Is the Bacteria Living in Our
Environment Harmful To us?
Disease Ecology:
Bacteria
A presentation created by: Tamanisha John & May Choi
What is Disease Ecology?
Ticks are skin parasites. They like
motion, warm temperatures, and
carbon dioxide exhaled by
mammals.
Disease Ecology is the
study on how diseases
spread through and
impact host populations,
and how hosts, pathogens,
and their environment
react and evolve in
response to one another.
I. What are Bacteria?
Bacteria are living singlecelled organisms who
are neither plants nor
animals. Instead, they
belong to their own
group.
Living Organisms Below:
Plants
Bacteria
Animals
single-celled microorganisms
appeared on earth about 4 billion
years ago. Scientists say they were
the first life forms on Earth.
II. What Are Bacteria?
Bacteria come in three
main shapes:
Spherical (like a
ball)
Rod Shaped
Spiral
Spherical are usually referred to as cocci
Rod Shaped are usually referred to
bacilli
Spiral are usually referred to as spirillia
Did you know that
Planet Earth is estimated to
hold at least 5 nonillion bacteria!
(Nonillion in U.S. means there are
30 zero’s after a number,
while in the U.K there are 54 zero’s
after the number.
We’re using the U.S. version)
(medicalnewstoday.com)
Bacteria: The Good, The Bad, &
The Ugly
Why do you
think we used
tooth pictures?
The Good:
The Bad & The Ugly:
Without bacteria we would die. The
good bacteria help us digest our
food and they live on our skin and
in our mouth to provide protection
against bad bacteria.
Simply put, can either
make us sick or dead.
Agar V.S. Gelatin
Jell-O
Why Can Gelatin Substitute Agar?
Gelatin can substitute agar because they are both
gelling agents. Agar, however, is more preferable
due to its long term solidity, meaning that unlike
gelatin, which is liquefied easier, agar will stay solid.
Think of Gelatin as ice, it
won’t stay solid forever.
The Aim Of Our Experiment:
Is to figure out whether or not the bacteria in our
school have a negative or positive impact on our
environment. To decide whether or not they are
harmful, we plan to harvest the bacteria we collect and
place it on an apple slice in order to see whether the
apple slices rot or turn bad quickly. If the bacteria have
a negative affect on the apple slices, it will probably be
a bad thing for our environment.
Our Hypothesis
Since bacteria can only be considered very dangerous
in large amounts, but even then, small amounts of
bacteria can reproduce rapidly, we do not think that
the bacteria in our school is any more harmful than
the common cold because we all act and interact with
our environment daily and nothing too serious (like
someone dying) happens.
Do you think the
bacteria in our school
is dangerous?
Materials:
Gelatin (Jell-O),
Microscope, Beaker with
Water, 3 Q-tips, 3 Petri
Dishes, 3 Zip Lock
Baggies, Marker, Knife,
Gloves, Tape, Bleach,
Apple
Before Starting Our Experiment:
we collected bacteria from a toilet handle in the girls
bathroom, one of the computer keyboards in Meghan’s
office, and one of the auditorium chairs in the auditorium.
Then we swiped the collected bacteria in our Gelatin,
secured our collected data and went on winter break
The Experiment
Safety Steps to Consider:
1.Wear Gloves when handling bacteria
2. Wash Hands Frequently
3. Bleach bacteria at the end of experiment
What Do They All Have In
Common?
Mold!
Mold is a type of fungus (an organism that lacks chlorophyll and feeds
on organic matter) and some funguses are pathogenic. Mold travels
through the air in the form of tiny spores (not visible to the naked eye)
and like to make their way to damp and moist areas so that they can
breed and multiply.
Data and Results:
25
20
Control
15
Girls Bathroom
10
M e ghan's Office
Auditorium
5
0
1/5/2011
1/6/2011
1/7/2011
All of the apple slices weight gradually decreased as they started to
rot. However, our control’s apple slice weighed more than any of the
other apple slices indicating it wasn’t rotting as quickly. We noticed
that our control’s apple slice will decreased by about 2grams while all
the other slices decreased by about 3grams.
I. Observations
On the second day of our experiment (1/6/2011), we observed
that our control apple slice and the one with bacteria from a
keyboard in Meghan’s office were soft around their edges, but
hard on their backs and middle slice while the other two were
softer.
II. Observations
On the second day we also noticed that our mold turned grey,
which, according to gardenline.usask.ca , means that our mold
must’ve gotten cooler and wetter than before, which did
happen since each day our Gelatin got more liquefied.
& Our Hypothesis Was…
Partially Correct! During the course of
our experiment, we found the bacteria
from the toilet handle in the girl’s
bathroom can be considered dangerous.
Looks like my
job won’t be
over
anytime soon
Thinking Outside The Box
To figure out why the girls bathroom
bacteria rotted its apple faster than
any other bacteria, besides the fact
that it must’ve multiplied faster, we
ran a survey in our school surveying
25 girls (both teachers and
students), in order to figure out how
they flush the toilet. Out of the 25
girls surveyed, 20 flushed the toilet
with their feet, while 5 girls flushed
the toilet with their hands.
Sources Of Error
•Other occurring experiments that could’ve added carbon to the air (i.e.
the experiments with fire)
•Natural air borne bacteria which could have had an effect on the
rotting processes of our apples, since they could have been attracted to
the bacteria we collected and put on them and speeded up the rotting
process
•Survey’s small sample size
Future Experiment:
Only collect bacteria from the girl’s bathroom toilet handle, but a week in
advance, “monitor” or put up a sign in the girl’s bathroom saying ‘Do Not
Flush Toilet With Your Shoes, Experimental Reasons,’ in order to collect
more accurate data without the possibility of shoe germs.
Why Would You Do That?
While conducting our survey, the usual response was: “Ew,
who touches that dirty handle?” If every girl assumes the
handle is dirty, then there’s less of a chance that any of
them would want to touch the handle, therefore, they will
use their shoe and shoe germs will get on the handle.
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