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The number of pythons found throughout Everglades National Park has increased in recent years. These huge snakes are not native to Florida and are believed to have been released into the wild by pet owners. Wildlife biologists have initiated attempts to capture and remove these pythons. Which statement best explains the biologists’ reason for removing these pythons from the Everglades?
The pythons could upset the territorial boundaries of native organisms.
The pythons could adapt to overcome diseases common to native snakes.
The pythons could prey on native organisms and cause native populations to decline.
The pythons could begin to interbreed with native snakes and produce a more successful species.
Which of the following statements account for the change in population seen between years 7 and 8?
The birth rate of the pigeons increased.
The emigration rate of the pigeons decreased.
The death rate of the pigeons exceeded the birth rate.
The neighborhood reached its carrying capacity for the pigeon population
A new species of snake was introduced to a tropical region. Scientists then noticed a steady decline in the presence of field mice and an increase in the number of snakes. Which of these is the most likely explanation about why the population size of each animal changed?
The snakes introduced to the region dominated the habitat, forcing the mice to find another place to live.
The mice became prey to the introduced snakes, allowing the snake population to increase but decreasing the mice population.
The snakes introduced to the region competed with the mice for food, allowing the snake population to increase but decreasing the mice population.
The people in the surrounding area set traps that killed the mice, allowing the snakes to live without any predators and therefore to increase in number.
The highest concentration of life exists in the top 200 meters of ocean water. What is the most important factor that influences the concentration of life?
amount of gases at the surface
amount of nutrients in the water
large number of predators at lower depths
amount of sunlight
Rabbits introduced into Australia over 100 years ago have become a serious pest to farmers. Rabbit populations increases so much that they displaced many native species of plant eaters. What is the most logical explanation for their increased numbers?
Rabbits have a high death rate.
There are few effective predators.
Additional rabbit species have been introduced.
There is an increase in rabbit competitors.
Scientists found, that over a period of 200 years, a mountain pond was transformed into a meadow. During that time, several communities of organisms were replaced by different communities. Which of these best explains why new communities were able to replace older communities?
The original species became extinct.
Species in the older community died from old age.
The abiotic characteristics of the habitat changed.
Diseases that killed the older organisms disappeared.
Although phosphorus is of great biological importance, it is not very common in the biosphere. Why is this?
Phosphorus doesn’t enter the atmosphere
Phosphorus doesn’t cycle through food webs
Phosphorus have been depleted by biological organism
Phosphorus evaporates easily and is quickly destroyed by sunlight
In the ocean nitrogen is often the limiting nutrient. What does this term mean?
An unlimited amount of nitrogen is in the ecosystem
Nitrogen is scarce or cycles very slowly through the ecosystem.
The presence of nitrogen limits the availability of other nutrients
Nitrogen is overabundant or cycles very quickly through the ecosystem
Ecologists study different levels of organization within the biosphere. Identify which level corresponds to a group of individuals that belong to the same species and live in the same area.
In addition to energy, organisms need matter to survive. Which of the following is true about matter in the biosphere?
The total amount of matter decreases overtime
The total amount of matter increases overtime
Biogeochemical cycles transform and reuse molecules
Matter flows through ecosystems in one direction
Each step in a food chain is called a trophic level. What percentage of energy available at one trophic level is transferred to organisms at the next level?
about 2 percent
about 10 percent
about 25 percent
about 50 percent
What is true about the pyramid of numbers?
A. There are more producers than first-level consumers
B. First-level consumers make up the greatest number of individuals
C. There are more third-level consumers than second-level consumers
D. There are more second-level consumers than first-level consumers