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

I. Living Things -organism – any living thing

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

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

Needs of Living Things A place to live Water Food

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

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

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

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

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

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

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 www.cellsalive.com Plant and Animal Cell Diagram

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

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

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

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

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

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

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.

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

C. Research with Viruses Gene Therapy HIV/AIDS research