General Biology

Anna Young

Herbivores are animals that feed exclusively on plants and herbivore damage represents significant annual losses to agricultural production. To combat crop losses due to herbivory, many farmers annually apply insecticides, which can have negative impacts on human and ecosystem health. Many techniques are being tested to reduce the rate of insecticide application while still attaining high yields from crops. his study was done to estimate the impact herbivores had on flowering plants and determine how effective annual insecticide application was on reducing herbivory compared to no application or intermediate application rates. This experiment used goldenrod, Solidago altissima and Phytophagous insects. It was performed in Ithaca, New York. It was planned out to see if the degree to which the herbivore damage done in one year can influence plant performance in succeeding years.

To test this, the experiment had phytophagous insects let loose onto a meadow of goldenrod Solidago altissima.  The experiment started with 6 fields dominated by the goldenrods in Ithaca, New York, USA. The control experiment was to let the herbivore insects dominate the goldenrod field. No insecticides were applied. This was done over a year’s time. Field 2 was measured out and this time insecticides were applied every year for 5 years. The last 3 fields had insecticides applied every 3rd year.

Field one had a heavy herbivore load. There was a large plant damage load. Field two with the insecticides sprayed every year had a different outcome. The insecticides suppressed the herbivores, but not all of them, nothing to cause major damage. Fields 3-6 did not have much of a difference from field two. It suppressed most of the herbivores, as well.

I think the results were interesting. You would think in fields 3-6 that herbivores would dominate the goldenrod fields again and cause plant damage, but that was not true. This disproves the hypothesis proposed in the introduction that herbivore damage done in one year can influence plant performance in succeeding years. I think the insecticides did help the plant growth and it controlled the growth in the following years after applied.

Citations:

Root, Richard B. Hebivore pressure on goldenrods (Solidago Altissima) its variation and   cumulative effects. Ecological Society of America, 1996. Web. 13 Sept 2013                             <go.galegroup.com>

Root, Richard B. Hebivore pressure on goldenrods (Solidago Altissima) its variation and   cumulative effects. Volume 77 Page 1074-1087. Frontiers Editorial. Web. 13 Sept                                  2013<Esajournals.org>

As the of study evolution for plants and animals continues to expand, researchers are able to better analyze how distinct characteristics of both groups can be better understood. For the Venus’s flytrap, Dionaea muscipula, researchers have been able to understand not only why it opens its jaw like mouth, but also how internally it can consume ATP to fuel the closure movement. When an insect becomes allured to the Venus’s mouth, the insect touches one of the plant’s hairs which are sensory structures. As the plant senses the touch of the insect, its receptor potentials from the sensitive hairs produce movement and the mouth, starting at the midrib, closes rapidly. Today, through the research of M.J. Jalle, we will analyze the hypothesis that ATP plays a role in mechanically stimulated rapid closure of the Venus’s-Flytrap.

To test the given hypothesis, Jalle first began research into other plants. After full review of the Venus’s flytrap, researchers were still unable to find the direct source of how it closes, but through the study other plants; researchers were able to find parallel answers. For example, pea tendrils and Mimosa plants both produce similar biochemical rapid movement which both use a contractile ATPase that consumes ATP for movement. Due to the similarity of the movements, these plants were used as a foundation for the study of the Venus’s flytrap movement.

Using that foundation, the following experiment was conducted and produced the given results. When the midribs of untreated traps of Dionaea muscipula are frozen in liquid nitrogen after rapid closure, they contained significantly less ATP than those frozen before closure. Exogenous ATP caused a significant increase in the rate of mechanically stimulated trap closure. Illuminated traps closed faster than those kept in the dark. The traps of plants placed in 100% 02 close much faster than do air controls, while 100% C02 inhibits closure. It is concluded that ATP is probably the native source of potential energy for contraction of the trap’s midrib, and that if the endogenous ATP titer is increased by oxidative phosphorylation or an exogenous source, the trap will close faster.

Through the research produced by Jalle, we are able to view the direct connection between plants that produce movement and how exactly ATP is used by these plants for energy. As the ATP increases, so does the speed of how fast the Venus’s flytrap midrib closes. So with an increase in an energy source, the movement and speed of the plants will increase. According to Thomas Sumner, Venus flytraps are continuously studied to view exactly not only the biological processes behind the closure of the midribs but also the physical one. With the research produced by Jalle, scientists are able to view the reasoning behind both processes.

Citations

Jalle, M.J. The Role of ATP in Mechanically Stimulated Rapid Closure of the Venuss-Flytrap. Diss. Department of Botany, Ohio University, 1972. Web. <http://www.plantphysiol.org/content/51/1/17.full.pdf html>.

Sumner, Thomas. “Inside Science.” Investigating the Venus Flytrap’s Speedy Snap. N.p., 20 Nov 2012. Web. 13 Sep 2013. <http://www.insidescience.org/content/investigating-venus-flytraps-speedy-snap/847>.

The study of the establishment of land plants has been an ongoing research topic for years. The latest accepted study suggests a symbiotic relationship of soil fungi assisting the earliest plants establish themselves on land. The research effort of this study is based only on evolutionary history and fossil record collected throughout time. Humphreys, a writer in Nature Communications, exhibited similar symbolic traits of carbon uptake, growth, and asexual reproduction between arbuscular mycorrhizal fungi (AMF) and historical land plants. If an arbuscular mycorrhizal fungi and an ancient land plant are generated in a lab and grown together to observe a symbiotic relationship, then this relationship can be supported based on the data collected from the experiment.

In this testing procedure, Glomeromycota, a historical fungi, and Marchantia paleacea, an ancient liverwort will be observed for a symbiotic relationship. Non-mycorrhizal plants were grown in AMF-free soil on top of or around AMF-colonized plants. Then, observe the symbiotic relationship conceived. Plants were grown in an ambient CO2 environment, consistent with the early Paleozoic period in which these plants first formed a relationship.

At ambient CO2 conditions, the AMF plants displayed photosynthetic gain. The AMF plants also consumed an increased amount of nitrogen and phosphorus. Increased growth and biomass in the AMF plants revealed the success of the relationship. The AMF plants promoted more asexual reproduction.  Lastly, fungal mycelium grew from the mutualistic relationship of the ancient land plant, Marchantia paleacea.

 The data collected by this experiment provides evidential support of the symbiotic relationship of fungi assisting historical plants move to land. The high CO2 atmosphere played a major role in the mycorrhiza relationships with the early plants. Land plants evolving to life on land, with the help of mycorrhiza fungi, was an important turning point towards the present day world. Photosynthesis of land plants removed CO2 from our atmosphere, contributing towards global cooling, rather than global warming. This made the land possible for animals to become terrestrial and branch into the many evolving species living today.  The collection of this data will help in future research of land plants. It gave a deeper understanding of the evolution of early plants and their move to land.

Sources:

Nature Reviews Microbiology; Jan2011, Vol. 9 Issue 1, p6-6, 1p

Humphreys , C.P. “Mutualistic mycorrhiza like symbosis in the most ancient group of land plants..” 103. (2010): n. page. Web. 24 Sep. 2013.

Allison Bankston

Blog #1

In our first couple weeks of classes we have been talking about land plants. Land plants include bryophytes such as mosses, lycophytes, pterophytes (ferns), gymnosperms (i.e. conifers), and angiosperms (flowering plants).  I decided to do some research on land plants, and were they have first appeared. Today land plants have diversified into numerous forms but their evolution and role in the formation of early ecosystems remains unclear.

It is hypothesized that large-scale removal of CO₂ – a greenhouse gas – by early plants may have contributed to the initial cooling of the planet and climate changes such as the ice ages. Scientists did experiments to see how these plants were causing Ice Ages and other climate changes. The scientists did an experiment with rocks and moss, and incubated it for three months. This is how they determined what the plants were doing. If it weren’t for this experiment they would not have a clue to what was causing all these climate changes.

Some scientists suspected the “first plants to take root on dry land cooled the Earth and brought Ice Ages.” The scientist figured out that the plants “drew down atmospheric carbon, by clinging to rocks and dragging the rocks down.”  What they mean by this is that plants are extracting inorganic nutrients from the rocks, taking the minerals out of the abiotic environment and enabling them to be used by other organisms.

In conclusion, I learned that plants could cause climate changes. Who knew something so small can cause something so large to happen, for instance an ice age. I think scientist need to continue to do more research on land plants to see what else they can cause.

Work Cited

http://www.theguardian.com/science/2012/feb/01/first-land-plants-ice-ages. By Ian Sample. 1 February, 2012. “First Land Plants.

Campbell Biology. Ninth Edition. Reece, Urry, Cain, Wasserman, Minorsky, Jackson. 2011.

Malaria is a blood disease caused by parasites in the genus Plasmodium. A female infected Anopheles mosquito bites the person and transmits this disease by inserting the malarial parasite into human blood circulation from its saliva. Around 240 million cases of malaria occurred every year worldwide which results in approximately 850,000 annual deaths according to WHO. Treatment used to control malaria can decrease the prevalence of this disease to a great extend, but mosquitoes are obtaining resistance to all pesticides, so a modern and permanent solution is needed. To find out a new solution, researchers tested whether a genetically modified fungus could be an efficient and eco-friendly means to fight malaria.

Researchers have created transgenic anti-malarial fungus, starting with Metarhizium anisopliae, a fungus which attacks mosquitoes naturally. They modified this fungus to carry genes for either an anti-malarial scorpion toxin or a human anti-malarial antibody. Both the scorpion toxin and the antibody attack the parasite Plasmodium falciparum, the most deadly malaria species. After that, scientists compared three different groups of mosquitoes infected by parasite P. facliparum. In first group, they sprayed mosquitoes with the genetically altered fungus. In second group, mosquitoes were sprayed with natural fungi. In last group, they sprayed mosquitoes without any fungus.

Researchers have found that transgenic fungus decreases the parasite growth. Mosquitoes sprayed with transgenic fungus shows a huge reduction in P. falciparum parasite loads. P.falciparum was present in only 25 percent of mosquitoes sprayed with transgenic fungus. While in second group, parasite was present in 87 percent of mosquitoes sprayed with natural fungus. In third group, parasite was present in 94 percent of mosquitoes sprayed alone. In 25 percent of mosquitoes of group one which still had parasites in them, parasites numbers were reduced by 95 percent compared to the mosquitoes sprayed with natural fungus.

This finding is an answer to problem such as resistance to pesticides. Genetic engineering can alter the genetic sequence to convert a harmful organism into useful organism. Genetic modification can be used in the future to combat other diseases, for example Lyme disease and dengue fever.

References:

1. http://newsdesk.umd.edu/uniini/release.cfm?ArticleID=2351

2. Development of Transgenic Fungi That Kill Human Malaria Parasites in Mosquitoes Science    25-Feb-2011.

Hi all, I would like to personally welcome you to our class blog. Here, we will get the opportunity to share with the public some of the amazing biological research that is of interest to you. Biology is a huge field, and our BIOL 1120 class will be covering general diversity, basics on structure and function of plant and animal systems, and basic ecological interactions, so anything from mind-controlling parasites to amazing adaptations is fair game. Have fun with this and show the world how truly awesome the realm of biology is.

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