Pyramids of Number and Biomass

Ecological pyramids are sometimes called a trophic pyramid. Ecological pyramids model and visualise what is happening in a food chain.

Food chains and webs

A food chain is a model that shows how energy flows through an ecosystem.
- A food chain shows which organisms eat one another.
- Food chains use trophic levels to represent which organisms eat one another.
A food web is a series of food chains that overlap.

Producers and primary consumers

A food chain exists between grass, rabbits, and foxes.
Grass is the producer in this food chain.
- Grass gets energy from the sun.
The rabbit is the primary consumer in this food chain.
- Primary consumers are normally herbivores.
- Primary consumers eat producers.

Secondary consumers

The fox is the secondary consumer in the food chain with grass, rabbits and foxes.
- Secondary consumers are normally carnivores.
- Secondary consumers eat primary consumers.
The predator at the end of the chain is also called the apex predator.

Pyramids of number

Pyramids of number represent the number of organisms in each trophic level.
The producer is at the bottom of the pyramid.
- If the producer is a large organism like a tree, it will not be at the bottom of the pyramid.
- Large organisms like trees can feed lots of small primary consumers.
The trophic levels go up in steps in the pyramid.
- The width of each trophic level represents the number of organisms at that level.

Pyramids of biomass

A pyramid of biomass shows the total mass of the organisms in a trophic level.
- Pyramids of biomass show mass in grams or kilograms.

1Biology

1.1Cells, Tissues & Organs

1.2Reproduction & Variation

1.2.1Reproduction in Humans

1.2.2Male Reproductive System

1.2.3Female Reproductive System

1.2.4Gestation

1.2.5Pregnancy

1.2.6Puberty

1.2.7The Menstrual Cycle

1.2.8Reproduction in Plants

1.2.9Pollination

1.2.10Dispersal Method

1.2.11Variation

1.2.12Causes of Variation

1.2.13Inheritance

1.2.14Adaptations and Evolution

1.2.15Species & Selective Breeding

1.2.16Genetic Conditions

1.2.17End of Topic Test - Reproduction & Variation

1.3Ecological Relationships & Classification

1.4Digestion & Nutrition

1.4.1Balanced Diets

1.4.2Vitamins & Minerals

1.4.3Protein

1.4.4Lipids, Oils and Fats

1.4.5Carbohydrates

1.4.6Starch

1.4.7Energy Needs

1.4.8Dietary Fibre

1.4.9Diseases Caused by Nutritional Deficiencies

1.4.10Digestion

1.4.11Plant Nutrition

1.4.12Enzymes in Digestion

1.4.13Required Practical - Enzymes in Digestion

1.5Plants & Photosynthesis

1.5.1Roots

1.5.2Photosynthesis

1.5.3Leaves

1.5.4Rate of Photosynthesis

1.5.5Testing the Rate of Photosynthesis

1.5.6Water Transport in Plants

1.5.7Translocation

1.5.8The Carbon Cycle

1.5.9Human Activities & Carbon Dioxide

1.6Biological Systems & Processes

2Chemistry

2.1Particles

2.1.1Particles

2.1.2States of Matter

2.1.3Changes of State

2.1.4Properties of States of Matter

2.1.5Diffusion

2.1.6Changing State

2.1.7Pressure

2.1.8Temperature Increase in a Gas

2.1.9Conservation of Mass

2.1.10Purity of Substances

2.1.11Pure Substances

2.1.12Evaporation

2.1.13Mixtures

2.1.14Separating Mixtures

2.1.15Distillation

2.1.16Chromatography

2.1.17Solubility

2.1.18Investigating Solubility

2.2Chemical Reactions

2.2.1Chemical Reactions

2.2.2Common Reactions

2.2.3Acids & Alkalis

2.2.4Reactions of Acids

2.2.5Testing for Hydrogen

2.2.6The pH Scale

2.2.7Titration

2.2.8End of Topic Test - Chemical Reactions

2.3Atoms, Elements, Compounds

2.3.1Atoms

2.3.2Elements

2.3.3Compounds & Mixtures

2.3.4Electron Configuration

2.3.5Chemical Symbols

2.3.6Chemical Formulae

2.3.7Conservation of Mass

2.3.8Vacuums

2.3.9Molecules

2.3.10End of Topic Test - Particles & Atoms

2.4The Periodic Table

2.4.1Physical Properties

2.4.2Chemical Properties

2.4.3The Periodic Table

2.4.4Metals

2.4.5Non-Metals

2.4.6Alkali Metals

2.4.7Halogens

2.4.8Oxides

2.4.9End of Topic Test - The Periodic Table

2.5Materials & the Earth

2.6Reactivity

2.6.1Ions

2.6.2Ionic Bonding

2.6.3State Symbols

2.6.4Balancing Chemical Equations

2.6.5Relative Formula Mass

2.6.6Calculating the Relative Formula Mass

2.6.7The Reactivity Series

2.6.8Carbon & The Reactivity Series

2.6.9Displacement Reactions

2.6.10Displacement Reactions - Halogens

2.6.11Alloys

2.6.12Metal Alloys

2.7Energetics

2.7.1Measuring Gas Production

2.7.2Observing a Colour Change

2.7.3Analysing Reaction Rates

2.7.4Factors Affecting the Rate of Reaction

2.7.5Catalysts

2.7.6Testing for Oxygen

2.7.7Energy Changes During Reactions

2.8Properties of Materials

2.8.1Testing for Gases

2.8.2Alloys

2.8.3Density

2.8.4Density of Solids, Liquids & Gases HyperLearning

3Physics

3.1Energy

3.2Forces & Motion

3.3Waves

3.4Electricity & Magnetism

3.4.1Circuit Symbols

3.4.2Resistors & Diodes

3.4.3Electric Current

3.4.4Measuring Current

3.4.5Potential Difference

3.4.6Series Circuits

3.4.7Parallel Circuits

3.4.8Resistance

3.4.9Charges

3.4.10Static Electricity

3.4.11Magnets

3.4.12Magnetic Fields

3.4.13The Earth's Field

3.4.14Electromagnetism

3.4.15Uses of Electromagnets

3.4.16Strength of Magnetic Fields

3.4.17Circuit Symbols HyperLearning

3.5Matter

3.6Space Physics

3.6.1The Sun

3.6.2The Planets

3.6.3Other Astronomical Bodies

3.6.4The Milky Way

3.6.5Beyond The Milky Way

3.6.6The Seasons

3.6.7Days, Months & Years

3.6.8The Moon

3.6.9Light Years

3.6.10End of Topic Test - Space

4Thinking Scientifically

4.1Models & Representations

4.1.1Strengths & Limitations of Models

4.1.2Symbols & Formulae to Represent Scientific Ideas

4.1.3Analogies in Science

4.1.4Changing Models – Atomic Theory

4.1.5Working Safely in the Lab

4.1.6Variables

4.1.7Writing a Hypothesis & Prediction

4.1.8Planning an Experiment

4.1.9Maths Skills for Science

4.1.10Drawing Scientific Apparatus

4.1.11Observation & Measurement Skills

4.1.12Types of Data

4.1.13Graphs & Charts

4.1.14Bias in Science

4.1.15Conclude & Evaluate

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