Population Ecology Flashcards
what is population ecology?
the study of intraspecific interactions
what are intraspecific interactions?
“intra” - within
organisms interacting with members of the same species in relation to environment
how both biotic and abiotic factors affect density, distribution, size, and age structure
what is density?
of individuals per unit area or volume
what is dipersion?
pattern of spacing among individuals within the population
what are two ways population ecologists measure density?
count individuals
quadrant sampling
what is count individuals?
count nests, burrows, tracks, or scat
what is quadrant sampling?
count number of oak trees in several randomly located 100m x 100m plots in Troy and calculate an average for the city
how can you create a more accurate representation with quadrant sampling?
increase sample size
what is the mark-recapture method? what is it also known as?
capture-recapture method
taking a sample of a population, marking those individuals and releasing them back into the population. after the individuals have mixed freely with unmarked individuals, take new samples and record marked to unmarked individual ratio
how to calculate ratio of marked to unmarked individuals?
1st catch x 2nd catch total
____________________
number of recaptures in 2nd catch
what increases population density?
birth/natality/fecundity
immigration
what decreases population density?
death/mortality
emmigration
what are the 3 types of dispersion? give examples
clumped - most common (seastars)
uniform - most rare (penguins)
random (dandelions)
what is a demography?
studies vital statistics of populations and how they change over time
what are life tables?
age specific summaries of the survival pattern of a population which tracks cohorts from birth to death
at are cohorts
individuals of the same age
what is a survivorship curve?
data from a life table put into a graph
what is a reproductive table?
based on female cohorts producing offspring from birth to death
hoe many days on average are many female squirrel species fertile each year?
few hours/1-3 days
what cycle do squirrels and most other mammals have that reabsorbs the endometrial lining when not pregnant? humans?
estrous cycle; menstrual cycle
most mammals have a bone in the penis to aid in copulation, what is called?
baculum
what is generation time?
the amount of time between the birth of an individual and the birth of their progeny (offspring)
how long are generation times for small organisms?
short
how to some bacteria divide?
asexually by binary fission every 20 minutes
how long are generation times of large animals? giev an example
long; redwood trees (tallest trees in the world) and sequoia trees (widest trees) do not reproduce until 10 years old
while some bacteria can reproduce this quickly, what are some limiting factors that affect their colony size? (4)
limited resources (food, water, nutrients, energy and space)
toxic waste accumulation
predation
bacteriophages
what are bacteriophages?
viruses that infect bacteria
what are two things a virus has at a minimum
nucleic acid (dna or rna)
capsid (protein coat)
what is exponential population growth? other name? what shape curve does it create?
geometric population growth
a population whose members all have access to abundant resources and reproduce without limits
J -shaped curve
when does exponential growth occur?
when a population is introduced into a new envirnoment after a catastrophic event
what does in vitro mean?
in glass
what is logistic population growth? what curve shape does it create?
a population with limited resources that cause a population to reach a plateau point as the population increases
S shaped curve/ sigmoid curve
what is the name of the plateau in a logistic growth curve?
carrying capacity
what letter do population ecologists use to represent the carrying capacity?
K
what are the two types of reproductive efforts an organism can make?
semelparity & iteroparity
what is semelparity?
a single large reproductive effort (salmon)
what is iteroparity?
repeated reproductions
agave americana plant grows in desert climates and send up large flowering stalk to produce seeds and die. what type of reproduction is this?
semelparity
fermented agave make what drink?
tequila
what are annual plants?
live for one growing season
what are perennial plants?
longer lives and come back each year
harvest energy into roots and freeze resistant buds
are petunias annual or perennial plants? what type of reproduction do they have?
perennial; semelparity
what is a life history chart?
they include traits that affect an organism’s schedule of reproduction and survival
what do life histories include?
when reproduction starts
how often an organism reproduces
how many offspring per reproductive episode
what is r-selected?
reproductive success in uncrowded (low density) environments
what is k selected?
life history traits that are sensitive to population density
is r-selected or K-selected life history associated with logistic population growth?
k selected
is an r selected or k selected life history associated with exponential population growth?
r selected
what does r mean?
per capita rate of increase
what is there between reproduction and adult survival?
“trade off”
what is the effect of larger/smaller clutch (# of baby birds) on parental survival?
fewer offspring=longer lifespan for parents
more offspring=more energy invested in reproduction and rearing of the offspring
what is the principle of allocation?
states an organism only has limited energy so if it uses energy for one function, it will have less energy for other functions
where do most organisms allocate their energy?
during breeding season
what is called when monarch butterflies allocate their energy by entering a non-reproductive phase till spring?
reproductive diapause
what are density dependent factors?
factors that affect populations as the number of individuals increase the population becomes more dense
what are density independent factors?
factors that affect population size regardless of the number of individuals (weather, wildfire, hurricanes)
will parasites increase or decrease as the population density increases?
increase
will reproduction/birthrates increase or decrease as the population density increases?
decrease
will nutrient availability increase or decrease as the population density increases?
decrease
will diseases increase or decrease as the population density increases?
increase
will food availability increase or decrease as the population density increases?
decrease
will toxic wastes increase or decrease as the population density increases?
increase
will territoriality increase or decrease as the population density increases?
increase
will smaller body size of organisms increase or decrease as the population density increases?
increase
will competition increase or decrease as the population density increases?
increase
what can monet do to produce larger, healthier plants?
space the plants out and prune (trim) them regularly
Is the bubonic plague density dependent or density independent factor?
density-dependent
bubonic plague was caused by a bacterium. what organism was the vector to transmitting this bacterium to humans?
fleas on rats
what is the death of tissue called?
necrosis
what children’s nursery rhyme is linked to the plague?
ring around the rosy
what is a boom and bust cycle? give two examples
cycles where some populations of organisms fluctuate in density
periodic cicada insects have cycles in 13-17 years depending upon the species
hare and lynx population - 10 years
what are the exoskeletons of cicadas made of?
chitin
how rare is a blue-eyed cicada?
one in a million
what is the cause of the hare population cycling?
a combination of
food supply decreasing in winter
other predators besides lynx eat hares
what is the cause of the lynx population cycling? is this a density dependent or density independent factor?
lynx almost feed exclusively on hares
density dependent
how is the global human population growing?
not increasing exponentially anymore, but still rapidly
how often is the population census taken?
every 10 years
approx how many people are there worldwide?
8 billion
country with most people?
china 1.45 bill
second country with most people
india 1.41 bill
the human population skyrocketed after the industrial revolution (1760-1830) but slowed in 1962, why?
famine in china
what is causing the human population to depart from true exponential growth?
diseases, decreased birth, china “voluntary” population control (1979-2015)
what are age structure pyramids?
the relative number of individuals of each age in the population graphed
which age structure has lots of young people who will most likely grow up and sustain explosive growth with their own reproduction?
wide bottom pyramids
afghanistan
what is the bulge in US age structure pyramid?
baby boom
what is the current reproduction rate in us per female?
1.8 children
what pyramid has no growth to their population?
small base pyramids as people younger than reproductive age are underrepresented in the population
italy
which sex tends to live longer?
females
why do people in industrialized nations tend to live longer?
better quality healthcare. sanitation, improved access to education
what is ecological footprint?
the land and water required by each person, city, or nation to produce all the resources it consumes and to absorb all the waste it generates
what benchmark do ecologists use to measure ecological footprint?
the planet can sustain 1.7 hectares (2.5 acres) per person per year
how much does an american use? is this sustainable?
10 ha/person/year; unsustainable for Earth’s resources
what limiting factors could lead to the Earth reaching its carrying capacity? (4)
food (malnutrition and famine)
sustainable space
running out of resources (nonrenewable metals and fossil fuels and renewable fresh water)
environment unable to absorb its waste
