What is Life?
What characteristics do all
living things share?
1. All living things have cellular organiza2on. A cell is the basic unit of life. Unicellular-­‐ single celled organism examples: amoeba, paramecium Mul,cellular-­‐ organism contains more than one cell examples: tree, human What characteristics do all
living things share?
1. All living things have cellular organiza2on. The cells are composed of chemicals. Water-­‐ the most abundant Carbohydrates-­‐ for energy Proteins & Lipids-­‐ building materials Nucleic Acids-­‐ contain gene2c material What characteristics do all
living things share?
2. Living things react to s,muli. A s,mulus is something in the environment that causes a reac2on, or a response. A response is an ac2on or change in behavior. What characteristics
do all living things share?
2. Living things react to s,muli. › An
organism must respond to changes
in the internal environment as well.
› the
level of water, nutrients, and
minerals inside the body
› body temperature and hormone levels
› The
regulation of an organism’s
internal environment to maintain
conditions suitable for life is called
homeostasis. What characteristics do all
living things share?
3. Living things grow and develop.
Growth- an increase in the size of an organism,
results in an increase in the amount of living
material and the formation of new structures.
Development- a progressive change in an
organism over time, all of the changes that
take place during the life of an organism
What characteristics do all
living things share?
4. All living things have the ability to
reproduce.
All living organisms must have the ability to
reproduce.
Whether the organism is a rabbit, or a tree, or a
bacterium, life will create more life.
If a species cannot create the next generation, the
species will go extinct.
Reproduction is the process of making the next
generation.
4. All living things have the ability to
reproduce.
Living things come from living things. ›  400 years ago people though that living things came from non-­‐living things (Spontaneous Genera2on). ›  Francisco Redi, Louis Pasteur did experiments to disprove this theory. Redi’s Experiment 1668 -Francesco Redi attacks spontaneous generation and
disproves it for large organisms
1745 -John Needham adds chick broth to a flask and boils it,
lets it cool and waits. Microbes grow and he proposes it as
an example of spontaneous generation.
1768 -Lazzaro Spallanzani repeats Needham's experiment,
but removes all the air from the flask. No growth occurs.
1859 -Louis Pasteur's swan-neck flasks show that
spontaneous generation does not occur.
1870 -Thomas H. Huxley gives his "Biogenesis and
Abiogenesis" lecture. The speech offered powerful support
for Pasteur's claim to have experimentally disproved
spontaneous generation.
1877 -John Tyndall publishes his method for fractional
sterilization, showing the existence of heat-resistant bacterial
spores.
What characteristics do all
living things share?
5. All living things use energy. ›  Energy
is the ability to make things change.
›  maintain balance
›  grow, reproduce
›  and carry out other life functions
›  Organisms that get energy from the food
they eat are called heterotrophs.
›  Organisms that use energy from the sun to
make their own food (which they then use
for energy) are called autotrophs.
›  The process is called photosynthesis.