Transcript Evidence Conclusion

• 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
Comparing old fossil to modern life
shows change
Ancient Kelp
Modern Kelp
Radiometric Dating
• Helps determine age of fossils
• Isotopes: atoms of the same element with differing neutrons
– Ex: 12C and 14C
12C = 6 protons + 6 neutrons
14C = 6 protons + 8 neutrons
Both are Carbon
• When organism dies: 14C starts to decay
• Fossil age determined by comparing ratio of 12C to 14C
Dinosaurs extinct
Land animals (amphibians)
Fish (first vertebrates)
Apes
Dinosaurs appear
Amniotic egg (reptiles)
Land plants & fungi
Multicellular plants
Outside links
Link 1
Link 2
Unicellular
eukaryotes
Scale:
1 minute = 3 million years
Land prokaryotes
(LUCA)
prokaryotes
24 Hour Earth Timeline
Whale
Evidence
Reptile
Fish
evidence
Evidence
Long
Teeth spine
Scales
Amphibian
evidence
Land
Bird Evidence
Eyes on
top of head
Wolf-like
Wishbone
teeth
Found
in dried up
Bony tail
Fins
oceans
Found in dried-up
oceans
Wrist Hind
bones
Features
legs
• 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
• Defined: similar body structures with very different
functions
• Different environments lead to adaptations
– Ex: The forelimbs of animals
• Evidence Conclusion : Indicates common ancestry
• 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
Human Embryo w/ Vestigial Structures
Pythons have tiny femurs (leg bone)
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DNA, RNA, proteins compared
Genetic code same for most life
More related species have more similar biochemistry
Evidence Conclusion : Indicates common ancestry
• Different
species show
similar
development
patterns
• Different body
plans become
noticeable later
in development
• Evidence
Conclusion :
Indicates
common
ancestry
Bacteria
Fungus
• 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
Bad
The antibiotics don’t kill the bacteria, that’s
why there is no clear area around them.
Good
The antibiotics kill the bacteria, so
the area around them are clear
• 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
• First life on earth were prokaryotes (bacteria)
• Changing environments lead to adaptation
• Much evidence indicates life has common
ancestors