1. Macroevolution and Modern Classification

2. Evolution involving groups larger than a single species
Microevolution
Macroevolution
Observing allele frequencies change in a single population over generations
Evolution involving groups larger than a single species

3. Think “Tree,” NOT “Ladder/Line”

5. What is a Cladogram?
A Cladogram is a diagram that represents a hypothesis about how species evolved
It shows common ancestry or phylogenic relationships
It may or may not include derived characters like the one below

6. Understanding Cladograms
This diagram shows a relationship between 4 relatives. These relatives share a common ancestor at the root of the tree.
Note that this diagram is also a timeline. The older organism is at the bottom of the tree.
The four descendants at the top of the tree are DIFFERENT species.
Stress that cladograms not only serve as a pictorial representation of lineage, but also as a snapshot in time.
Be sure to introduce the term SPECIATION. The four descendents are DIFFERENT species.
Image courtesy of 6

7. The event that causes the speciation is shown as the fork of the “V”.
Branches on the tree represent SPECIATION, the formation of a new species.
The event that causes the speciation is shown as the fork of the “V”.
Image courtesy of

8. Species B and C each have characteristics that are unique only to them.
But they also share some part of their history with species A. This shared history is the common ancestor.
Image courtesy of

9. What is the only thing A and B have in common?
Be sure to have students justify their answer to the question.
Image courtesy of 9

10. Counting Clades
A CLADE is a grouping that includes a common ancestor and all the descendants (living and extinct) of that ancestor.
Clades are nested within one another forming a nested hierarchy.
If you cut a branch of the tree, you could remove all the organisms that make up a clade.

11. SEVEN Video Clip on Constructing Cladograms
Look at the cladogram at the right. What conclusions can be drawn about the relationship between humans, chimps and bonobos?
How many clades are in this cladogram?
SEVEN
Video Clip on Constructing Cladograms
Image courtesy of 11

12. Cladistics (How Biologists Make Cladograms)
First, scientists observe unrelated groups of organisms and compare the presence of derived characters

13. Cladistics (cont.)
Then, biologists often use Venn Diagrams to help organize clades, then draw the cladogram
The diagram to the right shows 5 different ways to represent a single line of descent

14. Cladistics (Cont.) Organisms in a clade share a derived character
Ex: horse & monkey have hair and mammary glands so they are in the same clade
If an organism does not share the character that unites a clade, it is placed in broader, inclusive clade
Ex: lizard does not have hair or mammary glands, but does have 4 legs and amniotic eggs

15. Cladistics (Cont.)
Some characters can derive in unrelated clades due to convergent evolution (analogies)
However, the simplest scientific explanation that fits the data is the favored hypothesis

16. Cladograms are used to study the Evolution of Multicellular Organisms and Macroevolution

17. PATTERNS OF MACROEVOLUTION
ADAPTIVE RADIATION
When a single species or small group evolves into diverse forms that live in different ways (new niches available)

19. MASS EXTINCTION
When 80% of species die out or go extinct
Occur under intense environmental conditions like ice ages, asteroids, or many volcanoes

21. PUNCTUATED EQUILIBRIUM
Idea that evolution occurs at a rate that involves long stable periods interrupted by brief periods of rapid change

23. CONVERGENT EVOLUTION
When unrelated species evolve similarities due to a selective pressure or similar environments
Analogous Structures: structures with different parts, but the same function (wings of birds, bats, and insects)

24. Convergent Evolution Dolphin shape and Fish shape

25. Convergent Evolution Wing Structure

27. COEVOLUTION
When 2 species evolve in response to changes in each other over time (symbiosis)

28. CLASSIFICATION
Taxonomy is the branch of biology involving the identification, naming, and classification of species

29. The Linnaean System of Classification
Carolus Linnaeus ( ) developed a naming system that gave every species a 2-part Latin name and organized them into broader categories
“Binomial Nomenclature”
(2-name naming system)
Example: Homo sapiens or Homo sapiens
Format
- 1st word capitalized, 2nd word lowercase
- Both words of the name italicized or underlined.

30. Question: Which organisms are most similar? Why? A. Acer nigra
B. Luriodendrum tulipifora
C. Acer palustris
Answer: A+C because they belong to the same genus – Acer

31. Linnaean Classification Groups (and Human Classification Groupings)
Kingdom - Animalia
Phylum Chordata
Class Mammalia
Order - Primate
Family - Homididae
Genus - Homo
Species - sapiens
“Kings Play Chess On Fat Green Stools”

32. Classification and Evolution
Darwin used Linnaeus’s system to show evolutionary relationships → phylogenic trees
The more homologous structures organisms shared, the more closely related they were
Today we use molecular evidence- fewer differences in DNA or amino acid sequences means closer relatives

33. Kingdoms and Domains
Biologists use the largest taxons to show common ancestry among all of life on Earth (past and present)
The number of kingdoms and the formation of domains have changed in response to new discoveries and evidence

37. Classification of Living Things
Domain
Bacteria
Archaea
Eukarya
Kingdom
Eubacteria
Archaebacteria
Protista
Fungi
Plantae
Animalia
Cell Type
Prokaryote
Eukaryote
Cell Structure
Cell walls with peptidoglycan
Cell walls without peptidoglycan
Some have cell walls of cellulose; some have chloroplasts
Cell wall of Chitin
Cell walls of cellulose; chloroplasts
No cell walls or chloroplasts
Number of Cells
unicellular
Most unicellular; some colonial; some multicellular
Most multicellular; Some unicellular
multicellular
Mode of Nutrition
Autotroph or Heterotroph
Heterotroph
Autotroph
Examples
Streptococcus; E. coli
Halophiles, Methanogens
Amoeba, Paramecium, slime molds
Mushrooms, yeast
Mosses, ferns, flowering plants
Sponges, worms, insects, fish