Chapter 36: Population Ecology Flashcards
Population Ecology
The study of how members of a population interact with their environment
Population Density
the number of organisms that exist in a given area
Dispersion
how the organisms in a population are spread out in a given area
How many types of dispersion are there
3
What are the 3 types of dispersion
1) Clumping Dispersion Pattern
2) Uniform Dispersion Pattern
3) Random Dispersion Pattern
Clumping Dispersion Pattern:
when organisms are located extremely close together/ in the same portion of an area
Uniform Dispersion Pattern:
organisms are spread out somewhat evenly
What causes clumping
resources in one area, body heat, safety/protection from predators, society and family units, to get prey more successfully
What is an example of clumping
ants in an ant colony
What is the most common type of dispersion
clumping
What causes Uniform Dispersion Pattern
territorial behavior, organisms need a certain amount of space to grow
What are some examples of organisms that might follow uniform dispersion pattern
birds - nest uniformly because they each need space to teach their young how to fly, etc.
trees - need roots to grow
Random Dispersion is caused by
resources available everywhere (fertile soil everywhere, or sun reaching everywhere[for photosynthesis] )
What is the rarest dispersion pattern
random dispersion pattern
Life Table
a table that monitors the chance of survival/death (survivorship) of organisms in different age groups in a certain cohort of a population
cohort
a group of organisms in a population that are used in a life table
What does the data from a life table help construct
survivorship curves
Survivorship Curve
plot survivorship as the proportion of individuals from an initial population that are alive at each age
How many types of survivorship curves are there
3
What are the 3 types of survivorship curves
1) Type I
2) Type II
3) Type III
Survivorship Curve ~ Type I
organisms in a population live for a relatively long time but begin to die at a certain age
What are some examples of organisms that follow Survivorship Curve ~ Type I
humans and other mammals
Survivorship Curve ~ Type II
survivorship curve is the same for the entire life of the organism; so the organisms have equal amount of chance to live and die at any age range
What are some examples of organisms that follows the Survivorship Curve ~ Type II
invertebrates, lizards, rodents, squirrels
Survivorship Curve ~ Type III
many births and many deaths rapidly ( stabilize at low)
What are some examples of organisms that follow Survivorship Curve ~ Type III
fish and plants
In Survivorship Curve ~ Type I organisms produce _____ offspring but give them _____ care
few; good
In Survivorship Curve ~ Type III organisms produce _____ numbers of offspring provide ____ care
large
True or False
Organisms follow the different types of survivorship curves exactly
False
Exponential Growth
the growth rate increases as the population increases
What is exponential growth caused by
unlimited resources, no predators, large area of land/space, no disease/natural disasters
Exponential Growth Model
an idealized picture of unlimited population growth
Limiting Factors
environmental factors that restrict population growth as the population reaches its maximum sustainable size and that stop it from growing forever
What is the shape of an exponential growth model
J-shaped curve
Logistic Growth
starts with exponential growth but then levels out
What is the shape of the curve of a logistic growth model
S
Logistic Growth Model
description of idealized population growth that is slowed by limiting factors as the population size increases
Carrying Capacity
maximum population size that a particular environment can sustain
Can populations go past the carrying capacity
yes most populations go above the carrying capacity and then back under and continue to fluctuate
Carrying Capacity depends on
Depends on the species and resources available in the habitat
When ____ rate equals ____ rate, the population stabilizes at carrying capacity
birth; death
How many types of limiting factors are there
2
What are the 2 types of limiting factors
1) Density-Dependent Factors
2) Density-Independent Factors
Density-Dependent Limiting Factors
limiting factors whose intensity is related to population density
What do Density-Dependent Factors limit
growth in a natural population
Are more factors Density-Dependent Factors or Density-Independent Factors
Density-Dependent Factors
What are some examples of Density-Dependent Factors
intrinsic factor, competition, disease, predation, territoriality, and toxic waste
Density-Independent Factors
the size of the factor is not based on the amount of organisms in a population
What are some examples of Density-Independent Factors
Natural Disasters , seasonal changes in weather/temperature
“Boom and Bust Cycles”
a recurring pattern of increases and decreases of a population
What is a common example of the “boom and bust”cycle
Snowshoe hare and lynx the snow shoe hare first spikes (about every 10 years) because there are less predators
Then the lynx spikes because there is more prey
The snow shoe hare goes down because money predators eat them etc.
what is the boom bust cycle an example of
a population cycle
What also affects the snowshoe hare population going up in the Boom and Bust Cycle
UV radiation also affects because of the amount of food the hare gets (THE SUN SPOTS)
Life History traits
traits that affect an organism’s schedule of reproduction and death
Semelparity
an organism has one time reproduction (makes a shit ton of offspring in one go and then they die)
when is semelarity favorable
when the environment is low-key tough so the parent is like if imma die I might as well js make a bunch of copies of genes
R-Selection
when an area is not near or at carrying capacity so there’s a lot of resources so organisms make a lot of offspring bc they’re like oh I might as well js take advantage of this stuff
The R in R-Selection is a variable for
exponential growth
When do organisms in R-Selection thrive
when there are many resources (because of exponential growth)
Do organisms in R-Selection need their parents and why
no since there’s so much child making parents don’t care for them cuz they don’t know if its their genes
K-Selection
reproduce a few offspring and generally care for them (near carrying capacity)
Where does R-Selection occur
Occurs in environments where resources are abundant, permitting exponential growth.
What is an example of organisms that are in K-Selection
mammals
What is the K in K-Selection
variable for carrying capacity
Population growth is limited by _____ _____ ______ in a K-Selection group
Density-Dependent Factors
Do organisms in K-Selection need their parents
yes to teach them how to get their own resources and care for them
Are all organisms strictly K or R selection
no many organisms such as trees can be classified as both
Demographic Transition
transition of a human population from high birth rate to low death rate
What does demographic transition generally talk about
whole nations
How many stages does demographic transition have
3
What are the steps of Demographic Transition
1) Group has high life and death rate
2) Group has high life rate and low death rate
3) Group has low life rate and low death rate
Why is the death rate high in stage 1
because of recent war, lack of sanitation, more elderly people,etc.
Why is the birth rate high in stage 1
to populate a society so children can help out and make money
Why is the death rate low in stage 2
better medicine, natural selection, increased agriculture, herding animals, technology
Why does the birth rate go up in stage 3
because people have realized the deaf rate is not high so they need to make more children to work
Age structure diagram
divides between males and femlaes and breaks down into ages usually into pre reproductive age, reproductive age, and past reproductive age
Age Structure Diagrams are usually only made with _____
humans
How many types of age structure diagrams are there
3
What are the 3 types of age structure diagrams
1) Rapid Growth
2) Slow Growth
3) Negative Growht
Ecological Footprint
the measure of the amount of natural resources being utilized and the amount of waste being produced in comparison to how nature can replenish those resources and recycle the waster
is it good to have a large ecological footprint
no
Sustainability
idea that we can live and thrive on the planet while leaving it in good shape for future generations.
intrinsic factor
if ppl in ur personal bubble u like get tf out ur too close
disease
if ppl too close disease will spread
toxic waste as density dependent
too much shit kill ppl
do we know what the human global carrying capacity is
no bc of tech + advancements
immigration
moving INTO another place
immigration
moving OUT OF another place
metapopulations
diff populations that can move to different places to share genes
population dynamics
change in population to become more or less stable due to death, birth, immigration, immigration,etc.
wen is a population stable
at carrying capacity
when is a population unstable
changing factors that make something not at carrying capacity
mark recapture method
used to estimate the size of a population where it is impractical to count every individual by capturing organisms, putting a mark on them, and then letting them back
