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Assignment VI: Comments still no responses recorded.

Assignment V: FINAL DRAFT

Representing the second largest kingdom of life on earth and arguably the most important, plants are responsible for the existence and current survival of essentially every living and extinct multicellular organism. Plants are responsible for: the vast majority of oxygen present in earth’s atmosphere, providing nourishment throughout trophic levels within an ecosystem, as well as assimilating diversity in a variety of environments. Perhaps, the most prevalent characterization of plants is the notion that the chief method utilized in obtaining nutrients is solely photosynthesis. It is accurate to say that all members of this kingdom have the capacity to photosynthesize, but a number of plants engage in a variety of strategies in acquiring the bulk of their nourishment. Hence, depicting this group simply as producers is a misrepresentation of this kingdom as a whole. It neglects to include plant species that employ unconventional methods of acquiring the energy they need. These unusual plant species are classified into two categories: parasitic or carnivorous (“Carnivorous Plants,” 2011). Specifically, those depicted as straddling the fence between producers and consumers, carnivorous plants have evolved a trapping mechanism dedicated to capturing prey. Intermingling forces of strong ecological pressures and coerced nutritional adaptation have commissioned the rise of trapping mechanisms in a variety of plant species; these specialized structures have diverged and modified, resulting in the evolution of botanical carnivory as the primary approach of obtaining energy within these certain plant species. As mentioned in his article, “Carnivorous plants: phylogeny and structural evolution” Albert depicts that the botanical carnivory in these plants was a direct result from evolutionary agents (natural selection) acting on already existing variation (Albert et al. 1992). The analysis on carnivorous plants is to determine the specific ecological selective pressures that drove the nutritional adaptation of these plants to carnivory, which gave rise to the formation of a specialized trapping mechanism within this group. In addition, this analysis will provide a better understanding to the diverse trapping mechanisms throughout genus’s belonging to the carnivorous plant classification. Strong environmental pressures exerted upon certain members of this kingdom have been driven to a forced nutritional adaptation, in which they must modify ways in acquiring the necessary nourishment or succumb to extinction. The result of this coerced adaptation among plant species is the rise of a specialized morphological trapping device. This specialized structure is diverse among different carnivorous plant species, all of which ranging in complexity and methodology. These distinct means of obtaining sustenance through predation, in regards to the mundane photosynthetic approach are indicative that these environmental conditions have a strong selection against obtaining energy via photosynthesis and favors botanical carnivory as the chief method of acquiring nutriment (Albert et al. 2004). Carnivorous behavior in plants through their mode of procuring nourishment has evolved independently six times in five various lineages, exhibiting the presence of convergent evolution for this specialized strategy within this kingdom. Carnivorous plants are distinguished by their ability to attract and capture their prey through utilization of a trapping mechanism, followed by their capability to digest the recently captured prey, typically initiated by the release of enzymes (Albert et al. 1992). Eventual speciation of these plants, contributed by the divergence of the various trapping mechanisms interacting with slightly variable environments is facilitated by the rise of these numerous specialized physiological structures of these various plants, over time or being acted upon by an agent of evolution (selection, migration, bottleneck- if others of same species don’t adapt to carnivory). In the majority of carnivorous plants, these modified leaves has evolved with explicit intentions of ensnaring and securing prey. As a result of this dedicated structure, the plant typically becomes slightly inhibited in acquiring nutrients through photosynthesis, accompanied with enduring costs in energy due to creating and operating the trapping structure (Ellison and Adamec, 2011). Maintaining an evolutionary standpoint, one must question whether the costs of carnivory nutritional adaptation outweigh the predominant autotrophic methodology? These predatory plants more than often take up root in flooded areas with famished soils in which retain a limited supply of nutrients. The standard soil harboring these carnivorous plant species customarily maintains a relatively low pH with limited exposure to the sun. Provided a standard model of the common environment conditions at play in the habitats of carnivorous plants, some light can be shed on the environmental pressures that contributed to compelling these species to diverge from merely producers to employing botanical carnivory. The relationship between the environmental conditions and carnivorous plants exhibits positive Darwinian selection for the reason that these harsh ecological pressures compel these plants to undergo an adaptation, without which they will surely perish. The evolution of the trapping mechanism in carnivorous plants inhabiting these famished soils displays remarkable positive selection, in the sense that due to this adaptation in the plants’ methodology of acquiring food, these species are now able to thrive (Albert et al. 2004). The five trapping mechanisms encompassing carnivorous plants are: fly-paper traps, snap traps, pitfall traps, lobster-pot traps, and suction traps. The fly-paper trap is perhaps the simplest trapping mechanism The fly-paper trap mechanism is embodied in sundews which attract insect with its vibrant leaves, once landed, its many tentacles located on the modified leaves entrap the insect and simply bend in the direction of the insect ensuring its capture. The Venus fly trap is representative of the snap trap mechanism. Snap traps rely on two symmetrical leaves that, in essence swallow the prey once the hairs bordering these modified leaves have been stimulated (Poppinga et al. 2013). Results from phylogenetic evaluation of plants possessing Snap trap mechanisms verified that the snap trap mechanism evolved from fly-paper traps. The pit-fall trap mechanism, a rather complex trap is portrayed by monkey cups, the modified leaf of this trap takes the form of a pitcher, in which houses a vat of digestive fluid. The trap attracts its prey through bribes of nectar and in some cases, its coloration (Giusto et al. 2012). The rim of the pitcher is slippery and often results in aquaplaning of the prey into the central opening containing the digestive fluid (Bauer et al. 2012). Plants possessing the lobster-pot mechanism typically dwell in heavily flooded habitats for the reason that its modified leaves are beneath the water’s surface. These modified leaves, in a sense form an inescapable maze which direct its prey to a digestive cavity due to inner-directed hairs encompassing the anatomy of these specialized leaves. Suction traps represented by bladderworts are the most complex and largest genre of carnivorous plants. These traps rely on a dedicated bladder responsible for entrapping prey. Once stimulated by an insect the plants’ bladder immediately swells and creates a strong pull in which nearby prey are absorbed and consumed. In essence, the evolution of these specialized trapping mechanism exhibits a positive selection towards these respective species. Their coerced adaption for botanical carnivory due to selective environmental pressures lead to greater genetic diversity, specifically in the form of speciation via the pitcher plant Nepenthes (Bauer et al. 2012). The rise of trapping mechanisms in carnivorous plants represents convergent evolution, as it has arisen independently on six occasions in five different lineages. In addition, it also directly correlates with evolutionary biology for the reason that evolution is driven by selective pressures, predominantly environmental ones. The evolution of trapping mechanisms in plants is an exceptional example of positive Darwinian selection, in the sense that carnivorous plants became the best adapted to the environment in which they inhabited. These organisms inhabiting already famished soil, forfeited photosynthesis as their primary method of obtaining nutrients due to low exposure to the sun, and as a result evolved a trapping device from a modified leaf to serve as an alternative tactic to obtain the necessary nutrients (Ellison and Adamec, 2011). The demographic of carnivorous plants truly made the best of the situation they were given, through enduring strong environmental pressures and developing an adaptation in which would permit them to survive. As mentioned in his article, “Form follows function: morphological diversification and alternative trapping strategies in carnivorous Nepenthes pitcher plants” Bauer depicts of the carnivorous pitcher plant, Nepenthes as exhibiting an ideal speciation event for evolutionary biology as there are currently over one hundred different species, all of which diverged recently from a single species originating in Malaysia. This speciation event was reinforced by a recent examination executed by Bonhomme, as depicted in his article “Slippery or sticky? Functional diversity in the trapping strategy of Nepenthes carnivorous plants” in which he investigated 23 different taxa belonging to the Nepenthes genus and their pitcher walls. In the study, Bonhomme concluded that the wax located on the inner pitcher wall varied immensely (Bonhomme et al. 2011), which is remarkable for the reason that they all share diverged recently from a single species. Due to this analysis on the evolution of the trapping mechanism within those species classified as carnivorous plants, the botanical carnivory adaptation was a direct result of increased ecological pressures of the habitat in which these species dwelled. It is also apparent there is a selection against plants that only use photosynthesis within this habitat as well as a preference for botanical carnivory by selection, outlining the benefits of creating and operating a trapping mechanism within this environment outweigh the costs. From a combination of nutrient-deficient soil, lack of sun exposure and an increasing pressure to either evolve or face extinction, carnivorous plants adapted and gave rise to trapping mechanisms. Due to this evolved structure they experienced positive Darwinian selection, for the reason that they adapted the best with their capabilities. In addition, carnivorous plants also contributed to genetic diversity through evident speciation in the pitcher plant genus, Nepenthes exhibited through the divergence of 100 species from one common and recent ancestor.

Assignment IV: EDIT

article: https://en.wikipedia.org/wiki/Carnivorous_plant

Contribution: Evolution "The rise of carnivory in these plants represents convergent evolution for the reason that it rose in five independent lineages. The leading theory that drove these plants to develop a botanical carnivory strategy was due to intense ecological pressures. Predominately these factor include nutrient deficient soil, lack of sun exposure and strong selection to either adapt of face extinction. As an end result these various plant species chose to adapt and through time have evolved complex structures and strategies that contribute to their evolutionary success."

Assignment III: no comments submitted :(

Assignment II edited article: https://en.wikipedia.org/wiki/Carnivorous_plant

Suggestions:

1. Highlight the existing environmental factors that lead to the evolution of these specialized pitfall traps.

2. Distinguish the structural difference between the 'Old World' and 'New World' pitcher plants in the genus Nepenthes.

3. The varying degrees of visco-elasticity (waxiness) between pitcher plants; relative investment (cost-benefit) of trapping mechanism in comparison to photosynthesis.

Addition: ‘Old world' pitcher plants (genus: Nepenthes) are typically characterized as having reduced and symmetrical pitchers with a comprehensive waxy coating on the surface of the inner pitcher wall

Citation:

Bauer, Ulrike, et al. "Form Follows Function: Morphological Diversification And Alternative Trapping Strategies In Carnivorous Nepenthes Pitcher Plants."Journal Of Evolutionary Biology 25.1 (2012): 90-102. MEDLINE with Full Text.

Assignment I

Mitch Coale Yue Zhang TR 4:10-5:05 pm EEOB 3310 9/15/14 Annotated Bibliography Topic: The evolution of the trapping mechanism of terrestrial carnivorous plants

Albert, Victor A., Stephen E. Williams, and Mark W. Chase. "Carnivorous plants: phylogeny and structural evolution." Science 257.5076 (1992): 1491+. Academic OneFile. Web. 13 Sept. 2014.

The following authors present an analysis on the phylogeny of carnivorous plants, highlighting the discovery of an unconventional nucleotide sequence. They hypothesize that this specific nucleotide sequence is indicative that there exists independent evolution among the lineages of these various angiosperms. The authors reiterate that their distinctive carnivorous characteristic rose independently from their notorious “trap” mechanism. In addition, the authors also specify a degree of classification of trapping among these lineages due to their morphological qualities of: digestion, method of trapping and attraction.

Albert, Victor A., Richard W. Jobson, Rasmus Nielsen, Liisa Laakkonen, and Mårten Wikström. Adaptive evolution of cytochrome c oxidase: Infrastructure for a carnivorous plant radiation. PNAS 2004 101 (52) 18064-18068; published December 13, 2004, doi:10.1073/pnas.0408092101

The authors endeavor to describe the reasoning behind the significant increase in the evolutionary rate of the trapping mechanism of land dwelling carnivorous plants, specifically the increase in cytochrome c oxidase. The authors depict this is a result of Darwinian selection. In addition, the authors compare these on land carnivorous plants to that of aquatic ones, highlighting a major factor in their trapping evolution is due to environmental adaptation. Their findings suggest that the physical and morphological advances in trapping mechanisms are a direct result of adaptation in specific proteins.

Bauer, Ulrike, et al. "Form Follows Function: Morphological Diversification And Alternative Trapping Strategies In Carnivorous Nepenthes Pitcher Plants."Journal Of Evolutionary Biology 25.1 (2012): 90-102. MEDLINE with Full Text. Web. 13 Sept. 2014 In this article, the authors examine the evolution of the pitcher trap mechanism of tropical pitcher plants, specifically the slippery surfaces responsible for catching prey. The most notable characteristic of the tropical pitcher plant is that of a stem similar to a pit, with an internal slicked slope responsible for catching prey through an event characterized as insect aquaplaning. Through analysis of trap morphology, the authors hypothesize that environmental adaptation is responsible for the representation of one of the two mechanism styles of the carnivorous pitcher plant through forced speciation.

Bonhomme, Vincent, et al. "Slippery Or Sticky? Functional Diversity In The Trapping Strategy Of Nepenthes Carnivorous Plants." The New Phytologist 191.2 (2011): 545-554. MEDLINE with Full Text. Web. 13 Sept. 2014. In this article, the authors describe their analysis on a recent study on the pitcher walls of 23 various taxas of Nepenthenes, specifically the digestive fluid coated on the inside walls. In the findings of the study, the retention efficiency of the digestive fluid varied greatly among those evaluated. The authors hypothesize the viscoelasticity of this fluid is responsible for the different success rates of these plants. The authors believe there exists selection pressures and trade offs that are to contribute to these differences in digestive fluid viscoelasticity and retention efficiency.

Ellison, Aaron M., and Lubomír Adamec. "Ecophysiological Traits Of Terrestrial And Aquatic Carnivorous Plants: Are The Costs And Benefits The Same?."Oikos 120.11 (2011): 1721-1731. Academic Search Complete. Web. 13 Sept. 2014. Throughout this article, the authors describe the tradeoffs exhibited in carnivorous plants, noting the cost-benefit comparison between photosynthesis and nutrient collection. Roughly 10% of terrestrial carnivorous plants are displaced by their aquatic rivals. In addition the authors also note of the nutrient limitation apparent among land dwelling plants. The authors describe the cost-benefit of the trapping mechanism in comparison to the conventional photosynthesis. Although no significant findings are recorded, the authors provide an additional perspective into analyzing the trapping mechanism through comparing the evolutionary cost-benefit comparison between carnivory and photosynthesis.