Abiotic factors are factors that impact an ecosystem which do not arise from living things. Abiotic factors impact the organisms living within that ecosystem, but they are not generated by living things themselves. The phrase “abiotic” means “without life”, in contrast to biotic factors which are factors impacting an ecosystem generated by living things. Common examples of abiotic factors are things like: temperature, elevation, wind, and rain. When these abiotic factors are combined, they constitute much of the variation that different ecosystems possess. Levels of abiotic factors such as water, oxygen, and sunlight influence what kinds of organisms are able to live within an ecosystem. Let’s take a closer look at some specific examples of abiotic factors and how they impact ecosystems and the organisms that live within them.
Five Examples Of Abiotic Factors
Temperature and light are examples of abiotic factors that are linked together, as the amount of sunlight an area gets impacts the ambient temperature in that region. The temperature of both the ambient air and bodies of water in a region impacts how plants, animals, and humans can survive in an ecosystem. Increases and decreases in temperature impact how organisms develop, impacting the metabolic rate of the organism in question. Living organisms have different ranges of temperatures they can live within, and most animals cannot live at the extreme ends of the temperature gauge. Organisms capable of living in extremely cold or extremely hot environments are referred to as extreme of files. As mentioned, the amount of light an area gets often impacts the temperature. Areas near the equator of the earth are often hotter than areas near the poles, due in part to the increased amount of sunlight these regions get.
Living organisms need water to maintain homeostasis and continue their existence. Even though the planet’s surface is approximately 70% water, much of this water is saltwater and many organisms can only survive on freshwater. Water also descends as precipitation, snow or rain, over land. Environments with little water, such as the Sahara desert, have organisms which have evolved to survive on very little water. Many desert plants thrive on little water, and will actually die if rain brings too much water. In contrast, other animals need large volumes of water to survive, such as marine animals and aquatic plants. While all organisms need water survive, every organism requires its own unique amount of water.
The Earth’s atmosphere sustains life, as it is filled with oxygen and other necessary compounds that organisms need to survive. Organisms that require oxygen for cellular respiration pull oxygen from the atmosphere, while moisture in the air is often used by plants to carry out cellular respiration. Plants utilize the carbon dioxide in the atmosphere to respire and grow. In general, living things combine carbon and oxygen in order to create carbohydrates, chemicals which the cell uses as energy to drive cellular processes. Carbohydrates are necessary for the development of organic materials like proteins and DNA. The atmosphere is comprised of five different layers, the troposphere, the stratosphere, the mesosphere, the thermosphere, and the exosphere.
The environments that organisms live in are impacted by different chemical elements such as the acidity of water or soil. The chemical composition of soil and water impacts how acidic the material is, and different organisms have different levels of tolerance for things like acidity. Elements like zinc and copper serve as important micronutrients for a variety of organisms, and plants like holly or azaleas actually need acidic soils to survive. Chemical elements comprise all known matter, and as a result, they also comprise the other listed abiotic factors.
Abiotic factors influence other abiotic factors, and an excellent example of this is how the wind impacts the humidity and temperature of an area. The direction and speed that wind moves in impacts temperature, as high winds make an area cooler. High winds also affect the humility of an area, either by drying the area out or bringing in storms that make the area more humid. High wind speeds can often cause stunted plant growth, especially in mountainous areas, and these stunted plants, in turn, impact the types of animals that can live in an area. Wind can also play an important role in the reproduction of plant species, spreading pollen which some plants use to reproduce.
Examples Of Abiotic Factors Influencing Ecosystems
When the differences between abiotic factors in two regions are great enough, these two regions are considered different ecosystems. As an example, savanna and prairie ecosystems have distinct abiotic factors, having evolved different types of plant life and animal life because of differences in precipitation. Savanna and prairie ecosystems see substantially less precipitation than the jungle or forest ecosystems. However, while precipitation may be the biggest difference between the two ecosystems, other factors like soil composition and amount of land impact the ability for trees to grow in an area, creating environments where trees cannot survive but prairie plants may thrive (and vice versa).
Deserts are one of the most obvious examples of abiotic factors impacting the organisms which live within the ecosystem. Desert ecosystems are very different from other ecosystems because of their low precipitation. Deserts are defined by scientists as regions that receive less than 9.75 inches or 25 cm of snow or rain in a year, and because of this places like Antarctica are also considered deserts. Desert ecosystems can experience dramatic temperature changes, with hot days and freezing nights. Organisms that live within deserts have adaptations to deal with the lack of precipitation and the heat. For instance, the Fennec Fox has large ears which help it dissipate heat thanks to its larger surface area. Meanwhile, camels store fat in their homes which can be used as sources of both water and food when these resources are not readily available. Similarly, the Gila monster stores fat in its tail and thanks to this (and the fact that it lives most of its life on the ground) it can easily go months between meals.
While deserts are the dryest ecosystems on earth, tropical rainforests are the wettest ecosystems on earth, excluding underwater ecosystems. Rainforests are classified as regions that receive over 190 cm or 75 inches of rain every year, and most rain forests receive over 254 cm or 100 inches of precipitation a year. Rainforests found in the Earth’s tropics are tropical rainforests, and the tropics are found slightly North and South of the equator, forming a belt around the earth. These regions receive not only large amounts of precipitation but large amounts of sunlight every year, giving the regions mild seasons and warm temperatures overall. Because of the abundant amount of precipitation and warm environment, rainforest ecosystems can be extremely complex, and tropical rain forests are amongst the most biodiverse areas on the planet. Tropical rainforests are divided into six different layers, with the treetops or canopy being the topmost layer, and each of these different layers hosts different types of life.
Pollution can also be considered an abiotic factor. In fact, human pollution has radically altered some ecosystems, impacting the types of organisms that can survive there. For instance, at the beginning of the 19th century in the United Kingdom, there were two different kinds of moths living there. The white-bodied pepper moth was the most common type of moth, and its body was light colored with black specks, enabling it to blend in with tree bark and avoid being preyed on by birds. The Industrial Revolution’s pollution caused massive amounts of ash to be produced, with this ash covering for surrounding cities. As a result, the light colored moths were no longer camouflaged because the trunks of the trees were now dark. In contrast, the black-bodied moths could now hide against trees more effectively, even though they had once been at a disadvantage. Scientists who studied the two different forms of the peppered moth in the decades following the industrial revolution found that the white body moths were dominant in more rural areas (areas free of soot), while blackbody moths were dominant in forests near cities.
Biotic factors are factors that impact an ecosystem and originate from living things. Organisms in an ecosystem impact other organisms and the environment around them, affecting the ecosystem through actions like the production of waste, predation, and habitat construction. The actions of individual organisms alter the chances of success for other members of their species, the larger ecosystem, and the world as a whole. Types of biotic factors include detritivores, heterotrophs, and autotrophs.
Detritivores are organisms that subsist on dead organisms, breaking down the corpses of plants and animals in order to get energy. Examples of Detritivores are earthworms, fungi, and dung beetles. Detritivores are typically consumed by heterotrophs, which are organisms that have to consume other organisms in order to get energy. Heterotrophs can eat other animals or plants. Omnivores are organisms that subsist on both plants and animals, while herbivores subsist only on plants. Carnivores subsist only on other heterotrophs.
Autotrophs are organisms that create their own energy, converting the energy that comes from the sun into usable chemical energy through a process known as photosynthesis. Different autotrophs use different pigments to absorb different wavelengths of the light spectrum. The most notable example of pigments is chlorophyll, which is responsible for giving many plants their green color. That said, there are some autotrophs which don’t use photosynthesis and produce energy through a process known as chemosynthesis instead, which allows them to use organic material in the surrounding area to create food/energy in an environment that lacks some light. Chemosynthetic organisms include bacteria that live around hydrothermal vents deep in the ocean.
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