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)
Seismic waves are waves produced by earthquakes. This occurs
when rocks under the earth suddenly break or explode. There are two MAIN TYPES
of seismic waves called body waves and surface waves.
<span>Body waves have the capacity to travel through the Earth's
inner layers. They have a higher frequency and they are the ones that first
occur under water at the onset of an earthquake. They can be subdivided
into two types, the primary and secondary waves that arrive at seismic records
one after another.
Surface waves can only traverse through the surface of the planet like ripples
in the water. These waves can easily be detected on a seismogram result. These
waves arrive after body waves and they are the ones mostly responsible for
damages and destruction bought by earthquakes.</span>
<span> </span>
Answer:
Plants and other producers generate their own energy, which allows them to grow, reproduce, and live. They are the only living organisms on the planet that can produce their own supply of food energy, which makes them unique. They, of course, require sunlight, water, and air to survive.
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The fossil record shows a sequence from simple bacteria to more complicated organisms through time, it is very reliable because it is physical evidence and by studying fossils, scientists can learn how much (or how little) organisms have changed as life developed on Earth.
That students who study make better grades than those who do not.
