evidence for evolution direct instruction then synthesis on 24r
TRANSCRIPT
Evidence forEvolution
Direct Instruction
then synthesis on 24R
EVOLUTION = Change over Time
=Descent With Modification=Adaptation of a species
Takes Place Over Long Periods of Time
-usually millions of years
Descent With Modification
Species Today Look Different From Their Ancestors
Each Living Species Has-Descended-With Changes-From Other Species-Over Time
Descent With Modification
Implies
All Living Organisms Are Related
Single Tree of Life
DNA, Body Structures, Energy Sources
Common Descent
All Species, Living (Extanct) & Extinct, Were Derived From Common Ancestors
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Descent With Modification: An Example
Evidence of Evolution
1. Fossil Record2. Comparative Anatomy3. Comparative Embryology4. Comparative Biochemistry5. Comparative Biogeography
Evidence of Evolution—1. The Fossil Record
• Evidence of orderly change can be seen when fossils are arranged according to their age.
Derived Traits vs. Ancestral Traits
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Evidence for Evolution – The Fossil RecordEvidence for Evolution – The Fossil Record
Evidence of Evolution—2. Comparative Anatomy
• Anatomy has different functions but constructed of similar bones in similar way.
• Evo predicts that modifications of ancestral body parts are more likely than formation of entirely new parts
2 Kinds:
Homologous Structures: same structures/different functions
Analogous Structures: different structures/same functions
an analogy= a comparison using like or as (this snake tastes like chicken, but is it?)
Homologous Structures • Structures in different organism that
indicate a shared ancestry–Check out these vertebrate forelimbs.
Homologous StructuresHomologous Structures
Analogous Structures
• Different Structures in different organisms that have a common function.
–Check out these flying machines.
Type of Homologous StructureVestigial Structures • Reduced or nonfunctional structures
• provide evidence of an organism’s evolutionary history.
http://www.pbs.org/wgbh/evolution/library/03/4/l_034_05.html
5 min, 9 sec
Whale Evolution
Video
Ex of vestigial structures
Similarities In Embryonic Development
Evidence of Evolution—3. Comparative Embryology
Human Fetus – 5 weeks
http://www.pbs.org/wgbh/evolution/library/04/2/l_042_02.html
Comparative Embryology
Shows common ancestry
Video:
Proteins (Amino Acid) • MORE differences in AA sequences of distant
related species• LESS differences = species that are more
closely related.Nucleic Acids • MORE differences in DNA sequences of
distant related species• LESS differences = species that are more
closely related.
Evidence of Evolution—4. Comparative Biochemistry
Similar DNA = Similar AA = Similar Organisms
Which is more related to the human,
the snake or the tuna?
Different Species On Different Continents Have Similar Adaptations due to similarities of the Environments
Evidence of Evolution—5. Comparative Biogeography
• Organisms from different land masses look similar
• The most recent common ancestor is those of the same geographical region.
• But, the similar comparative anatomy demonstrates a distant common ancestor before the land masses separated.
ElephantsElephantsEx of a species with a common ancestor that became geographically isolated over 5.5 MYA from others in their species and then continued to evolve.
And the evolution was convergent –Becoming the African and Asian Elephants we know today.
Asian African
Evidence of Evolution
1. Fossil Record2. Comparative Anatomy3. Comparative Embryology4. Comparative Biochemistry5. Comparative Biogeography