COEVOLUTION WITH PARTICULAR REFERENCE TO HERBIVORY
Of all the extant organisms in the world, it is believed that terrestrial plants and their natural ‘enemies’ constitute more than forty percent. Moreover, plants exhibit a remarkable diversity of supposedly defensive characteristics including trichomes, spines, silica, secondary chemical compounds, temporal avoidance of enemies, and structures along with chemicals that attract predators of their natural enemies. In addition, the exploitation of the plants and their defences is facilitated by a vast number of behavioural, morphological and physiological adaptations by herbivores
Accounting for this diversity has been a major area of research for nearly a century. The seminal article, attributing this diversity to coevolution, was published in 1964 by Ehrlich and Raven. They suggested plants and herbivorous insects evolved reciprocally by the following events: Plants, through occasional mutations and recombinations, produced a series of chemical compounds not directly related to their basic metabolic pathways. Some of these compounds, by chance, serve to reduce or destroy the palatability of the plant in which they are produced. Such a plant, protected from the attack of phytophagous animals, would in a sense have entered a new adaptive zone. Evolutionary radiation of plants might follow.
If a new recombinant or mutant appeared in a population of insects that enabled individuals to feed on some previously protected plant, selection could carry the line into a new adaptive zone. Here it would be free to diversify in the absence of competing herbivores. Ehrlich and Raven (1964) emphasised the importance of the reciprocal selective responses between ecologically linked organisms.
Since 1964, studies have questioned Ehrlich and Ravens postulates. Due to the nature of evolutionary study, ideas are only as strong as the background in the literature; that is, acceptance by the scientific community depends upon its knowledge. In time people learn more and previously weak theories become more feasible. Alternatively, and more so in science, accepted work in time becomes disregarded (example; until the 1950’s geologists believed in static continents, now all believe in plate techtonics and continental drift). The significance of this is that any theory published is only speculation of what is happening in these in...
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 Vail, SG. (1992) Selection for overcompensatory plants responses to herbivory: A mechanism for the evolution of plant –herbivore mutualism. Am. Nat.139(1) 1-8
 Van Valen note: get Van Valens 1973 red queen hypothesis reference.
 Vermeij, GJ. (1994) The evolutionary interaction among species: Selection, Escalation and Coevolution. Annu. Rev. Ecol. Syst. 25 219-236
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However, evidence such as fossils is more than enough to lend support and disprove any other theory to the development of species. Examples used by Root-Bernstein and McEachron also provide strong support to evolution. The authors detail how natural selection works in both insects and germs to create organisms better adapted to methods of control. Disease used to run rampant, until the creation of vaccines which led to many diseases becoming extinct. Root-Bernstein and McEachron note that the diseases that have survived to this day have been constantly mutating and evolving to become more resistant to any attempts at suppression. The same can be said for insects that have been consistently exposed to pesticides. The ones that survived the pesticides were able to reproduce and pass along a resistance to their offspring which in turn makes the species more resilient and better suited to their
Many variations and species of plants can be found all around the world and in different habitats. These variations and characteristics are due to their adaptations to the natural habitat surrounding them. In three of many climatic zones, the arid, tropical and temperate zone, plants that vary greatly from each other are found in these locations. In this experiment, we’ll be observing the connection between the adaptations of the plants to their environment at the Fullerton Arboretum. The arboretum is a space containing numerous plants from different environments. The plants are carefully looked after and organized into their specific habitat. Therefore, we’ll be able to take a look at the plants within multiple
Thomas R. Warne, Leslie G. Hickok and Rodney J. Scott. (1988). Botanical Journal of the Linnean Society. Characterization and genetic analysis of antheridiogen-insensitive mutants in the fern Ceratopteris. 96 (1), 371-379.
Each plant species has a unique pattern of resource allocation that is genetically determined but not fixed. Plants can adjust there allocation pattern when they experience different environments and the presence of other species. Phenotypic plasticity goes hand in hand with resource allocation as well. When a plant has to adjust itʻs resource allocation, sometimes it uses itʻs resources to help the plant grow different characteristic so that the plant can have a greater chance of living in the environment. For example, if a plant from an environment that does not experience wind on the regular basis enters a new environment that has a lot of wind the plant may change itʻs resource allocation and spend more of itʻs resources growing deeper
Atheistic evolution can be defined as a belief that everything was created without any supernatural phenomenon (God). Atheistic evolution is thus basically the opposite of theistic evolution. One of the most well-known atheists is Richard Dawkins.
Reginald B. Cocroft, of the Neurobiology and Behavior Department at Cornell University in Ithaca, New York, researched insects known as Umbonia crassicornis, or the thornbug treehopper. U. crassicornis offspring thrive in large aggregations on the often exposed stems of host-plants. These offspring are incredibly vulnerable, making them easy targets and subject to intense predatio...
As a result of these factors, the flora has adapted to these conditions in a variety of ways including their shape, leaf type, root system, and color. One of the most prominent adapt...
The lignin in plants also works as a barrier against attack by insects and fungi
The communities of various native plants have been significantly minimized as a result of ...
Baucom, R. & de Roode, J. (2011). Ecological immunology and tolerance in plants and animals. Functional Ecology, 25(1), 18- 28.
It has been noted that intraspecific competitions tend to be more intense than interspecific ones (Ciara, 1993). This is because members of the same species need the same types and amounts of nutrients. When these similar species are in the same habitat with fixed resources, then they consequently have to "fight " for their needs. This is was basis for our hypothesis. We hypopthesized that the species that were involved with the interspecific competitions would have greater production (by ave. weight of grams) than their counterparts involved in the intraspecific competitions. Furthermore, we hypothesized that as the density of the intraspecific and interspecific competition species increased, then the production of the plants (by ave, weight in grams) would go down.
Nicolson, S. W., & Fleming, P. A. (2003). Nectar as food for birds: the physiological consequences of drinking dilutesugar solutions. Plant Systematics & Evolution, 238(1-4), 139-153. doi:10.1007/s00606-003-0279-7
Milewski, A.V. and R.E. Diamond. 2000. Why are very large herbivores absent from Australia? A new theory of micronutrients. Journal of Biogeography. 27(4): 957-978.
If you look at any standard definition of atheism, as a movement or as a commonly-accepted worldview, it's usually something like 'the rejection of theological claims of the existence of a god or gods'. Atheism is probably the most unapologetically 'scientific' worldview, as it uses the scientific method as its starting point - that is, the burden of proof is upon those making the hypothesis (the positive claim about the nature of the universe), which in this case is the particulars of the existence of a god or gods. The atheist position is that no such definitive proof has ever been forthcoming, from any religion or holy book, components of which are often debunked by actual scientific and historical research (which in the sciences would
Insect pollination as we all know, is the process that enables reproduction and fertilization by the transfer of pollen performed by insects. Insects are some of the oldest pollinators of plants. Pollinating insects date back to 140 million years ago. Since then, due to how effective insect pollinators are, these flowering plants have become the major group of terrestrial vascular plants. Flowering plants, also known as angiosperms, have imperative roles within our ecosystems, both natural and agricultural. For instance, insects provide food, fiber and shelter for wildlife and humankind alike (2007). It is commonly know that in humans, high levels of fruit and vegetable consumption are associated with decreased risk of chronic disease (Calderone 2012). Aside from these important roles, plants have also been considered as a viable option for fuel sources (Calderone 2012). There are around 300,00 species of flowering plants in the world and without pollination, the reproductive process would be very difficult since pollination causes the production of seeds (Calderone 2012). Of the 300,000 plant species worldwide, a little over 3,000 of these plants have been used as a source of food. Close to 300 of these species are grown around the world today and only 12 of these plants make up about 90 percent of the food sources in our world. These 12 include the grains...