Chapter 5 ENSC
A brown bear and a salmon are engaging in predator-prey relationship.
true
What happens to a population if a dieback occurs, and which portion of the graph represents this?
a population suffers a sharp decline, also called a population crash. It is represented by letter C.
Which of the following exhibits primary succession?
a rock exposed by a retreating glacier
If the resilience of a damaged ecosystem is low enough, the degraded area may not be restored by secondary succession. When this happens, the damaged ecosystem has reached ____.
a tipping point
When plotting the number of individuals in a population against time, the data yield a J-shaped curve. What does this curve indicate?
exponential growth
The situation in which one set of species makes an area suitable for species with different niche requirements and often less suitable for itself is called ____.
facilitation
Intraspecific competition plays a larger role in most ecosystems than interspecific competition. T or F.
false
Organsims with clumped distributions are fairly rare. T or F.
false
The carrying capacity of any given area is not fixed. T or F.
false
The growth rate of a population increases as its size nears the carrying capacity of its environment. T or F.
false
The most common interatction between species is commensalism. T or F.
false
The population of white-tailed dear has soared and this can pose a problem for humans since they are carriers of malaria. T or F.
false
The capacity to withstand external stress and disturbance is called ____.
stability
What is a feature of r-selected species?
the have populations that fluctuate between high and low
Late successional plants are largely unaffected by plants at earlier stages of succession because they are not in direct competition for resources, a factor called ____.
tolerance
A late loss population (K-selected species) is exemplified by species such as elephants and rhinoceroses. T or F.
true
A survivorship curve shows the percentages of the members of a population surviving at different ages. T or F.
true
Animal predators tend to kill the sick, weak, aged, and least fit members of a species because they are the easiest to catch. T or F.
true
Grasslands have a high resilience and therefore can recover quickly following a fire. T or F.
true
Humans compete with many other species for space, food, and other resources. T or F.
true
In communities and ecosystems, the types and numbers of species change in response to changing environmental conditions. T or F.
true
Species with a capacity for a high rate of population growth are called ____.
r-selected species
Each population in an ecosystem has a ____ to variations in its physical and chemical environment
range of tolerance
the ability of an ecosystem to be restored
resilience
What occurs when an interation benefits one species but has little, if any, efffect on the other?
commensalism
Humans are exempt from population overshoot and dieback. T or F.
false
The pollinaion of flowering plants by species such as honeybees is ____.
mutualism
If multiple species find themselves competing for the same resource, the competition can be reduced by which of the following?
resource partitioning
Through natural selection, different species of birds called honeycreepers have shard resources by evolving specialized beaks to take advantage of certain types of food such as insects, seeds, fruits, and nectar from certain flowers. This is called ____.
resource partitioning
A group of interbreeding individuals of the same species in the same geographic region called a(an) ____.
population
What is the number of individuals in a population found within a defined area or volume that can limit the size of some populations?
population density
gradual establishment of sommunities of species in lifeless areas
primary succession
Parasites ____.
rarely kill their hosts
Which of the following exhibits secondary ecological succession?
recently flooded land
What refers to the ability of a living system to be restored after a period of moderate to sever disturbance?
resilience
Kelp forests play key roles in marine ecosystems, in part by supporting important biodiversity. These kelp forests are threatened by ____.
sea urchins
What type of succession begins in an area where an ecosystem has been disturbed, removed, or destroyed, and that contains soil or bottom sediment?
secondary succession
gradual establishment of communities after a wild fire
secondary succession
Kelp forests help reduce ____ by blunting the force of incoming waves and trapping some of the outgoing sand.
shore erosion
an example of a predator that uses camouflage.
snowy owl
Some species that tend to reproduce later in life and have a small number of offspring with long life spans ____.
are vulnerable to extinction
Determine which portion of the accompanying graph represents the number of reindeer that can be sustained indefinitely in a given area. What term illustrates this?
Letter A represents the carrying capacity
A population increases through birth and ____.
immigration
The ability of a living system to survive moderate disturbances is called ____.
inertia
What occurs when members of two or more species interact to gain access to the same limited resources?
interspecific competition
an example of prey species that exerts a selective pressure on lion and cheetah populations
zebra
Most ecologists now recognize that mature, late-successional ecosystems ____.
are in a state of continual disturbance and change
use behavioral strategies to scare off predators
blowfish
At the population level, parasite are always harmful to the host species. T or F.
False
Kelp forests are composed of large concentrations of ____.
seaweed
An example of an internal parasite is a ____.
tapeworm
What is an example of a K-selected species?
whales
In predator-prey relationships, the predator is seeking food for itself and its offspring, while the prey is seeking not to become food for the predator. As a result, predator and prey populations exert tremendous natural selection pressures on each other. T or F.
true
Large mammals, such as elephants and rhinoceroses, are especially vulnerable to extinction because of their reproductive patterns. T or F.
true
Populations of most plants and animals depend, directly or indirectly, on solar energy. T or F.
true
Primary and secondary ecological successions tend to increase biodiversity of communiies and ecosystems by increasing species richness and interactions among species. T or F.
true
Scientists have changed their view about stable type of climax community as the end produce of succession and are now suggesting that we cannot predict the course of succession. T or F.
true
The nonpoisonous ____ butterfly gains protection by looking like the bad-tasting ____ butterfly, whichis a protective device known as ____.
viceroy; monarch; mimicry
Describe what happens when species partition resources.
Resource partitioning occurs when species competing for similar scarce resources evolve specialized traits that allow them to shar resources by using parts of them, using them at different times, or using them in different ways.
At the present time, the global human population surpasses seven billion people. If we exceed the carrying capacity of the earth, the human population may suffer a substantial collapse. Consider the following formula for population change: population change=(births+immigration)-(deaths+emigration) What will be required of humans in order to stabilize or reduce our population?
Speaking on a global scale, there is no place for us to come from (immigration) or go to (emigration). That means population chang is limited to births minus deaths. To put it in the crudest of terms, we must either reduce the number of births or increase the number of deaths in order to stabilize or reduce our population. If we choose not to undertake that change, nature will do as we exceed our carrying capacity.
Describe the three factors ecologists have identified that affect how and what rate succession occurs.
The first factor that affects how and at what rate succession occurs is facilitation. This is when one set of species makes an area suitable for species with different niche requirements, and often less suitable for itself. For example, lichens and mosses gradually build up soil on rocks in primary succession, which allows grasses and other plants tp move in and crowd out the lichens and mosses. The second factor is inhibitation, in which some species hinder the establishment and growth of other species. For example, needles dropping off some pine trees make the soil beneath too acidic for most other plants to grow there. The third fractor is tolerance, whereby plants in the late stages of succession succeed because they are not in direct competition with other plants for key resources. For example, shade-tolerance species can live in shady forests because they do not need as much sunlight as the trees above them do.
What does it mean when a population uses up their resource supplies and temporarily overshoots? Which letter on this graph represents when this has occured to a certain reindeer population?
The population exceeds the carrying capacity of their environment. It is represented by letter B.
Using a small rodent, such as a field mouse, and a predator, such as a snake, explain how coevolution works.
The rodent responds to the environmental pressure applied by the snake through changes in behavior, anatomy, or physiology to reduce the predation. The snake, facing reducing predatory success, changes in response to the rodent. The rodent again responds to the specifics to the environmental pressure. This step-by-step adaptation is known as coevolution
Some people blame white-tailed deer for invading suburban yards and gardens. Discuss potential solutions to this problem.
There are no easy answers to the deer population problem in the suburbs. Changes in hunting regulations that allow for the killing of more female deer have cut down the overall deer population. However, since widespread hunting is not allowed in suburban areas, some areas have hired experienced archers to help reduce deer numbers safely. Some communities spray scent of deer predators or rotting deer meat on the edges of suburban areas to scare off deer. Others have used equipment that emits high-frequency sounds, which are undetectable to humans. Some people surround their yards with high fences over which deer cannot jump. In addition to these deterrents, deer can be trapped and moved, but this is expensive and must be repeated whenever the deer return. People could try birth control for deer to keep their numbers down or they could try trapping dominant males and sterilizing them.
What was the primary reason the southern sea otter nearly went extinct by the early 1900s?
They had thick, luxurious fur
There are ____ limits to population growth in nature.
always
What method of hunting do Arctic foxes use?
arctic foxes use camouflage by blending into their snowy background to avoid detection, and then they ambush their prey.
The primary reason why southern sea otter recovery is ecologically important is because they ____.
are a keystone species
The maximum population of a given species that a particular habitat can sustain indefinitely is the definition of ____.
carrying capacity
Some prey species discourage predators with chemicals that are poisonous, irritating, foul smelling, or bad tasting. What is this called?
chemical warfare
What is the most common distribution of populations?
clumped
Bats prey on certain species of moths by using high-frequency echolocation to locate them. Certain moths have evolved ears that can hear these frequencies allowing them to escape. This is an example of ____.
coevolution
When populations of two different species interact over long periods of time, changes in the gene pool of one species can lead to changes in the gene pool of other. What is this called?
coevolution
What is the most common interaction between species?
competition
The hind wings of the Io moth resemble eyes of a much larger animal. What is this called?
deceptive looks
Emigration is the ____.
departure movement of individuals from a population to another area
Plants such as pitcher plants share a commensalistic interaction with large trees in tropical and subtropical forests by attaching to the trunks or branches of the trees. The pitcher plants are examples of ____.
epiphytes
By 1900, white-tailed deer populations in the United States were drastically reduced, but now, since laws have been passed to protect them and their natural predators, their population has ____.
exploded
Explain why it is important to care about the survival of the endangered southern sea otters of California.
first, ethical reasons, as many people believe it is wrong to allow human activities to cause the extinction of a species. Another reason is that people love to watch playful and intelligent otters and as a result, they help to generate millions of dollars a year in tourism revenues. Finally, biologists classify southern sea otters as keystone species, which menas that in their absence, sea urchins and other kelp-eating species on which sea otters feed would probably destroy the Pacific coast kelp forests and much of the biodiversity they support
an example of a species using resource partitioning
honeycreepers
Too much or too little of any physical or chemical factor can prevent the growth of a population, even if all other factors are at or near the optimum conditions. What is this ecological principle?
limiting factor
Exponential growth followed by a steady decrease in population growth until the population size stabilizes is typical of ____.
logistic growth
Grasslands have ____ and can burn easily.
low inertia
The relationship between clownfish and sea anemone is called ____.
mutualism
When two species behave in ways that benefit both by providing each with food, shelter, or some other resource, it is called ____.
mutualism
What has caused the population of the southern sea otters to fluctuate?
parasites that breed in cats
What is said to occur when one organism feeds on another organism by living on or in the other organism?
parasitism
the ability of an ecosystem to survive moderate disturbances
persistence
