Chapter 51 Biol 2130 Population Ecology
(in logistic growth) when N = K, there is _ growth
0
Assume there are 200 MendAliens living on an island in my back yard. If my island has an area of 20 hectares, what is the population density of MendAliens in terms of MendAliens per hectare?
200 MendAliens / 20 hectares = 10 MendAliens per hectare
humans originated (time place)
200,000 yo africa
7 billion ith an increase of _ million people a year
80
Which of the following statements are true of logistic growth? As the population approaches carrying capacity, it grows more slowly. The population grows at a steady rate. When the population reaches carrying capacity, it stops growing. As the population approaches carrying capacity, it grows more rapidly.
As the population approaches carrying capacity, it grows more slowly. When the population reaches carrying capacity, it stops growing.
bleh. 2
Both curves show exponential growth. True The slope of the lines at 90 days is determined by rN in both cases. True If r2 = 0.02, then r1 > 0.02. True The value of r increases over time in both cases. False Ninety days after the introduction of 10 aphids, there would be more aphids in the population with r1 than in the population with r2. True
dN / dt = rM
DISCRETE (like over one year) instantaneous growth rate
why the age structure of human populations differs between developed and developing nations
Developed nations have roughly equal numbers of individuals in each age class because the fertility rate has been constant and survivorship high for many years. Developing countries have many more children and young people than older people, because the fertility rate and survivorship have been increasing.
why human population is projected to continue its rapid growth even though fertility rates are declining
Fewer children are being born per female, but there are many more females of reproductive age due to high fecundity rates in previous years combined with increased survival of infants and children.
carrying capacity (variable)
K
You are doing a mark-recapture experiment to determine the population size of the MendAliens living on an island in my back yard. Initially, you catch and mark 130 MendAliens, which you then release. Next, you capture 90 MendAliens, of which 20 are marked. What is your estimate of the population size of MendAliens living on the island in my back yard?
N = (M1 x C) / M2 Or: (130 x 90) / 20 = 585.
Suppose you trap 255 stickleback fish in a lake and mark them by clipping the first spine of their dorsal fins. One month later you recapture a total of 162 individuals, 78 of them marked. Estimate their total population size.
N = Mn/m = (255 × 162)/78 = 530.
How do i predict size of a population in the future if growth is continuous?
Nt = N0 * e^rt
how to determine population size at the end of time t given a finite growth increase
Nt = N0 * finite rate of increase^t
Total population (N) =
Number of marked animals (M), x Total number of individuals marked and unmarked in the recapture (n) / Number of marked animals in the recapture (m)
whats a density-dependent factor that limits growth in the lizards and design an experiment to test it
One possible density-dependent factor is competition for food. To test this idea, compare carrying capacity in identical fenced-in areas that differ only in the amount of food added. (You could also test a hypothesis of space limitation by doubling the size of the enclosure but keeping the amount of food the same.)
The mark-recapture method would be best for sampling a population of _____.
Sharks. The mark-recapture method works best for active species whose individuals tend to be highly mobile.
explain how natural selecion leads to populations of lizards with different life-history traits in different parts of their range
Since resources are limited in every habitat, lizards that allocate resources in a way that increases their fitness will produce the most offspring, which will in turn pass on heritable life-history traits, such as maturing late and having few offspring in colder areas versus maturing early and having many offspring in warmer areas.
net reproductive rate: R0 equals
Sum of all ages * survivorship at age x * fecundity at age x
Which of the following statements are true of a population at carrying capacity? The birth rate equals the death rate. The population continues to grow at a constant rate. The population growth rate equals zero. The rate at which resources are used is equal to the rate at which they are supplied.
The birth rate equals the death rate. The population growth rate equals zero. The rate at which resources are used is equal to the rate at which they are supplied.
At 50% of maximum life span, how does the survivorship of Albertosaurus compare to the survivorship of the crocodile?
The survivorship of Albertosaurus is about 100 times greater than that of the crocodile
calculate r for a population of lizards with R0 = 1.0 and g = 3 years
Using Equation 51.5, r = (ln1)/3 = 0, which means that the population is neither growing nor declining.
population currently has 50 individuals and is expected to sustain an r of 0.048, predict the size of the population in 10 years
Using Equation 51.6, Nt = 50e(0.048)(10) = 81; the orchid population will grow to only about 81 individuals in 10 years
for 2 years, gamma = 1.2, about 225 now, predict the population size in 5 years
Using Equation 51.8, Nt = (225)(1.2)5 = 560; the squirrel population will reach about 560 individuals in 5 years.
bleh
You can infer from this curve that the sunlight, nutrients, water, and space available to the dandelions are plentiful (that is, are not limiting population growth). True Population growth is exponential. True The value of r is higher after three months than after one month. False The slope of the curve is steeper after three months than after one month. True Each dandelion is producing more seeds after three months than after one month. False More dandelions are reproducing after three months than after one month. True
Zootoca vivipara lizards maintain feeding and mating territories within their range. Based on these facts, what would you conclude? See Section 51.1 ( page 1072) .
Zootoca vivipara are likely uniformly distributed within their range.
meta-population
a population of populations connected by migration
determines range
abiotic and biotic factors
In a population of 1,000 elephants, how many individuals would survive for 50% of the species' maximum life span?
about 100
Oyster populations are primarily, if not exclusively, composed of _____.
adults
density-independent factors
alter birthrates and death rates irrespective of the indivisuals, usally abiotioc like drought volcanoes etc
Look closely at the scale on the y-axis. What number would be represented by the point midway between the tick mark labeled 10 and the tick mark labeled 100?
approximately 32
replacement rate
average fertility required for each woman to produce exactly enough offspring to replace herself and her offspring's father.
fertility rates
average number of survivnf children that each woman has during her lifetime
density-dependent factors that limits population size
biotic usually
Which of the following factors does not contribute to environmental resistance? environmental toxins competition for food weather conditions birth rate competition for space
birth rate
intrinsic rate of increase, rmax is
birth rates per individual are as high as possible and death rates per individual are as low as possible
Is the following statement supported or not supported by the data shown in the graph? The maximum life span of Albertosaurus was about 100 years
cannot be determined from graph
maximum number of individuals that can be supported by a particular habitat in a sustained period of time
carrying capcity
where is exponential growth common in nature:
colonization of a new habitat and recovery after a disaster
uniform arrangement
competition, water, space, or other resources
growth rate begins to _ when N increases
decline
R0 less than 1
declining
(In logistic growth) as N increases, K _
decreases
r is _ (increasing or decreasing) in humans?
decreasing, but still above 1 (so the population is increasing)
must be intraspecific
density-dependent factors
competition for resources (d-dep or d-indep)
dependent
disease and parasitism (d-dep or d-indep)
dependent
predation (d-dep or d-indep)
dependent
social behavior (d-dep or d-indep)
dependent
toxic wastes like ammonia, alchol, carbon dioxide, and uric acid (d-dep or d-indep)
dependent
random arrangement
each individual is independent of each other (example: seed dispersal)
best way to control fertility rates?
educate women on birth control and let them go to school.
Which of these organisms has a survivorship curve similar to that of humans?
elephants
individuals leaving a population
emigration
type ii surviorship
equal chance of dying throughout all their life
deltaN / deltat = (birth rate per individual - death rate per individual ) * number of individuals
exponential growth equation
instantaneous finite rate of increase
finite rate of increase = e ^ r
how do i predict the size of a population if the future growth is not continuous?
finite rate of increase = population size one breeding interval later/ population size at time 0
Scientists grew a population of yeast cells in a flask to which they provided a constant supply of nutrients. As the population of yeast cells increased, competition for the nutrients also increased. This caused the population to grow more slowly, until the rate at which the yeast cells used the nutrients was equal to rate at which the nutrients were supplied to the flask. Which of the three graphs shown in Part G best represents the growth of these yeast population?
graph a
A pair of coyotes colonized a large island where rodents (their prey) were abundant. At first the number of coyotes increased. But as the coyote population increased, competition for prey also increased and the coyote population grew more slowly. In some years, weather conditions killed many of the rodents, causing some coyotes to starve. In other years, weather conditions were favorable for the rodent poulation, allowing the coyotes to thrive, reproduce, and raise many pups. Which of the three graphs shown in Part G best represents the growth of this coyote population?
graph b
A female darkling beetle laid her eggs in a sack of corn meal. The corn meal was an excellent source of food for the beetle larvae (mealworms), and the beetle population quickly increased. After four months, the beetles had eaten all of the corn meal, and the adult beetles flew away to find new food sources. Which graph best represents the growth of the beetle population in the sack of corn meal?
graph c
Which of these organisms has a survivorship curve similar to that of oysters?
grasses
cohort
group of same age that can be followed through time
age class
groups of individuals of a specific age exp. all females 4-5 yo
high survivorship tend to _ slowly; and invest resources to survival shit
grow/reproduce
(in logistic growth) if N is small, the growth rate should be _
high
rmax of species that breed at a young aage and produce may offspring a year
high
type iii surviorship
high death for larvae or seeds but higher survival in later life
many offspring small offspring small body early maturity low resistance to disease and predators short life span
high fecundity and low surviorship
The Type III survivorship curve has _____. See Section 51.2 ( page 1073) .
high initial death rates but later high survivorship (e.g., plants)
age structure
how many individuals of each age are alive
Populations grow due to births and _____. See Section 51.2 ( page 1073) .
immigration
addition of new individuals from other populations
immigration
fecundity of z. vivipara :
in netherlands 1 year olds dont reproduce. intermediate death, in britnanny half of the 1 yos reproduce, die alot in austria females dont breed until they are 4, survive long
As a population approaches carrying capacity, environmental resistance (increase/ decrease/ same)
increases
R0 greater than 1
increasing
net reproductive rate
indicate whether the population is increasing or decreasing as long as immigration and emigration are insignificant
deltaN / deltat = births - deaths
isolated population
What is r max in a species like the giant panda? See Section 51.3 ( page 1077) .
it is low
four attributes that will persist
large population sizes, occupy large geographical ranges, cloe to neigboring populations (more likely to be colonized), high genetic diversity
What does the orange graph line represent?
logistic growth
rmax of a species that take years to mature and produce few offspring each year
low
few offspring large offspring late maturity large size high disease resistance high predator resistance long life span
low fecundity high survivorhip
top-down hypothesis
lynx populations reach high density in response to increases in hare density. at high density, lynx eat so many hares that the prey population crashes
who said that population needs to be checked and food will run out (inspired darwin)
malthus
moving animals capture
mark-recapture
can restore extinct populations
migration
deltaN / deltat = births - deaths + immigration - emigrants
normal population growth
Is the following statement supported or not supported by the data shown in the graph? The mortality rate of Albertosaurus dinosaurs aged between 25% and 50% of their maximum life span was far greater than the mortality rate of dinosaurs that reached 75% of their maximum life span.
not supported (bcs it shows survival, not mortality)
biotic factors
past and current presence of other species that provide habitat, food, or competition
(r) = (ln * R0 ) / (generation time)
per capita growth rate
deltaN / deltat = number of individuals * r
per capita rate of increase
What is shown on the x-axis?
percentage of the maximum life span of a species
b < d and r < 0
population decaying
r > 0 and b > d
population growing
r = 0
population size does not change
density independent
population size does not limit the growth rate
the key to understanding populations change through time in their abiotic and biotic environments
population thinking
wildlife corridors
preserve large tracts of lands arent possible so they construct small tracts split by highways or rivers that could divide dispersal
when growth is exponential _ is constant
r
when population density gets very high, the populations per capita birth rate will decrease and per capita death rate increases, _ will decline
r
which is better r or R0?
r because its independent of generational time
What does the right y-axis represent?
resources, with quantity decreasing from bottom to top
Which of these species typically has a mortality rate that remains fairly constant over an individual's life span?
robins
According to the graph, which modern animal has a relatively constant mortality rate throughout its life span?
starling
clumped arrangement
stay in social groups
demography
study of factors tat determine the size and structure of populations through time
population ecology
study of how and why the number of individuals in a population changes over time and space
life table
summarizes the probability that an individual will survive and reproduce in any given time interval over the course of its lifetime
type i survivor-ship
survivorship throughout life is high and plummets at old age
abiotic factors
temperature, rainfall, mountains, oceans, continental drift
generation
the average time between a mother's first offspring and her daughter's first offspring
The study of the Zootoca vivipara lizard showed that _____. See Section 51.2 ( page 1073) .
the low-elevation Netherlands population was intermediate for fecundity and survivorship when compared with other populations
fecundity
the number of female offspring produced by each female in the population
why can population increase with decreasing fecundity?
they have so many young women that the overall number of births will remain high even though the average number of children per female is much lower than the generation before
sessile or sedentary capture
transects and quadrants
bottom-up hypothesis
when their populations reach high density, hares use up all their food and starve; in response lynx also starve
