Clad is Tics
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Transcript of Clad is Tics
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IntroductionA dichotomous key is a tool that allows the user to
determine the identity of items in the natural world,such as trees, wildflowers, mammals, reptiles, rocks,and fish.
"Dichotomous" means "divided into two parts".
Therefore, dichotomous keys always give two choicesin each step.
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Dichotomous key
1 With flower.
Without flower
Angiosperms
Go to 2
2 Seedless.
Seed bearing
Go to 3
Gymnosperms
3 Plant body do not differentiated into root,
stem and leaves.
Plant body differentiated into root, stem and
leaves
Go to 4
Go to 5
4 Without photosynthetic pigment.
With chlorophyll or other photosynthetic
pigment
Algae
Fungi
5 No vascular tissues.With vascular tissues
MossesFern
Example of a dichotomous key
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Dichotomous key the dichotomous key can also be expressed in a diagrammatic form
Non-flowering p lants
Without pho tsyn-thetic p igment
With chlorophyll orothe r pho tosyntheticpigment
Algae Fungi
No vasc ula rtissues
With vascula rtissues
Mosses Gym nosperms
Plant bo dy notdifferentiated intoroo t, stem and
leaves
Plant bo dydifferentiatedinto stem and
leaves
See d less Seed -bearing
Ferns
Flowering Plants(Angiosperm )
Without flowe rWith flower
Plants
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1. a. wings covered by an exoskeleton go to step 2b. wings freely observed Go to step 3
2. a. body has a round shape .ladybug a red beetle with black spots
b. body has an elongated shape .grasshopper a green insect that hops
3. a. wings point out from the side of the body .dragonfly an insect that is 10- 15 cm long and lives in marshes
b. wings point to the posterior of the body .housefly a flying insect with red eyes and an annoying buzz
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Hints:Use constant characteristics rather than variable ones. (Flowers change with the seasons)Use measurements rather than terms like "large" and "small".
Make the choice a positive one - something "is" instead of "is not".
If possible, start both choices of a pair with the same word.
Finish the dichotomous key with a description of the organism
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5 Kingdom classification system in use through the late 1900sgave way toWoeses 3 Domains
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DOMAIN
KINGDOM
CELL TYPE
CELL
STRUCTURES
NUMBER OF
CELLS
MODE OF
NUTRITION
EXAMPLES
Bacteria
Eubacteria
Prokaryote
Cell walls with
peptidoglycan
Unicellular
Autotroph or
heterotroph
Streptococcus,
Escherichia coli
Archaea
Archaebacteria
Prokaryote
Cell walls
without
peptidoglycan
Unicellular
Autotroph or
heterotroph
Methanogens,halophiles
Protista
Eukaryote
Cell walls ofcellulose in some;some have
chloroplasts
Most unicellular;some colonial;somemulticellular
Autotroph orheterotroph
Amoeba,Paramecium,
slime molds,giant kelp
Fungi
Eukaryote
Cell walls ofchitin
Mostmulticellular;someunicellular
Heterotroph
Mushrooms,yeasts
Plantae
Eukaryote
Cell walls ofcellulose;chloroplasts
Multicellular
Autotroph
Mosses, ferns,floweringplants
Animalia
Eukaryote
No cell walls orchloroplasts
Multicellular
Heterotroph
Sponges,worms, insects,fishes,mammals
Eukarya
Classification of Living Things
Section 18-3Key Characteristics of Kingdoms and Domains
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Did King PhilipCome Over For
Gumbo Sunday?
Panthera= genuspardus= specific epithet
that refers to onespecies in the genus
Panthera
Taxon (taxa) = the
named taxonomic unit(s)at any level in thistaxonomic hierarchy
Fig. 25.8
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Linnaeus convincedus to use a
hierarchical
classification system
Darwin provided us withthe mechanism by which
evolution results in
descent with modification
Taxonomy naming & classifying organisms
Systematics naming & classifyingorganisms according to
their evolutionary relationships
Phylogenetics reconstructing theevolutionary relationships
among organisms
SystematicPhylogenetics
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Cladistics Making and testing
hypotheses ofrelationship.
ModernEvolutionary
Classification
02 June 2011 Cladistics2108.ppt 11
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Cladistics Grouping by
common descent.
3-taxon statement: Aand B are more
closely related toeach other thaneither is to C.
02 June 2011 Cladistics2108.ppt 12
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hypothesized genealogy traced
back to the last common ancestor (i.e., the most recent)through hierarchical, dichotomous branching
Phylogenetic tree
Cladistics the principles that guide the production ofphylogenetic trees, a.k.a., cladograms
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Phylogenetic tree, phylogeny, or cladogram
Node branch point,
speciation event
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Synapomorphies arise at evolutionary branch points
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Lineage or clade an entire
branch
Phylogenetic tree, phylogeny, or cladogram
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MONOPHYLETIC group(s): Grouping of species
including all
descendants of acommon ancestorand the commonancestor.
02 June 2011 Cladistics2108.ppt 17
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A clade is a monophyletic group, i.e., an ancestral species and
all of its descendents
Phylogenetic tree, phylogeny, or cladogram
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Aparaphyletic group consists of an ancestor and some of its
descendents
Phylogenetic tree, phylogeny, or cladogram
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Apolyphyletic group lacks the common ancestor of species in the
group
Phylogenetic tree, phylogeny, or cladogram
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Fossil Record
Thanks to radiometric dating methods likeradiocarbon, uranium-lead, and potassium-argon,scientists are able to date and order both fossils andthe rock around them.
The fossil record allows us to develop a timeline for lifeon earth and see important events like the generationof oxygen, land colonization, the adaptive radiation ofanimals, and mass extinctions.
F il id d id f
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Fossils provided evidence of
evolutionHowever, we almost never have a continuous record from one
species to the next
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Cladistic principles allow us to construct hypothesized phylogenetic
trees
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Homologies and Analogies
Homologous structures areshared traits the resultfrom common ancestry.
Analogous structures areshared traits that result
from similarenvironmental demands,not from commonancestry (convergentevolution).
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Cladistic AnalysisHomologouscharacters share common ancestry
Lack of similarity among taxa results from divergence
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Cladistic AnalysisAnalogouscharacters do not share common ancestry
Similarity among taxa results from convergence
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Embryology
Another way todetermine relatednessis to see how similarstructures develop indifferent species.
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Cladistic AnalysisAs a general rule, the more homologous
characters shared by two species, themore closely they are related
Sequences of DNA & RNA (nucleotides) and proteins (amino acids)are used as characters; as a general rule, the more recently two
species shared a common ancestor, the more similar their sequences
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Cladistic AnalysisEach nucleotide can be treated as a character
Character changes (mutations) from the ancestralto the derived state include:
Substitutions
Insertions
Deletions
AGCTCTAGG
AGCTATAGG
AGCTCTAGG
AGCTGATCTAGG
AGCTCTAGG
AGCTCTAGG
Mutations
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Similarities in DNA and RNA
Similarities at themolecular level
show how closelyorganism arerelated
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DNA Evidence and Bootstrapping
DNA Bootstrapping is a process of using computer analysesof DNA sequences from different species to compare DNAsimilarities and develop cladograms to indicate relatednessand descent
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Cladistic Analysis
All similarcharacters
Analogies
Homologies
Shared
PrimitiveCharacters(ancestral)
SharedDerivedCharacters(u
nique to aclade)
The sequence of branching in a cladogram then represents thesequence in which evolutionary novelties (shared derived
characters) evolved
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Cladistic Analysis
Fig. 25.11
Ingroup vs. Outgroup
Ingroup = the group whose relationships we are trying to resolve
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Cladistic Analysis
Fig. 25.11
Ingroup vs. Outgroup
Outgroup = a species (or group) known to have an older most recentcommon ancestor with the ingroup than the ingroups most recent
common ancestor
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Cladistic Analysis
Fig. 25.11
Ingroup vs. Outgroup
An outgroup helps identify shared ancestral and shared derivedcharacters (unique to a clade)
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HOW TO RECOGNIZE A MONOPHYLETIC
GROUP: Shared derived
characteristics
= Homology = Distinguishing
character.
Classification byshared derivedcharacters only.
primitive &/orconvergent similarities
will mislead.
02 June 2011 Cladistics2108.ppt 36
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Cladistics Reading a cladogram
X-axis
Y-axis Line, line segment
Node, branchingpoint
Line end
02 June 2011 Cladistics2108.ppt 37
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Cladistics
02 June 2011 Cladistics2108.ppt 38
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HYPOTHESIS of relationship
02 June 2011 Cladistics2108.ppt 39
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CLADOGRAM
Crab Barnacle Limpet
Crustaceans Gastropod
Moltedexoskeleton
Segmentation
Tiny free-swimming larva
Section 18-2
Traditional Classification Versus Cladogram
Appendages Conical Shells
Crab Barnacle Limpet
CLASSIFICATIONBASED ON VISIBLE
SIMILARITIES
A. Evolutionary ClassificationA. Lines of evolutionary descent
Traditional Classification Versus Cladogram
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CLASSIFICATIONBASED ON VISIBLE
SIMILARITIES
CLADOGRAM
Appendages Conical Shells
Crab Barnacle Limpet Crab Barnacle Limpet
Crustaceans Gastropod
Moltedexoskeleton
Segmentation
Tiny free-swimming larva
Section 18-2
g
B. Classification Using CladogramsDerived characters
Characteristics that appear in recent parts of the lineage
How the leopard got its spots
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How the leopard got its spots