Transcript Is It Alive?

Is It Alive?
Unknown #2
Chris, Isabelle, Max and Perla
What did we do to
investigate the answers to
your questions?
What questions did we
try and answer?
1. Is it made of one or more cells?
2. Does it adapt to different
environments?
3. Does it convert energy?
4. Does it grow and develop?
5. (Does it reproduce?)
1.
2.
3.
4.
We looked at it under the microscope and
compared it to other pictures of cells.
We put the sample into different environments
and then observed any changes in size, shape,
color, movement, and growth.
We put food (sugar) with the Unknown to see if it
produced carbon dioxide and then placed it into
bromothymol blue to see if it changed from blue
to green or yellow.
We measured the growth and development of the
Unknown in different environments.
The Environments That We Used To
Stimulate Growth and The Organisms We
Expected To Thrive In Them
Environments to stimulate growth:
Organisms expected to thrive in each
environment:
Soil
Plant
Wet Paper Towel
Plant
Sugar Water
Bacteria, animal, microorganism, algae
Salt Water
Bacteria, animal, microorganism, algae
Room Temperature Water
Algae, microorganism
Warm Temperature
Animal from an egg, algae
Room Temperature
Control/Used to measure the Unknown’s
response
Cold Water
Used to measure the Unknown’s response
Results
Does It Have Cells?
Characteristics To Determine Whether Or Not It Has Cells:
•We looked at other pictures of cells under the microscope and
compared them to our unknown under the microscope
•We looked for key parts of cells:
•Nucleus- dark spot inside the cell
•Cell walls- darker area surrounding the cell
Bromothymol Blue Experiment
Results
Tube #1 (with sugar)
No color change
Tube #2 (without sugar)
No color change
Tools That We Learned How To Use:
•
•
•
•
Microscope
Hot Plate
Bromothymol Blue
Computers In The Lab
Evidence Of Reproduction:
• We did not find any evidence of reproduction.
• Firstly we looked for any other signs that it
was alive and when we determined that it was
not alive (because it didn’t have cells, convert
energy, respond to stimuli or grow and
develop) we assumed that it also couldn’t
reproduce.
Independent Variables, Dependent
Variables and Controls
• Independent Variables: different environments
(addition of sugar and salt to water, addition of
soil and the wet paper towel, temperatures of
the water)
• Dependent Variables: responses of the
Unknown to the environments
• Controls: room temperature water with no
additives, room temperature unknown with no
additives
Final Answer: Is It Alive?
•
•
No, Unknown #2 is not alive.
Reasons: None of the 4 characteristics of life appeared in the sample. (We could not
test the 5th characteristic.)
• It lacked cells. We knew this because, under the microscope it did not have any
of the characteristics of cells.
• It did not grow or develop in the environments. We knew this because we
made observations in a number of environments that would have supported
many types of life and there were no signs of any growth.
• It did not convert energy because it didn’t excrete carbon dioxide and change
the color of the bromothymol blue.
• It did not respond to the stimuli (extreme temperatures and different
environments).
Information That We Learned That
Helped Us Make Our Conclusion
• How To Use The Microscope
• What Bromothymol Blue is and how to use it to
prove energy conversion
• Characteristics of Cells
• All living organisms excrete CO2
• Organisms’ Reactions to extreme temperatures
• Different environments that promote growth of
organisms
Unanswered Questions:
• How can you prove that something can/can’t
reproduce?
Bibliography
• Biology by McDougal Littell and Stephen
Nowicki pages: R8-R9
• http://chem.lapeer.org/Bio1Docs/PhotoLab.ht
ml
• http://www.prsd.k12.ca.us/classrooms/Student
_links/7th_sci_resource/microscopes_cells/7_c
ells_rescource.html
• Various Pictures from THE INTERNET