What is ecology?
Ecology (from the Greek oikos, home, and logos, study) is the scientific study of the interactions between organisms and the environment.
Explain the relationship between the variation in latitude and sunlight intensity.
Because of Earth's curved shape, the intensity in which the sunlight strikes Earth varies. At higher latitudes, the sun hits Earth at an indirect angle, which causes the light's energy to be more dispersed. Adversely, the tropics (regions between 23.5� no
Explain how global air circulation affects patterns of precipitation.
Solar radiation close to the Earth's equator initiates a global pattern of air circulation and therefore precipitation. In the tropics, high temperature causes water to evaporate and warm, wet air masses to rise and flow towards the poles. As they rise, t
What is climate?
Climate is defined as the long-term, prevailing weather conditions in a given area. It is the most significant influence on the distribution of organisms on land and in the oceans.
Name the four physical factors that make up the important components of climate.
Temperature, precipitation, sunlight, and wind are the four components of climate.
Distinguish between biotic and abiotic factors of the environment.
Abiotic, or nonliving, factors are the chemical and physical attributes of the environment that affect organisms. Biotic, or living, factors are other organisms that are part of an individual's environment.
Explain how large bodies of water, mountain ranges, and seasonal variation influence climate.
Ocean currents influence climate by heating or cooling overlying air masses that pass across land. Because of cool, misty currents (ex: California Current), coastal regions tend to be wetter. The high specific heat of water allows oceans and lakes to mode
What is a biome; a climograph; and a disturbance?
Biomes are major life zones characterized by vegetation type or by physical environment. A climograph is a graph used to plot the annual mean temperature and precipitation of a particular region. A disturbance is an event, such as a storm, fire, or human
Distinguish between the photic and aphotic zone.
The upper photic zone is the area of a body of water in which there is sufficient light for photosynthesis, and the lower aphotic zone is where little light penetrates.
What is dispersal?
Dispersal is the movement of individuals or gametes away from their area of origin or from centers of high population.
How do biotic factors limit the distribution of a species?
Negative interactions with predators or herbivores restrict ability of a species to survive and reproduce. Presence of absence of pollinators, food resources, parasites, pathogens, or competing organisms can act as a biotic limitation on species distribut
List the types of abiotic factors that might limit a species distribution. Explain the effect each factor might have on species distribution.
Abiotic factors, such as temperature, water, oxygen, salinity, sunlight, or soil might limit a species' distribution. Because most organisms function best within a specific range of temperature, extreme variation can limit a species distribution.
Differen
What is the difference between population density and dispersion?
The density of a population is the number of individuals per unit area of volume. Dispersion is the pattern of spacing among individuals within the boundaries of the population.
Define three patterns of dispersion.
Clumped is the most common pattern in which individuals are aggregated in patches. It may also be associated with mating behavior protection. A uniform, or evenly-spaced, pattern of dispersion may result from direct interactions between individuals or ter
What is demography?
Demography is the study of the vital statistics of populations and how they change over time.
What is a life table; a cohort?
Life tables are age-specific summaries of the survival pattern of a population. A cohort is a group of individuals of the same age.
What is a survivorship curve?
A survivorship curve is a plot of the proportion of numbers in a cohort still alive at each age, a graphing method of representing some of the data in a life table. A Type I curve is flat at the start, reflecting low death rates during early and middle li
What is exponential population growth?
Population increases under ideal conditions in which all members have access to abundant food and are free to reproduce at their physiological capacity is called exponential population growth.
What is rmax?
The per capita rate of increase that assumes the maximum rate for the species is denoted as rmax.
What is the equation for exponential population growth? Explain what the letters in the equation stand for.
dN / dt = rmaxN
N represents the population size and t represents time. dN represents the change in population in a small period of time. dt is the time interval in a certain period. rmaxN is the maximum per capita rate of increase for the species of a ce
What is the shape of the growth curve of a population showing exponential growth?
The size of a population that is growing exponentially increases at a constant rate, resulting in a J-shaped growth curve when population size is plotted over time.
What is carrying capacity?
Carrying capacity (K) is the maximum population size that a particular environment can sustain.
What is k?
K represents the carrying capacity in an equation.
What does the logistic growth model illustrate? What is the shape of the curve?
In the logistic population growth model, the per capita rate of increase approaches zero as the population size nears its carrying capacity. To construct, we start with the exponential population growth model and add an expression that reduces the per cap
Write and explain the equation for the logistic growth model.
dN / dt = rmaxN (K - N)/K
dN represents the change in population in a small period of time. dt is the time interval in a certain period. rmaxN is the maximum per capita rate of increase for the species of a certain size. It uses the equation for exponenti
What is k-selection; r-selection? Describe each.
Selection for traits that are sensitive to population density and are favored at high densities is known as k-selection, or density-dependent selection. The k-selection operates in populations living near to carrying capacity, where competition among indi
Name and describe six mechanisms of density-dependent regulation.
As population density increases, many density-dependent mechanisms slow or stop population growth by decreasing birth rates or increasing death rates.
Competition for resources and nutrients results in reduced reproductive rates. Predation occurs if a pre
What is a community?
A community is a group of populations of different species living close enough to interact.
What is an interspecific interaction?
Interspecific interactions are those made by an organism with individuals of other species in the community. These interactions include competition, predation, herbivory, symbiosis, and facilitation.
What is competition?
Interspecific competition is a -/- interaction, meaning that it has a negative effect on both (groups of) individuals engaged. It occurs when individuals of different species compete for a resource that limits their growth and survival.
What is competitive exclusion?
An ecological situation in which a slight reproductive advantage is given to one species and therefore leads to the elimination of the inferior competitor.
What is an ecological niche?
An ecological niche is the specific set of biotic and abiotic resources that an organism uses in its environment.
What is resource partitioning?
The differentiation of niches that enables similar species to coexist in a community is called resource partitioning.
Distinguish between a fundamental and realized niche.
A species' fundamental niche is the niche potentially occupied by that species. However, due to competition, a species is often limited to the portion of its fundamental niche that it actually occupies in a particular environment - its realized niche.
What is predation?
Predation is an interaction in which one species, the predator, kills and eats the other, the prey. It is a +/- interaction with a positive effect on the survival and reproduction of the predator population and a negative effect on that of the prey popula
Distinguish between cryptic coloration; aposematic coloration; Batesian mimicry; and M�llerian mimicry. Give an example of each.
Cryptic coloration, also known as camouflage, is used by prey, such as the canyon tree frog, so as to hide themselves from predators. Vivid aposematic coloration, or warning coloration, is exhibited by animals including poison dart frogs with effective ch
What is herbivory?
Herbivory is an interaction in which an organism eats the parts of a plant or alga. It is a +/- interaction with a positive effect on the survival and reproduction of the herbivore population and a negative effect on that of the plant population.
How do plants protect themselves from herbivores?
Because plants are stationary, their defenses are limited to chemical toxins (for example: nicotine, strychnine, cinnamon, cloves, and peppermint) and harmful structures (spines and thorns).
Name and describe 3 symbiotic associations.
The three symbiotic associations are parasitism, mutualism, and commensalism. Parasitism is a +/- symbiotic interaction in which one organism, the parasite, derives its nourishment from another organism, its host, which is harmed in the process. Mutualism
What is facilitation?
Facilitation is the interspecific interaction that has positive effects on the survival and reproduction of other species without the species necessarily living in the direct and intimate contact of a symbiosis
Describe the 2 components that make up the species diversity of a community.
The species diversity of a community has two components. One component is species richness, the number of different species in the community. The second component is the relative abundance of the different species, which is the proportion each species rep
What is biomass?
Biomass is the total mass of all individuals in a population.
What is the trophic structure of a community?
The feeding relationships between organisms in different trophic levels make up the trophic structure of a community.
Distinguish between a food chain and a food web.
A food chain is the transfer of food energy up the trophic levels from its source in plants and other autotrophs through herbivores, carnivores, and eventually to decomposers. When a series of food chains are linked together, they form a food web.
Differentiate between a dominant species and a keystone species.
Two types of species that have an especially large impact on the structure of entire communities are dominant species and keystone species. The dominant species in a community are either the most abundant or collectively have the highest biomass. The keys
What is ecological succession? Primary succession? Secondary succession?
Ecological succession, a process in which a disturbed area is colonized by a variety of species, which are in turn continually replaced over time by other species, has two different forms. One is primary succession, which occurs in a virtually lifeless ar