1.2 Characteristics of Life Chapter 1

All living things share 8 characteristics

1. Made up of cells  Cell: collection of living matter enclosed by a barrier that separates the cell from its surroundings  Cells are the smallest part of an organism that is “alive”

1. Made up of cells  Unicellular organisms are only 1 cell  Ex: paramecium, bacteria, yeast  Microscopic

1. Made up of cells  Multicellular organisms contain many cells  Ex: humans, trees, fungi  Some cells are specialized (they have special functions)  Ex: cardiac cells, muscle cells, nerve cells, skin cells…

2. Reproduction  Reproduction is the process of producing more living things  Asexual reproduction:  One parent reproduces by itself

2. Reproduction  Sexual reproduction:  Two cells from two parents join to make an offspring  Most organisms reproduce using sexual reproduction

3. Based on Genetic Code  Directions for inheritance of traits are found in the DNA of an individual

4. Growth and Development  Every organism has a pattern of growth and change through its life cycle

4. Growth & Development  During development, cells in a organism multiply and become different  Ex: caterpillar to butterfly

5. Need for Materials & Energy  Organisms need a constant supply of energy to grow, develop and reproduce  An organism’s metabolism is the combination of chemical reactions during which:  Materials are broken down & energy is made  Materials are combined & energy is needed

5. Need for Materials & Energy  How do organisms get this material?  Plants & other small, green organisms make it in photosynthesis  These organisms are called autotrophs

5. Need for Materials & Energy  How do organisms get this energy?  Animals & most other organisms need to consume others (plants, other animals)  These organisms are called heterotrophs

5. Need for Materials & Energy  How do organisms get this material?  Decomposers get energy by using the remains of dead organisms

6. Response to Environment  Organisms detect & respond to stimuli in their environment  Ex: light, temperature  What do you do when you’re cold?

7. Homeostasis  Homeostasis is the process that organisms use to ensure that their internal conditions stay the same  Internal thermostat that responds to changes to environment

Set Point Heater turns on Air conditioner turns on

8. Evolve as a member of a population  Individuals cannot majorly change  A group of individuals can have more successful members  These more successful members mate and leave more successful children  As a result, the make-up of the population has changed

8. Evolve as a member of a population

Levels of Organization

 All living organisms can be looked at in two ways:  Small molecules/structures that make up the organism  i.e. cells, mitochondria, atoms  Large groups that the organism belongs to & interacts with  i.e. populations of an organism, its community, its role in the ecosystem

Molecule Cell TissueOrgan Organ System Organism Population Community Ecosystem Biosphere