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
• Evidence Conclusions
• 1) Newer fossils are more complex
• 2) Common ancestors similarities between ancient
  modern life

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Comparing old fossil to modern life shows change
Ancient Kelp
Modern Kelp
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Radiometric Dating
Isotopes atoms of the same element with
differing neutrons Ex 12C and 14C 12C 6
protons 6 neutrons 14C 6 protons 8 neutrons

• Isotopes are unstable in their nuclei, so they
  decay
• Isotopes have a known half life (rates of decay
  are known).
• Half life number of years it takes for half of
  the isotopes to decay
• 14C has a half life of 5700 years, and 14N is a
  decay product
• Age determined by comparing ratio of 14C to 14N
• Wider ratio older samples

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C14
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24 Hour Earth Timeline
Amniotic egg (reptiles)
Land plants fungi
Multicellular plants
Dinosaurs appear
Land prokaryotes
Scale 1 minute 3 million years
Apes
(LUCA) prokaryotes
Land animals (amphibians)
Fish (first vertebrates)
Unicellular eukaryotes
Dinosaurs extinct
Outside links Link 1 Link 2
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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 Features
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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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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Vestigial Structures

• Defined Organs which have lost most or all their
  original function
• Vestigial Human Parts
• Gill slits once used to breath 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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• 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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• Antibiotics drugs designed to kill bacteria
• Obtained from fungi
• Antibiotic Resistance Bacteria are adapting to
  the use of antibiotics
• Misuse of antibiotics speeds up the process
• Importance Bacteria infections are becoming
  harder to treat
• Example of natural selection

Antibiotic Resistance
Bacteria
Fungus
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Strong Survive
Most bacteria killed
Bacterial Resistance
Strong Reproduce
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Antibiotic Resistance
Good
Bad
The antibiotics kill the bacteria, so the area
around them are clear
The antibiotics dont kill the bacteria, thats
why there is no clear area around them.
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Pesticide Resistance
"crop dusting"

• Pesticides
• Chemicals designed to kill pests (rodents,
  insects, etc)
• Pesticides sprayed on crops to kill pests
• Pesticide Resistance pests are adapting to the
  use of pesticides
• Strong pests survive to reproduce
• Importance Crops are being destroyed by pests

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Quick Review

• First life on earth were prokaryotes (bacteria)
• Changing environments lead to adaptation
• Much evidence indicates life has common ancestors