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)
The correct option is B.
In the ecosystem, energy flows from one trophic level to the other. The first trophic level is that of the producers which use the energy of the sun to produce their own food. Out of the energy obtained from the sun by the producers only about 3% of it is converted into food products. The second trophic level is made up of the herbivores and the omnivores which eat the plant. Only about 10% of the energy from the plant is transferred to the animals in the second trophic level. These second trophic level animals will also transfer about 10% of the energy they obtain to the animals in the third trophic level when they are eaten. Thus, it can be seen that the energy that is transferred in the ecosystem is gradually reducing from one trophic level to another.
Answer:
B. CO2 out
Explanation:
The excretion is the process of removal of the waste product from the body. The carbon dioxide is the byproduct of the aerobic respiration, which is carries from the tissues and the lungs by blood. In the lungs at alveoli, the carbon dioxide is transferred from the blood to the lungs and released out through the nostrils. Hence, the out of the carbon dioxide represent excretion through lungs.
I think the answer is C but i am sorry if i am wrong i took this test but i am pretty sure it is C have a good day and good luck on the test
Using the fossil record, you can categorize species based on analogous or homologous structures
