8.8. Ecological pyramids

Trophic or ecological pyramids

The trophic pyramids or ecological are a graphical representation of the trophic relationships in an ecosystem, which shows how different vary trophic levels according to the energy, the biomass or number of individuals.

In these pyramids, each trophic level is represented by a horizontal bar of the same height, but with a width proportional to the characteristic to be represented. At the base of the pyramid are the producers, in charge of synthesizing organic matter from inorganic matter and the energy of the Sun. Above these are the primary consumers, who feed on the producers, the secondary consumers, who feed on primary consumers, and lastly, tertiary consumers.

There are three types of ecological pyramids:

Of the energy that is stored in each trophic level.
Of the amount of biomass or organic matter in each trophic level.
Of the number of individuals of each trophic level.

Pyramids of energy

The energy pyramids represent the energy stored in each trophic level at a certain time and that is available to the higher level. These pyramids are the ones that provide the greatest amount of information about the ecosystem.

They are usually expressed in units of energy per unit area or volume and per unit of time, such as g/m² .year, cal/m² year, etc.).

The energy transfer from one level to another is approximately 10%. Much of the energy is used for metabolism.

These pyramids can never be inverted, since the energy of the lower trophic level always has to be greater than that of the upper level.

By Roddelgado (Own work) [CC BY-SA 4.0], via Wikimedia Commons

Interactive activity: Pyramids of energy.

Biomass pyramids

The biomass pyramids represent the amount of biom handle (organic matter alive or dead) of any trophic level.

It is measured in grams or kilograms of organic matter per unit area or volume. For example, g/m², kg/ha, etc.

It is possible that some pyramids of biomass are inverted, as for example in an aquatic ecosystem in which the producers represent little biomass but reproduce at high speed.

By Roddelgado (Own work) [CC BY-SA 4.0], via Wikimedia Commons

Pyramids of numbers

In number pyramids, each bar represents the number of individuals at each trophic level. Generally, the number of individuals decreases in the upper levels, but we can also find inverted pyramids, such as the numerous aphids that feed on a rose bush. Therefore, this information does not provide much information about the real importance of each organism in the ecosystem.

By Roddelgado (Own work) [CC BY-SA 4.0], via Wikimedia Commons

Licensed under the Creative Commons Attribution Share Alike License 4.0

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Skip navigation Biology and Geology 4th ESO Biology and Geology 4º ESO 1. The cell 1.1. Levels of organization of living beings 1.2. Cell theory 1.3. The cell 1.3.1. Prokaryotic cell 1.3.2. Eukaryotic cell 1.3.2.1. Common organelles 1.3.2.2. Organelles of the animal cell 1.3.2.3. Plant cell organelles 1.4. Cell nucleus 1.5. Vital functions of cells 1.6. Cellular cycle 1.6.1. Mitosis 1.6.1.1. Cytokinesis 1.6.2. Meiosis 1.6.2.1. Meiosis I. First meiotic division 1.6.2.2. Meiosis II. Second meiotic division 1.6.2.3. Result of meiosis 1.6.3. Differences between mitosis and meiosis 1.6.4. Biological importance of mitosis and meiosis 1.7. Bibliography 2. Genetic information 2.1. Nucleic acids 2.1.1. DNA 2.1.2. RNA 2.1.3. Control of protein synthesis 2.2. DNA and molecular genetics 2.3. Gene concept 2.4. Replication of DNA 2.5. DNA to RNA transcription 2.6. Genetic code 2.7. Translation of RNA to proteins 2.8. Mutations Relations with evolution 2.9. Biotechnology 2.10. Genetic engineering: techniques and applications 2.10.1. Cloning 2.10.2. Human Genome Project 2.11. Bioethics 2.12. Bibliography 3. Biological inheritance 3.1. The inheritance and transmission of characters 3.2. Introduction and development of Mendel's Laws 3.2.1. Mendel's First Law 3.2.2. Mendel's second law 3.2.3. Mendel's third law 3.3. Chromosomal basis of Mendel's Laws 3.3.1. Exceptions to Mendel's Laws 3.3.2. Chromosomal theory of heredity 3.3.3. Genetics concepts 3.3.4. Types of inheritance 3.4. Human genetics 3.4.1. Inheritance of blood groups 3.4.2. Sex inheritance 3.4.3. Sex-linked inheritance 3.4.4. Heredity influenced by sex 3.5. Genetics problems 3.5.1. Inheritance of a character (problems solved) 3.5.1.1. Albinism (problems solved) 3.5.1.2. Rh groups (problems solved) 3.5.1.3. Eye color (problems solved) 3.5.1.4. More inheritance problems of a character 3.5.1.5. More inheritance problems of a character 3.5.1.6. More inheritance problems of a character 3.5.1.7. More inheritance problems of a character 3.5.2. Two-character inheritance (problems solved) 3.5.2.1. More two-character genetic inheritance solved problems 2 3.5.2.2. More two-character genetic inheritance solved problems 3 3.5.2.3. More two-character genetic inheritance solved problems 4 3.5.2.4. More two-character genetic inheritance solved problems 5 3.5.3. Codominance and intermediate inheritance (problems solved) 3.5.3.1. More codominance and intermediate inheritance problems 2 3.5.4. Sex-linked inheritance (problems solved) 3.5.4.1. Color blindness or daltonism (problems solved) 3.5.4.1.1. More color blindness problems or daltonism 3.5.4.2. Hemophilia (problems solved) 3.5.4.3. Sex-linked inheritance (two characters) 3.5.4.4. More sex-linked inheritance problems 3.5.5. Sex-influenced inheritance (problems solved) 3.5.6. Multiple alleles (problems solved) 3.5.6.1 AB0 blood groups (problems solved) 3.5.6.1.1. More AB0 blood group problems solved 2 3.5.6.1.2. More AB0 blood group problems solved 3 3.5.7. Genealogical trees 3.5.7.1. Family Trees 2 3.5.7.2. Family Trees 3 3.6. Bibliography 4. Origin and evolution of living beings 4.1. Hypothesis about the origin of life on Earth 4.2. Evolution of living beings 4.3. Theories of evolution 4.3.1. Lamarck 4.3.2. Darwin and Wallace 4.3.3. Neo-Darwinism 4.3.4. Other evolutionary theories 4.4. Evidences of evolution 4.4.1. Anatomical evidence of evolution 4.4.2. Embryological evidence of evolution 4.4.3. Paleontological evidence of evolution 4.4.4. Biogeographic evidence of evolution 4.4.5. Biochemical evidence of evolution 4.5. Mechanisms of evolution 4.5.1. Genetic variability 4.5.2. Natural selection 4.5.3. Consequences of evolution 4.5.3.1. Adaptation of organisms 4.5.3.2. Speciation 4.5.3.3. Species diversification 4.6. Human evolution: process of hominization 4.6.1. Primates 4.6.2. Hominids 4.6.3. The human being 4.7. Bibliography 5. The history of the Earth 5.1. The origin of the Earth 5.2. Earth, a changing planet 5.3. Geological time: historical ideas about the age of the Earth 5.4. Dating methods 5.4.1. Relative dating 5.4.1.1. Geological history exercises - relative dating 5.4.2. Absolute dating 5.5. Fossils 5.5.1. Fossils in Aragon 5.6. Geological history of the Earth 5.6.1. Precambrian 5.6.2. Phanerozoic 5.6.2.1. Paleozoic 5.6.2.2. Mesozoic 5.6.2.3. Cenozoic 5.7. Bibliography 6. Structure and dynamics of the Earth 6.1. Earth study methods 6.1.1. Seismic discontinuities 6.2. Structure and composition of the Earth 6.2.1. Geochemical model 6.2.2. Dynamic model 6.3. Bibliography 7. Plate tectonics 7.1. From continental drift to plate tectonics 7.1.1. Wegener continental drift 7.2. Plate Tectonics and its manifestations 7.2.1. Lithospheric plates 7.2.2. Oceanic ridges 7.2.2.1. Expansion of the ocean floor 7.2.3. Ocean trenches 7.2.4. Transforming faults 7.2.5. Formation of mountain ranges 7.3. The Wilson cycle 7.4. Rock deformation 7.4.1. Folds 7.4.2. Faults 7.4.3. Joints 7.4.4. Mixed structures 7.5. Bibliography 8. Ecosystems 8.1. Ecosystem structure 8.1.1. Types of ecosystems 8.1.1.1. Aquatic ecosystems 8.1.1.2. Terrestrial ecosystems 8.1.1.2.1. Urban ecosystems 8.2. Components of the ecosystem: community and biotope 8.2.1. Biotope 8.2.2. Biocenosis or community 8.3. Habitat and ecological niche 8.4. Limiting factors and adaptations 8.5. Tolerance limit 8.6. Trophic levels 8.7. Trophic relationships: chains and networks 8.8. Ecological pyramids 8.9. Self-regulation of the ecosystem, the population and the community 8.9.1. Intra and interspecific relationships 8.10. Matter cycle and energy flow 8.11. Biogeochemical cycles 8.11.1. Carbon cycle 8.11.2. Nitrogen cycle 8.11.3. Phosphorus cycle 8.12. Ecological successions 8.13. Bibliography 9. Resources and environmental impacts 9.1. Human activity and the environment 9.2. Natural resources and their types 9.3. Environmental impacts 9.3.1. Pollution of the atmosphere 9.3.1.1. Air pollutants 9.3.1.2. Acid rain 9.3.1.3. The smog 9.3.1.4. Ozone layer hole 9.3.1.5. Increased greenhouse effect 9.3.1.6. Climate change 9.3.2. Noise pollution 9.3.3. Light pollution 9.3.4. Water contamination 9.3.4.1. Water pollutants 9.3.4.2. Water eutrophication 9.3.4.3. Aquifer reduction 9.4. Soil 9.4.1. Soil contamination 9.5. Main environmental problems of Aragon 9.6. Overpopulation and its consequences 9.7. Waste and its management 9.8. Bibliography and student work « Previous \| Next » 8.8. Ecological pyramids Trophic or ecological pyramids The trophic pyramids or ecological are a graphical representation of the trophic relationships in an ecosystem, which shows how different vary trophic levels according to the energy, the biomass or number of individuals. In these pyramids, each trophic level is represented by a horizontal bar of the same height, but with a width proportional to the characteristic to be represented. At the base of the pyramid are the producers, in charge of synthesizing organic matter from inorganic matter and the energy of the Sun. Above these are the primary consumers, who feed on the producers, the secondary consumers, who feed on primary consumers, and lastly, tertiary consumers. There are three types of ecological pyramids: Of the energy that is stored in each trophic level. Of the amount of biomass or organic matter in each trophic level. Of the number of individuals of each trophic level. Pyramids of energy The energy pyramids represent the energy stored in each trophic level at a certain time and that is available to the higher level. These pyramids are the ones that provide the greatest amount of information about the ecosystem. They are usually expressed in units of energy per unit area or volume and per unit of time, such as g/m² .year, cal/m² year, etc.). The energy transfer from one level to another is approximately 10%. Much of the energy is used for metabolism. These pyramids can never be inverted, since the energy of the lower trophic level always has to be greater than that of the upper level. By Roddelgado (Own work) [CC BY-SA 4.0], via Wikimedia Commons Interactive activity: Pyramids of energy. Biomass pyramids The biomass pyramids represent the amount of biom handle (organic matter alive or dead) of any trophic level. It is measured in grams or kilograms of organic matter per unit area or volume. For example, g/m², kg/ha, etc. It is possible that some pyramids of biomass are inverted, as for example in an aquatic ecosystem in which the producers represent little biomass but reproduce at high speed. By Roddelgado (Own work) [CC BY-SA 4.0], via Wikimedia Commons Pyramids of numbers In number pyramids, each bar represents the number of individuals at each trophic level. Generally, the number of individuals decreases in the upper levels, but we can also find inverted pyramids, such as the numerous aphids that feed on a rose bush. Therefore, this information does not provide much information about the real importance of each organism in the ecosystem. By Roddelgado (Own work) [CC BY-SA 4.0], via Wikimedia Commons Licensed under the Creative Commons Attribution Share Alike License 4.0 « Previous \| Next » You can ask, comment, contribute, get in touch with other users in the forum of this course. This course is translated from https://biologia-geologia.com/BG4/
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Trophic or ecological pyramids

Pyramids of energy

Biomass pyramids

Pyramids of numbers