Evolution: Change Over Time

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Evolution Change Over Time
Evolution Change Over Time
The Evidence
The Evidence
Evolution Change Over Time
Evolution Change Over Time
The Evidence
The Evidence
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Fossil Record

• Defined Collection of every known fossil
• Most fossils found in sedimentary rock
• Age determined by depth
• Law of Superposition new rock forms on top of
  older rock
• A.k.a. Relative Dating
• Evidence Conclusions
• 1) Newer fossils are more complex
• 2) Common ancestors similarities between ancient
  modern life

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Missing Link Fossils
Whale Evidence Long spine Found in dried up
oceans
Amphibian evidence Eyes on top of head Wrist
bones
Reptile Evidence Teeth Bony tail
Bird Evidence Wishbone Feathers
Land Evidence Wolf-like teeth Hind legs
Fish evidence Scales Fins Found in dried-up
oceans

• AKA Transition Fossils
• Archaeopteryx shares both bird reptile
  features
• Basilosaurus shares whale land mammal features
• Tiktaalik shares fish amphibian features
• Evidence Conclusion Indicates common ancestry

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Comparing old fossils to modern life shows change
Ancient Kelp
Modern Kelp
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Radiometric Dating

• Helps determine age of fossils. More accurate
  than relative dating.
• Isotopes atoms of the same element with
  differing neutrons
• Ex 12C and 14C
• 12C 6 protons 6 neutrons
• 14C 6 protons 8 neutrons
• Organisms collect carbon throughout their
  lifetime.
• When organism dies 14C starts to decay into 14 N
  at a known rate (half-life)
• Fossil age determined by comparing ratio of C to
  N
• Wider ratio older sample

Both are Carbon
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Dating Fossils
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• Geography
• The study of geography provides evidence of
  evolution.

• island species most closely resemble nearest
  mainland species
• populations can show variation from one island to
  another

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• Different species show similar development
  patterns
• Different body plans become noticeable later in
  development
• Evidence Conclusion Indicates common ancestry

Embryo Development
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flipper
leg
wing
arm
Homologous Structures
walking
flight
grasping
swimming

• Defined similar body structures with very
  different functions
• Different environments lead to adaptations
• Ex The forelimbs of animals
• Evidence Conclusion Indicates common ancestry

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• Homologous structures are different than
  analogous structures

• Analogous structures have similar functions but
  different structures.

• Analogous structures are not evidence of a common
  ancestor.

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Vestigial Structures

• Defined Organs or structures which have lost
  most or all their original function
• Vestigial Human Parts
• Gill slits once used to breathe oxygen in water
• Yolk sac once used to nourish developing embryo
• Tailbone once used for balance
• Appendix once used to digest plants
• Wisdom teeth once used to grind plant tissue
• Evidence Conclusion Indicates common ancestry

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Human Embryo w/ Vestigial Structures
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Pythons have tiny femurs (leg bone)
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Biochemical Evidence

• DNA, RNA, proteins compared
• Genetic code same for most life
• More related species have more similar
  biochemistry
• Evidence Conclusion Indicates common ancestry

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• Constant creation of chemicals for human use is
  eliminating the unfit (invading)organisms
• Ex Antibiotics eliminating invading bacteria
• Ex Pesticides eliminating unfit pests
• Ex Antivirals
• Ex Fungicides
• Allows resistant to survive and reproduce

Resistant Organisms
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Strong Survive
Most bacteria killed
Bacterial Resistance
Strong Reproduce
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Antibiotic Resistance
penicillin
vancomycin
ampicillin
Amoxycillin
tetracyclin
Which antibiotics would successfully treat this
infection?
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Review

• How does antibiotic and pesticide resistance show
  natural selection?
• How do the following lines of evidence show
  change over time?
• Fossils
• Homologous structures
• Vestigial structures
• Resistant organisms
• Embryo development
• Biochemical (molecular) evidence
• Fossil age can be determined two ways. What are
  they?
• Which type of anatomical structures do not show
  evidence of common ancestry?