Example 11.3. Hypotheses with One Sample of One Measurement Variable
Example 11.4. Hypotheses with Two Samples of One Categorical Variable
Example 11.5. Hypotheses with Two Samples of One Measurement Variable
Over time (from left to right), new adaptations may evolve during periods of (A) relatively stable environment; (B) directional or progressive change, such as from wet to dry; or (C) highly variable habitat, as predicted by the variability selection hypothesis.
An example of a hillside of sediments in the Olorgesailie region. The hillside, which represents about 10,000 years of time with a volcanic ash at its base dated around 1 million years ago, shows evidence of strong environmental shifts. Inset: Layers of sediments show the fluctuation between dry and wet environments and a time when volcanic ash covered the ancient landscape.
Rival hypothesis (edition) | Open Library
Environmental instability may have been a factor not only in shaping adaptations but also in contributing to the extinction of some lineages. Environmental variability associated with the extinction of large mammal species has been proposed for the southern Kenya region. Sediments, stone artifacts, and animal faunal at the site of Olorgesailie span most of the past 1.2 million years. Numerous environmental shifts are recorded in the Olorgesailie deposits. The ancient lake level and its chemistry, for example, changed frequently, and sometimes the lake dried up, leaving small wetlands and streams as the main source of water in the basin. Volcanic eruptions also blanketed the landscape in ash, killing off grass and reshaping the properties of the ecosystem.
For example, the zebra Equus oldowayensis had large and tall teeth specialized for eating grass. Its last known appearance in the fossil record of southern Kenya is between 780,000 and 600,000 years ago; it was replaced by Equus grevyi, which can graze (feed on grass) as well as browse (feed on leaves and other high-growing vegetation). The fossil baboon Theropithecus oswaldi, which weighed over 58 kg (over 127.6 pounds), lived on the ground exclusively; it had very large teeth and consumed grass. It also went extinct between 780,000 and 600,000 years ago. Its extant relative, Papio anubis, is omnivorous and moves easily on the ground and in trees. Two other large-bodied animals that specialized in eating grass, the elephant Elephas recki and the ancient pig Metridiochoerus, were also replaced by related species that were smaller and had more versatile diets (Loxodonta africana and Phacochoerus aethiopicus). The aquatic specialist Hippopotamus gorgops was replaced by the living hippopotamus, which is capable of traversing long distances between water bodies.
Rival hypothesis by Schuyler W. Huck, unknown edition,
Violent actions that are committed in order to reduce future suffering are not to be condemned, he said, citing World War II as an example of a worthy effort to protect democracy.
As predicted by the variability selection hypothesis, hominins were not found solely in one kind of habitat, but rather in a variety. A major signal of the ability to tolerate different environments was the dispersal of the genus early Homo beyond Africa into Asian environments. After 1.9 million years ago, the genus Homo is found in a variety of locations in Asia, including some that are relatively far north.
Rival hypothesis | Open Library
What is PLAUSIBLE RIVAL HYPOTHESIS? definition of - …
Example 11.8. Hypotheses about comparing the relationship between Two Measurement Variables in Two Samples
Hypothesis Definition, Checklist, and Examples
Rival Hypotheses: Alternative Interpretations of Data Based Conclusions [Schuyler W
RIVAL hypothesis book easy essay strategy! - …
Rival hypothesis: alternative interpretations of data based conclusions by Schuyler W
11.2 Setting the Hypotheses: Examples | STAT 100
A different hypothesis is that the key events in human evolution were shaped not by any single type of habitat (e.g., grassland) or environmental trend (e.g., drying) but rather by environmental instability. This idea, developed by Dr. Rick Potts of the Human Origins Program, is called variability selection. This hypothesis calls attention to the variability observed in all environmental records and to the fact that the genus Homo was not limited to a single type of environment. Over the course of human evolution, human ancestors increased their ability to cope with changing habitats rather than specializing on a single type of environment. How did hominins evolve the ability to respond to shifting surroundings and new environmental conditions?
Research Hypothesis - Explorable
Another response to environmental change is to evolve structures and behaviors that can be used to cope with different environments. The selection of these structures and behaviors as a result of environmental instability is known as variability selection. This hypothesis differs from those based on consistent environmental trends. Environmental change in an overall direction leads to specializations for those specific conditions. But if the environment becomes highly variable, specializations for particular environments would be less advantageous than structures and behaviors that enable coping with changing and unpredictable conditions. Variability selection refers to the benefits conferred by variations in behavior that help organisms survive change. To test the variability selection hypothesis, and to compare it with habitat-specific hypotheses, Potts examined the hominin fossil record and the records of environmental change during the time of human evolution.
What would be an appropriate rival hypothesis - …
There are many ideas about the role of the environment in human evolution. Some views assume that certain adaptations, such as upright walking or tool-making, were associated with drier habitat and the spread of grasslands, an idea often known as the savanna hypothesis. According to this long-held view, many important human adaptations arose in the African savanna or were influenced by the environmental pressure of an expanding dry grassland.
Nondirectional Hypotheses - SAGE Research Methods
Overall, the hominin fossil record and the environmental record show that hominins evolved during an environmentally variable time. Higher variability occurred as changes in seasonality produced large-scale environmental fluctuations over periods that often lasted tens of thousands of years. The variability selection hypothesis implies that human traits evolved over time because they enabled human ancestors to adjust to environmental uncertainty and change. The hypothesis addresses the matter of how, exactly, adaptability can evolve over time.
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