Density Independent Factor Definition Biology

Density Contained Factors Definition

Density contained factors, in environmental, refer to any influences on a population's nascence or death rates, regardless of the population density. Density independent factors are typically a physical gene of the surround, unrelated to the size of the population in question. Density independent factors vary depending on the population, only ever affect the population the aforementioned regardless of its size. At that place are many common density independent factors, such as temperature, natural disasters, and the level of oxygen in the atmosphere. These factors utilise to all individuals in a population, regardless of the density.

Withal, density independent factors are often dislocated density dependent factors for a number of reasons. First, density independent factors for one population of organisms is not the aforementioned for every organism on the planet. While oxygen is a density independent factor for nigh oxygen breathing organisms, it may exist a density dependent factor for some. Image an obligate anaerobe leaner, for instance. Oxygen is toxic to these organisms. Equally they abound in density, the bacteria furthest from the nearest source of oxygen is protected. If these bacteria where to grow thick, oxygen would not bear on each bacteria, and the event on the death rate would be lessened. This would make oxygen a density dependent factor for these particular bacteria.

Analyzing each population specifically allows scientists to place their unique density independent factors. Beneath are several examples of common density independent factors and how they bear upon various species.

Examples of Density Independent Factors

Natural Disaster

Natural disaster is a perfect example of a density independent factor. Consider a hurricane, slamming into the coastline. While nosotros often see the devastation of these storms on the news, we rarely consider the impacts of such a storm on wild animals and vegetation in the surface area. The fact is, hurricanes increase the death rate for many species, while some species see a highly increased birthrate after the destruction.

During a hurricane, winds increment to dangerous speeds, tearing large copse out of the ground. Trees like the i in the image to a higher place would survive any regular storm. For many species, a hurricane drastically increases the death rate, as the trees only cannot withstand the wind and waves. Many animals, such every bit fish and amphibians, succumb to speedily rising and falling tides. Many news images show pictures of fish washed upward into roadways. These animals and plants die, regardless of how dense their population was. They could have been the last of their species, or one in a billion.

However, hurricanes do not only bring death. Consider the expanse unearthed by the tree in the above paradigm. New, smaller plants will be given an opportunity to abound where they were previously restricted by the shade cast by the big tree. Fungi and insects living on dead institute matter will be able to banquet and reproduce on the expressionless wood. The standing water left from the hurricane provides many insects, such every bit mosquitos, aplenty breeding sites. While this is ofttimes a nuisance for humans, it increases the food source of birds and bats, perhaps increasing their birthrates as well. Yet, the hurricane affects all species and individuals within its path, regardless of how many there were.

Pollution

Similar other density contained factors, pollution is a practiced example of a density independence. While humans are concentrated in cities around the world, the emissions and chemicals we create are dispersed into the temper. From hither, they are carried globally and affect all organisms. Fifty-fifty organisms in the oceans are affected, every bit pollutants deliquesce from the temper into various water sources.

Therefore, whether yous are the concluding pair of endangered clownfish in the ocean or take a huge population like sparrows, your birthrate is still negatively impacted. Density independent factors similar these oftentimes cause a slow and steady elevate on populations over time. Even the human population sees drastic health effects from pollution, from atomic number 82 poisoning do to drinking h2o to increased lung diseases.

Honeybees

Instead of looking at density independent factors in general, permit's turn our view to a population of honeybees and the factors that likely touch the size of their population. Density independent factors for honeybees include things similar weather and temperature. Regardless of the current size of their population, bees demand the temperature and weather to stay within certain ranges. If the atmospheric condition does not stick to this design, many bees will die. For case, if at that place was of a sudden snowstorm in the middle of summer, the bees would be defenseless off guard and would die in the cold.

Yet, the bees likewise face up a number of density dependent factors. For instance, their food source and its effects on their population is direct related to the size of their population. If they have a small-scale population, in that location will exist plenty of food for all and the bees will grow. If the population is larger than the amount of food bachelor, bees volition starve and the death charge per unit will increase. Food, and other usable biological resources, are density dependent. Density independent factors will touch on the bees regardless of how many bees are present.

Quiz

1. In a small garden patch under a pocket-size tree, several species of plant are planted in differing numbers. Consider the sunlight as a resources for the plants. Is sunlight i of the density independent factors, or is it density dependent?
A. Density Independent Factor
B. Density Dependent Factor
C. Neither

Reply to Question #one

B is right. As the plants abound, they will accept up a larger and larger expanse, competing for the sunlight. Equally the years go by, the tree will become larger, and have upwards more of the sunlight. If more than plants are added to the surface area, there will exist even less sunlight to go around. Density contained factors, such as weather condition events, volition bear on the plants regardless of how many are in the garden. Sunlight will be more beneficial to the plants if there are less of them in the garden.

2. Exercise density independent factors always limit the population? That is, do they e'er increase the death rate or lower the birth charge per unit?
A. No
B. Yeah
C. Only Density dependent factors practice that

Answer to Question #two

A is correct. Any factor, density dependent or independent, tin be either beneficial or negative. This all depends on the population being afflicted. Some density independent factors, such as hurricanes, assistance some species while they hurt other species. Hurricanes are a density independent factor because they generate the same event regardless of the current population density.

three. A population of field mice increases after a farmer leaves his field unharvested for a season. Which of the following categories does this factor fall into?
A. Density Independent Factors
B. Density Dependent Factors
C. Increased death rate

Answer to Question #iii

B is right. Food is almost always a density dependent gene, considering if the population gets also large the food abundance will quickly turn to a nutrient shortage. Density contained factors would exist things like temperature and tornadoes, which would affect the mice regardless of their current or future density.

References

Cain, M. L., Bowman, W. D., & Hacker, South. D. (2008). Ecology. Sunderland, MA: Sinauer Associates, Inc.

Feldhamer, Thou. A., Drickamer, L. C., Vessey, S. H., Merritt, J. F., & Krajewski, C. (2007). Mammology: Adaptation, Diversity, Ecology (3rd ed.). Baltimore: The Johns Hopkins University Press.

Kaiser, Thousand. J., Attrill, Chiliad. J., Jennings, S., Thomas, D. Due north., Barnes, D. K., Brierley, A. S., & Hiddink, J. G. (2011). Marine Environmental: Processes, Systems, and Impacts. New York: Oxford University Printing.