D.N.A (LET’S CLASSIFY) ROOT WORD – DI (apart/away)Objective: SWBAT explain how phylogenetic trees and cladograms are graphical representations of evolution Organize/ group the following ice cream flavors in any
way that makes sense to you. Example: Start broad (how are they all related) to
more specific Vanilla Chocolate Rocky Road Mint Chocolate Chip Cookies and Cream Rainbow
D.N.A please write on a separate sheet of paper
Reflection Questions(Use Complete Sentences!)
How do you believe you performed on the unit exam?
What came easy to you? What parts were more difficult?
How did you prepare for the exam?
What can you improve on when preparing for the next exam?
What can Ms. Nakamura do to improve?
Unit 2: Diversity of Organisms CLASSIFYING LIFE’S DIVERSITY – BUILDING DARWIN’S TREE OF LIFE
2004-2005
Phylogeny & Systematics Phylogeny
evolutionary history of a species based on common ancestries inferred
from fossil record morphological & biochemical resemblances molecular evidence (DNA)
Systematics Using phylogeny as an analytical
approach to the study of the diversity of life and relationships between organisms
2004-2005
Fossil record
Sedimentary rock are richest source of fossils fossil record is a substantial, but
incomplete, chronicle of evolutionary history incomplete historical documents of biology
history of life on Earth is punctuated by mass extinctions
5000 year old ice mummy found on an Alpine ridge dividing Austria from Italy at 10,500 feet above sea level.
Two approaches
1) Linnean system of groups
2) Phylogenic Trees/Cladistics
2004-2005
Systematics
Connecting classification to phylogeny hierarchical system Carolus Linnaeas
(taxonomist who named and classified species)
latin binomial genus (Homo) Species (sapiens)
#1 – Linneaus and taxa
Taxa – group names that we create to classify organisms
domain kingdom phylum class order family genus species
Keep Pond Clean Or Froggy Gets Sick!
Early systems primarily based on structural analysis(anatomy – dissections by surgeons)
Binomial nomenclature rules Organism’s scientific name: Felix catus
Genus = Felix, species =catus
Humans: Homo sapiens
Problems with Linnean system Analogous structures result in mis-
classifying
Transitional organisms strain the definitions of groups Ex: Platypus – the egg-laying mammal (or
should that be mammary-gland containing reptile?)
A challenge for biologists
Homology Shows deep
relatedness, common ancestry
Similar components or materials – may now serve different functions
Shows divergence from ancestry
Analogy Superficial relatedness
Components or structure significantly different
Shows convergence from separate ancestries
Example of analogy
Australian mole (marsupial)
European mole (mammal)
similar adaptations to live in current environment (underground), but very different ancestries
Homology Analogy
Divergent evolution Convergent evolution
common ancestor
modern related species
different ancestries
superficially related species (may live in similar environment)
2004-2005
Connection between classification & phylogeny
Tracing possible evolutionary relationships between some of the taxa of the order Carnivora, a branch of the class Mammalia.
Building phylogentictrees
LeopardDomestic
cat
Common ancestor
•Each branch point
–Represents the divergence of two species
•“Deeper” branch points
–Represent progressively greater amounts of divergence
LeopardDomestic
cat
Common ancestor
Wolf
Cladistics
Depiction of patterns of shared characteristics among taxa (groups)
Organisms at base of cladogram share ancestral traits of others (primitive character)
Organisms further up cladogram have additional derived traits (present in an organism but not in the previous
common ancestor)
common ancestor with a jaw
Cladistics
4 limbs? air sac? amniotic egg?
jaws? mammary glands?
dogs yes yes yes yes yeslampreys no no no no nosalamanders yes yes no yes nosharks no no no yes notuna no yes no yes noturtles yes yes yes yes no total “no”
3 2 4 1 5
common ancestor to all these animals
lamprey
salamander
shark
tuna turtle
dog
connection to other organisms on tree
outgroup – representative with no further derived traits in cladogram, but fundamental similarities to others
evolution of jaws
the jaw clade
evolution of air sac (swim bladder)
the lung / lung derivative clade
common ancestor with an air sac
evolution of tetrapody (4 legs)
the tetrapod clade
common
ancestor
with 4 legs
evolution of amniotic egg
the amniote clade
common amnioteancestor
evolution of mammary glands
the mammal clade
Cladistics
What is a valid clade?
Any group that includes all modern derived species and their common ancestor
In many cases, Linnean taxa are valid clades (ex: vertebrates, mammals)
In some cases, they are NOT valid clades(ex: protists, prokaryotes, reptiles)
One last misconception
“Humans evolved from chimpanzees”
No, they are both modern species … BOTH evolved to their modern forms from a common ancestor more recent in history than other species
the rest of the primates, mammals, vertebrates, and all other life really
chimpanzees
humans
common ancestor
D.N.A
Take 5 minutes to compare and contrast your cladogram with a partner
Discuss why you placed the organism the way you did based off of the derived trait
22
Homoplasy: a shared character trait that was not been inherited from a common ancestor Results from convergent evolution Results from evolutionary reversal
Cladistics
24
Cladistics
25
Other Phylogenetic Methods
Evolutionary changes occur in a clock-like fashion
Mutations may build up in any given stretch of DNA at a reliable rate. Ex: The gene that codes for the protein
alpha-globin (part of hemoglobin) experiences base changes at a rate of .56 changes per base pair per billion years.
Molecular clock: rate of evolution of a molecule is constant through time
D.N.A - Objective: SWBAT create and design an AP Biology FRQ essay IOT receive the maximum points on the AP exam
For the hemoglobin protein, the following information was given about the differences in amino acid sequences between organisms.
Draw a possible cladogram illustrating the relationship of these organisms to a common ancestor and summarize what can be obtained from this specific cladogram in a paragraph.
Baboon
Chimpanzee
Lemur Gorilla Dog Chicken Frog
Human 7 0 9 1 10 13 14
“Winnie the Pooh” – source of attraction beginning at a young age
“Yes, I believe that as humans we tend to show favoritism to things that are more attractive because that is how we choose our mates…”
Importance to the ecosystem Oleander flower – pretty in
appearance, but poisonous…looks can be deceiving!
GREAT DISCUSSION!Love,AYE AYE
How about a rat?
Writing AP Biology Free Response Essays
1. READ THE QUESTION 2. OUTLINE the answer 3. Define your terms
Underline your key terms 4. Answer each subject/point in detail! 5. GET TO THE POINT!
Background information is not necessary unless instructed to
REVIEW FROM LAST CLASS
What are the three hypothesis in regards to the origin of life?
What were the key events in the origin of life?
How did endosymbiosis affect the origin of life of eukaryotes?
1) SPECIAL CREATION, 2) EXTRA-TERRESTRIAL ORIGIN, 3) SPONTANEOUS ABIOTIC ORIGIN1) SPECIAL CREATION, 2) EXTRA-TERRESTRIAL ORIGIN, 3) SPONTANEOUS ABIOTIC ORIGIN
1) ORIGIN OF CELL (PROTOBIONTS), 2)ORIGIN OF GENETICS, 3) ORIGIN OF EUKARYOTES1) ORIGIN OF CELL (PROTOBIONTS), 2)ORIGIN OF GENETICS, 3) ORIGIN OF EUKARYOTES
MUTUAL BENEFICIAL RELATIONSHIP!MUTUAL BENEFICIAL RELATIONSHIP!
REVIEW FROM LAST CLASS
How are fossils beneficial in evolution?
What are the two major hypotheses on how evolution takes place?
How are they different from each other?
AGE AND MORPHOLOGIES (APPEARANCES) OF FOSSILES SHOW PATTERS OF CHANGES THAT HAVE OCCURRED BETWEEN SPECIES (RELATIONSHIP!)
AGE AND MORPHOLOGIES (APPEARANCES) OF FOSSILES SHOW PATTERS OF CHANGES THAT HAVE OCCURRED BETWEEN SPECIES (RELATIONSHIP!)
GRADUALISM AND PUNCTUATED EQUILIBRIUMGRADUALISM AND PUNCTUATED EQUILIBRIUM
GRADUALISM – organisms evolve through a slow and constant changePUNCTUATED– species evolve very rapidly
GRADUALISM – organisms evolve through a slow and constant changePUNCTUATED– species evolve very rapidly