Clad is Tics

8/3/2019 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.



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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



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MONOPHYLETIC group(s): Grouping of species

including all

descendants of acommon ancestorand the commonancestor.



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A clade is a monophyletic group, i.e., an ancestral species and

all of its descendents



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Aparaphyletic group consists of an ancestor and some of its

descendents



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Apolyphyletic group lacks the common ancestor of species in the

group



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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


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


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.



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Cladistics Reading a cladogram

X-axis

Y-axis Line, line segment

Node, branchingpoint

Line end



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Cladistics



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HYPOTHESIS of relationship



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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

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