1. (S-shaped). The curve has three distinct regions.B A
A typical line graph for population growth shows a curve that is sigmoidal
(S-shaped). The curve has three distinct regions.

2. A. Region of slow population growth:
• Only a small number of organisms are sexually mature and able to reproduce.
• The organisms may be adjusting to a new environment. A

3. B. Region of rapid population growth:
• Many organisms have reached sexual maturity. They are able to reproduce.
• The organisms have adjusted to the conditions around them.
They have
found food, shelter, and water for survival.

4. C. Region of steady population growth:
• The carrying capacity is reached. Population growth becomes constant.
• The number of deaths equals the number of births.

5. Unrestricted Population
Year
# of Mating Pairs
# of Offspring
Total # of rats 10 20 1
10 x 4 = 60 2 30
30 x 4
180 3 90
90 x 4
540 4
270
270 x 4
1620 5
810
810 x 4
4860

6. Rat Population Unrestricted Growth
5000
4000
3000
2000
1000
Year

7. Population Control Populations are controlled by Limiting Factors
May be
May be
Density
Independent
Density
Dependent
Effect is
Effect is
Same regardless
of population
size
More intense as
population increases
examples
examples
competition
disease
Food
supply
climate
Oxygen level
Natural
disasters
parasitism
predation

8. Population Terms
When two organisms from the same species are after the same resources and food they are in intraspecific competition
When a population has reached an amount where growth can no longer occur, it has reached its carrying capacity
The number of organisms that live in a given area can be referred to as population density
The relationship between two different organisms (either from the same species or from different species) after a common goal can be called competition

9. 5) When two organisms from different species are after the same resources and food they are in interspecific competition
6) Factors that increase in significance as a population grows are called density-dependent.
7) Factors such as forest fires, than can limit a population regardless of its size are referred to as density - independent.
8) Give a concrete example to show that you understand each term below.
Interspecific competition wolf and coyote
Intraspecific competition wolf and wolf

10. 9) Compare and contrast density-dependent and density –independent factors. Write words that show similarities where circles overlap. Write words what show contrasts inside the circles.
Density-dependent factors
Density-Independent Factors
Water supply
Natural disasters
Population
density
Food supply
Chemicals (poisons)
space
Climate
disease