4.3: Explain How Quadrants can be Used to Sample the Distribution of Organisms in their Habitats

QUADRANTS: Square Made of Wires that is Divided into Smaller Areas in which Organisms underneath are Identified and Counted

MEASURING DISTRIBUTION OF ORGANISMS:

DISTRIBUTION OF ORGANISMS IN HABITAT

Diagram showing How Quadrants are Utilised in the Field

METHOD: Place Quadrant Randomly within Sampling Area Count the Populations of Different Species within the Quadrant Repeat this Numerous Times within Sampling Area using the Same Size Quadrant Show Results on Map of Sampled Area, Showing in Which Areas Populations of Different Species are Dense or Not

INCREASING RELIABILITY OF RESULTS: Randomly Placed Use Same Size Quadrant Each Time Reliability of Results will Increase as More Samples are Taken

4.2: Explain How Quadrats can be Used to Estimate the Population Size of an Organism in Two Different Areas

QUADRANTS: Square Made of Wires that is Divided into Smaller Areas in which Organisms underneath are Identified and Counted

MEASURING POPULATION OF ORGANISM:

ESTIMATING POPULATION SIZE OF ORGANISM

Diagram showing How Quadrants are Utilised in the Field

METHOD: Place Quadrant Randomly within Sampling Area Count the Number of Members of an Organism (Same Species) within the Quadrant Repeat this Numerous Times within Sampling Area using the Same Size Quadrant Repeat the Process in another Area to Compare Results

CALCULATION: The Equation to Calculate the Estimate of the Population Size of an Organism: Population Size = ( Total Area / Sampled Area ) x Number of Organisms Found

4.1: Understand the Terms Population, Community, Habitat and Ecosystem

DEFINITIONS:

TERM	DEFINITION
POPULATION	Number of Members of a Single Species
COMMUNITY	Different Species of Organisms Living in the Same Area
HABITAT	Where Living Organisms Live
ECOSYSTEM	Population of Different Species of Organisms and the Habitat that they Live in

4.4: Explain the Names Given to Different Trophic Levels to Include Producers, Primary, Secondary and Tertiary Consumers and Decomposers

TROPHIC LEVELS: Feeding Level in a Food Chain

DEFINITION:

TERM	DEFINITION
PRODUCERS	Organisms that Produce their Own Organic Nutrients such as Plants through Photosynthesis
PRIMARY CONSUMERS	Herbivores and Feed on Plants (Producers)
SECONDARY CONSUMERS	Predators that Feed on Primary Consumers
TERTIARY CONSUMERS	Predators that Feed on Secondary Consumers
DECOMPOSERS	Bacteria and Fungi that Breaks Down Dead Animal’s Body, Urea and Undigested Waste for Energy (Using Enzymes to Break Down Compounds)

4.5: Understand the Concepts of Food Chains, Food Webs, Pyramids of Number, Pyramids of Biomass and Pyramids of Energy Transfer

FOOD CHAINS: Shows the Feeding Relationships Between Living Things (What Eats What in a Habitat)

FOOD CHAINS

Diagram Showing an Example of a Food Chain

EXPLANATION: In the Diagram, the Flower will be the Producer as it is Produces their Own Organic Nutrients through Photosynthesis The Flowers will be Eaten by Snails which are Primary Consumers as they will Eat Plants and are Herbivores The Snails will be Eaten by Frogs which are Secondary Consumers as they are Predators The Frogs will be Eaten by Foxes which are Tertiary Consumers as they are Predators at the Top of the Food Chain

FOOD WEBS: Shows All the Food Chains in an Ecosystem, Showing the Flow of Energy in a Habitat

FOOD WEBS

Diagram Showing an Example of a Food Web

EXPLANATION:     Shows the Food Chains Joined Together: Grass → Insect → Vole → Hawk Grass → Insect → Frog → Fox Grass → Insect → Vole → Fox     Food Webs will Show Interdependence (Change in Population of One Organism     will Affect the Population of Another Organism): If Population of Insects Fall, Population of Vole may Decrease as they will Have Less Insects to Feed on so will Starve and Die If Population of Rabbits Increase, Population of Fox may Increase as they will Have More Rabbits to Feed on so will Increase Chances of Survival

PYRAMIDS OF NUMBERS: Shows the Population of Each Organism at Each Trophic Level in a Food Chain

PYRAMIDS OF NUMBERS

Diagram Showing an Example of a Pyramid of Numbers

EXPLANATION: The Bars represents the Population so Wider the Bar, the Larger the Population The Producer will Always be at the Bottom Energy is Lost to the Surroundings from One Trophic Level to the Next so there are usually Fewer Organisms at Each Trophic Level (Less Chances of Survival) But Sometimes May Not Look like a Pyramid as One Large Producer can Feed Many Small Consumers (E.g One Oak Tree can Feed many Insects)

PYRAMIDS OF BIOMASS Shows the Transfer of Energy at Each Trophic Level by Calculating the Dry Mass of Each Population of Species

PYRAMIDS OF BIOMASS

Diagram Showing an Example of a Pyramid of Biomass

EXPLANATION: Biomass is the Mass of Living Material in Each Organism Multiplied by their Population at Each Trophic Level Pyramids of Biomass will Always Look like a Pyramid as Biomass is a Measure of the Amount of Food Available, this Decreases from One Trophic Level to the Next as Energy is Lost to Respiration, Not Digested or Not Eaten

PYRAMIDS OF ENERGY TRANSFER: Shows the Transfer of Energy at Each Trophic Level from One Trophic Level to the Next

PYRAMIDS OF ENERGY TRANSFER

Diagram Showing an Example of a Pyramid of Energy Transfer

EXPLANATION: Each Trophic Level Reduces the Amount of Energy Available for the Next  as Only 10% of Energy is Passed On Energy is Lost to Respiration, May Not be Digested or May Not be Eaten, Causing the Availability of Energy to be Passed on to Decrease This results to a Limit of Trophic Levels in a Food Chain

4.6: Understand the Transfer of Substances and of Energy Along a Food Chain

FOOD CHAINS: Shows the Feeding Relationships Between Living Things (What Eats What in a Habitat)

TRANSFER OF SUBSTANCES AND ENERGY:

TRANSFER OF SUBSTANCES AND ENERGY IN FOOD CHAIN

Diagram Showing the Transfer of Energy in Food Chain

EXPLANATION: The Sun is the Ultimate Source of Energy as Plants will Absorb Sunlight through Photosynthesis to Produce Organic Food which is Consumed by Other Organisms, Passing Energy Down the Food Chain Each Trophic Level Reduces the Amount of Energy Available for the Next as Only 10% of Energy is Passed On

ENERGY IS LOST TO: RESPIRATION Respiration to Release Energy for Life Processes such as Movement or Heat Energy     2.   NOT EATEN Food May Not All be Eaten Such as Bones or Fibres     3.   NOT DIGESTED Food May Not be Digested, Resulting in Energy Lost to Faeces which are Broken Down by Decomposers

4.7: Explain Why Only 10% of Energy is Transferred from One Trophic Level to the Next

TROPHIC LEVELS: Feeding Levels in a Food Chain

ENERGY IS LOST TO:

REASON	EXPLANATION
RESPIRATION	Respiration to Release Energy for Life Processes such as Movement or Heat Energy
NOT EATEN	Food May Not All be Eaten Such as Bones or Fibres
NOT DIGESTED	Food May Not be Digested, Resulting in Energy Lost to Faeces which are Broken Down by Decomposers
EXCRETED AS WASTE	Food Eaten is Broken Down and Excreted as Waste, E.g, Urea

4.10: Describe the Stages in the Nitrogen Cycle, Including the Roles of Nitrogen Fixing Bacteria, Decomposers, Nitrifying Bacteria and Denitrifying Bacteria (Specific Names of Bacteria are Not Required)

NITROGEN CYCLE: Describes the Movement of Nitrogen Compounds in the Environment

THE NITROGEN CYCLE

Diagram Showing the Nitrogen Cycle

EXPLANATION: NITROGEN FIXATION Nitrogen Gas in the Atmosphere is Too Unreactive to be Used Directly so Needs to be Converted into Soluble Ions Nitrogen Fixing Bacteria in Root Nodules of Legumes will Convert Nitrogen Gas into Nitrates for Use Lightning will Convert Nitrogen Gas into Nitrates Haber Process will Convert Nitrogen Gas into Ammonia, in which Nitrifying Bacteria will Convert into Nitrites, then Nitrates ABSORPTION BY PLANTS Plants will Absorb Nitrates through the Roots by Active Transport Nitrate Ions Help Produce Amino Acids which will become Protein, Becoming Part of Plants Biomass MOVING ALONG FOOD CHAINS Animals will Eat Plants and Nitrogen from the Plant’s Protein will become Protein in the Animal Nitrogen is also Passed from One Animal to Another by Feeding DEATH OF ORGANISMS Decomposers (Bacteria and Fungi) will Break Down urea, Egested Material and Dead Bodies and Nitrogen Compounds will be Returned to the Soil as Ammonium Ions Nitrifying Bacteria will Convert Ammonium Ions into Nitrites, then Nitrates for Plants to Absorb DENITRIFICATION Denitrifying Bacteria in the Soil will Break Down Nitrates and Return Nitrogen Gas into the Air This Occurs in Waterlogged Soil so can be Prevented by Reducing Drainage