Transcript How do we define life? - Watchung Hills Regional High School

How do we define life?
Processes and characteristics of Living things
Key Experiments
Redi – Question: Where do maggots come from?
- Conclusion:
Louis Pasteur – Question: Where does the bacteria come from?
- Conclusion:
Spallanzani – Question: similar to Pasteur
- Conclusion:
Stanley Miller – Question: Can we create molecules of life based
on conditions of early earth?
- Conclusion:
Bottom Line: __________________________________
Essential Processes of Living things
Metabolism: final result of all chemical reactions that keep the
living alive; Includes all of the following
 Nutrition: taking in materials to use for energy
 Excretion: getting rid of the waste
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Respiration: converting energy in food into ATP
 ATP is the energy molecule all living things use
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Respiration uses???
Respiration produces???
Assimilation: making the food part of you
 Added as muscle, fat, bone, etc.
Essential Processes
Regulation: all activities that help maintain an organisms
homeostasis
 Homeostasis: a stable internal environment

Examples???
Growth: either bigger cells or More cells
Reproduction: making more of oneself to continue the species
All Living things also:
Have a definite and limited size
Have a limited life span
Respond to changes
 Stimuli
Evolve
Are highly organized
Are made of complex chemical substances
If a cell is the smallest living thing, what is it made
of?
Biotic:
Abiotic:
 Examples important to us?
Cells (Biotic) are made of organelles which are made of
molecules which are made of atoms (all abiotic)
So the abiotic is important!!
Interacting with the environment
We can’t make more of the elements
None of your atoms are ‘new’. Many elements, especially
CHONPS are recycled constantly.
 Conveniently these are the elements we are made of!!!
So a carbon in you might have once been a carbon in a giraffe
from the past!
Natural Recycling
Carbon:
Natural Recycling
Oxygen:
Natural Recycling
Nitrogen:
Natural Recycling
Rocks: