• ENERGY FLOW THROUGH

• PRODUCERS

• CONSUMERS

• DECOMPOSERS


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


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


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


2.1.5 Discuss how the pyramid structure affects the functioning of an ecosystem.


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


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.




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.




Think this one………


IDENTIFY THE ENDANGERED ANIMAL


Blackbuck


• 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



• 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




http://upload.wikimedia.org/wikipedia/commons/4/4f/The_mantis_which_eats_a_Bee20080829.jpg

• 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



• 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


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


• 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




2.3.5 APPLY SIMPSON’S DIVERSITY INDEX

AND OUTLINE ITS SIGNIFICANCE

Simpson’s Diversity Index


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.



• 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


• Where:

• D = diversity index N = total number of organisms of all species found n = number of individuals of a particular species



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


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


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.


2.2.2 Abiotic factors in Marine

Ecosystems

Describe and evaluate methods for measuring at least three abiotic (physical) factors within an ecosystem.


Marine Ecosystems


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.


Limiting factor fro Marine Ecosytem

• Light

• Temperature

• Salinity

• Dissolved Gases

• Pressure


Light is needed for photosynthesis and

vision.

• Blue light penetrates deepest.


Temperature

influences the

metabolic rate,

the rate at which

reactions proceed

within an

organism.


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,



• 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.


Salinity greatly affect cell membranes and

protein structure.

• Disrupts cells osmotic pressure.

• Varies because of rainfall, evaporation and

runoff from land.


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.




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.


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


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.



Marine Zones • Areas of homogeneous physical

features.

• Usually based on light, temperature,

salinity, depth, latitude, behavior

and/or water density.




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.


By Location Pelagic zone between water and ocean

bottom.

a. Neritic zone = near shore over the continental shelf


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.



Classification of

Organisms





MEASURING THE ABIOTIC

FACTORS

You should be able to describe & evaluate three methods in details with references to a named

ecosystem


1.TEMPERATURE:-Normally measured using

thermometers or temperature probes attached

to data logger.

Seasonal & diurnal variations important ,as is

the influence of aspect


2.LIGHT INTENSITY:

• This measured using a light meter in lux.

• Seasonal,latitide influence incident the radiation


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


4.WIND SPEED:

• This is measured using an anemometer; an

instrument with cuts that spin in the wind


5.SALINITY:

• This measured using refractometer by placing

a droplet of sample water on a lens and

allowing light to enter through the water


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


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.


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


(presence/absence of legs; number of legs; presence/absence of tentacles; number of tentacles; shape; visible eyes; bristles


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.


Methods for Estimating Population Size

1. Quadrats

2. Capture/Mark/Release/Recapture (Lincoln

Index)


• 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?


• ESTIMATING THE

POPULATION USING THE

NETS



1.Freshwater nets for lake and stream

invertebrates





2.Sweep nets for grassland and scrub

Sweep nets are sturdy nets used to collect insects from long grass.




4.Pit trapping and baited traps for terrestrial

invertebrates




5.Beating trays for invertebrates in trees




• 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.


•Quadrats METHOD






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.



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.


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


Capture and Marking


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


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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