Study of Abiotic and Biotic Factors
NGSSS:
SC.912.L.17.7 Characterize the biotic and abiotic components that define freshwater systems, marine
systems and terrestrial systems.
Background:
An ecosystem can be divided into biotic and abiotic components. The communities of the organisms
living in the area are the biotic components of the ecosystem. This includes the organisms and their
actions such as mutualism and predation, to name some. The environment in which the organisms
thrive is the abiotic component of the ecosystem. The abiotic components include the energy produced
through the cycling of nutrients, the solar energy, and other non-living components in the system.
Temperature, light, air current, etc. are all abiotic components of the ecosystem.
Biotic components shape an ecosystem and are the living components in the organism's environment.
In a grassland ecosystem for example, the biotic components can be categorized as producers,
consumers, and decomposers. The producers capture the solar energy, use the nutrients available to
them, and produce energy. 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 to survive.
They are the herbivores, carnivores, omnivores and detritivores. Decomposers break down the organic
material 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 since they depend on the environmental
components to thrive well in the system. In a barren ecosystem new organisms start colonizing it and
these environmental components or abiotic factors are the ones that facilitate the thriving of the new
organisms. These factors can include the soil, climate, water, energy, and anything helping the
sustenance of the organism.
In an ecosystem, if one factor is altered, it can impact the whole system. The availability of the
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, which affects
many organisms like plants and microbes, is an example of how humans have changed the physical
environment. Acid rains, also caused by human activity, have resulted in the destruction of certain
populations in an ecosystem. This is why by familiarizing ourselves with both the biotic and abiotic
factors of an ecosystem we can better understand how they are related and adjust our actions to protect
the environment instead of harming it. This lab will help you get acquainted with both the biotic and
abiotic factors of an ecosystem.
Problem Statement: What are the biotic and abiotic components of an ecosystem?
Safety: Do not touch poisonous plants of animals. If in doubt, don't touch it!
Vocabulary: ecosystem, environment, abiotic, biotic, temperature, plant, insect, bird, mammal, reptile,
amphibian, soil, wind.
Materials
•
4 stakes
•
hammer
•
rope or twine (40 m)
•
•
•
thermometer
pH test kit
trowel or hand shovel
Procedure:
1.
Select a study site.
2.
Groups will accomplish the following tasks:
•
Staking Group: Using the measuring rope, mark a 10m x 10m square in the selected area.
Mark the corners of the square with stakes. Connect the stakes with the rope or string. At the end of
the lab you are responsible to rewind the string or rope and collect the stakes.
•
Trees Group: You will count each type of tree in the marked area. In order to count a plant
as a tree, it must have a stem that is more than 1 cm in diameter. Record your count and
observations in the table.
•
Shrubs Group: You will count each type of shrub in the marked area. In order to count a
plant as a shrub, it must have a stem of more than 0.5 cm but less than 1 cm in diameter. Record
your count and observations in the table.
•
Primitive Plants Group: You will count each type of primitive plant in the marked area. In
order to count a plant as a primitive plant it must have a stem that is less than 0.5 cm in diameter.
Record your count and observations in the table.
•
Insects Group: You will count and identify each insect collected. Record your count and
observations in the table and make sure to release the insects afterward.
•
Birds Group: You will count and identify any birds in the vicinity of the study site. Record
your count and observations in the table.
•
Mammals, Reptiles and Amphibians Group: You will look for tracks, burrows, or other signs
of these animals in or near the marked area. Count the tracks, burrows or other signs that you find. If
you see one of these animals, count it and identify it. DO NOT PICK IT UP WITHOUT MY
AUTHORIZATION!!! Record your count and observations in the table.
•
Temperature Group: You will take the soil temperature in the open, under a tree and under a
shrub within the marked area. Record at least 3 temperatures for each location, the record the average
temperature for each location in the table.
•
Soil Group: You will take soil samples out in the open, under a tree and under a shrub within
the marked area. Describe the color and texture of the soil in each sample. If available, use a pH kit to
test the pH of the soil in each location. Record your results and observations in the table.
•
Description Group: You will describe the whole study area, what the site looks like. Try to
paint a picture with words, or draw an actual picture of the area. Make sure to include as many details
as possible.
3. Once every group has finished their task we will share all the information so that every student has a
completed table.
DATA TABLE
Number identified
(divided by type)
Trees
Shrubs
Primitive Plants
Insects
Birds
Mammals
Reptiles
Amphibians
Open:
Under Tree:
Temperature
Under Shrub:
Open:
Under Tree:
Soil
Under Shrub:
Description and Observations
(by type)
Is this an
Abiotic or
Biotic Factor?
Data Analysis:
Create a sketch of your ecosystem. Color code all the abiotic and biotic components in your sketch.
Make sure to indicate which color represents each in the legend.
Legend:
Abiotic Components
Biotic Components
__________________________________________________________________________________
Results and Conclusion:
Using the information gathered in this investigation, write an analysis where you address the following
questions:
 What ecological relationships did you observe? Give specific examples of each.
o These may be feeding relationships, energy-flow relationships, etc.
 Describe the niche or role of one of the organisms found to the best of your ability.
 Discuss if you saw any relationships between the abundance of an organism, its size and its
place in the food chain.
o For example, if you observed many cows, what was their size, and why do you think
that there is an abundance of cows in the marked area? (Don't use cows in your
analysis as this is only an example, use one of the organisms observed, whichever
you found to be more abundant.)
 Discuss how the abiotic factors affect the biotic factors of the ecosystem in the selected area.