Ch. 20 Quiz
Which ecological definition is incorrect?
A. A community is made up of biotic and nonliving components. none of these A population is a group of individuals of the same species living in the same region. An individual is a single organism of a particular species. An ecosystem consists of individuals, populations, and communities.
Which statement is true of distribution patterns in nature?
A. Uniform distribution allows individual organisms to maximize space between them. Clumped distribution has no advantages and is rarely observed in nature. Species can always be categorized into one distinct type of distribution, and populations never vary from this categorization. Four main types of distribution exist. all of these
Ecologists often study the spatial distribution of animals. Which of these descriptions of common distribution patterns is incorrect?
A. Uniform: moose are highly territorial creatures and move around an island habitat in large groups. Clumped: wolves cluster together in packs that generally move around together. All of these examples are consistent with their descriptions. Random: fish on a coral reef occur in small groups and alone all around the reef, and are equally likely to be anywhere on the reef. None of these examples is consistent with its description.
By studying the data collected from Isle Royale, ecologists have discovered that a large wolf population correlates to vigorous tree growth. Which statement best explains this pattern?
A. Wolves decrease the moose population, which consumes trees as its main diet all of these When there is a large wolf population on the island, the moose swim to the mainland. The decrease in moose allows for more tree growth. The remains of moose carcasses fertilize the soil, which allows for increased tree growth. none of these
Which event or condition is a density-independent factor that could influence population growth?
A. a volcanic eruption that covers an island in a layer of lava all of these a sudden decrease in the food supply due to usually dry conditions a new predator that moves into an area with hunting tactics that the prey species are not adapted to avoid a disease that spreads through direct physical contact
How have warmer-than-normal climatic conditions affected moose populations on Isle Royale?
A. all of these An increase in the tick population has resulted in weight loss for the moose, which increased their death rate. all of these Moose escaped the heat by resting in the shade, but then had less time for eating, which resulted in thinner moose that were not as prepared to survive winter temperatures. none of these Tick populations have grown and they have fed on the moose, which resulted in blood loss and higher death rates for moose
Once the carrying capacity of an environment is reached, the population generally ___
A. all of these may fluctuate by slightly exceeding the carrying capacity, and then dropping below it may experience cycles of "boom and bust" cannot continue growing exponentially none of these
When moose first arrived on Isle Royale and found a habitat without predators, the moose population ____
A. all of these re-grew after a starvation period that allowed the vegetation to recover. could be categorized as going through a cycle of "boom and bust" population dynamics. grew exponentially, and then crashed due to lack of food. was not regulated by predator-prey interactions.
Why are truly random distributions rare in nature?
A. all of these Individuals of a particular species often need certain types of conditions to survive and grow, so more individuals are found in these areas. none of these Many species have social behaviors that promote clusters of individuals for increasing foraging success or for predator avoidance Resources are unevenly distributed across most landscapes
The island of Guam traditionally has not had any snakes that prey on birds; however, brown tree snakes that prey upon birds were introduced. Use your knowledge of wolf-moose population dynamics to determine what happened to the population dynamics of birds and the new snakes on Guam. Which statement is probably one of the results of the snake introduction?
A. all of these happened As snake populations became very large, they reached the carrying capacity of Guam and caused bird populations to crash. Because bird populations crashed, one of the birds' main prey items, spiders, increased their population size. Because prey was abundant and few predators existed, snakes spread throughout the island. Snake populations increased exponentially as they preyed upon birds that had no defenses against the predators.
Imagine a system where a finch feeds on thistle seeds and the finch population size is linked to the productivity of the thistle, and the thistle population size is related to foraging pressure of the finch population. This is an example of population dynamics at the _____ level
A. community species ecosystem biosphere population
Which of these is NOT an example of something that ecologists would generally study?
A. how the mitochondria of a mouse function in its cells how the Amazon tropical rain forest is affected by its plants, animals, weather, and geology how one species of butterfly forages and reproduces in its habitat how predators, such as sharks, affect the population of prey, such as fish the population dynamics of one species of sea urchin
Ecologists study organisms at a number of levels with different numbers of components. Which sequence correctly orders these levels, from smallest to largest?
A. individual, population, community, ecosystem population, individual, community, ecosystem none of these community, individual, population, ecosystem ecosystem, population, community, individual
All of these statements can be advantages of a clumped distribution pattern EXCEPT ____
A. it allows individuals to maximize space between them it allows organisms to hunt prey more efficiently it helps organisms defend themselves against predators all of these are advantages of a clumped distribution pattern organisms can match their distribution to resource-rich areas
Which phrase is NOT a biotic factor affecting population growth of moose on Isle Royale?
A. summer temperatures food availability infectious disease tick population growth wolf population size
All of these statements regarding ecosystems are correct EXCEPT _____.
A. sunlight and water are good examples of living components of an ecosystem individuals, populations, and communities are all part of an ecosystem studying an ecosystem can help scientists understand individual populations an ecosystem is composed of the living and nonliving components of an environment moose and wolves are part of the Isle Royale ecosystem
Growth rates are _____
A. the difference between birth and death rates in a population logistic when the populations increase at a constant rate positive when the birth rates are less than the death rates none of these not influenced by immigration or emigration patterns
Population dynamics are influenced by birth and death rates. Which situation is NOT a factor that can cause early death for wolves on Isle Royale?
A. warmer temperatures causing tick populations that feed on wolves to increase dramatically, which causes wolves to lose blood and decreases their hunting abilities starvation if wolves cannot find and catch enough prey to survive bone deformities causing impairments in hind leg use, probably from inbreeding all of these warmer temperatures decreasing the frequency with which ice bridges form between Isle Royale and the mainland, which reduces the chances for immigration by new wolves that might increase the genetic diversity of the island population
Carrying capacity is NOT the point _____.
A. where additional resources are available only to individuals that immigrate into the population where available resources are being fully exploited by the population at which a population reaches the maximum number of individuals that an environment can support all of these around which a population's size tends to fluctuate
