Elements found in living things:

C (carbon)

H (hydrogen)

N (nitrogen)

O (oxygen)
What do living things need

Place to live and raw place to live and raw materials.
A Place to live: the environment limits where organisms can live. An organism’s
surroundings must provide for all its needs.
All living things need water. Most organisms are composed of more than 50 %
water
proteins, fats, and sugars.
Animals take in most of these substances from the foods they eat.
Plants and some bacteria make these using raw materials from their
surroundings.
What are the life processes by which the life of an organism is
maintained?
Life functions:
1. Nutrition: the taking materials from the external
environment and changing them into useful forms (nutrients).
2 types of nutrition:
 Autotrophic: organisms make their own nutrients:
photosynthesis
CO2 + water + Solar energy
Sugar + O2
Heterotrophic: Organisms cannot make their own nutrients
and must find them in their environment.
Processes involved:

Ingestion: taking in food

Digestion: breaking down food

Egestion: elimination of indigestible food
Essential Nutrients are:



Carbohydrates
Proteins
Lipids (fats)
Digestion:
Carbohydrates
Proteins
Lipids (fats)
Used in the body for:
Energy
Grow
Repair and Build
Breaking down of nutrients to materials needed
Glucose
Amino Acids
Fatty acids
Synthesis:To build nutrients into molecules used by the body. Ex: Proteins
(hair, nails ...)
2. Transport: the ability to move materials into, out of and throughout
an organism.
Involves absorption (taking in) and distribution (circulation) of
nutrients.
3. Respiration: the ability to convert food into energy
Sugar + O2
CO2 + H2O + Energy
4. Excretion: Removal of wastes from chemical
reactions: (Carbon Dioxide, Water & Urea)
5. Growth: The ability to increase in size

Unicellular organisms: cell increases size

Multicellular organisms: the number of cells
increases.
6. Reproduction: When an organism produces new
organisms of its own kind.
1.
Sexual Reproduction: 2 parents, offspring not identical to
either parent. Results in variation.
2.
Asexual Reproduction: one parent. Offspring identical to
the parent
Metabolism is the sum total of ALL chemical reactions occurring in an
organism to maintain
life.
Homeostasis is the ability to maintain a balanced, steady-state,
internal environment within an organism. Failure to maintain
homeostasis leads to illness, disease or even death.
What is this man responding to?
Cold temperature: Stimulus
Shivering: Response
How might shivering help him?
Shivering helps your body generate heat to keep his body temp. stable.
He is trying to ADJUST to the changing environment