Chapter 6: Population Ecology (Alex) Flashcards
What is a group of organisms of the same species that inhabits a defined geographic area at the same time?
A population
What term refers to the number of individuals of a population that inhabit a certain unit of land or water area.
Population density
What term refers to how individuals are spaced within a region.
Population dispersion
What type of population spacing does random describe?
The position of each individual is not determined or influenced by the other members of the population.
What type of population spacing does clumping describe?
Clumping is the most common dispersion pattern for populations. In this type of dispersion, individuals “flock together.”
What type of population spacing does uniform describe?
The members of the population are uniformly spaced throughout their geographic region.
What is the biotic potential of a population?
The amount that the population would grow if there were unlimited resources in its environment. Not very practical
What is the carrying capacity (K) of a particular region?
The maximum population size that can sustainable be supported by the available resources in the region.
What is logistic population growth?
Logistic population growth is a much better model for what exists in natural settings and it basically says that when populations are well below the size dictated by the carrying capacity of the region they live in, they will grow exponentially, but as they approach the carrying capacity, their growth rate will decrease and the size of the population will eventually become stable.
What is the Rule of 70?
A rule that lets you approximate the time it will take for a population to double by dividing 70 by the current growth rate of the population.
What is an r-selected organism?
An r-selected organism is one that reproduces early in life and often has a high capacity for reproductive growth. Some examples are bacteria, algae, and protozoa. Little or no care is given to offspring and many are created.
What is a k-selected organism?
A k-selected organism reproduces later in life, produces less offspring, and devotes significant time and energy to the nurturing of their offspring. Some examples are humans, lions, and cows.
What is the boom-and-bust cycle?
The boom-and-bust cycle is very common among r-strategists. In this type of cycle, there is a rapid increase in population and then an equally rapid drop off.
What are some density-dependent factors in population growth?
Increased predation, competition for food or living space, disease, and the buildup of toxic materials.
What are some density-independent factors in population growth?
Fires, storms, earthquakes, and other catastrophic events
What organism does a Type I (K-selected) survivorship curve represent?
One where the majority of it’s offspring will live for a long period of time; eventually they will start to die off
What organism does a Type II survivorship curve represent?
One where its offspring have a fifty-fifty chance of surviving to old age.
What organism does a Type III (r-selected) survivorship curve represent?
One where most of its offspring will die young, but if they live to a certain age, they will live a longer life
According to the U.S. Census Bureau as of January 2017, what is the estimated world population?
7,366,958,890
What is the crude birth rate?
The number of live births per 1,000 people in a year
What is the crude death rate?
The number of deaths per 1,000 people in a year
What is the movement of people out of a population called?
Emmigration
What is the movement of people into a population called?
Immigration
What is the total fertility rate (TFR)?
The number of children a woman will bear in her lifetime on average.
What is the replacement birth rate?
The number of children a couple must have to replace themselves in a population.
What are age-structure pyramids (age-structure diagrams) used for and what subcategories are they split into??
They are used to graphically represent human populations and they are split into pre-reproductive (0-14), reproductive (15-44), and post-reproductive (45+).
What is the demographic transition model used for?
It is used to predict population trends based on the birth and death rates of a population.
When a population moves from the ____ stage to the ____ stage it is called demographic transition.
First, second
Describe the preindustrial state (stage 1)
In this state, the population exhibits a slow rate of growth and has a high birth rate and high death rate because of harsh living conditions. Harsh living conditions can be considered environmental resistance, an umbrella term for conditions that slow a population’s growth.
Describe the transitional state (stage 2)
In this second state, birth rates are high, but due to better food, water, and health care, death rates are lower. This allows for rapid population growth. Birth rates remain high due to cultural or religious traditions and a lack of education for woman.
Describe the industrial state (stage 3)
In the third state, population growth is still fairly high, but the birth rate drops, becoming similar to the death rate. Many developing countries are in the currently in the industrial state.
Describe the postindustrial state (stage 4)
In the final stage, the population approaches and reaches a zero growth rate. Populations may also drop below the zero growth rate and some consider this a 5th stage.
What are four of the most significant factors that have contributed to the increase in human population?
Improved nutrition, the availability of clean water, newly implemented systems for sanitary waste disposal, and better medical care. Another significant factor is the increase in food production.
What type of nutrients are needed in large amounts and include proteins, carbohydrates, and fats?
Macronutrients
What type of nutrients are needed in smaller amounts and include vitamins, iron, and minerals?
Micronutrients
What is hunger?
Hunger is when insufficient calories are taken in to replace those being expended.
What is malnutrition?
Poor nutrition that results from an insufficient or poorly balanced diet.
What is undernourishment?
When one has not been provided with sufficient quantity or quality of nourishment to sustain proper health and growth/
What is a food desert?
A place where access to fresh, healthy food is difficult. The residents rely on low quality processed foods for subsistence.
