StudySmarter - The all-in-one study app.
4.8 • +11k Ratings
More than 3 Million Downloads
Free
Americas
Europe
Humans (Homo sapiens) are a species that walks upright and has a large, complex brain with a capacity for the use of tools, language, symbolic expression, and culture.Since the evolution of our species, we have been creating environmental changes through subsistence and, within the past 10,000 years, agricultural practices (such as clearing land andselective breeding).
However, most of the significant changes and alterations toecosystemshave occurred within the past century.At present, we continue to change our environment through rapid urbanization, industrialized production, and global trade.
Here we will discuss the impact of human activities onecosystems: what these activities are, howecosystemsare negatively affected, and what practices are being done to mitigate these negative effects.
Human activities have a significant impact onecosystems,affectingbioticandabioticfactors alike.
Anecosystemis a biological community composed of all living organisms (biotic factors) and their interaction with the physical environment (abiotic factors).
Biotic factorsare living organisms such asanimals,plants, and fungi that exist within an ecosystem.
Abiotic factorsare non-living chemical and physical environmental conditions such as temperature, water, wind, light, and chemical composition that exist within an ecosystem.
By affecting both生物和非生物因素, human activities can significantly alter or compromise the function and balance of ecosystems.Let’s discuss a few examples of things that humans do that put tremendous pressure on the environment.
Humans use natural resources –whether for subsistence, trade, or other social, economic, and cultural activities. The exploitation of natural resources can put pressure on the species that depend on these natural resources for their survival.
For example, the extraction of timber in forest ecosystems can deprive organisms that live in trees of their food and shelter.
With the growth of the human population, these impacts are amplified. The widespread loss ofspecies diversityin the past centuries can be attributed to the explosive growth in the human population: from approximately 1 billion in 1850 to over 7.8 billion in 2020. The world's population is projected to grow to 10 billion by 2050.
Additionally, while our technology has advanced such that our food and medicine can increase the lifespan of humans, the challenges caused by human overpopulation increased as well.
Many human activities–especially when not properly regulated or managed–create pollution.
Pollutionis the introduction of pollutants into the environment.Pollutantsare substances that cause undesirable changes in the environment.
Pollutants can be natural or man-made.Natural pollutantsinclude volcanic ash, soot, salt spray, and natural gas. These come from natural activities such as volcanic eruptions, petroleum seeps, and forest fires.Man-made pollutantsinclude garbage, agricultural runoffs, and industrial waste.
Pollution can cause undesirable changes in the air, water, and land alike, which generally harm organisms by altering environmental conditions, to which species respond differently.
早期农业使我们的祖先能够解决in one area and cultivate their own food. This involved clearing tracts of land, domesticating plants and animals, and introducing non-native species to new areas. Clearing land has led to habitat loss, grazing animals has led to the decline in native grasses, and breeding cattle has led to changes in the composition of atmospheric gasses.
On the other hand, the introduction of species where they do not naturally occur (whether deliberately or by accident) can cause competition with the native species. Although the introduction of non-native speciesdoes not necessarily cause harm, it can be a problem if it causes damage to the ecosystem by outcompeting native species for resources necessary for survival, carrying parasites or diseases, or altering abiotic factors such as soil chemistry in the ecosystem.
Such non-native species that cause harm are calledinvasive species.
Fishing is also a vital source of food and livelihood for humans. However, fishing can be unsustainable and can destroy marine ecosystems. Overfishing has depleted fish populations all over the world.
Besides the extraction of fish itself, fishing can also indirectly affect fish and other marine life. Lost or abandoned fishing gear can cause seabirds (Fig. 1) and marine animals to get entangled and deep-sea corals to get damaged. The discharge ofballast water(water contained in the cargo holds and ballast tanks of ships that are used to stabilize ships during a voyage) can also unintentionally introduce invasive species. Additionally, some fishing methods such as bottom trawling and dredging can destroy natural seafloor habitats.
We have discussed some human activities that cause a significant impact on ecosystems. This time, let’s discuss how specific ecosystems are affected by different human activities. We will discuss forest, aquatic, and mountain ecosystems as our examples.
Many forest ecosystems are affected by human settlements and logging.
Tropical forests–which are one of the most diverse habitats on the planet– have long been used by humans for settlement and the extraction of natural resources. In modern times, many tropical forests are subject to land conversion for use as farmland, urban settlements, industrial production, and other human activities.
Land use has caused massive habitat loss and fragmentation (where a large habitat is divided into smaller, isolated habitats). In fact, over half of the tropical forests that existed in the early 1900s have already been destroyed. The destruction of tropical forests generally causes a decline in the abundance and diversity of species that inhabit them.
In addition to tropical forests,temperate broadleaf forestswhich are found in temperate climates have also been heavily settled on by humans. Almost all of the original deciduous forests in North America have been affected by logging and land clearing foragricultureand urbanization.
Likewise,northern coniferous or boreal forestswhich are forests that contain cone-bearing evergreens have not been heavily settled by humans but they are affected by logging (Fig. 2), mining, and hydroelectric development projects.
Aquatic ecosystemsinclude freshwater habitats like rivers, wetlands, lakes, and swamps as well as marine habitats like oceans, coral reefs, and marine benthic zones.
Lakeshave been impacted by agricultural runoff and the dumping of waste.
Agricultural runoffis the surplus water from farms that contains or picks up natural and man-made pollutants such as pesticides, fertilizers, and sediments as it travels toward bodies of water. Both can cause algal blooms, the overgrowth of algae that depletes water of oxygen and potentially kills fish.
Coral reefshave been affected by overfishing and the collection of coral skeletons; such activities have caused an alarming decline in coral and reef fish populations. Global warming and pollution which can cause changes in the temperature, salinity and chemical composition of water have also been contributing to the death of many corals. This is because when water temperatures get too high or when there are other changes that put stress on the symbiotic relationship between corals and microscopic algae, the microscopic algae leave the coral tissue and the coral slowly dies.
Mountain ecosystemsconsist of living organisms that can be found on the slopes of mountains. Mountains provide a wide range of habitats that vary with the gradation of mountain slopes: from harsh environmental conditions at higher altitudes to forests, savannas, deserts, or other habitats at lower altitudes.
Human activities that have caused a significant impact on mountain ecosystems include logging, mining, livestock grazing, and energy production. Human activities that use high mountains such as skiing can also cause physical disturbance to the ecosystem.
在前面的章节中,我们已经讨论了代理s negative impacts of humans on ecosystems. This time, let’s discuss a few human activities that have a positive impact on ecosystems.
Conservationrefers to the efforts done to manage natural resources and prevent the loss of biodiversity. Conservation practices include waste management as well as the protection of threatened species and habitats.
Waste managementrefers to the systematic collection, treatment, and disposal of waste.
Waste management can contribute to conservation by preventing pollution and reducing waste that ends up in landfills and water systems. This includes strategies such as reusing, recycling and composting.
Theprotection of threatened species and habitatsis done by preventing or regulating potentially destructive human activities such as hunting, mining, and logging and by promoting sustainable activities such as reforestation, ecotourism, and community-based resource management.
By affecting both biotic and abiotic factors, human activities can significantly alter or compromise the function and balance of ecosystems.
Human activities that interfere with ecosystems include agriculture, fishing, logging, and land conversion.
An example of human impact on the ecosystem is the decline in coral and reef populations due to overfishing, global warming, and climate change.
The human activities with the largest impact on forest ecosystems are land conversion for settlement and agriculture, as well as logging.
Humans can positively affect ecosystems through conservation practices such as waste management and the protection of threatened species and habitats.
Be perfectly prepared on time with an individual plan.
Test your knowledge with gamified quizzes.
Create and find flashcards in record time.
Create beautiful notes faster than ever before.
Have all your study materials in one place.
Upload unlimited documents and save them online.
Identify your study strength and weaknesses.
Set individual study goals and earn points reaching them.
Stop procrastinating with our study reminders.
Earn points, unlock badges and level up while studying.
Create flashcards in notes completely automatically.
Create the most beautiful study materials using our templates.
Sign up to highlight and take notes. It’s 100% free.
Over 10 million students from across the world are already learning smarter.
Get Started for Free