Section 13.1: Ecologists
Study Relationships
Biology
Objectives
 What do ecologists study?
 Explain the different levels of organization seen in
ecology.
 Describe in detail the three different methods used in
ecological research, and give an example of each.
 Observation
 Experimentation
 Modeling
Ecology
 Ecology is the study of the interactions among living
things, and between living things and their surroundings
 Plants and animals do not exist in isolation, they affect
each other
Levels of Organization
 Study of nature from local to a global scale
 Organism: An individual living thing
 Population: Group of the same species that live together in one
area
 Community: Group of different species that live together in one
area
 Ecosystem: Includes all organisms as well as climate, soil,
water, rocks, and other non-living things in an area
 Biome: Regional or global community of organisms
Ecological Research Methods
 Variety of methods and tools used, including:
 Observation
 Experimentation
 Modeling
Observation
 The act of watching something over a period of time
 Can be long or short depending on what you are observing
 Visual Surveys:
 Direct: Watch animals with naked eye or with tools to help
the naked eye
 Indirect: Signs of presence, which could include feces or
recent kills
 Radio Telemetry: Use of a radio collar to track movements
 Can you think of different species you could use one of
these tools on?
Observation
 Population size is also an important piece of information to
ecologists
 To do this they generally use a sample of the population
instead of attempting to count EVERY member of a
population (imagine how difficult THAT would be)
 Mark-Recapture: Scientists catch and mark an animal, then
release it back into the wild
 When animals are recaptured they take note of marked and
unmarked animals
 This allows them to estimate the total population size
Observation
 Calculating Plant Populations = Quadrat Sampling
 Rectangular frames are placed randomly on the
study site
 Plants are identified and counted within the plot
 The number of counted plants is then entered into a
mathematical formula to determine the plant
population of the entire study site
Quadrat Sampling
1. Measure and calculate the area (ft2) that you will be
studying
2. Measure and calculate the area of your quadrat.
3. Place your quadrat in three random (non-overlapping)
spots of your study area
4. Count the number of species per quadrat and enter
into a table
Quadrat Sampling
10 Feet
6
F
e
e
t
Quadrat Sampling
10 Feet
6
F
e
e
t
Total Area = Base x Width
Total Are = ?
Quadrat Sampling
10 Feet
6
F
e
e
t
Quadrat = 1 ft x 1 ft
Total Area = ?
Total Area = 60 ft2
Total Area = 60 ft2
Quadrat Sampling
10 Feet
6
F
e
e
t
Quadrat = 1 ft2
Total Area = 60 ft2
Quadrat Sampling
10 Feet
6
F
e
e
t
Quadrat = 1 ft2
Total Area = 60 ft2
Quadrat Sampling
10 Feet
6
F
e
e
t
Quadrat = 1 ft2
Total Area = 60 ft2
Quadrat Sampling
10 Feet
6
F
e
e
t
Quadrat = 1 ft2
Quadrat Sampling
Quadrat #
Banana
Lettuce
Red Pepper
1
0
0
0
2
1
1
1
3
0
0
1
Total
1
1
2
• Total Population = NA (of same species)
• N = Total number of individuals counted / number
of quadrats
• A = Total area/ Area of Quadrat
Quadrat Sampling
Quadrat #
Banana
Lettuce
Red Pepper
1
0
0
0
2
1
1
1
3
0
0
1
Total
•
•
•
•
1
1
2
Total Population = NA (of same species)
N = 1/3 = 0.33
A = 60 ft2 / 1 ft2 = 60
T = (0.33)(60) = 19.8 individual bananas
Quadrat Sampling
Quadrat #
Banana
Lettuce
Red Pepper
1
0
0
0
2
1
1
1
3
0
0
1
Total
1
1
2
• Now find the total population estimate for lettuce
and red pepper
• Can you identify any problems with our
experiment?
Experimentation
 Occurs in the lab or in the field, each with its own set of
pros and cons
 Lab Experiments:
 Gives a significant amount of control
 Does note reflect the complexity of interactions in nature
 Field Experiments:
 Give an accurate picture of organisms interacting in a natural
setting
 Difficult to determine cause and effect due to large number of
compounding factors
Lab Experimentation
 Controlled, indoor environment
 Allows focus on one specific part of an ecosystem, such
as a single organisms
 Allows control of variables that would not be possible in
the field
 Can you think of something that would be better
studied in a lab and not in the field (another example
other than the one given in the book…)?
Field Experimentation
 Performed where organisms live
 Have controls and manipulated variables
 In the book example, look at how browsing by deer
affects plant and small animal communities
 Fence off parts of an area to keep deer out
 Determines how deer affect the areas where they
browse for food
 Can you think of another field experiment?
Modeling
 Some questions are difficult to answer either through
observation and/or experimentation
 Computer and mathematical models are then used to
help describe and model nature
 Allows manipulation of whole ecosystems that would not
be possible in nature
 Models are created with the use of real data, even
though they test hypothetical situations
Modeling
 Creating a virtual model of Yellowstone




Movement of elk, bison, bear, and wolf
Location of different types of vegetation
The amount of snow
Activities of geothermal landforms (geysers)
 Creating an ecosystem along with a map allows for the
hypothetical manipulation of one variable at a time to
witness overall changes to the ecosystem
 Used to study the reintroduction of gray wolves into the
park and surrounding areas
 How would we use a model to study something in our
ecosystem?
Output
 With your table partner calculate the total population
estimate of the study area and quadrat handed out to
you by Mrs. Lorenz.