environmental science a - unit 5: population dynamics
in the demographic transition model, which stages are associated with a population experiencing near zero population growth? select all that apply.
0.25 of 1 declining low stationary
what scenario describes a characteristic of a population? select all that apply.
100 goats make up a single population in a small town. a population of ants can be very small or very large depending on the sources available.
a population of geese has 3,000 individuals. in one year, 15,000 goslings were born. there were 7,000 deaths in that same year. what is the birthrate of the population?
5,000 per 1,000
study the graph. https://cdstools.flipswitch.com/asset/media/1238790 what represents carrying capacity on a graph?
90
there are, on average, 23,700 chickens on a farm. each day, 62 chicks are hatched. what is the birthrate of chickens over one year?
954.85 per 1,000
study the image. https://cdstools.flipswitch.com/asset/media/1238794 which of the labeled locations model the relationship between carrying capacity and limiting factors?
a and c
what situation can affect population size? select all that apply.
a country has become unsafe due to the threat of war causing people to move to other countries. a country has a terrible drought causing the available food to decline and therefore forcing people to move out.
what are examples of how population size can be affected? select all that apply.
a few birds leave a population due to low resources. hunting of deer increases and causes more deer to die. some bears join a population after their forest has been cut down.
what does a steady upward incline of a population growth curve signify?
a higher birth rate than death rate
what is a population?
a population includes members of a species that live in one area and interact with one another.
what is a limiting factor?
anything that limits the growth or abundance of a population
study the graph. https://cdstools.flipswitch.com/asset/media/1238787 the graph shows four different population growths. two are linear and two are exponential growth curves. which two are the linear?
b and d
which example population shows a stable population that is also stationary?
birth rate = 31 per 1,000 death rate = 31 per 1,000
how would birth and death rates compare in linear versus exponential population growth?
birth rates exceed death rates in a consistent pattern in linear growth, while birth rates far exceed death rates in exponential growth.
how is birthrate defined?
birthrate is the number of offspring per individual over a period of time.
what characteristics apply to a population? select all that apply.
can be small or large in scale only made up of one species
lesson 24
carrying capacity
what is the term for the largest number of individuals an environment can support over a sustained period of time?
carrying capacity
what is an example of a micronutrient that can affect the carrying capacity of the environment?
copper
study the graph. https://cdstools.flipswitch.com/asset/media/1238792 the graph represents the size of a plant population. in 2010, a small amount of copper was added to the soil. what can be concluded from the graph?
copper was a limiting factor
what can decrease a population's size?
death rate and emigration
how is death rate defined?
death rate is the number of deaths in a population per unit of time.
in the transition demographic model, a population at which stage is likely to be experiencing exponential growth?
early expanding
study the graph. https://cdstools.flipswitch.com/asset/media/1238785 what type of growth does this graph show?
exponential growth
lesson 25
human populations in the future
which description best models the relationship between limiting factors and carrying capacity?
if iron is the limiting factor for plant growth, increasing the amount of iron will increase the carrying capacity.
study the graph. https://cdstools.flipswitch.com/asset/media/1238791 a scientist tried growing plants with and without adding nutrients to the soil. the population sizes are recorded on the graph. which are true statements about the experiment?
iron and potassium are limiting factors carrying capacity is greatest when iron and potassium are both present
what term refers to a nutrient that limits the growth or abundance of a population?
limiting factor
in a graph, how is linear growth different from exponential growth? select all that apply.
linear growth appears as diagonal lines sloping upwards while exponential growth curves are j-shaped. linear growth shows consistent growth over time while exponential growth curves show sudden rapid increase in growth. linear growth goes in only one direction while exponential growth curves changes from almost horizontal to being almost vertical.
which scenario distinguishes linear from exponential growth?
linear growth will occur in a population which increases by 2 million organisms a year, whereas exponential growth will occur in a population which doubles each year.
what could cause the population of a small town to change? select all that apply.
more people are born than die in a year many people move into the town, but none move out
which of the following factors would be the limiting factor for plants growing on a farm?
nitrogen
why is it difficult to know the carrying capacity of the environment for humans? select all that apply.
not all human populations use the same amount of resources. humans artificially add energy resources into their environment to increase resources.
what are characteristics of a population?
occurring at different scales and containing only one species
the axes of population growth curves all depict population size against what variable?
period of time
lesson 22
population calculations
lesson 23
population growth
what are characteristics of populations? select all that apply.
populations can occur at different scales. populations have individuals from one species.
which statement is true of the sustainable use of resources?
resources are used at the rate they are replaced.
which letter of the alphabet best defines the shape of a logistic growth curve?
s
what characterizes a logistic growth curve? select all that apply.
s-shaped population growth curve slow growth, exponential growth, slowing growth, flattens
which are associated with a logistic growth curve? select all that apply.
slow initial growth sudden rapid growth flattening growth at the end
what is a micronutrient?
something an organism needs in very small amounts
what characteristics can be true of a stable population? select all that apply.
stable populations can grow. stable populations can decrease. stable populations can have neither an increase nor a decrease.
exponential growth in a population can be identified by which shape of a population growth curve?
sudden rapid upward trend
when a population is at its carrying capacity, the environmental resources it depends on are _[blank]_.
sustainable
lesson 21
the circle of life
what is the death rate? select all that apply.
the death rate is the number of deaths in a population per unit of time. the death rate is the number of deaths per year per 1,000 people in a human population.
what is the birthrate in a human population?
the number of births per year per 1,000 people
according to the graph showing populations of arctic hares, and their major predator the lynx, what limits the lynx population?
the number of hares available as prey limits the lynx population
blight is a fungal disease that can affect the entire haul of a crop in very little time. what would be the likely impact on the population of potato crops on a farm if some potatoes get infected by this disease, assuming no other factor impacts the population size?
the population of potatoes will begin to decline.
the graph depicts a population of woodland animals that has recovered after a large forest fire. based on the graph, what would be expected to happen to the population at time z if its food source is reduced?
the population size will decrease to a value of less than 100.
what is meant by sustainable?
what is used is replaced
what factors can increase a population's size? select all that apply.
when more individuals are born when more individuals join the population
what does the flattening of the line of a population growth curve signify?
zero to no growth in population