1. Module 1: How to Define Life
The Nature of Biology
Module 1: How to Define Life

2. How do you know something is alive?
A. Biology means the study of (-ology) all life (bio-) and includes many branches.
B. Biologists organize living things into kingdoms. There are currently six kingdoms
Kingdom
Example
Archaebacteria
Extremophile bacteria
Eubacteria
Typical bacteria
Protista
Seaweed, Amoeba, Slime Mold
Fungi
Yeast, Mushrooms
Plantae
Moss, Fern, Holly, Oak tree
Animalia
, Fish, Birds, Frogs, Humans

3. How do you know something is alive?
C. Characteristics of Life - Alive! Videoclip
1. Organization (The level of complexity) a.
Organism
Organ System
Organs
Tissues
Cells
Molecules
Atoms / Elements
Meet the Elements - They Might Be Giants

4. How do you know something is alive?
b. All living things need six essential elements (atoms): Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur (CHNOPS)
c. All living things are made of cells.
i. One-celled organism – unicellular
ii. Many-celled organism - multicellular

5. How do you know something is alive?
2. Energy Use
a. Organisms need energy constantly to build molecules (synthesis) and cells and to break down (digest) substances (such as breaking down food for nutrition)
b. Organisms must transport nutrients to be used in cellular respiration to produce energy.
c. An organisms’ chemical reactions are called its metabolism

6. How do you know something is alive?
3. Reproduction
a. Organisms must replace themselves so the entire species will survive.
b. May be asexual (only one individual contributes genetic material) or sexual (two individuals contribute genes).

7. How do you know something is alive?
4. Growth and Development
a. Growth – to increase in size. Increases the number of cells of a multicellular organism.
b. Development – change that takes place in structure and function of an organism during its life cycle.
Example: Embryo becomes a fetus

8. How do you know something is alive?
5. Respond to Stimuli
a. A quick, non-permanent change
b. Stimulus – any condition that causes an organism to react.
Example – A loud noise (stimulus) causes your dog to run under the bed (response).

9. How do you know something is alive?
6. Adjust to Environment
a. Homeostasis - the regulation of an organism’s internal environment to maintain conditions suitable for life
Ex: Getting rid of wastes by excretion

10. How do you know something is alive?
b. An adaptation is an inherited structure, behavior, or internal process that enables organisms to better survive an environment.
Ex: Gills on a fish

11. Life Processes: STERNGRR
Synthesis – making materials
Transport – moving materials
Excretion – getting rid of wastes
Respiration – gas exchange AND production of energy (ATP)
Nutrition – gaining and using energy from food
Growth and Development – getting bigger and/or changing
Regulation – controlling internal processes
Reproduction – producing new cells or new organisms