Download - Evolutionary Classification
EVOLUTIONARY CLASSIFICATION
Sz2- Students will explain the evolutionary history of animals over the geologic history of Earth.
Geologic History Geologic time- time that began when earth was
formed until present day
Important Dates
4.6 billion years ago=Earth 3.8 bya = 1st LIFE2.0 bya= oxygen in atmosphere670 millions of years= 1st ANIMALS@500 mya= 1st FISH@365 mya=1st AMPHIBIANS@300 mya= 1st REPTILES@250 mya= DINOSAURS@200 mya= 1st MAMMALS@150 mya= 1ST BIRDS@100 mya= 1st primates@5 mya= 1st humans
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
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
Natural Selection- the process by which
individuals that are better adapted to their environment are more likely to survive and reproduce.
Charles Darwin
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.
SpeciationWhen a group of individuals remain
separated from the rest of the species long enough to evolve different traits
How Speciation OccursGeographic isolation-
○ Pangaea /Continental Drift○ Landform isolation- river, mountain,
water. (ex. Squirrels of N. Grand Canyon)
Competition Gene flowEnvironmental change- local
adaptation to local environment
Speciation of Squirrels- Grand Canyon
The Kaibab squirrel (Sciurus aberti kaibabensis, left) became isolated in the Grand Canyon ~ 10,000 years ago. Features have gradually evolved that separate it from close relative, the Abert squirrel (S. aberti aberti)
A Problem with Traditional ClassificationExample: 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.
Related
This incorrect because crabs and barnacles are actually related
Crustaceans
Even though they do not look a like, crabs & barnacles are actually
related
Gastropods
Molted Exoskeleton
Segmentation
Free swimming Larva
A Problem with Traditional Classification
physical feature comparisons only
convergent evolution, organisms that are quite different from each other evolve similar body structures when adapting to similar
environments.
.
Modern Evolutionary Classification
Evolutionary Classification: strategy of grouping organisms together based on their evolutionary history, instead of physical features.
Use DNA and RNA, embryological development, comparitive anatomy to classify species.
Modern Three-Domain System As scientists further analyzed cell structure and DNA , a
broader category was added- The domain is the most inclusive taxonomic category;
larger than a kingdom The three domains are:
Bacteria : kingdom Eubacteria
Archaea,: kingdom Archaebacteria;
Eukarya :Kingdom Protista, Fungi, Plantae, and Animalia.
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
Checkpoint1. When did the first animals appear in
geologic time? Humans?2. What is a theory?3. What is the process by which evolution
occurs?4. Why did traditional classification have
to change to evolutionary?5. What is the most inclusive taxonomic
category?
Classification Using CladogramsCladogram: A diagram that shows the evolutionary relationships among a group of organisms.
Derived trait- new traits that show up in a lineage ex. jaws, lungs, mammary glands
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
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
22
Phylogenetic Tree Shows evolutionary
relationships More historical than
cladogram
23
Myxozoa
Arthropoda AnnelidaMollusca
Lophophorates
Hemichordata
Chordata
Other pseudocoelomates
Nematoda
Porifera
CtenophoraCnidaria
Placozoa
PlatyhelminthesNemertea
CiliophoraSarcomastigophora
MicrosporaApicomplexa
Mesozoa
Echinodermata
CrustaceaChelicerata
Uniramia
Protochordates
24
Birds MammalsReptile
AmphibianFish
Four LimbsAmniotic Egg
EndothermicFur
Feathers
Vertebrae
25
Monophyletic A group of all the
descendants of a common ancestor
The common ancestor is in the group
Example: Birds and ReptilesAncestor was a bird
like reptile
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
27
Cladogram Evolutionary
relationship of a group of organisms
Each clade (group) shares something in common
Ancestral traits are the oldest
Derived traits evolved later
28
Cladogram for Transportation
Wheels are the most ancestral
Wings are the most derived
29
Construct a Cladogram
30
Gorilla Four limbs Fur Lost tail
31
Tiger Four limbs Fur Tail
32
Lizard Four limbs Tail
33
Fish Tail
34
Chimpanzee Four limbs Fur Lost tail
35
Clad With 4 Limbs
36
Clad With Fur
37
Clad With No Tail
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
39
Gorilla ChimpanzeeTiger
LizardFish
Four LimbsFur
Tail Lost
40
Gorilla Tail? How do we know the
gorilla lost its tail?
41
Gorilla’s Vestigial Tail
Gorilla Human