How Scientists Work Ch. 1 Mrs. Griffin

What Is Science?  Goal: To investigate and understand the natural world.  Deals only with the natural world  Observation, data, and inference

Analyzing Data  Rules of Graphing  Be sure to title, label X & Y axis, provide a key (if needed).  Independent vs. dependent variables  X: independent  Y: dependent CORRECTINCORRECT

Explaining and Interpreting Evidence  Designing an experiment:  What is the problem/asking a question  Again, how should this be stated?  Forming a hypothesis  Setting up a controlled experiment  1, 2, 3, 4, etc.  Record and analyze data  Drawing a conclusion  Two things need to be stated here: Did results support or refute your hypothesis, “measurement” of error(s).

Francesco Redi’s Experiment on Spontaneous Generation  His proposal/hypothesis  Flies laid eggs to small for ppl. to see/ flies produce maggots  The experiment  How many variables should be tested?  Controlled variable, manipulated variable, responding variable

John Needham’s & Lazzaro Spallanzani Needham  The “attack” on Redi & spontaneous generation  The experiment: Spallanzani  Spallanzani tests Needham  The experiment:

Louis Pasteur on Spontaneous Generation  The experiment:  How a theory develops:  It is a well tested explanation that unifies a broad range of observations.

Studying Life & the Characteristics of Living Things  Living things:  Are made up of cells-  unicellular/multicellular  Reproduce-  sexual vs. asexual  Are based on a universal genetic code-  DNA  Grow and develop  Obtain and use materials & energy-  Metabolism  Respond to their environment-  stimulus  Maintain a stable internal environment-  HOMEOSTASIS  Change over time (taken as a group)- change over time.

Classification Ch. 18

Review/It’s All in the Name…..  Why is it important to have a control?  Comparison  How many variables should be changed when performing an experiment?  One  When graphing, where would you find the dependent/independent variable?  X & Y axis  Yesterday we briefly discussed a “type” of key used for classification. What was the name of that key?  Dichotomous key  What do you think are the common names for:  Felis catus?  Canis familiaris?  Cat, dog

Why Classify?  Way to group/name organisms in a logical manner.  Mountain lion, puma, cougar, panther?  The science of classifying organisms is known as taxonomy. Felis concolor

The Scientific Name  18 th century Carolus Linnaeus a two-word naming system called binomial nomenclature.  Each species is assigned a two-part scientific name (Genus species)  It is always written in italics, the first word is always capitalized, and the second word is lowercased.  Ursis arctos (grizzly)  Ursis maritimus (polar bear)  Genus is a group of closely related species and the second part is unique to each species.

Linnaeus's System of Classification  Hierarchical, consists of seven levels:  Kingdom  Phylum  Class  Order  Family  Genus  Species

 What are the seven classification groups?  King  Phillip  Came  Over  For  Great  Spaghetti

Common Name:Human Nine-Banded Armadillo Kingdom:Animalia Phylum:Chordata Class:Mammalia Order:PrimataCingulata Family:HominidaeDasypodidae Genus:HomoDasypus Species:Homo sapiens Dasypus novemcinctus Here are two examples of the Linnaean taxonomic system of classification, for humans and armadillos:

Kingdoms and Domains  Linnaeus named two kingdoms : Animalia & Plantae  What’s the problem w/ only two?  Then came Fungi  Followed by Monera  Eventually Monera is split into two kingdoms……..  The six-kingdom system of classification includes the kingdoms Eubacteria, Archaebacteria, Protista, Fungi, Plantae, and Animalia.

The Three-Domain System  Scientific analysis has given rise to a taxonomic category: domain. The three domains include Bacteria, Archaea, and Eukarya. (Pg 459) DOMAIN KINGDOM CELL TYPE CELL STRUCTURES NUMBER OF CELLS MODE OF NUTRITION EXAMPLES Bacteria Eubacteria Prokaryote Cell walls with peptidoglycan Unicellular Autotroph or heterotroph Streptococcus, Escherichia coli Archaea Archaebacteria Prokaryote Cell walls without peptidoglycan Unicellular Autotroph or heterotroph Methanogens, halophiles Protista Eukaryote Cell walls of cellulose in some; some have chloroplasts Most unicellular; some colonial; some multicellular Autotroph or heterotroph Amoeba, Paramecium, slime molds, giant kelp Fungi Eukaryote Cell walls of chitin Most multicellular; some unicellular Heterotroph Mushrooms, yeasts Plantae Eukaryote Cell walls of cellulose; chloroplasts Multicellular Autotroph Mosses, ferns, flowering plants Animalia Eukaryote No cell walls or chloroplasts Multicellular Heterotroph Sponges, worms, insects, fishes, mammals Eukarya Classification of Living Things

Review Why is classifying living things important? What is taxonomy? Describe binomial nomenclature. Who developed a system for naming living organisms? What is a scientific name of an organism and how is it written?