Download Population Growth - Bethel Local Schools

Population Growth
Goals
Exponential Growth
Population Distribution
Logistic Growth
Carrying Capacity
Created: 9/13/13 Revision: 9/13/13
Revision Number: 0
Population Concept Map
Carrying
Capacity
Zero
Exponential
Growth
Models
Clumped
Uniform
Density &
Distribution
Plot
r
Populations
Type I
Survivorshi
p Curves
Sampling
Random
Life History
Patterns
Logistic
K
Type II
Type III
Mark
Goals
• Why study population?
• Introduce real life issues with populations.
• Collect data on population box.
Who Studies Populations?
Photos from http://www.ocearch.org/
http://limnology.wisc.edu
Why Study Populations?
Photos from http://rogerbourland.com/http://www.ocearch.org/
Endangered Species
http://worldwildlife.org/
COMMON NAME
SCIENTIFIC NAME
CONSERVATION STATUS ↓
Amur Leopard
Panthera pardus orientalis
Critically Endangered
Black Rhino
Diceros bicornis
Critically Endangered
Cross River Gorilla
Gorilla gorilla diehli
Critically Endangered
Hawksbill Turtle
Eretmochelys imbricata
Critically Endangered
Javan Rhino
Rhinoceros sondaicus
Critically Endangered
Leatherback Turtle
Dermochelys coriacea
Critically Endangered
Mountain Gorilla
Gorilla beringei beringei
Critically Endangered
Saola
Pseudoryx nghetinhensis
Critically Endangered
South China Tiger
Panthera tigris amoyensis
Critically Endangered
Sumatran Elephant
Elephas maximus sumatranus
Critically Endangered
Sumatran Orangutan
Pongo abelii
Critically Endangered
Sumatran Rhino
Dicerorhinus sumatrensis
Critically Endangered
Sumatran Tiger
Panthera tigris sumatrae
Critically Endangered
Vaquita
Phocoena sinus
Critically Endangered
Western Lowland Gorilla
Gorilla gorilla gorilla
Critically Endangered
Yangtze Finless Porpoise
Neophocaena asiaeorientalis ssp. asiaeorientalis
Critically Endangered
Hunting Limits
why-youmad.com
deertagmuseum.com
Gain and Loses in Population
Size
• What are some factors that can affect the
size of a population?
Ohio Treats
Photo provided by: www.nytimes.com
Populations
• Populations = N
• Organisms of the same species that
occupy a particular area and breed with
one another more than they breed with
members of other populations.
• Population size - is the number of
individuals in a population.
Plot Sampling and MarkRecapture
• Video on mark-recapture
• Simulation
Photos provided by: www.junicoast.gr
http://www.ocearch.org/
Population Density &
Distribution
• Population Density – number of
individuals per unit area or volume.
• Clumped – A patchy distribution of
resources encourages clumping.
• Near-Uniform- Competition for resources
can produce a near-uniform distribution.
• Random – When resources are uniformly
available and proximity to others neither
benefits nor harms an individuals.
Name The Population
A Distribution
B
C
Photos provided by:
wps.pearsoncustom.com
Population Box Activity
• Goals of Activity:
– Collect data on population (N) size.
– Collect data on population (b) births.
– Collect data on population (d) deaths.
– Graph data population size and time.
– Observe the trends of the data.
www.dailymail.co.uk
Peppered Moth Game
http://www.techapps.net/interactives/pepperMoths.swf
http://www.blackwellpublishing.com/
Homework
• What is poaching? Reflection?
• Look up some info on shark finning and
how it is affecting the population.
Population Growth
Goals
Exponential Growth
Population Distribution
Logistic Growth
Carrying Capacity
Survivorship
Created: 9/13/13 Revision: 9/13/13
Revision Number: 0
Mark-Recapture
(# Captured First Run)(# Captured Second Run)
--------------------------------------------------------------(# Tagged from Second Run)
• Video on mark-recapture
• Simulation
Photos provided by: www.junicoast.gr
http://www.ocearch.org/
Zero Population Growth
• Anyone Know?
What is Exponential Growth ?
• Anyone know?
• As long as the rate is constant and greater than
zero exponential growth will occur.
• Exponential growth when graphed out represents
a
J-shaped curve.
• The number of new individuals added increases
each generation, although the growth rate stays
the same.
• In exponential growth each generation is larger
than the prior one.
Variables and Equations
Variables
Population Size = N
Time = t
Growth Rate = r
Births = b
Deaths = d
Equations
r= (Births – Deaths) / N
dN/dt= r(N)
Time
Populatio
n
0
10
1
2
3
4
http://www.supercoloring.com/
J-Shaped Curve
Assess
• Supposed we have no deaths in a
population of 1 and we have a birth of
1.
• What is the growth rate?
Problem of the day.
Limiting Factor – is an essential resource that is
in short supply acts as a limiting resource.
Populations obliviously can’t exponentially grow
forever, there are factors that limit a population
and its size, list some limiting factors that
controls a populations growth.
Density - Dependent
• Factor(s) that limits population growth and
has a greater effect in dense populations
than less dense ones.
flyrv7.com
www.panoramio.com
Density-Independent
• Factor(s) that limits population growth and
arises regardless of population density.
www.wildlandfire.com
www.boston.com
Assess
www.dailymail.co.uk
jonlieffmd.com
Carrying Capacity (K)
• It is the maximum number of individuals
of a population that a given environment
can sustain indefinitely.
• Resources determine population size.
Question?
• Do you think there is a carrying capacity
for humans?
• One child policy
Exponential Growth (J-Shaped
Curve)
Exponential Equation
dN/dt = r(N)
t
N
0
2
30
http://www.supercoloring.com/
dN/dt
Logistic Growth (S-Shape)
Carrying Capacity Equation
dN/dt = r(N)(K-N/K)
r=1
K = 10
t
N
0
2
K-N/K
dN/dt
Logistic Growth (S-Shaped
Curve)
Inflection Point –
Point at which in the
logistic growth curve
where population
growth is maximal,
and after this point
the population starts
to slow growth.
peterhuff.wordpress.com
Rabbits and Grass
Bozeman Biology
Life History Strategies
Life History Pattern - How an organism
allocates its resources between growth,
maintenance, and reproduction over the course
of its lifetime.
r-Selected Species
• Adapted to conditions that change rapidly
and unpredictably.
• Density Independent factors effect them
the most.
• r-selected species produce multiple
offspring at once, maximizing offspring
quantity rather than quality.
r-Selected Species
•
•
•
•
Early Reproduction
Less Parental Investment
Short Life Span, high mortality rate
Short Development
www.lemonbayconservancy.org
info.franklinpestsolutions.com
K-Selected Species
• Adapted to life in a stable environment.
• Allow population size to approach carrying
capacity of the environment.
• Density-dependent factors limits individual
reproductive success.
• Favors individuals who maximize their
reproductive success by producing high
quality offspring capable of outcompeting
others for resources.
K-Selected Species
•
•
•
•
Long development
Later reproduction
More parental investment
Longer life span lower mortality rate.
www.wildaid.org
Survivorship Curves
Cohort – Group of
individuals born
during the same
time interval.
Survivorship
Curve – Graph
showing the
decline in
numbers of a
cohort over time.
biology-forums.com
Asses Endangered Species
Homework
Self-Quiz pg. 806-807
2,3,6,10,11, and 13
Critical Thinking pg. 807A
1,5,7, and 9
Exponential Growth (J-Shape Curve)
Variables
Growth Rate = r
Births = b
Deaths = d
Population = N
Carrying Capacity = K
Time = t
Equations
(Births –
Deaths)
r = ---------------------N
ΔN
1.) Starting population is 10.
----- = r (N)
2.) We birth 5 rabbits, and 2 die.
Δt
3.) Calculate growth rate.
4.) 5-2 / 10 = 0.3 = r
5.) Calculate the change in population over time
6.) ΔN/Δt = 0.3(10) = 3
7.) 3 + 10 = New Population = 13
8.) Starting population is 13.
9.) Growth rate is constant
10.) Use previously calculate r = 0.3
11.) Calculate the change in population over time
12.) ΔN/Δt = 0.3(13) = 3.9
13.) 3.9 + 13 = New Population = 17
Data Given
t
N
0
10
1
t
N
0
10
1
13
2
17
Exponential Growth (J-Shape Curve) leading into Carrying
CapacityVariables
K.
Equations
Data Given
Growth Rate = r
Births = b
Deaths = d
Population = N
Carrying Capacity = K
Time = t
(Births –
Deaths)
r = ---------------------N
ΔN
1.) Starting population is 2.
----- = r (N)
2.) We birth 2 rabbits, and 0 die.
Δt
3.) Calculate growth rate.
4.) 2-0 / 2 = 1 = r
5.) Calculate the change in population over time
6.) ΔN/Δt = 1(2) = 2
7.) 2 + 2 = New Population = 4
8.) ΔN/Δt = 1(4) = 4
9.) 4 + 4 = New Population = 8
10.) ΔN/Δt = 1(8) = 8
Use the r = 1 to take to the next slide
ΔN/Δt
t
N
0
2
t
N
ΔN/Δt
0
2
2
1
4
4
2
8
8
3
16
16
Logistic Growth Carrying Capacity K (S-Shaped Curve)
Variables
Growth Rate = r
Births = b
Deaths = d
Population = N
Carrying Capacity = K
Time = t
Equations
(Births –
Deaths)
r = ---------------------N
ΔN
----- = r (N)
Δt
ΔN
(K-N)
----- = r (N) ---
Data Given
t
N
0
2
Data
K-N / ΔN/Δ
K
t
1.) Using r = 1 from previous slide
2.) Solve K-N/K, 10-2/10 = 0.8
3.) Solve ΔN/Δt = r(N)((K-N)/N), ΔN/Δt =
(1)(2)(0.8)= 1.6
4.) Solve 1.6 + N, 1.6+2 = 3.6
5.) Repeat Previous Steps
6.) Solve K-N / K, 10-3.6 / 10 = 0.64
7.) Solve ΔN/Δt = r(N)((K-N)/N), ΔN/Δt =
(1)(3.6)(0.64)= 2.3
8.) Repeat Previous Steps
Notice how the population gets so close
to the carrying capacity, I didn’t round
any figures in this problem so we can
observe the 9.99 value.
r =1 K =
10
t
N
K-N
/K
ΔN/
Δt
0
2
0.8
1.6
1
3.6
0.64
2.3
2
5.9
0.41
2.4
3
8.3
0.17
1.4
4
9.7
0.03 0.29
5
9.99 0.00 0.00
1
9
• Equations and explanation from
Bozeman Science, click the links (words)
below for a step by step explanation.
• Exponential
• Logistic
Evidence of Life History
Patterns
• Life History is a set of traits related to
growth, survival, and reproduction, such
as age-specific mortality, life span, age of
first reproduction and number of breeding
events.
– Evolutionary Biologists J. Endler and D.
Reznick studied the effects of predation on life
history traits.
– Pressures such as predation and commercial
fishing may change life history patterns
influencing the evolution of a species.
Human Population Growth
• The population growth rate of humans
began to increase about 10,000 years ago
and during the last 2 centuries it has
SOARED.
• 3 Trends promoted the large increases
– 1st Humans were able to migrate into new
habitats
– 2nd Humans developed new technologies that
increased the carrying capacity.
– 3rd Humans sidestepped some limiting factors
Human Populations
• Historically disease always kept population
growth regulated (density dependent
factor)
– 1300’s Black Death killed 1/3 of Europeans!!
– Twelve disease that altered our history
Things began to change
– 1700’s Edward Jenner demonstrates the
effectiveness of vaccines against small pox.
– Mid 1800’s Ignaz Semmelweis began urging
surgeons to wash their hands between
patients.
– 1800’s Louis Pasture popularized the idea
that unseen organisms cause disease.
(pasteurization)
– Late 1800’s first modern sewers in London
divert waste water from drinking water areas.
– Early 1900’s chlorination and sterilization of
drinking water.
Population Demographics
• Total fertility rate of a human population is
the average number of children born to a
woman during her reproductive years.
• Age structure greatly affects a population’s
growth rate.
– China and India have more than 1 billion people
a piece.
– Next highest is the US with 310 million.
• The broader the base of an age structure
diagram, the greater the anticipated
population growth.
Demographic Transition
• Demographic factors vary among
countries, with the most highly developed
countries having the lowest fertility rates
and infant mortality and the highest life
expectancy.
• Demographic transition models describe
how changes in population growth often
occur in four stages of economic
development.
Stages of Demographic
Transition
• Preindustrial stage- before technological and medical
advances, birth and death rates are high, growth rate
low.
• Transitional stage- industrialization begins, food
production and healthcare improve, death rate drops
fast, birth rate decline more slowly, population growth
rate increases rapidly.
• Industrial stage- birth rates decline, move from farms to
cities, birth rates move closer to death rates, population
grows less rapidly.
• Postindustrial stage- populations growth becomes
negative, birth rate falls below death rate and population
size slowly decreases.
Sustainability
• Sustainability is the ability for a system to supply
resources needed, while never running out of
those resources.
• Per capita resource consumption rises with
economic and industrial development.
• Ecological footprint is the amount of Earth’s
surface required to support a particular level of
development and consumption in a sustainable
fashion.
• For everyone now alive to live like an average
American would require four times the
sustainable resources available on Earth.