I.
II.
Classification, Bacteria and Viruses
Classification (Chapter 18)
a. Why Classify?
i. To name a group organisms in a logical manner.
b. Scientific Names
1. Early Efforts: first attempts often described the physical characteristics of species in great detail. Which
lead to very long names and names that varied from one language or region to the next.
ii. Binomial Nomenclature
1. Carolus Linnaeus (Swedish botanist, 1700s) came up with the idea of binomial nomenclature
2. Binomial Nomenclature- two name naming system of the genus and species of an organism.

Genus is always capitalized (Homosapien), species is never capitalized (sapien)

When typed place the scientific name in italics

When written underline the genus and species separately
c. Linnaeus- developed a classification structure with seven levels; each level is called a taxon. The levels are:
i. Kingdom, Phylum, Class, Order, Family, Genus, and species.
Modern Evolutionary Classification
a. Evolutionary Classification
i. Phylogeny- evolutionary relationships among organisms that show descent from a common ancestor, not similarities
based off of physical characteristics.
ii. Evolutionary classification groups organisms based on their evolutionary history
b. Cladogram- a graphic that shows the evolutionary relationships among a group of organisms.
i. Derived characteristics are characteristics that appear in evolutionary history, which show as nodes on the
cladogram.
c.
Similarities in DNA and RNA- genes of many organisms show important similarities at the molecular level. Similarities in DNA
can be used to help determine classification and evolutionary relationships.
i. The more similar the DNA/RNA sequences of two species, the more recently they shared a common ancestor.
d. Molecular Clocks- uses DNA comparisons to estimate the length of time that two species have been evolving independently.
The more different two strands of DNA are the longer they have been evolving independently.
III.
Kingdoms and Domains
a. Tree of Life
b. Kingdom System
i. Kingdom Archaea
ii. Kingdom Bacteria
iii. Kingdom Protista
iv. Kingdom Fungi
v. Kingdom Plantae
vi. Kingdom Animalia
c.
Three Domain System
Major Differences Among the Three Domains
Bacteria
Archaea
Unicellularity
Membrane Lipids
Cell Wall
Nuclear Envelope
Membrane-bound
Organelles
Ribosomes
Eukarya
i.
d.
Archaea vs Bacteria
1. Archaea- live in extreme habitats and resemble the first cells on earth. Believed to be the ancestors to
Eukarya.
a. Extreme halophiles- live in very salty places lakes/ocean sinks.
b. Methanogens- cannot use oxygen (it is fatal to them) they use CO2 and convert it to methane.
Found in swamps and ruminant guts.
c. Thermoacidophiles- live in very hot places like ocean floor vents or sulfur springs.
2. Bacteria- all other prokaryotes
Endosymbiotic Theory- states that eukaryotic cells originated from a symbiotic relationship of two different prokaryotic cells.
The focus of this theory is with organelles that have their own DNA: the mitochondria and chloroplast, which scientists believe
were prokaryotic cells on their own.
i. Reasons the mitochondria and chloroplast are believe to be from prokaryotes:
1. They are the same size as bacteria
2. They reproduce the same way bacteria do, binary fission.
3. Ribosomes resemble prokaryotic ribosomes
4. They contain their own DNA
Domain
Kingdom
Cell Type
Cell Structures
Number of Cells
Mode of Nutrition
Examples
Bacteria
Eubacteria
Classification of Living Things
Archaea
Archaebacteria
Protista
Fungi
Eukarya
Plantae
Animalia