Factors Affecting the Extinction of Species

Ecosystems rely on every aspect of that ecosystem. This includes the different kinds of species that inhabit those ecosystems. If a species becomes extinct, it could result in many different ways that are possibly detrimental to that ecosystem along with the biodiversity of that ecosystem and in turn affect humans. Human activity has a major impact on all different kinds of species. The species of the Earth are affected in so many ways, such as global warming, destruction of habitats and the overexploitation of the ecosystems that the species dwell in. The study conducted at the University of Auckland in New Zealand, along with the University of Dalhousie in Nova Scotia simulates just how these affect a certain species. Humans are a huge threat to the biodiversity of the world’s ecosystems. We are a main cause of rapid global warming because we emit such large amounts of carbon dioxide and other pollutants. Also, humans cause habitat fragmentation, or the destruction of habitat, for reasons such as land development and agriculture. Another reason that follows is due to overexploiting the lands resources, which means that we harvest a resource to the point where it is destroyed. Camilo Mora displays with multiple simulations of how the effects of human beings can be terrible for the different species of the Earth.

This study was conducted in a way that simulated real life. The specimen that was chosen was Brachionus plicatilis, which is a rotifer species (also known as a ‘wheel animals’) because they are easy to culture in a man-made environment. Also, this species is able to thrive easily in a changing environment, so this species will demonstrate very convincing data because it should show that not even a species such as this can thrive under these conditions. Simulating a natural environment with twelve hour intervals of light and at an average temperature of 25 degree Celsius provided ideal conditions for the growth of this species.

The three suspect reasons of species extinction were all measured individually and in all possible combinations. Warming was simulated by the increase of temperature and was accurate to 0.1 of a degree. The habitat fragmentation was controlled by the amount of immigration of other species. The logic here is that when a habitat is destroyed, the distance between the neighboring habitats has been increased, and therefore there is less migration. Immigration increases the amount of variation in diversity and therefore the species are not able to thrive as easy. Thirdly, the overexploitation was controlled by removing a certain amount of this species. This is because when one takes away all the resources, one also takes away many individuals of that species and in turn, the species loses diversity in itself and therefore are less likely to thrive. Instead of taking away the species indirectly, it has been done directly.

It turns out that all the variables of this study had a negative effect on the populations of the future generations, although certain combinations had an effect that was not just adding the two together. For example, for both individual effects of warming and deprivation of immigration there were about 15 percent decline. One would expect a decline of 30 percent. Although, the results show that there was an approximate 50 percent decline. This was also true for warming and overexploitation there was a 50 percent decline in the populations of future generations. However this was not true for the combination of overexploitation and deprivation of immigration. This only had an additive result, in other words, the two 15 percent declines were added together to make about a 30 percent decline. When all three variables were applied to the populations, there were not any significant declines, even though it was the most dramatic decline of about 70 percent.

It is concluded by these researchers that warming was the greatest factor in the extinction of species. However, all of the variables had a significant impact on the population of this certain species. These variables are very real conditions in today’s environment. Global warming is only increasing, along with overexploitation and land clearing. Pollution is increasing drastically, and humans are only using more and more resources and clearing more and more land. These are perfect conditions for the extinction of many species, and these are partly the reasons for recent extinctions. To prevent the extinction of further species, human’s as a whole must cut down on the emission of pollution, and things such as deforestation, land clearing and development.

Work Cited

Mora, C., Metzger, R., Rollo, A., Myers, R.A. 2007. Experimental simulations about the effects of overexploitation and habitat fragmentation on populations facing environmental warming. Proceedings of the Royal Society B, 247: 1023-1028.

Measuring the surface temperature of trees

Trees are useful to the urban environment because they help cool the atmosphere of the city. The cooling effect of trees is an alternative solution to reduce the costs of air condition and to overall save money. Although trees are beneficial as they can reduce the temperature of warming climate, some trees have better cooling effect than others within cities of certain temperature range. Planting the right tree in the right location is critical to maximizing the efficiency of the trees ability to reduce temperature in warming climates. Not all types of trees have the same cooling effects and the heat tolerance for tree survival could be an issue in seasonal climates (Jenerette et al., 2007). The question arises to which tree will benefit urban environment most? Or How do we determine what species of trees is suitable for the conditions in urban areas? A study was done to determine the temperature of the upper regions of trees through a simple data set. This data provided a comparison between the trees within the streets of the city Basel and the trees within the parks.

The experiment "Tree surface temperature in an urban environment" was lead by Sebastian Leuzinger along with Roland Vogt and Christian Korner. It was conducted in the city Basel, Switzerland. Leuzinger and his colleagues performed the experiment using a high definition thermal camera and a helicopter. On July 16 2004, the helicopter was flown over the city Basel and the thermal camera was used to record the temperature of the city between the times of 11:44 and 12:10 CET (This was done to reduce the shadows created by the trees). The experiment was conducted in the temperature of 298.25K (25.1 degree Celsius). From the observations, Leuzinger was able to differentiate the specific temperature of trees and other objects like rooftops and bodies of water. A thermal image illustrated trees being in the temperature range of 1K below mean air temperature (trees in parks) to 4K above mean air temperature (trees on streets). The rooftops of houses were at 45 degree Celsius and the bodies of water were at around 18 Degree Celsius. Trees with lower foliage temperature would cool their environment more than trees with warmer temperature (Leuzinger et al., 2009).

According to the experiment presented, it did not specify exactly who did what during the experiment and what was contributed by whom. Instead it was assumed that Leuzinger and his colleagues worked together to produce the results of the experiment. From the results of the analysis, it was shown that trees with particularly smaller leaves have a lower surface temperature than trees with larger leaves (leaves with bigger surface area). This information helped to conclude that urban environments require more trees with smaller leaves to aid in the cooling of cities at high temperatures.

Trees with small leaves such as Roinia pseudoacacia and Pinus sylvestris have relatively low temperature in Basel and it would be recommended to have more of these species of trees within the cities of Basel. The trees’ effect for cooling may rely on factors such as the anatomy of the leaf of a tree. From the work done by Sebastian Leuzinger and his colleagues, the leaves from the trees are an important factor to investigate when trying to determine the right species of trees to have within a warming urban climate. Methods to help support urban vegetation may be to grow trees on top of rooftops to allow the reduction in temperature and to ease the complaints of human discomfort.

As the result of this experiment, we can acknowledge that the work done by Leuzinger, Vogt and Korner was an important message that illustrates how crucial it is to have urban vegetation. Trees are the solution to not only recycle the air quality but also to provide a cooler atmosphere within the urban environment.



Reference
Leuzinger S., Vogt R., Korner C., 2009. Trees surface temperature in an urban environment. Agriculture and Forest meteorology 150, 56-62.
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Decline in Whale Shark size

Many of our marine species are being harvested and the overfishing is affecting the way our aquatic friends are growing and maturing. The biological processes of marine fish have been severely disrupted and the main portion of this study is about the size or more specifically the decrease in size of Whale sharks in the Ningaloo Reef, Australia over the past decade. According to this examination our over harvesting of whale shark has significantly decreased the size of the species by nearly 2 feet in the past 8-10 years. Is over harvesting the main reason for this and if so can we stop it?

This study is important to understand that marine species harvesting may cause the species to be more susceptible to extinction. The whale shark has become much smaller and the main suspect of this is size selective fishing, which is removing particular size classes of a marine species. The larger whale sharks are being harvested over the smaller ones. This may change the population’s age structure, growth and maturation rates. “Changes to demographic rates and the evolutionary patterns induced by size-selective fish- ing can increase extinction risk in harvested species” says Jennings about the selective harvesting.

The whale shark is the world’s largest fish and that is why the decrease in the size of them has been very shocking. The whale shark like most sharks grow slowly, matures late, and has extended life spans. Such traits are likely to limit annual recruitment and increase susceptibility to over-exploitation by humans, adds Smith and Bradshaw. With the whale shark size decreasing the main suspect is the overfishing of larger species, which in turn cause breeding of the whale shark to become between only smaller ones. Ratner and Lande state, there are three main mechanisms that may drive changes in body size of harvested populations: (1) abiotic factors affecting growth and development (e.g., large-scale climate or regime shifts); (2) biotic changes such as density-modified growth rates and (3) changes to demography and genetic composition via harvesting.

The sharks were studied in much detail and many other factors were taken into consideration when tracking them. The study had spotter planes used with boat skippers and in-water shark spotters all with experience in the field of shark tracking. The pilots estimated the lengths but they collaborated with the boat skippers and further validation of the whale shark size was done with the snorkelers. Lengths of sharks were only accepted when all the groups agreed. The presence of the snorkeler does not influence the shark’s behavior and the vessels also used strict rules. This ensures that pa- trons do not approach within 3m of the shark while snorkeling, and vessels must remain a minimum of 30 m from the shark for a maximum of 90 minutes, says Davis. Tracking the same shark was taken into account and so was the weather the shark was found in. They made sure they did not affect the sharks behavior and lifestyle.

Fig. 1

(Credit: http://journals2.scholarsportal.info/tmp/15565618855922104545.pdf)

Many whale sharks were tracked; in fact the study made one of the largest ever databases of whale sharks. The study used a lot of math and used graphs and equations to create important ways to contrast and compare the whale shark size and change. Four linear and non-linear models were made to compare the lengths of the sharks across the years. The whale lengths from 1995-1996 differ greatly to that of 2003-2004 with many of the larger whale sharks decreasing in size. The 1995 sharks averaged a length of 7.0m. In 2004 the sharks average length decreased to only 5.4m in length. These changes go along with the studies idea of over harvesting of fish because the larger fish are disappearing faster then the other sizes.

The team suspects the whale shark fishery of Southeast Asia the reason for most of the harvesting. Chen and Phi-pps add, the commercial harvest of whale sharks principally supplies markets in Taiwan, where fins (preferably from large individuals) are used for soup and the flesh is sold for human consumption. The examiners believe this to be the main reason for the fish decrease. Although Taiwan has recently halted the commercial harvest of the species, with other countries doing the same. They still suspect illegal and legal exploitation of whale sharks in much of Asia.

With many of the whale shark commercial harvesting companies slowing down or coming to a halt the whale shark should have a better chance of survival. The study believes a slow but coming change in the downward trend in whale shark size because of the exploitation coming to an end. They still want to be precautionary and proactive about adopting more conservation efforts for the all-marine species. Whale sharks are protected in all Australian waters, to truly save the marine species we need to become international to have fish mortality decrease. The experimenters hope to potentially see entire ocean basins protected and an increase in tagging to identify and learn more about whale shark living.

By: Tashi Nanglo

Works Cited

Bradshaw, Corey . "Decline in whale shark size and abundance at Ningaloo Reef over the past decade: The world’s largest fish is getting smaller." Science Direct (2008): 12. Web. 13 Oct 2010.

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A Flower's Importance in Our Climate

We may picture flowers as delicate symbols of beauty; however flowers are much more than meets the eye. In a recent study at the University of Chicago it was discovered that not only are flowering plants beautiful, but also they play a vital role in maintaining our climate.

When plants use photosynthesis to create food they must "breathe in" carbon dioxide, but in order to do so they must also lose water. This water is then evaporated into the air in a process called transpiration. The amount of water lost and carbon dioxide gained is closely related with the amount of veins a plant has within its leaves. Much of transpiration happens within a plants leaves and the higher the concentration of veins within those leaves means more water lost and carbon dioxide gained. Angiosperms (flowering plants) have leaves with many dense veins that cause them to transpire more than other types of plants, allowing them to recycle more water back into their environment.

C. Kevin Boyce and Jung-Eun Lee headed the study performing several simulated scenarios investigating the impacts of removing angiosperms from certain ecosystems. Two different ecological and atmospheric models were used to produce data that were then coupled with previously observed data concerning average rainfall and temperature. Results were particularly shocking in rainforests, which are more abundant in species and number of angiosperms than any other type of ecosystem. Angiosperms near the Amazon increased rainfall in the driest month of the year by 20 mm and decreased the length of the dry season dramatically. However, angiosperms also worsen the monsoon season, but lengthen the overall wet season by as much as 85 days. More rainfall allows plants to flourish and grow rapidly which allows for heightened plant biodiversity. More plant biodiversity means more animal biodiversity; herbivores that are attracted by the variety and abundance of plants will in turn attract predators attracted by the variety and abundance of prey. Also, due to the increased moisture produced by flowering plants, many ecosystems that contain a large amount of angiosperms have high air humidity. High levels of humidity maintain ecosystem temperatures by cooling the air temperature during the day and by allowing them to retain heat given off by the sun at night.

Boyce and Lee demonstrate in the figure below how average temperature would increase without angiosperms present in the Southern American rainforest (red-dotted line) as opposed to observed and simulated temperatures of the ecosystem with angiosperms (black and blue lines respectively).


Figure 1. (Boyce and Lee 2010)

Temperatures are observed as being consistently several degrees colder in ecosystems that contain angiosperms in comparison to the same ecosystem where angiosperms have been removed. There is a particularly large disparity between the temperatures in October the start of the rain season where increased rain provided by flowering plants is necessary to maintain temperature.

It may be that flowering plants help increase rainfall, maintain temperature and promote biodiversity, but what does this mean for us? Without angiosperms many environments we live in would probably have a much different climate. The increased humidity produced by angiosperms would cease to exist meaning increased air temperature during the day and much lower temperatures at night. The Earth, especially in tropical areas such as the rainforests of South America, would be much drier without flowering plants due to a shorter rain season. Plant growth and diversity would be compromised by the lack of rainfall and the abundance of plants would diminish. Rainforests also recycle a large portion of the Earth's oxygen, removing carbon dioxide from the atmosphere. Fewer plants in these rainforests would mean less carbon dioxide recycled which would more than likely contribute to higher temperatures all over the Earth. Therefore, flowers not only help maintain Earth's temperature, but they also prevent it from increasing. Angiosperms also play an important role in industry. For instance, in agriculture almost all produce are angiosperms such as corn, wheat and apples. Many farmers rely on rainfall for the growth of their crops and look to angiosperms to produce feed for their livestock. Flowering plants are an essential part of the world's ecosystems and our lives, providing stabilized climates, increased rainfall, heightened biodiversity and are essential elements in our diets.

References:


Boyce, C.K., Lee, J. 2010. An exceptional role for flowering plant physiology in the expansion of tropical rainforests and biodiversity. Proceedings of the Royal Society B, 277: 3437-3443.

Green practices at public health conferences could be greener

The environment’s wellbeing and the health of the public are related. Thus, it is important for environmentally friendly products and practices to be implemented at public health conferences where the general population can be educated. Simple and cost-effective measures can be taken at these public health conferences (and even in our daily activities) to reduce our environmental waste and the impact we have on the environment.

K.S. Mohindra, a global health researcher of the University of British Columbia in Vancouver, Canada has attended several public health conferences for research. Based on her experiences at the conferences, Mohindra has noted a general increase in the practices of the three important R’s: reducing, reusing, and recycling. A more common trend that Mohindra has noticed is the use of electronics to advertise at the public health conferences rather than paper to reduce the amount of waste created. However, there are still more practices that can be applied and that should be adopted in order to have the smallest impact on our environment.

The American National Recycling Coalition has developed some key strategies more specific to public health conferences that individuals and groups can take. To address the matter of printed materials, they encourage using recyclable signs and limiting the practice of printing on glossy paper, etc. which are difficult to recycle. For food and beverage services, it is best to serve using china glass, however this is often a neglected option due to cost and maintenance issues. Biodegradable disposal and composting should be available if non-reusable items must be used. Garbage bins and recycling bins with the appropriate labels (paper, glass, etc.) should be distributed and placed in key locations. The attendants of the public health conferences can also be educated on green practices through short speeches, displays, and other channels. At the end of a conference, the effects and/or results of the green practices can be evaluated and altered for future conferences. This list of green practices can be applied at the public health conferences with a small impact on budget, while its effects would have a strong impact on reducing environmental waste.

It is important to ensure that the green practices being applied really are green. A situation this applies to is the placing of reusable plastic water bottles in conference kits, according to Mohindra. The intention of giving the plastic bottles is to reduce waste caused by bottled water; however, depending on the plastic the water bottles are made of, they can suggest recycling and health problems. Recyclable materials are labeled with numbers 1-7 depending on the plastic it is composed of. Mohindra claims that the reusable plastic bottles she receives in the conference kits are mostly comprised of plastic #7 – often polycarbonate or a mix of other materials. This plastic is very difficult to recycle. Plastic #7 is usually, but not always, polycarbonate, a plastic known to leach the chemical bisphenol A (BPA) into water. BPA is believed to have harmful health effects as it can act as a hormone disruptor in the body. Polycarbonate, with its recycling and possible health problems associated with it, should be avoided. The best alternative for reusable water bottles are stainless steel bottles because they have been proven to be the safest material to drink from, yet these can be costly. Alternative options for the issue of water bottles could involve encouraging conference attendants to bring their own reusable water bottles, selling reusable water bottles, and donating unwanted bottles.

There are several alternative methods and options we can choose when considering on taking a more environmental approach towards something. Because there is a relationship between the public health and the environment, greener practices should be implemented at public health conferences. These practices, whether it includes using electronics for advertisement or having biodegradable disposal and composting services, would educate the public and hopefully encourage individuals to reevaluate their actions which affect the environment. Although some of the greener practices at conferences require a little more effort or money, they can reduce our waste and consumption of resources and reduce our impact on the environment.


Works Cited
Mohindra, K.S. "Greening Public Health Conferences: Educating Ourselves." Health Education 108.4 (2008): 269-71. Print.