Study of Abiotic and Biotic Factors
Objective:
 Characterize the biotic and abiotic components that define freshwater systems, marine systems and terrestrial systems.
Purpose of the Lab/Activity:
 Identify organisms living in the soil, plants, insects, and any other animals living within the site.
 Examine abiotic factors in the same study site.
 Compare abiotic and biotic factors in an ecosystem.
Prerequisites:
 Understand the role of photosynthesis in ecosystems.
 A general sense of the major groups of organisms in order to help determine their role and habitat.
 Knowledge of weather instrumentation and soil analysis kits.
Problem Statement: What are the biotic and abiotic components of an ecosystem?
Background:
An ecosystem can be divided into biotic and abiotic components. The community of the organisms living in the area comprise of the biotic
components of the ecosystem. The community includes the organisms and actions such as mutualism and predation. And the environment in
which the organisms thrive is the abiotic ecosystem. The abiotic components include the energy produced through the cycling of nutrients, the
solar energy, and other non-living components in the ecosystem. The abiotic components of the ecosystem can be temperature, light, air
current, etc.
Biotic components shape an ecosystem and are the living components in the organism’s environment. In a grassland ecosystem, biotic
components can be categorized as producers, consumers, and decomposers. The producers capture the solar energy, use the nutrients available,
and produce energy. For example, grasses, trees, lichens, cyanobacteria, etc are producers. Consumers do not have the ability to produce or
capture energy on their own and depend on the producers. They are the herbivores, carnivores, and omnivores. Decomposers break down the
organic layer providing nutrients for the producers. Insects, fungi, bacteria, etc. are examples of decomposers. In the grassland ecosystem, soil
is the important link between the biotic and abiotic components.
Abiotic factors affect the living organisms in a community. In a barren ecosystem new organisms start colonizing the ecosystem. They depend
on the environmental components to thrive well in the system. These environmental components which facilitate the thriving of the organisms
are the abiotic factors. It can be the soil, climate, water, energy, and anything helping the sustenance of the organism. The abiotic components
impact the evolution cycle.
In an ecosystem, if one factor is altered, it can impact the whole system. The availability of the other resources in the system can be impacted
as a whole. Human beings are capable of altering the physical environment through development, construction, farming, and pollution. As a
result the abiotic components in the system change and affect the biotic organisms. Global warming affects many organisms like plants and
microbes. Acid rains have resulted in the destruction of the fish population.
Pre-Lab:
Think of favorite outdoor spot. Close your eyes and spend a couple of minutes imagining it in your head. Now write a description that includes
biotic and abiotic factors you see there.
Vocabulary: ecosystem, environment, abiotic, biotic, temperature, pH, plant, insect, bird, mammal, reptile, amphibian, soil, wind,
anemometer, wind vane
Safety: Do not touch poisonous plants or animals.
Extension:
 Show video clip: Abiotic vs. Biotic
 Interactive Lab: How do organisms react to changes in abiotic factors?
 Gizmo: Pond Ecosystem
Materials (per group):
 4 stakes
 hammer
 measuring rope (10 m) marked in meters
 soil pH test kit




thermometer
wind vane
anemometer
trowel or hand shovel
Procedures:
1. Select a study site close by.
2. Groups will accomplish the following tasks: (the list gives the name of the group and the procedure for that group)
a. Staking (3 students minimum). Using the measuring rope, mark a 10 m x 10 m square. Mark the corners of the square and
rectangles with stakes, and then connect the stakes with string. At the end of the period rewind the string and take up the stakes.
b. Trees (a plant with a stem more than 1 cm. in diameter): Count each type of tree in the 10 m x 10 m square.
c. Shrubs (a plant with a stem greater that .5 cm. in diameter but less than 1 cm. in diameter): Count each type of shrub in the 10 m
x 10 m square.
d. Primitive plants (a plant with a stem less than .5 cm in diameter): and Herbs (ferns, mosses, liverworts, etc.): Count each
one in the 10 m x 10 m square.
e. Insects: Count and identify insects collected, then release them.
f. Birds: Count and identify any birds in the vicinity of the study site.
g. Mammals, reptiles and amphibians: Look for tracks, burrows, or other signs of these animals in or near the 10 m x 10 m area.
Identify animal or its sign. DO NOT PICK UP ANY SNAKES.
h. Temperature: Take the air temperature at head, shoulder, waist, knee, and ground level in the open, under a tree, and under a
shrub.
i. Soil: Take soil samples at the same location as the soil and litter group. Follow directions of the soil pH kit. Describe the color
and texture of the soil.
j. Wind: On the first day, set out the rain gauge in the study site at a location that is not sheltered by vegetation. Check each day for
any rain. Read and record.
k. Description: Describe what the study site looks like. Try to paint a picture with words.
3. Each student is responsible for finding ecological relationships and identifying it within the study area.
4. Return to classroom and share data. Some groups may need help with identifying their samples.
Observations/Data:
# Identified
(divided by type)
Trees
Shrubs
Primitive Plants
Herbs
Insects
Birds
Mammals
Reptiles
Amphibians
Temperature
Soil
Wind
Description
(by type)
Abiotic /
Biotic
Data Analysis:
Create a sketch of your ecosystem. Color code the abiotic and biotic components.
Sketch of School Yard Ecosystem
Results/Conclusion:
1.
2.
3.
4.
5.
6.
7.
8.
What are abiotic factors? Identify at least three abiotic factors in your ecosystem.
What are biotic factors? Identify at least three biotic factors in your ecosystem
Predict the role of abiotic factors on an ecosystem.
Using the information you have, construct an energy-flow diagram for the area.
Show the abundance and type of producers, consumers, herbivores, carnivores, and decomposers in the food web. This may be
diagrammed.
Describe examples of 3 different ecological relationship you saw in the ecosystem (symbiosis, competition, predation/disease)
Describe the niche of one organism to the best of your ability.
Can you see any relationship between the abundance of an organism, its size and its place in the food chain? Explain.