An ecologist studying plants in the desert performed the following experiment. She staked out two identical plots, which included a few sagebrush plants and numerous small, annual wildflowers. She found the same five wildflower species in roughly equal numbers on both plots. She then enclosed one of the plots with a fence to keep out kangaroo rats, the most common grain-eaters of the area. After two years, to her surprise, four of the wildflower species were no longer present in the fenced plot, but one species had increased dramatically. The control plot had not changed. Using the principles of ecology, propose a hypothesis to explain her results.
Explanation:
- This example highlights the impact of plant predation on species selection. In the fenced off plot animal predation is not a factor on plant selection.
- In this case plants will compete for resources only with each other and in this case one plant had a selective advantage over the other 3 species of plants. In the plot exposed to animal predation the ratio of the four species is equal.
- This is likely do to an increased preference of animals for the plant species that dominates in the fenced off plot and/or anti-animal predation tactics by the other three species.
a.Hypothesis: kangaroo rats are keystone species
-Reintroduce kangaroo rats (and the other locally extinct species)
-Should observe equilibrium re-established
b.Hypothesis: kangaroo rats exert top-down control on community
-Reintroduce kangaroo rats (and other locally extinct species)
-Increase kangaroo rat population in other plot
-Decrease (but don't eliminate) kangaroo rat population in other plot
c.Hypothesis: Locally extinct species inferiorly competed with the extant species of plant
-Remove surviving species from other plot (and remove kangaroo rat population)
Gene, as such traits are passed down through genes
Hello,
Please find below a short summary on the subject you have been assigned. This will help you in completing your project and also give you an overview on the current research on this subject.
Food additives are chemical substances added to food in order to either maintain or improve its physical characteristics such as taste, texture, appearance and even freshness.
The long term effects that these substances have on the human body are still largely unstudied. According to the hypothesis called "chemical obesogen", these synthetic compounds are contributing factors to the global obesity epidemic.
Although evidence-based scientific research is still lacking, the support for this hypothesis is growing as many of these additives have been found to disturb the body's endocrine functions.
Furthermore, artificial preservatives used today may increase the risk of inflammatory bowel disease. This has been shown by a study on mice in which the food additives known as emulsifiers (carboxymethylcellulose and polysorbate-80) have been shown to affect the animal's health.
Due to these chemicals, the mice not only became obese but also developed metabolic problems such as glucose intolerance. It seems that these chemicals affect the gut bacteria population in a negative way, as mice lacking gut bacteria did not become ill.
The mice study was followed by another study in which the human simulated through a series of flasks. Under the influence of the emulsifiers arboxymethylcellulose (E566 on EU labels) and polysorbate-80 (E433), the levels of bacterial protein called flagellin increased. This protein is known to cause inflammation at high concentrations. The next step in the study will be the first human trials.
Due to the long road our food takes from the farm to our table more extensive research is required. There are thousands of compounds that change the biochemical properties of the plants and animals that constitute our diet. The effects of the degradation and accumulation of these compounds are still unknown and thus many more studies and approaches are required in order to insure healthy food and stop the current obesity epidemic. Everything that is added to our food should be carefully analyzed.
Answer: (B)
Explanation: They are asking for a comparison between light waves and sound waves.
A and C is wrong because it only says about sound waves
D only says about sound waves
E is completely wrong because they are affected differently in different mediums.
