Unit 7: Ecology
Left Side
Pg # Right Side
Pg #
Unit Page
34
Table of Contents
35
Levels of Organization
36
C.N. – Ecology Part 1
37
Sources of Energy Tree Map
38
C.N. – Energy Flow
39
Food Chain Activity
40
Food Chain/Web Worksheet
41
Community Interactions Tree
Map
42
C.N. – Community
Interactions
43
Population Growth
44
C.N. – Populations
45
Populations
Chapter 5-1
Population Ecology
Population: group of individuals of
the same species living in an area.
The size of a population can effect its
interactions within an ecosystem.
There are several factors that
determine the size of a population.
Characteristics of Populations
3 Characteristics of a Population
1) Geographic Distribution: describes
the area inhabited by a population
2) Population Density: the number of
individuals in a given area
3) Growth Rate: rate at which a
population increases or decreases
Population Size
Population size is affected by:
Things that cause a population to
GROW:
1) Births
2) Immigration (new individuals
join a population)
Things that cause a population to
DECLINE (decrease):
1) Deaths
2) Emigration (individuals move
out of the the population)
Limiting Factors
2 Types of Factors limit population growth
(result in deaths & population decline):
1) Density-dependent
The larger the population, the faster
resources are used.
This results in limiting factors such as:
 Competition for food, water, space, & mates
 Disease and Predation
2) Density-Independent
Limiting factors like natural disasters,
climate changes, and temperature can
affect any population, regardless of its
size
Lynx & Hare
Populations
Patterns of Growth
1) Exponential Growth
2) Logistic Growth
1) Exponential Growth
Under ideal conditions, individuals in a
population reproduce at a constant
rate
Many births & few deaths
Must have:
unlimited resources
no predators or disease
Produces J-shaped curve
Exponential
Growth Curve
Model for Exponential
Growth
In natural
conditions,
exponential growth
does not last long.
Limiting factors
control how large a
population can
grow.
Logistic Growth
Logistic Growth: as
resources become limited, a
population’s growth slows
or stops
The population reaches the
limit the environment can
support
Produces a S-shaped curve
Logistical
Growth Curve
Carrying Capacity: the maximum # of
individuals the environment can
support
The population size has leveled off
Birth rate = death rate
# of immigrants = # of emigrants
Human Population
Currently, the human population is
growing at an exponential rate.
With more people on the
planet, we require more
resources to keep us alive and
produce more waste with our
activities.
Most ecological problems are
caused by human activities.
Habitat destruction, pollution,
global warming, ozone depletion,
and endangered species