1. Life’s Structures and Classification
Chapter 8
Life’s Structures and Classification

2. I. Living Things
-organism – any living thing

3. A. Characteristics of Living Things
Living things are organized
a) cell – smallest unit of an organism that carries on functions of life
Living things grow and develop
Living things respond to a stimulus
a) stimulus – anything that causes some change in an organism

4. Living things maintain homeostasis
a) homeostasis – the regulation of an organism’s internal, life-maintaining condition despite changes in its environment
Living things use energy
Living things reproduce

5. Needs of Living Things
A place to live
Water
Food

6. II. How are Living Things Classified?
-Classification – putting objects into groups based upon common characteristics

7. A. Modern Classification
-Aristotle classified living things into 3 groups – air, land, and water
-Carolus Linnaeus came up with the modern system of classification

8. 1. Modern Classification System
Kingdom
Phylum
Class
Order
Organisms are more similar than the group above it.
More members in it than the group below it.
Family
Genus
Species

9. Modern Scientific Naming System
Binomial Nomenclature – two word naming system
-Uses Latin.
-First word is the Genus and is capitalized.
-Second word is the species and is lowercase.
-Both words are underlined or italicized.
Link to Scientific Names Worksheet

10. 3. Tools for Identifying Organisms
Field Guide – book with descriptions and illustrations
Dichotomous Key – a detailed list of identifying characteristics that includes scientific names
Link to Norns worksheet
Link to Dichotomous Key for Quozes Identification
Link to Quozes Pictures
Link to Quozes Answer Sheet

11. III. Cell Structure
A. Cell Theory (developed by Hooke, Schleiden, Schwann, and Virchow)
1. All organisms are made up of one or more cells.
2. The cell is the basic unit of organization in organisms.
3. All cells come from cells.
Link to Microscope Parts and Functions

12. B. Cellular Organization
-Prokaryotic – cells without membrane bound structures (bacteria)
-Eukaryotic – cells with membrane bound structures (animals and plants)
-Organelles – structures in cytoplasm of eukaryotic cells
Link to cells under microscope lab worksheet
Link to cellsalive.com worksheet
Plant and Animal Cell Diagram

13. 1. Animal Cells
a) Nucleus – largest organelle; It controls all activities of the cell
b) Cell Membrane – a protective layer that covers the cell
c) Cytoplasm – a gelatin-like substance inside the cell

14. Ribosomes – structures that make proteins
Mitochondria – where energy is produced from food
Endoplasmic Reticulum (E.R.) – folded membrane in which materials can be processed and moved inside the cell

15. Golgi Bodies – sort and package proteins
Lysosomes – break down food molecules, cell wastes, and worn out cell parts
Vacuoles – store water, food, and waste products
Link to cell city intro
Link to cell city descriptions
Sample Cell City
Link to Cell City Instructions
Link to Cell City Rubric
Link to Cell City Sketch

16. 2. Plant Cells
-Plant cells have the same organelles as animal cells but also have the following:
a) Cell Walls – tough, rigid outer coverings that protect the cell and give them shape
b) Chloroplasts – green organelles where food is made

17. C. Many-Celled Organisms
1. Cells→Tissue→Organs→Organ Systems
Tissue – a group of similar cells that work together to do one job
Organs – structures made up of 2 or more types of tissue that work together
Organ System – a group of organs working together to perform certain functions

18. IV. Viruses What are Viruses?
-virus – strand of hereditary material surrounded by a protein coating
-host cell – a living cell that helps the viruses to make copies of themselves

19. Active Viruses – the viruses cause the host cells to make new viruses which destroys the host cells.
Latent Viruses – viruses do not immediately make new viruses or destroy the cells.

20. B. Treating and Preventing Viral Diseases
Natural Immunity
a) Interferons protect noninfected cells.
2. Vaccines

21. C. Research with Viruses
Gene Therapy
HIV/AIDS research