8.9. Self-regulation of the ecosystem, the population and the community

Ecosystem self-regulation

Ecosystems have great resistance to changes that occur in their environment. The self-regulation of an ecosystem consists of a set of mechanisms (relationships, interactions, feedbacks, natural selection and other ecological phenomena) that keep the ecosystem stable in a dynamic balance. If the balance is broken, the ecosystem is destroyed. Thus, over time, ecosystems can overcome the alterations that, due to natural or human causes, could have affected them. Two examples of these ecosystem self-regulation mechanisms are:

Feedback between predators and prey

The relationship between an ecosystem's predators and its prey is also self-regulating.

If there are many prey in an ecosystem, there is a lot of food available for predators and they will be able to have more young, so in a short time the number of predators will increase.

The high number of predators will need many prey to feed, so the number of prey will decrease, leaving less food available to predators. As a consequence, some will die, have fewer young, and the number of predators will decrease. Then, as the predators will hunt less prey, the number of these will increase, returning to the starting point, keeping the balance between the two populations stable.

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

Simulator: Predator-prey model.

Simulator: Rabbits and wolves (rabbits and wolves).

Game: Ecodetectives. The Peril River problem.

Self-purification of polluted water

When ecosystems are altered by human activities, they also have mechanisms to resist and maintain themselves, if the damage is not too great.

Water has self-purification mechanisms when pollutant discharges or organic remains alter its quality.

When contaminated water is discharged from industrial, urban, agricultural or livestock activities, these substances cause a loss of quality of these waters.

The self-purification of water occurs when physical, chemical and biological processes that take place in the water, naturally, destroy the substances that have been incorporated into the river. The aerobic bacteria mainly consume organic matter, and aquatic plants assimilate some substances as nutrients, so that these get the biodegradation of pollutants and recovering clean water quality.

Interactive activity: Self-regulation of the ecosystem.

Population dynamics

Growth rate of a population

The growth rate of a population is the increase (or decrease) of the population due to births and deaths that have occurred in a certain period of time.

We must consider that the population is a system, with its own dynamics and relationships. If it had no limits, the population would grow progressively.

Growth curves

According to the population growth strategy, two different types of growth curves are distinguished:

S-shaped growth curves

This type of growth curve is characteristic of balanced media, in which the environmental characteristics are relatively constant.

"J" shaped growth curves

The "J" growth curve is characteristic of environments where ecosystems are easily created and destroyed. Growth proceeds exponentially to environmental limits instead of reaching equilibrium and then almost disappearing when the nutrients in the environment are depleted. For example, herbaceous plants with annual growth or insects that depend on annual crops.

Imagen de dominio pública tomada de https://it.wikipedia.org/wiki/File:Curva_logistica.png#/media/File:Curva_logistica.png

Interactive activity: Growth curves.

Factors affecting the population

The abiotic factors limiting population growth, but the interactions between organisms of the ecosystem are also biotic factors that regulate growth and condition. These relationships that occur in biocenosis can be:

Intraspecific.
Interspecific.

Interactive activity: Relationship between the organisms of an ecosystem.

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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 » 8.9. Self-regulation of the ecosystem, the population and the community Ecosystem self-regulation Ecosystems have great resistance to changes that occur in their environment. The self-regulation of an ecosystem consists of a set of mechanisms (relationships, interactions, feedbacks, natural selection and other ecological phenomena) that keep the ecosystem stable in a dynamic balance. If the balance is broken, the ecosystem is destroyed. Thus, over time, ecosystems can overcome the alterations that, due to natural or human causes, could have affected them. Two examples of these ecosystem self-regulation mechanisms are: Feedback between predators and prey The relationship between an ecosystem's predators and its prey is also self-regulating. If there are many prey in an ecosystem, there is a lot of food available for predators and they will be able to have more young, so in a short time the number of predators will increase. The high number of predators will need many prey to feed, so the number of prey will decrease, leaving less food available to predators. As a consequence, some will die, have fewer young, and the number of predators will decrease. Then, as the predators will hunt less prey, the number of these will increase, returning to the starting point, keeping the balance between the two populations stable. By AspidistraK (Own work) [CC BY-SA 4.0], via Wikimedia Commons Simulator: Predator-prey model. Simulator: Rabbits and wolves (rabbits and wolves). Game: Ecodetectives. The Peril River problem. Self-purification of polluted water When ecosystems are altered by human activities, they also have mechanisms to resist and maintain themselves, if the damage is not too great. Water has self-purification mechanisms when pollutant discharges or organic remains alter its quality. When contaminated water is discharged from industrial, urban, agricultural or livestock activities, these substances cause a loss of quality of these waters. The self-purification of water occurs when physical, chemical and biological processes that take place in the water, naturally, destroy the substances that have been incorporated into the river. The aerobic bacteria mainly consume organic matter, and aquatic plants assimilate some substances as nutrients, so that these get the biodegradation of pollutants and recovering clean water quality. Interactive activity: Self-regulation of the ecosystem. Population dynamics Growth rate of a population The growth rate of a population is the increase (or decrease) of the population due to births and deaths that have occurred in a certain period of time. We must consider that the population is a system, with its own dynamics and relationships. If it had no limits, the population would grow progressively. Growth curves According to the population growth strategy, two different types of growth curves are distinguished: S-shaped growth curves This type of growth curve is characteristic of balanced media, in which the environmental characteristics are relatively constant. "J" shaped growth curves The "J" growth curve is characteristic of environments where ecosystems are easily created and destroyed. Growth proceeds exponentially to environmental limits instead of reaching equilibrium and then almost disappearing when the nutrients in the environment are depleted. For example, herbaceous plants with annual growth or insects that depend on annual crops. Imagen de dominio pública tomada de https://it.wikipedia.org/wiki/File:Curva_logistica.png#/media/File:Curva_logistica.png Interactive activity: Growth curves. Factors affecting the population The abiotic factors limiting population growth, but the interactions between organisms of the ecosystem are also biotic factors that regulate growth and condition. These relationships that occur in biocenosis can be: Intraspecific. Interspecific. Interactive activity: Relationship between the organisms of an ecosystem. 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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