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Diversity and Unity of Life
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Welcome!
• Clock Hours
• Restrooms
• Introductions
Slides and resources can be found at
http://lifescienceworkshop.wikispaces.com/
Schedule of Events
-Evolution activities and discussion
-Children’s misconceptions of evolution
-Introduction and history of taxonomy
-Introduction to cladistics
-DNA and protein analysis
-Unity and diversity in a stream ecosystem
-New classification scheme
Evolution
To understand the unity and diversity of life,
we must understand evolutionary principles
bean evolution activity
Evolution
• What was the mechanism you observed in this
scenario?
• How does it work?
Evolution
• Natural Selection Principles
– Overproduction
• capable of producing huge numbers of offspring
– Variation
• those offspring have hereditary physical variations in
phenotype
– Competition
• those offspring must compete for limited resources
– Differential Reproduction
• those whose phenotypic characters allow them to best
exploit those limited resources will leave the most
genes to succeeding populations.
Natural Selection:
Fitness does not mean strength
 More Fit
Less Fit 
Evolution
“Evolution is not survival of the strongest, or
failure of the weakest. Evolution is not fair; it's
not predictable; it's not kind. Nor is it cruel, or
chaotic, or unfair, for that matter. It's what
happens when environmental pressures
change.”
Michael Jon Jensen
Children’s Misconceptions of
Evolution
Adaptation
• Individuals adapt to their
environment for survival
– By need or desire
• Traits are passed on to
offspring
• Lamarckian
– Ex. Giraffes stretching neck to
reach leaves
Evolution Questions
Q4: Cheetahs are able to run faster than 60 miles per hour
when chasing prey. How would a biologist explain how the
ability to run fast has evolved in cheetahs, assuming their
ancestors could only run 20 miles per hour?
Student answer: Because cheetahs needed to run fast for food, nature
allowed them to develop faster running skills.
KEY: Thinks that “need” for a trait by an individual would cause them to
produce mutations that will solve the problem. This would require that
mutations themselves be directed and therefore evolution is directed.
Mutations are thought to occur randomly based on happenstance errors
in replication, assaults on the DNA by agents such as viruses, chemicals,
radiation.
Bean Evolution
• Scenario 2
– Randomly select 10 beans from your habitat
Bean Evolution
• How did the new population change in
comparison to the original population?
• What evolutionary mechanism is at work?
• How does this mechanism differ from natural
selection?
Bean Evolution
Suppose the beans sexually reproduce and
attract mates by singing a high pitched call.
Beans in the new habitat have evolved a lower
frequency call that transmits better through
the habitat. What would happen if these two
populations (new and old) remained isolated
for millions of generations and then were
reunited? Would they be able to reproduce?
Explain your reasoning.
• What do you suppose happened to the two
populations when they reunited?
• Are they considered two different species?
• Explain your reasoning
How would a biologist explain how these two
species diverged from a common ancestor
through evolutionary mechanisms?
Barred tiger salamander photo © user "Opencage" on Wikipedia Creative Commons Attribution ShareAlike 2.5 license
Children’s Misconceptions of
Evolution
• Concept of species
– Species is defined as a “kind” of organism and can
vary in specificity (eg. Birds, ducks, mallard)
– New species are derived from hybridization
jack rabbit + antelope = jackelope
– Few recognize or understand genetic basis of
species(even at age 16).
Taxonomy: Classifying Buttons
• Organize all of your group’s buttons into a
classification scheme within 5 minutes.
• Be prepared to share your scheme
Classifying Buttons
• How does this activity demonstrate
taxonomy?
• What are the limitations?
• What activities do you use in your classroom?
Taxonomy & Classification: a history
Aristotle first to classify as a “science”
animalia and vegetebilia
Classification included mobility by land, air, or water
as well as reproduction mode. Led to Great Chain
of Being.
Similar to buttons?
Aristotle’s Great Chain of Being
Taxonomy & Classification: a history
• Linnaeus touted “Father
of Taxonomy”
animalia and
vegetebilia
Developed bionomial
nomenclature still used
today
Species, Genus, Class,
Order, Phylum
Taxonomy & Classification: a history
• Small single-celled organisms recognized in
1866 (Haekel)
Protista, Plantae, Animalia
Taxonomy & Classification: a history
Bacteria recognized
• 2 empires (Chatton 1937)
Prokaryota, Eukaryota
• 4 kingdoms (Copeland 1956)
Monera, Protista, Plantae, Animalia
Taxonomy & Classification: a history
• 5 kingdoms (Whittaker 1969)
Fungi recognized separately from plants
Taxonomy & Classification: a history
• What do these schemes all have in common?
phenetic
(based on morphological observation)
Morphology and Evolution
Vertebrate Relatedness
1. Consider how these organisms are related.
2. Working in groups, arrange the images you
were given. Organize them according to
evolutionary relationships to the best of your
ability.
3. Be prepared to share your ideas.
Which is most closely related to Alligators?
A. Lizard
B. Bird
C. Bat
Which animal is most closely related to whales?
A. Hippo
B. Walrus
C. Shark
Which animal is most closely related
to the wolverine?
A. Tasmanian Devil
B. Rhino
C. Walrus
Which animal is most closely related to rhinos?
A. Walrus
B. Hippo
C. Zebra
Which is most closely related to Alligators?
A. Lizard
B. Bird
C. Bat
Hippos are most closely related to whales.
A. Hippo
B. Walrus
C. Shark
Walruses are most closely related
to wolverines.
A. Tasmanian Devil
B. Rhino
C. Walrus
Zebras are most closely related to rhinos.
A. Zebra
A. Walrus
B. Hippo
Cladograms
• We can organize organisms while showing
evolutionary relationships with a cladogram
• Cladograms are a visual representation of
heredity
• Cladograms are a HYPOTHESIS and subject to
change with new information
Arrange the animals listed below on the cladogram.
Alligator
Shark
Hippo
Zebra
Bird
Whale
Tasmanian Devil
Rhino
Cladogram with identified nodes
Even
Toes
Shelled eggs
Diapsid skull
Odd
Toes
Hooves
Live Birth
Fur/Hair
Synapsid skull
Legs
Pikaia
Jaws
DNA Analysis
• Primate evolution
• Explain how two species can evolve from a
common ancestor (use the following words):
variation, mutation, geographic isolation, natural selection, population
• Why has DNA sequencing changed the way
modern taxonomists classify organisms?
Evidence for Speciation
•
•
•
•
•
Morphology & behavior
Physiology
Chromosomes
Amino acid sequences
Nucleic acid sequences (DNA, RNA)
Unity and Diversity in a Stream
Ecosystem
• Find your organism’s CLOSEST relative
• Determine what trait you have in common
that no others in larger groups above you
would have
– Write down characteristic on a sticky on place in
upper right hand corner of a baggie
– Place these organisms in the baggie together
Unity and Diversity in a Stream
Ecosystem
• Locate your sister group (closest related
baggie)
– Determine shared trait
– Write on sticky
Kingdom Animalia
Kingdom Fungi
Kingdom Plantae
Unity of Life
• Form a group with representatives from each
of the 3 kingdoms we covered
• Determine the unifying characteristics all of
these organisms share together.
– How does this also fit in with their diversity?
Unifying Characteristics of Life
•
•
•
•
•
•
•
Homeostasis
Complexity
Continuity
Development
Acquiring/processing energy & matter
(Evolution)
(Role in ecosystem)
Kingdom Protista?
• Why didn’t we include them?
The most current scheme has categorized previous
Protista members into other categories
New Classification Scheme
Eukaryota Tree image © user "Vojtech.dostal" on Wikipedia Creative Commons Attribution ShareAlike 2.5 license
What you are likely to see in
textbooks
But not entirely correct!
Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates
(www.sinauer.com) and WH Freeman (www.whfreeman.com)