Biotic and abiotic factors affecting development pdf
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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.
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. 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. 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. 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. Toward the bottom of a lake, pond, or ocean, there is a zone that light cannot reach.
Photosynthesis cannot take place there and, as a result, a number of adaptations have evolved that enable living things to survive without light. For instance, aquatic plants have photosynthetic tissue near the surface of the water; for example, think of the broad, floating leaves of a water lily—water lilies cannot survive without light.
In environments such as hydrothermal vents, some bacteria extract energy from inorganic chemicals because there is no light for photosynthesis. Ocean upwelling is an important process that recycles nutrients and energy in the ocean. As wind green arrows pushes offshore, it causes water from the ocean bottom red arrows to move to the surface, bringing up nutrients from the ocean depths.
The availability of nutrients in aquatic systems is also an important aspect of energy or photosynthesis. Many organisms sink to the bottom of the ocean when they die in the open water; when this occurs, the energy found in that living organism is sequestered for some time unless ocean upwelling occurs.
As the wind pushes ocean waters offshore, water from the bottom of the ocean moves up to replace this water. As a result, the nutrients once contained in dead organisms become available for reuse by other living organisms. In freshwater systems, the recycling of nutrients occurs in response to air temperature changes.
The nutrients at the bottom of lakes are recycled twice each year: in the spring and fall turnover. The spring and fall turnover is a seasonal process that recycles nutrients and oxygen from the bottom of a freshwater ecosystem to the top of a body of water.
These turnovers are caused by the formation of a thermocline : a layer of water with a temperature that is significantly different from that of the surrounding layers. In wintertime, the surface of lakes found in many northern regions is frozen. The deepest water is oxygen poor because the decomposition of organic material at the bottom of the lake uses up available oxygen that cannot be replaced by means of oxygen diffusion into the water due to the surface ice layer.
The spring and fall turnovers are important processes in freshwater lakes that act to move the nutrients and oxygen at the bottom of deep lakes to the top. Surface water temperature changes as the seasons progress, and denser water sinks.
How might turnover in tropical lakes differ from turnover in lakes that exist in temperate regions? In springtime, air temperatures increase and surface ice melts. The water at the bottom of the lake is then displaced by the heavier surface water and, thus, rises to the top. As that water rises to the top, the sediments and nutrients from the lake bottom are brought along with it. During the summer months, the lake water stratifies, or forms layers of temperature, with the warmest water at the lake surface.
The oxygen-rich water at the surface of the lake then moves to the bottom of the lake, while the nutrients at the bottom of the lake rise to the surface. During the winter, the oxygen at the bottom of the lake is used by decomposers and other organisms requiring oxygen, such as fish.
This colorful hot spring in Yellowstone National Park, located in Midway Geyser Basin, is the largest hot spring in the United States and the third largest in the world.
Its rich color is the result of thermophilic organisms living along the edges of the hot spring,. Temperature affects the physiology of living things as well as the density and state of water. Enzymes are most efficient within a narrow and specific range of temperatures; enzyme degradation can occur at higher temperatures. Therefore, organisms either must maintain an internal temperature or they must inhabit an environment that will keep the body within a temperature range that supports metabolism.
Some animals have adapted to enable their bodies to survive significant temperature fluctuations, such as seen in hibernation or reptilian torpor. Similarly, some bacteria are adapted to surviving in extremely hot temperatures such as geysers. Such bacteria are examples of extremophiles: organisms that thrive in extreme environments.
Temperature can limit the distribution of living things. Animals faced with temperature fluctuations may respond with adaptations, such as migration, in order to survive. Migration, the movement from one place to another, is an adaptation found in many animals, including many that inhabit seasonally cold climates. Migration solves problems related to temperature, locating food, and finding a mate. In migration, for instance, the Arctic Tern Sterna paradisaea makes a 40, km 24, mi round trip flight each year between its feeding grounds in the southern hemisphere and its breeding grounds in the Arctic Ocean.
Monarch butterflies Danaus plexippus live in the eastern United States in the warmer months and migrate to Mexico and the southern United States in the wintertime. Some species of mammals also make migratory forays. Reindeer Rangifer tarandus travel about 5, km 3, mi each year to find food. Amphibians and reptiles are more limited in their distribution because they lack migratory ability. Not all animals that can migrate do so: migration carries risk and comes at a high energy cost.
Chipmunks hibernate for the winter, but they come out of sleep every few days to eat. Some animals hibernate or estivate to survive hostile temperatures. Hibernation enables animals to survive cold conditions, and estivation allows animals to survive the hostile conditions of a hot, dry climate. Animals that hibernate or estivate enter a state known as torpor: a condition in which their metabolic rate is significantly lowered.
This enables the animal to wait until its environment better supports its survival. Temperature and moisture are important influences on plant production primary productivity and the amount of organic matter available as food net primary productivity.
Net primary productivity is an estimation of all of the organic matter available as food; it is calculated as the total amount of carbon fixed per year minus the amount that is oxidized during cellular respiration. In terrestrial environments, net primary productivity is estimated by measuring the aboveground biomass per unit area, which is the total mass of living plants, excluding roots.
This means that a large percentage of plant biomass which exists underground is not included in this measurement. Net primary productivity is an important variable when considering differences in biomes.
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Not a MyNAP member yet? Register for a free account to start saving and receiving special member only perks. Many environmental factors, including water diversions, affect the structure and functioning of biotic communities in the delta. Although the ecosystem has been radically altered over the past years, it nonetheless remains a biologically diverse and productive ecosystem. In addition, species composition and environmental conditions in the delta have undergone large changes over the period.
An environmental factor , ecological factor or eco factor is any factor, abiotic or biotic, that influences living organisms. Biotic factors would include the availability of food organisms and the presence of biological specificity , competitors , predators , and parasites. An organism's genotype e. In this context, a phenotype or phenotypic trait can be viewed as any definable and measurable characteristic of an organism, such as its body mass or skin color. Apart from the true monogenic genetic disorders , environmental factors may determine the development of disease in those genetically predisposed to a particular condition. Stress , physical and mental abuse , diet , exposure to toxins , pathogens , radiation and chemicals found in almost all [ quantify ] personal-care products and household cleaners are common environmental factors that determine a large segment of non-hereditary disease.
Wing phenotype polymorphism is commonly observed in insects, yet little is known about the influence of environmental cues on the development or expression of the alternative phenotypes. Here, we report how both biotic and abiotic factors affect the wing morph differentiation of a bethylid parasitoid Sclerodermus pupariae. Low intensity light and short-day photoperiod conditions also significantly induced the development of winged morphs. Interestingly, wingless maternal parasitoids produced more winged progeny. Furthermore, the degree of wing dimorphism was significantly influenced by the interactions between light intensity and maternal wing morphs. The percentage of winged female progeny was not significantly influenced by foundress densities, but increased significantly with parasitoid brood sizes.
Abiotic factors affect the ability of organisms to survive and reproduce. Abiotic limiting factors restrict the growth of populations. They help determine the types and.
physiological role of cytokinin in plants pdf
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.
Metrics details. Ticks are increasingly acknowledged as significant vectors for a wide array of pathogens in urban environments with reports of abundant tick populations in recreational areas. The study aims to contribute to a better knowledge of the abiotic and biotic factors which impact the ecology of hard ticks in urban and peri-urban habitats in Romania.
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Plants are affected by several aspects of the soil, which have the potential to exert cascading effects on the performance of herbivorous insects. The effects of biotic and abiotic soil characteristics have however mostly been investigated in isolation, leaving their relative importance largely unexplored. Such is the case for the dune grass Ammophila, whose decline under decreasing sand accretion is argued to be caused by either biotic or abiotic soil properties. By manipulating dune soils from three different regions, we decoupled the contributions of region, the abiotic and biotic soil component to the variation in characteristics of Ammophila arenaria seedlings and Schizaphis rufula aphid populations. Root mass fraction and total dry biomass of plants were affected by soil biota, although the latter effect was not consistent across regions. None of the measured plant properties were significantly affected by the abiotic soil component.
Build background on the abiotic and biotic components of ecosystems. Elicit from students that a biotic factor is any living component of the environment and ask for examples, such as plants, animals, fungi, algae, and bacteria. Elicit from students that an abiotic factor is any non-living component of the environment and ask for examples, such as sunlight, temperature, moisture, wind or water currents, soil type, and nutrient availability. Display the illustration of ocean abiotic factors. Tell students that the interaction of multiple biotic and abiotic, or physical, factors determines which species can survive in a particular ecosystem.