Phylogeny & classification

This is a PowerPoint to supplement chapter 18 in Miller and Levine's Dragonfly book.

1. Phylogeny &
Classification
All of chapter 18. Yup, the
whole thing in one class.

2. Linnaean Classification
This system was created long before
scientists understood that organisms
evolved. Because the Linnaean system is
not based on evolution, most biologists
are switching to a classification system
that reflects the organisms'
evolutionary history.
King Philip Came Over For Good Soup.

3. Binomial Nomenclature
Each species is assigned a two part
scientific name.
Written in italics
First word is capitalized
Second word is lowercase

4. Binomial Nomenclature
Homo sapien
Oncorhynchus keta
human
chum salmon
Genus species

5. What is a Phylogeny?
The context of evolutionary biology is
phylogeny
The connections between all groups of
organisms as understood by
ancestor/descendant relationships.

6. Different ways of drawing trees

7. When a lineage splits (speciation),
it is represented as branching on
a phylogeny.

8. Clades
A clade is a grouping that includes a common ancestor and all the descendents
(living and extinct) of that ancestor. Using a phylogeny, it is easy to tell if a group of
lineages forms a clade. Imagine clipping a single branch off the phylogeny—all of
the organisms on that pruned branch make up a clade.

9. Identifying CladesAre reptiles a clade?

10. Sample Practice Question*
For the tree above, you would need to say:
the frog and salamander are more closely related to each other than to the
lizard, snake, bird, and mouse
the lizard and snake are more closely related to each other than to the bird,
mouse, frog, or salamander
the bird is more closely related to the lizard and the snake than it is to the
mouse, frog, or slamander
the mouse is more closely related to the lizard, snake, and bird than it is to the
frog or salamander
* Information for this practice question comes from: http://www.utm.edu/departments/cens/biology/rirwin/391/391Phylog.htm

11. Practice Question*
Note that the previous example gives four statements about the
relationships: one for each ancestral species on the tree. See if you
can give the same kind of description of relationships for each of the
phylogenies pictured above.
* Information for this practice question comes from: http://www.utm.edu/departments/cens/biology/rirwin/391/391Phylog.htm

12. Homologies help determine how
species are related.

13. Homology vs. Analogy
Homologies are similar
characteristics shared by
two different organisms
because they were
inherited from a common
ancestor.
Analogis are similar
characteristics shared by
two different organisms
because of convergent
evolution.

14. Molecular Biology is a powerful tool
in classification
DNA & RNA comparisons
A molecular clock can be calibrated in actual
time. Possible to graph base substitutions
against known evolutionary landmarks.

15. Molecular Clocks

16. Kingdoms & Domains
Linnaeus’s two kingdoms, Animalia and
Plantae don’t adequately represent the full
diversity of life.
 Instead, scientists made five kingdoms
Monera, Protista, Fungi, Plantae and Animalia

Then they split Monera into Eubacteria
and Archaebacteria
Leading to the three kingdom system

17. Bacteria Archaea Eukarya
EubacteriaArchaebacteriaProtista Fungi PlantaeAnimalia
ProkaryoteProkaryote Eukaryote
E.coli halophiles Amoeba Mushroom,
yeast
Moss,
ferns,
flowering
plants
Sponges,
worms,
insects,
fishes,
mammals