Before the Practical...
Some tings to take note of...
1) Characteristics of Living things
2) Conditions to support life
1) Characteristics that have been come up with...
~Ability to reproduce
~Grow
~Die
~Respond to changes (stimuli) in environment (also known as adaptation)
~Evolve
~Move
~Have hereditary information
~Made up of protoplasm (not Cytoplasm but P-R-O-T-O-P-L-A-S-M)
Protoplasm-> Living matter=Cells
*~Excrete liquid waste from metabolism
~Respire
the equation is: O2+C6H12O6-> H2O+CO2+large amount of energy.
In other words, oxygen+glucose-> water+ carbon dioxide+ lots of energy.
* plants do not release solid waste. the term excrete is used for liquids/fluids only.
The term for solid waste is: egestion
2) Condition needed...
Air, food, water, shelter (not all), warmth, energy, adaptation to changes, and light for plants
Also, ~Homeostatis (ability to control) ~Continuity (of own kind) ~Development (growth) and ~Ecology (interactions with other living things) are needed
WARMTH is necessary for all living things because it is needed to carry out all life processes. If there was no warmth then particles would not be able to move and the particles would be just FROZEN. so warmth is necessary.
On to the pre-practical question:
Designing an experiment to test if an object is LIVING.
~Characteristics to test--Respiration
~How to carry out the experiment.
~What evidence will show it's living--Chalky limewater
~Can you infer from evidence that it is living?--Yes, for respiration gives out CO2 and if limewater is chalky means CO2 has been given out so substance is living.
Experiment
Place substance in glucose solution filled container. Place it in an ait tight container with limewater inside. Check after a few hours to see if limewater has turned chalky due to presence of carbon dioxide. This shall prove that the substance is living.
Practical Question:
Testing for life in objects.
Here are the results when substance was put in WATER.
Substance: Physical appearance: Changes after 10min: Evidence/Inference to show life:
A coarse and grainy no change, settles to bottom.
B smooth and powdery clumpy, settles to bottom, cloudy respiration
C hard, transparent, around expanded growth
2mm diameter
D hard and tiny, brown settles to bottom, no change
particles, negligible
diameter
E Brown, small particles suspended all over water, no change.
Same was observed for glucose, except for B, where bubbles were observed and glucose was more cloudy.
Pause to Ponder:
Why was glucose used?
Glucose is used for respiration as a form of food. Therefore, to supplement the substances with food, glucose was used.
3rd part:
Substances placed in soaked cotton wool in petri dish and left for observation.
No changes observed in any of the substances except for D, where plants had sprouted from the particles (now to be confirmed as seeds).
4th part:
Observation of substance E under salt water through microscope.
Picture of substance E in salt water under microscope:
some tadpole like creatures swimming (wriggling) about, past molecules.
Revelation of substances...
E: Brine Shrimp
D: Seeds
C: Water Babies
B: Yeast
A: Sand/Gravel
will continue soon..bb 4 now! :)
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