Sz2- Students will explain the evolutionary history of animals
over the geologic history of Earth. Slide 2 Geologic History
Geologic time- time that began when earth was formed until present
day Slide 3 Slide 4 200 Million Years Ago 150 Million Years Ago 100
Million Years Ago 50 Million Years Ago Present Evolution of the
Earth with Time: Continental Drift Slide 5 Important Terms
Evolution- gradual change in a species over time- sci. theory
Theory-well-tested explanation that explains a wide range of
observations. Adaptation- any trait that helps an organism survive
and reproduce Slide 6 Natural Selection- the process by which
individuals that are better adapted to their environment are more
likely to survive and reproduce. Charles Darwin Slide 7 Natural
Selection cont. Over a long time, natural selection can modify a
population enough to produce a new species Helpful variations
accumulate in a species while unfavorable ones disappear. Slide 8
Speciation When a group of individuals remain separated from the
rest of the species long enough to evolve different traits HOW this
happens- Pangaea /Continental Drift Landform isolation- river,
mountain, water. (ex. Squirrels of N. Grand Canyon) Australia Slide
9 A Problem with Traditional Classification Traditional
classification systems relied on body structure comparisons only
Due to convergent evolution, organisms that are quite different
from each other evolve similar body structures. Convergent
Evolution Convergent Evolution : Process by which unrelated
organisms independently evolve similarities when adapting to
similar environments. Slide 10 A Problem with Traditional
Classification Example: The Crab, The barnacle, & The limpet
The barnacle and the limpet have similarly shaped shells & look
alike The crab has a very different body form Based on anatomy, the
barnacle & limpet could be classified together and the crab in
a different group. Slide 11 Related This incorrect because crabs
and barnacles are actually related Slide 12 12 TRADITIONAL
CLASSIFICATION CLADOGRAM AppendagesConical Shells Crab Barnacle
Limpet Crab Barnacle Limpet CrustaceansGastropod Molted exoskeleton
Segmentation Tiny free-swimming larva Section 18-2 Traditional
Classification Versus Cladogram Go to Section: Slide 13 Crustaceans
Even though they do not look a like, crabs & barnacles are
actually related Gastropods Molted Exoskeleton Segmentation Free
swimming Larva Slide 14 Evolutionary Classification Biologists now
group organisms into categories that represent lines of
evolutionary descent, not just physical similarities Evolution
Classification Evolution Classification : Is the strategy of
grouping organisms together based on their evolutionary history.
Slide 15 If these three species belong to the same genus, they are
descended from a common ancestor. Genus species Felis domestica leo
margarita Sand cat` Lion Domestic Cat Felis domestica Felis leo
Felis margarita Slide 16 Classification Using Cladograms Cladogram
Cladogram : A diagram that shows the evolutionary relationships
among a group of organisms. Slide 17 Crustaceans Using Cladograms,
you can see that crabs and barnacles share similar characteristics
because they both molt & are segmented Gastropods Molted
Exoskeleton Segmentation Free swimming Larva Slide 18 Crustaceans
You can also see that ALL have a free swimming larval stage
Gastropods Molted Exoskeleton Segmentation Free swimming Larva
Slide 19 Modern Evolutionary Classification Similarities in DNA and
RNA The genes of many organisms show important similarities at the
molecular level that can be used as criteria to help determine
classification. 19 Slide 20 Modern Evolutionary Classification
Molecular Clocks A model known as a molecular clock uses DNA
comparisons to estimate the length of time that two species have
been evolving independently. Comparison reveals more DNA in common,
the more recent the common ancestor 20 Slide 21 Terminology
Classification Assigning organisms to different catagories based on
their relationship Taxonomy The science of naming organisms
Systematics Determining evolutionary relationships of organisms
Phylogeny Evolutionary history 21 Slide 22 Phylogenetic Tree Shows
evolutionary relationships More historical than cladogram 22 Slide
23 23 MyxozoaMyxozoa ArthropodaArthropoda AnnelidaAnnelida
MolluscaMollusca LophophoratesLophophorates
HemichordataHemichordata ChordataChordata
OtherpseudocoelomatesOtherpseudocoelomates NematodaNematoda
PoriferaPorifera CtenophoraCtenophora CnidariaCnidaria
PlacozoaPlacozoa PlatyhelminthesPlatyhelminthes NemerteaNemertea
CiliophoraCiliophora SarcomastigophoraSarcomastigophora
MicrosporaMicrospora ApicomplexaApicomplexa MesozoaMesozoa
EchinodermataEchinodermata CrustaceaCrustacea
ChelicerataChelicerata UniramiaUniramia
ProtochordatesProtochordates Slide 24 24 Birds Mammals Reptile
Amphibian Fish Four Limbs Amniotic Egg Endothermic Fur Feathers
Vertebrae Slide 25 Monophyletic A group of all the descendants of a
common ancestor The common ancestor is in the group Example: Birds
and Reptiles Ancestor was a bird like reptile 25 Slide 26
Polyphyletic group that has some similarities Contains organisms
that have not descended from a common ancestor Based on physical
characteristics instead of evolutionary evidence Example: Flying
vertebrates- pterosaurs, birds, mammals 26 Slide 27 Cladogram
Evolutionary relationship of a group of organisms Each clad (group)
share something in common Ancestral traits are the oldest Derived
traits evolved later 27 Slide 28 Cladogram for Transportation
Wheels are the most ancestral Wings are the most derived 28 Slide
29 Construct a Cladogram 29 Slide 30 Gorilla Four limbs Fur Lost
tail 30 Slide 31 Tiger Four limbs Fur Tail 31 Slide 32 Lizard Four
limbs Tail 32 Slide 33 Fish Tail 33 Slide 34 Chimpanzee Four limbs
Fur Lost tail 34 Slide 35 Clad With 4 Limbs 35 Slide 36 Clad With
Fur 36 Slide 37 Clad With No Tail 37 Slide 38 Characteristics for
Constructing Cladogram Tail is the most ancestral Four limbs is the
oldest derived trait Fur is a later derived trait Loss of tail is
the most derived trait 38 Slide 39 39 GorillaChimpanzee Tiger
Lizard Fish Four Limbs Fur Tail Lost Slide 40 Gorilla Tail? How do
we know the gorilla lost its tail? 40 Slide 41 Gorillas Vestigial
Tail 41 Gorilla Human Slide 42 The End.
