Transcript Peppy Population - Pregitzersninjascienceclasses

Peppy Population
Riddle: A father complained that his son’s allowance of $5
per week was too much. The son replied, “Okay, dad. How
about this. You give me a penny for the first day of the
month, 2 cents for the next, 4 cents for the next, 8 cents for
the next and so on for every day of the month.” The father
readily consented!
Who was more clever?
What would be the son’s allowance for day 31?
Peppy Population Terms
Population- The number of a certain
species living in the same place at the
same time.
Changes in Population
Natality- Birth rate
Mortality- death rate
Immigration- number
of individuals moving
into an area
Emigration- number
of individuals moving
out of an area (exit)
Carrying Capacity
Maximum number of
individuals an area
can sustain or support
for a long time
How many Homo Sapiens can
Earth support???
Doubling Time
Time it takes for a
population to double.
Bacteria can double
every 20 minutes!



1 bacteria at 8am
4096 bacteria by noon
134,217,728 by 5 pm
Proper Population Problems
Step 1: Make two columns… one for increase
and one for decrease
Step 2: Fill in your chart with the natality and
immigration in increase column and mortality
and emigration for decrease.
Step 3: Figure out change. Were there more in
the increase or decrease column.
Step 4: Circle increase or decrease
Step 5: Do the math to figure out by how much!
Let’s Do a Class Example…
Initial population___34___
Increase
Decrease
+3
-5
+1
-2
=4
= -7
Difference- 4-7=-3
Increase or Decrease
At what rate? -3/ year
Predict the population after three years of this
change 34-3= 31- 3= 28 – 3= 25
Now you try…
A peppy, yet pesty population of cockroaches was
observed over one year. During that time there were 500
births, YUK! There were 100 deaths (humans love to
squash those pesky roaches). There were 50 immigrants
to the population and 40 roaches left to go live in a
cracker box down the road. Is the population increasing
or decreasing and at what rate?
Increase
Decrease
+500
-100
+50
-40
= + 550
= -140
Difference of +550 – 140= +410
YUK!