Ecosystem Development and Relationships - AP Environmental Science

Heavy decomposition of plant and animal matter contribute to highly acidic soil in tropical rainforests. Additionally, abundance of plant life in tropical rainforests results in "soil leaching," which means that the nutrients in the soil are drained and taken up by the plants themselves.

Boreal forests have extremely low temperatures and are characterized by pines and other evergreens. "Temperate forests" are characterized by moderate and more fluctuating temperatures, whereas the taiga stays cold year round. Taiga is found in parts of the world such as Northern Alaska, Canada, and Siberia.

Top predators will generally never "grow unchecked". By the very nature of their diet (dependent on other populations), predator population growth is limited by the availability of their food. The famous study of lynx-hare population fluctuations demonstrates how a predator population will adjust to lower prey populations.

Latitude is not considered in climate evaluations; for instance, the poles are considered deserts based on their precipitation levels per year, meaning deserts can occur along the equator or the poles. Temperate and tropical forests also exhibit similar precipitation levels, but due to their temperature differences, they are considered separate biomes.

Though grasslands and deserts share some of these characteristics, the tundra is the only biome listed that is characterized by a short growing season, harsh winters, no trees, mostly migratory animal species, and less than 10in of rain per year.

Don't be fooled into associating moisture retention with rainforests: Those plants don't require such an adaptation since rainfall is plentiful. A subtropical desert, however, is characterized by high temperatures, very low precipitation and warm soils, and thus plants must adapt to prevent water loss.

The correct response is deciduous forest **.**The unique characteristic of the deciduous forest is that the trees shed their leaves each year. Maple and Oak trees are common in this biome. Prairie grasslands do not contain trees, rather they contain fields of grasses. The desert biome does not receive as much rainfall as the deciduous forest, nor does it contain many hardwood trees that shed their leaves. While the coniferous forest contains lots of hardwood trees, they very rarely shed their leaves. The coastal chaparral biome does not receive as much rainfall, and is dominated by small trees and shrubbery.

Humidity, atmospheric pressure, and wind are all aspects of climate but not the determining factors. In the higher latitudes, temperature is the more important factor. In the lower latitudes, precipitation is the more important factor.

The correct response is desert. The desert environment is characterized by low rainfalls (less than 25 cm per year). They are one of the most dry biomes on the planet. The desert biome also has highly variable temperature swings, with high temperatures during the day and low temperatures at night.

Polar forests are also known as "taiga"

There is no arid forest, as most arid regions are home to mostly shrub and brush-like plants. Arid areas with trees are not dense like true forests.

Brazil, Indonesia, Peru, and Zaire contain over half of the world's tropical rainforest biome. Mexico does contain some rainforest that extends into Guatemala, but not as large an area as the other countries listed.

Boreal forest, also known as "taiga," is a biome spread across the northernmost latitudes, including Canada, Alaska, Russia, and parts of northern Europe. It is characterized by coniferous forests and generally low temperatures.

The correct answer is genetic drift. This is the only answer choice that refers to random, natural process by which allele frequencies are reduced in general populations. All the other terms are events that occur in response to small population sizes or colonization.

The question describes a mutualistic relationship in which both the bee and the flower benefit. Mutualistic relationships can be described as win-win interactions between species. Facilitative relationships occur when one species benefits and the other species is not impacted in any way. Competitive relationships are win-lose interactions where one species benefits and the other species is detrimentally impacted.

Coevolution is a process by which two or more species evolve in response to one another, and generally describes competing species. While the hummingbird and the flower may evolve due to this relationship, coevolution more freqeucntly describes the evolution of defense mechanisms in response to a predator-prey relationship. Parasitism is the relationship in which one species benefits at the expense of the host. This can sometimes lead to coevolution, depending on how the host reacts. Neither species is being harmed in the given scenario, so this is incorrect. Commensalism is when one species benefits, but the other species is not impacted. In this case, both the hummingbird and the flower are benefiting, so this is not our answer. Resource partitioning is when species evolve together to share resources in a sustainable way. The hummingbird is using a resource that the flower provides, but they are not "sharing" in the sense of the definition of resource partitioning. Competitive exclusion describes the phenomenon when two species share the same niche, and the stronger one forces out the weaker competitor.

Mutualism, the correct answer, describes a relationship wherein species exploit each other mutually. In this case, the hummingbird gains nutrition from the flower, and the flower gains a reproductive advantage from the hummingbird.

Sharks have been shown to be very resistant to infection when they have been wounded. It is also notable how low cancer rates are in sharks—in fact, researchers from MIT have isolated a potential anti-tumor agent in sharks' skeletons that could further cancer research with regard to human patients.

The over-browsing by the invasive jackrabbit population has resulted in harm being done to the desert plant communities with no negative impact on the rabbits, resulting in amensalism.

Species evenness is a measure of diversity that takes into account the relative proportion of different species in a given area. Richness can also be classified as a measure of diversity; however, it refers to the number of different species in an area rather than proportion. Last, phylogeny refers to the construction of branched models that illustrate evolutionary pathways.

Bottleneck effect occurs after a drastic reduction in population size due to events such as a natural disaster, or widespread disease. The remaining population lacks genetic diversity because there are fewer individuals and fewer genes present within the population. This is the correct answer. The founder effect is not correct because it is defined as the loss of genetic variation as a result of a few numbers of individuals establishing a population. Geographic isolation occurs when a population is isolated from others due to geographic boundaries such as mountains, cliffs, or large bodies of water; therefore, it is not the correct choice. Last, genetic drift refers to the change in frequency of gene variation due to random sampling and does not correctly answer the question.