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Question: Homework:

Question: Homework:. How many species that once lived on Earth do you think are still present today? Give a % p. 422 #1, 2, p. 440 #2, 5 (lab) Comparing Bird Adaptations. The History of the Earth. Earth's Timescale. 4.6 Billion Years Old 4 BYA- early life originates

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Question: Homework:

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  1. Question: Homework: • How many species that once lived onEarth do you think are still present today?Give a % • p. 422 #1, 2, p. 440 #2, 5 • (lab) Comparing Bird Adaptations

  2. The History of the Earth

  3. Earth's Timescale • 4.6 Billion Years Old • 4 BYA- early life originates • 3.2 BYA- oxygen released into atm. • 2.1 BYA- first eukaryotes • 530 MYA- first life on land • 246-144 MYA- dinosaurs • 150-160 KYA- earliest Homo sapiens on Earth

  4. Origins of Life • Early Earth’s atmosphere • NO ORGANIC COMPOUNDS • contained building blocks (Carbon, hydrogen in various compounds • Organics require lots of energy to form • Thought to have formed as result of lightning • bubbles made holding organic cpds.

  5. How we know- • Index Fossils • Fossils used to be compared to other unknown fossils • Can see relative age • if above, = younger • Carbon Dating • Method of using radioactive carbon to give date fossil was formed • Can use these two to give dates that different species existed on Earth

  6. Extinction • By looking at fossil records, can see 5 major extinctions in Earth’s history • last one 65 MYA- dinosaurs along with MANY others • The 6th extinction? • Currently, species disappearing at rates unparalleled in Earth’s history • Caused by humans?

  7. How life came about? • Primordial soup • Molecules present on early Earth • Combined with energy added, can make organic compounds • made simple bacteria • lipid surrounding DNA

  8. How life came about? • From bacterial life to multicellular life… • **Endosymbiotic theory • one bacteria ingested another, and developed the ability to work with that structure • over time, different bacteria with different functions were taken in, resulting in the modern eukaryote • evidence: mitochondria with their own DNA!!!

  9. Patterns of Evolution • Punctuated Equillibrium • Adaptive Radiation • Coevolution • Convergent Evolution

  10. Punctuated Equillibrium • Theory to explain that long periods of equillibrium exist, followed by short, rapid phases of evolution • Generally follow mass extinctions in Earth’s history • **WHY?

  11. Coevolution • When two species evolve in response to each other • *Think of snake and newt as example- • one develops greater toxicity to protect itself, while other evolves higher resistance to toxicity

  12. Adaptive Radiation • When one species evolves into a number of different species • Think about Darwin’s finches- • began as one species, but evolved into 14 different species depending on the niche being filled

  13. Convergent Evolution • When two species evolve similar, but distinctly different structures • Ex- bat wing and fly wing

  14. Question: Homework: • How is the “6th extinction” different from the 5 • prior extinctions in Earth’s history? • p. 422 #1, 2, p. 440 #2, 5 • (lab) Comparing Bird Adaptations

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