#### Transcript CP Ecology Notes Part 7

```Populations
A particular species living in a
particular place at the same time
Population Growth


Biotic Potential: The highest rate of
reproduction a population can reach.
Sentence:
Population Growth


Biotic Potential: The highest rate of
reproduction a population can reach.
Sentence: The biotic potential of fruit
flies is reached when 120 eggs laid by
the female hatch into successful
offspring.
Fruit Fly Population
Growth

Generation
1
2
3
4
5
6
7

# of Offspring
Fruit Fly Population
Growth

Generation
1
2
3
4
5
6
7

# of Offspring
120
Fruit Fly Population
Growth

Generation
1
2
3
4
5
6
7

# of Offspring
120
7,200
Fruit Fly Population
Growth

Generation
1
2
3
4
5
6
7

# of Offspring
120
7,200
432,000
Fruit Fly Population
Growth

Generation
1
2
3
4
5
6
7

# of Offspring
120
7,200
432,000
25,920,000
Fruit Fly Population
Growth

Generation
1
2
3
4
5
6
7

# of Offspring
120
7,200
432,000
25,920,000
1,555,200,000
Fruit Fly Population
Growth

Generation
1
2
3
4
5
6
7

# of Offspring
120
7,200
432,000
25,920,000
1,555,200,000
93,312,000,000
Fruit Fly Population
Growth

Generation
1
2
3
4
5
6
7

# of Offspring
120
7,200
432,000
25,920,000
1,555,200,000
93,312,000,000
5,598,720,000,000
Number of Flies
Fly generations
Number of Flies
Fly generations
The graph looks like the shape of what letter?
Population Growth

We call this type of curve a J – shaped
curve and the population growth it
represents exponential growth
Population Growth (cont.)


Population may be limited by factors
called Limiting Factors.
Examples:
Population Growth (cont.)


Population may be limited by factors
called Limiting Factors.
Examples:
– Water
– Shelter
– Nutrients
– Mates
– Nesting Sites
Population Growth

Carrying Capacity: The maximum
population of a particular species that
a given habitat can support over a
given period of time.
S - shaped Growth Curve
Number of
Individuals in the
population
K = Carrying
Capacity
Time




Growth = Births exceed Deaths
Decline = Deaths exceed Births
Natality: birthrate; the production of new
individuals by birth, hatching, germination,
or cloning.
Mortality: deathrate; the ratio of deaths in
an area to the population of that area.

Immigration: migration into a place

Emigration: migration out of a place
The number of organisms in a
population tends to rise above and fall
below the carrying capacity.
Number of
Individuals in the
population
K = Carrying
Capacity
Time
Limiting Factors

1.
2.
Limiting Factor: an environmental
factor that limits the growth,
abundance, or distribution of a
population of organisms in an
ecosystem (e.g. water, nutrients,
sunlight, prey, etc.).
Density Dependent
Density Independent
Density Dependent

Examples:
Density Dependent

Examples:
– Food
– Water
– Living Space
– Predation
– Disease: High densities makes it easier for
parasites to find hosts and spread the
disease
– Stress: usually has a negative effect on
populations. Stress can make organisms
weak and more prone to disease.
Density Independent

Examples:
Density Independent

Examples:
– Natural Disasters/Weather
(e.g. drought, hurricane, flood, fire)
– Sunlight
– Temperature
– Human Activities
Population Growth Practice:


Bacteria reproduce by splitting (binary fission).
A certain species reproduces every 20
how many cells will there be at the end of
3hrs?
Show your work in the form of a population
GRAPH. The independent variable is TIME and
the dependent variable is the
GROWTH/NUMBER of bacteria.
Note: Graph the time in minutes
Data:
Time
(in minutes)
0 min
20 min
40 min
60min (1hr)
80 min
100 min
120 min (2hrs)
140 min
160 min
180 min (3hrs)
Number of
Bacteria
1
```