1. What Does It Mean To Be Alive?
The Characteristics of Life

2. What Do These Organisms Have In Common?
Organism means “living thing”  so what do these “living things” have in common; what makes them “living”
Reach and grab dna – all have dna: genetic material , reproduce , composed of cells , adapt/evolve , growth (flower bloomed), etc.

3. Characteristics of life
Life is based on organic chemistry
Composed of cells- smallest living unit
Use energy
Form and size range
Growth (and development)
Life span
Response to environment
Reproduction
Adapt/evolve over time
Definite form and size range / grow within means (ex: size between us and grasshoppers – there’s a huge difference!)
Limited life span
* non-living objects may exhibit a few of these chara, but never show all (ex: virus – reproduce)

4. LIFE PROCESSES
Homeostasis

5. Homeostasis Not a Life Process, but a reason for them
Condition of a constant internal environment  balance
Life processes are needed to maintain a fairly constant environment within an organism in spite of its constantly changing external environment.
Examples of homeostasis in action:
Body Temp --Heart Rate
Blood pressure --Water levels/pressure
pH levels --Gas exchange (CO2 and O2)
Glucose (sugar) levels

6. Nutrition
Take materials (nutrients, energy) from external environment and change them into forms they can use.
Ingestion (taken in)
Digestion (broken down)
Heterotroph vs. Autotroph

7. Transport
Process by which substances enter & leave cells and become distributed within the cells.
(small organisms)-materials exchanged directly with external environment
(large organisms)-circulatory system moves materials to and wastes from the cells of an organism
Fluid/blood in circulatory system is kept in motion, distributing materials among all the cells within the organism – in plants, transport structures aid in root to leave transportation

8. Respiration Process which releases chemical energy stored in food.
Respiration is NOT BREATHING!
Aerobic Respiration Anaerobic Respiration
All life processes require a constant supply of energy – obtain their energy by releasing chemical energy stores in nutrients
**ORGANISMS THAT BREATHE DO SO TO EXCHANGE GASES NEEDED FOR RESPIRATION – RESPIRATION HAS TO DO WITH ENERGY RELEASED WITHIN CELLS AND MAY/MAY NOT INVOLVE BREATHING**
Respiration involves a complex series of rxns – aerobic respiration (sugar/food molecules broken down to produce water and CO2 – require O2 , so call aerobic
Anaerobic – breaks down food without using oxygen

9. Synthesis
Synthesis-combine simple substances (products of digestion) chemically to form more complex substances.
Assimilation-incorporation of materials into an organism’s body.
Synthesis – “ making or constructing “ something – photosynthesis- making food with light (photo) energy
Then, glucose that is synthesized by a plant is assimilated in form of starch

10. Growth Process by which organisms increase in size
(unicellular) Increase in cell size
(multicellular) Increase in BOTH number and the size of the cell (accompanied by cellular specialization)
Due to the assimilation of nutrients!
Cellular specialization – cells become specialized for different fxns (blood cells, liver cells, etc.)

11. Excretion Removal of wastes from the organism.
Wastes are products of chemical reactions that occur within cells.
All organisms produce waste substances (can no longer be used, may be harmful to body if accumulation occurs)

12. Regulation
All activities that help maintain an organism’s homeostasis.
Examples: nervous & endocrine system
N.S. – carries messages ; endocrine – release chemicals/hormones into bloodstream (chemical messengers) * both bring about changes in the organism due to response to changes in either internal or external environment

13. Reproduction
Process by which living things produce new organisms of their own kind.
NOT necessary for survival of an individual!
Asexual Reproduction-
Sexual Reproduction-
Not necessary for survival or individual, but it is for the survival of that type of organism!
Asexual – single individual produces offspring identical to parent
Sexual – two parents produce offspring that are not identical to parent(s)

14. Metabolism
All of the chemical reactions occurring within the cells of an organism.
Continuous release & use of energy
Catabolism + Anabolism = Metabolism
MOST important life process!
Metabolism = (anabolism) builds complex substances from simpler ones AND (+) breaks down complex substances into simpler ones (catabolism)

15. Metabolism
Anabolism = putting together simple substances to make complex substances
ex: photosynthesis where plant uses CO2 & O2 to make energy for plant
Catabolism = breaking down complex substances in order to use material for other substances
ex: food digested in humans used to make energy and materials for body
Metabolism = (anabolism) builds complex substances from simpler ones AND (+) breaks down complex substances into simpler ones (catabolism)