In contrast, lucerne and many species of xerophytes are adapted to alkaline conditions. Other soil attributes which can affect organisms include soil texture, soil air and water content, soil temperature and soil solution the decaying remains of plants and animals and feces. Cathel Hutchison began editing and writing in and has worked with various institutions and publishers, including editing courses for the Open University and captioning for the cultural archive "Am Baile.
The Effect of Darkness on Photosynthesis. What Is the Role of Pigments in Photosynthesis? Two Nonliving Parts of an Ecosystem. What Are the Functions of Photosynthesis? How Long Does Photosynthesis Take? Roles of Cyanobacteria in the Ecosystem. How Does Eutrophication Affect pH?
Why Are Ecosystems So Important? Some plants, like azaleas, grow best in acidic soils and will quickly die if planted in alkaline soils. Others, like clematis, prefer alkaline soils. Some, like the hydrangea, can grow in both. These plants are unusual in that their flower colour changes in different soils.
Just like universal indicator paper, hydrangea flowers are pink in acidic soils and blue in alkaline soils. The pH of water can also affect the aquatic organisms that are found there.
Different species have evolved to survive at different pH levels found within water. The graph highlights the various pH tolerances of different species found in water. Many plants require high levels of soil minerals to grow well.
An example of this is magnesium, which is required to produce chlorophyll. Plants with unnaturally yellow leaves may have a magnesium deficiency. Carnivorous plants, such as pitcher plants, have evolved to catch insects to supplement the low levels of minerals found in the soils in which they grow. The strength of the wind and its direction has a huge impact on where organisms are found within ecosystems. Many organisms prefer more sheltered locations. Plant seeds are more likely to settle and germinate there, and animals which depend upon these are more likely to live close to where they grow.
The strength of the wind can also affect the growth of individual organisms. Many forces influence the communities of living organisms present in different parts of the biosphere all of the parts of Earth inhabited by life. The biosphere extends into the atmosphere several kilometers above Earth and into the depths of the oceans. Despite its apparent vastness to an individual human, the biosphere occupies only a minute space when compared to the known universe.
Many abiotic forces influence where life can exist and the types of organisms found in different parts of the biosphere.
The abiotic factors influence the distribution of climates, flora, and fauna. Biogeography is the study of the geographic distribution of living things and the abiotic factors that affect their distribution. Abiotic factors such as temperature and rainfall vary based mainly on latitude and elevation. As these abiotic factors change, the composition of plant and animal communities also changes.
For example, if you were to begin a journey at the equator and walk north, you would notice gradual changes in plant communities. At the beginning of your journey, you would see tropical wet forests with broad-leaved evergreen trees, which are characteristic of plant communities found near the equator.
As you continued to travel north, you would see these broad-leaved evergreen plants eventually give rise to seasonally dry forests with scattered trees. You would also begin to notice changes in temperature and moisture.
At about 30 degrees north, these forests would give way to deserts, which are characterized by low precipitation. Moving farther north, you would see that deserts are replaced by grasslands or prairies. Eventually, grasslands are replaced by deciduous temperate forests. These deciduous forests give way to the boreal forests found in the subarctic, the area south of the Arctic Circle.
Finally, you would reach the Arctic tundra, which is found at the most northern latitudes. This trek north reveals gradual changes in both climate and the types of organisms that have adapted to environmental factors associated with ecosystems found at different latitudes. However, different ecosystems exist at the same latitude due in part to abiotic factors such as jet streams, the Gulf Stream, and ocean currents. If you were to hike up a mountain, the changes you would see in the vegetation would parallel those as you move to higher latitudes.
Ecologists who study biogeography examine patterns of species distribution. No species exists everywhere; for example, the Venus flytrap is endemic to a small area in North and South Carolina. An endemic species is one which is naturally found only in a specific geographic area that is usually restricted in size.
Other species are generalists: species which live in a wide variety of geographic areas; the raccoon, for example, is native to most of North and Central America.
Species distribution patterns are based on biotic and abiotic factors and their influences during the very long periods of time required for species evolution; therefore, early studies of biogeography were closely linked to the emergence of evolutionary thinking in the eighteenth century. Some of the most distinctive assemblages of plants and animals occur in regions that have been physically separated for millions of years by geographic barriers. Biologists estimate that Australia, for example, has between , and , species of plants and animals.
Figure 1. Australia is home to many endemic species. The a wallaby Wallabia bicolor , a medium-sized member of the kangaroo family, is a pouched mammal, or marsupial. The b echidna Tachyglossus aculeatus is an egg-laying mammal. Sometimes ecologists discover unique patterns of species distribution by determining where species are not found. Hawaii, for example, has no native land species of reptiles or amphibians, and has only one native terrestrial mammal, the hoary bat. Most of New Guinea, as another example, lacks placental mammals.
Check out this video to observe a platypus swimming in its natural habitat in New South Wales, Australia. Note that this video has no narration. Plants can be endemic or generalists: endemic plants are found only on specific regions of the Earth, while generalists are found on many regions.
Isolated land masses—such as Australia, Hawaii, and Madagascar—often have large numbers of endemic plant species. Some of these plants are endangered due to human activity. The forest gardenia Gardenia brighamii , for instance, is endemic to Hawaii; only an estimated 15—20 trees are thought to exist. Figure 2. The spring beauty is an ephemeral spring plant that flowers early in the spring to avoid competing with larger forest trees for sunlight. Energy from the sun is captured by green plants, algae, cyanobacteria, and photosynthetic protists.
These organisms convert solar energy into the chemical energy needed by all living things. Light availability can be an important force directly affecting the evolution of adaptations in photosynthesizers. For instance, plants in the understory of a temperate forest are shaded when the trees above them in the canopy completely leaf out in the late spring. Not surprisingly, understory plants have adaptations to successfully capture available light.
One such adaptation is the rapid growth of spring ephemeral plants such as the spring beauty Figure 2. These spring flowers achieve much of their growth and finish their life cycle reproduce early in the season before the trees in the canopy develop leaves. In aquatic ecosystems, the availability of light may be limited because sunlight is absorbed by water, plants, suspended particles, and resident microorganisms.
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