1. Introduction to Biology
Chapter 1

2. Characteristics of Life
Cells:
Cell theory: all living things are made of cells, cells are the basic unit of structure and function, cells come from pre-existing cells
Cellular structures: plasma membrane, cytoplasm, DNA
Prokaryotes: no internal membrane-bound organelles
Eukaryotes: internal membrane-bound organelles, including a nucleus
Unicellular versus multicellular: generalists versus specialists

3. Characteristics of Life…
Growth
Increase in size
Increase in number of cells
Or both
Development
Increase in complexity
Changes in function

4. Characteristics of Life…
Internal regulation
Metabolism – chemical reactions and energy transformations
Example:
Homeostasis – maintenance of internal balance

5. Characteristics of Life…
Response to stimuli
Changes – physical or chemical; internal or external… sensory information
Examples:
Responses – reactions can be physical or chemical

6. Characteristics of Life…
Reproduction
Asexual – simple organisms
Advantages:
Disadvantages:
Sexual – complex organisms

7. Characteristics of Life…
Evolution
On the population scale
Means to change over time
Become more ‘suited’ to the environment… more adapted
Examples:

8. Organism organization
Atom (one kind of thing)
… molecules (different atoms)
… macromolecules (different functional groups)
… organelles (one function)
… cells (all functions of life)
… tissues (one type of cell)
… organs (several tissue types; one function)
… organ systems (several organ types; one function)
… organism (all the organ systems must work together)

9. Ecological organization
Individual organism (species)
… population (all members of one species in one place at one time)
… community (all the populations in an area)
… ecosystem (the community and nonliving parts of an area)
… biosphere (all places on Earth where life can exist)