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Worksheet 1-1:
Tree of Life
Supplemental Instruction
Iowa State University
Leader:
Course:
Instructor:
Date:
Jessica ANSWER KEY
Biol 211 (4)
Holscher
08/30/15
Lecture #1 Review
Biology and the Tree of Life/Phylogenies and the History of Life
Chapter 1 and 28
List the Five Fundamental Characteristics of Life: (Briefly describe them)
1.
energy
3. Information
2.
cells
4. Replication
5. evolution
Explain the difference between:
Hypothesis: testable statement to explain a
Theory: explanation for a very general class
set of observations.
of observations supported by a wide body of
evidence. Ex: The Cell Theory, The Theory
of Evolution
Who introduced a system for placing living organisms into progressively smaller
heirarchial groups?
Carl von Linne
Define:
Taxonomy
Science of describing, naming, and classifying
organisms
The first part of a scientific name is called
species
.
Phylogenetics
Graphic summary of evolutionary history of a
species or group of organisms. The basis for
phylogenetic trees is morphological traits and
molecular traits (DNA sequencing)
Genus
, and the second part is called
Which is correct?
A. Canis Familiaris
B. Canis familiaris
C. Canis familiaris
D. Canis Familiaris
1060 Hixson-Lied Student Success Center  515-294-6624  [email protected]  http://www.si.iastate.edu
What is the difference between extinct and extant species?
Extint: disappeared or destroyed; gone forever  ex: dinosaurs
Extant: still here ex: humans
Think of a funny saying (mnemonic device) so you’re able to remember Kingdom, Phylum,
Class, Order, Family, Genus, Species.
Ex: King Phillip Came Over From Great Spain
What are the three domains?
Bacteria, Archaea, and Eukarya
Define homology:
Similarity in organisms due to common ancestry
Define monophyletic group:
Evolutionary unit that includes an ancestral population and all of its descendants but no others
Define synapomorphy:
Shared, derived trait
The basis for phylogenetic trees is
traits.
morphological
traits and
molecular
The Cambrian explosion is an example of
a. Adaptive radiation
b. Mass extinction
Lecture #2-3 Review
Inside the Cell/Bacteria and Archaea
Chapter 7 and 29
Which has a membrane-bound nucleus?
a. Eukaryotic cells
b. Prokaryotic cells
Describe prokaryotic cell structure:
The chromosome is the most prominent structure. There’s only one and it’s circular and consists
of one large DNA molecule with genes. It’s located in the nucleoid region. They also have
plasmids which are independent of the chromosome and help cells adapt.
True or False: compared to the cell, chromosomal DNA is very long.
How do bacteria and archaea reproduce? How often do they do this?
Binary fission (asexually) most divide every 1-3 hours
Describe the function of these cell parts…
 Cell organelles: storage for calcium ions, organizing enzymes
 Cytoskeleton: help maintain cell shape
 Plasma membrane: encloses cytoplasm
 Cell wall: prevents lysing in a hypotonic environment
What is the purpose of external structures like flagella and fimbriae?
Enables movement and attachment
Compare and contrast Bacteria and Archaea:
Bacteria
Cell walls contain
peptidoglycan
Both
Prokaryotic
Simple cell structure
Unicellular
Microscopic
Archaea
Cell walls do not contain
peptidoglycan
Unique phospholipids in
plasma membrane
Process info differently than
bacteria
List the 2 Extremophiles you learned about in lecture and describe them.
Hypothermophiles: thrive in hot environments
Halophiles: live in highly saline environments
Koch’s postulates… Fill in the missing one!
1. First, the pathogen must be present in individuals and suffering from the disease
and absent from healthy individuals.
2. Second, the pathogen must be isolated and then grown in culture away from the
host organism.
3. Thrid, pathogenic cells from the culture must cause disease symptoms in an unifected
host
4. Fourth, the pathogen should be isolated from the second-infected host, grown in
culture, and shown to be the same pathogen.
List 4 examples of morphological diversity:
1. size
2. shape
3. motility
4. cell wall composition
Name the shapes for each picture below:
sphere-shape; cocci
rod-shaped; bacilli
comma-shaped; vibrios
spiral-shaped; spirochaetes
Tell me everything you know about Gram stains:
Gram stains detect peptidoglycan in bacteria. Positive = purple, negative = pink
This is important because if a doctor knows whether it’s positive or negative, he can prescribe
the correct antibiotics
Describe each…
Phototrophs: light energy
Chemoorganotrophs: organic; sugars
Chemolithotrophs: inorganic molecules
Autotrophs: self-synthesized; make their own food
Heterotrophs: molecules produced by other organisms
What is nutrition?
Obtaining energy and carbon
True or False: Bacteria and archaea are tremendously diverse in how they obtain the
nutrition they need.
Describe the relation of each to oxygen…
Obligate aerobes: require oxygen
Facultative anaerobes: can use it but not required
Obligate anaerobes: poisoned by it
Aerotolerant anaerobes: don’t use it but aren’t poisoned by it
Does nitrogen fixation occur in aquatic ecosystems?
Yes
What is nitrogen fixation?
Chemical process where nitrogen is converted into organic compounds
Describe what a symbiotic relationship is.
2 different organisms having a relationship
Describe mutualism.
Direct association between 2 organisms where they both benefit
Describe parasitism.
Association where only 1 organism benefits