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Evolution

Learn about the rate of evolution and different types of evidence, such as fossils, molecular records, and anatomical records. Practice radioactive dating and explore homologous and analogous structures.

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Evolution

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  1. Monday 2/8/2016 Evolution • Agenda: Evolution Part II • Activity: Darwin’s Natural Selection Worksheet • Notes: Rate of Evolution • Homework/Class Work: • No Homework Tonight….unless…….

  2. Start: Q3 WK4 D4&5 Darwin’s Natural SelectionWorksheet

  3. Q3 WK4 D4&5 The Rate of Evolution • Different kinds of organisms evolve at different rates • Bacteria evolve much faster than complex cells • The rate of evolution also differs within the same group of species • In punctuated equilibrium, evolution occurs in spurts • In gradualism, evolution occurs in a gradual, uniform way

  4. Gradualism Punctuated equilibrium

  5. Draw me  GRADULISM PUNCTUATED EQUILIBRIUM

  6. Evidence of Evolution 1. Fossil Records 2. Molecular Records (Carbon Dating and DNA) 3. Anatomical Records

  7. Fossil Records • Fossils are the preserved remains, tracks, or traces of once-living organisms • Fossils form when organisms become buried in sediment and calcium in hard surfaces mineralizes • Arranging fossils according to age often provides evidence of successive evolutionary change • Robert Hooke in 1668- 1st to propose that fossils are the remains of plants & animals. • Provides the most direct evidence for macroevolution

  8. Missing Links Ardi (Ardipithecus ramidus) : stood about 47 inches tall and weighed about 110 pounds. Took 15 years to unearth. Lived 4.4 million years ago Lucy (Australopithecus afarensis) : 40 % complete skeleton. Lived 3.2 million years ago

  9. Fig. 13.4 Whale “missing links” • Fossils have been found linking all the major groups • The forms linking mammals to reptiles are particularly well known

  10. More Missing Links Archaeopteryx. The most primitive known bird. Lived ~150 million years ago. Ambulocetus: The walking whale. This animal could walk as well as swim. It lived ~50 million years ago.

  11. Tuesday 2/10/2016 Evolution • Agenda: Evolution Part II • Notes: Fossil Records • Activity: Radioactive Dating Worksheet • Homework/Class Work: • Radioactive Dating Practice Worksheet due • Wednesday/Thursday 2/10-2/11/2016

  12. Fossil Records • Relative Dating (aka Law of Superposition) by Nicolaus Steno • By looking at where the fossils are in relation to therock depth or layers, scientists can see when an organism goes extinct or when there is a mass extinction • In other words, in a cross section of the Earth or rock layers, the lowest layer is the oldest

  13. Molecular Records • Certain atoms are known to decay (break down) at a specific rate. Scientists can look at these atoms to determine how old an organic object is. • Radioactive isotope 14C- gradually decays over time back to 14N (known as Carbon Dating) • It takes 5600 years for half of the 14C present in a sample to be converted to 14N. • This length of time is called the half-life. • Half life (t1/2): the time needed for half of the atoms of the isotope to decay • For fossils older than 50,000 yrs scientists use potassium isotope • t1/2 of 40K = 1.3 billion years to turn to argon (40Ar)

  14. How do we use the method? Uranium-235 has a half-life of 700 million years. How much of the 12 g sample of Uranium-235 will be left after: • a. 700 million years _______ • b. 1400 million years _______

  15. Radioactive Dating Practice worksheet • Lets practice radioactive dating • Attach into your sci. ntbk

  16. Wednesday/Thursday 2/10-2/11/2016 Evolution • Agenda: Evolution II • Review: Radioactive Dating Worksheet • Activity: Dating the Iceman Worksheet • Activity: Iceman Murder Mystery • Homework/Class Work: • Finish Radioactive decay worksheet due Friday 2/12/2016

  17. Radioactive Dating Practice Lets practice radioactive dating to better understand the homework: How much of 20.0 grams of a substance will be left after 1 hour if the half life is 15 minutes (answer in grams) The half life of thorium-27 is 16.32 days. How many days are required for 2.63 to remain if you start with 84.25 grams?

  18. Notebook Check • Notes: Rate of Evolution • Activities: Natural Selection of Cacti, Blood Donor Mix Up Questions, Darwin’s Natural Selection worksheet, Adaptations of Rabbits Foldable Worth 27 points 

  19. Friday 2/12/2016 Evolution • Agenda: Evolution Part II • Notes: Anatomical Records • Activity: Anatomical Records Foldable • Homework/Class Work: • Radioactive Dating Practice Worksheet due • Wednesday/Thursday 2/10-2/11/2016

  20. Relict developmental forms Anatomical Record • Similar structural forms can be seen in different living organisms • Homologous structures • Analogous structures • Vestigial structures • All vertebrates share a basic set of developmental instructions

  21. Fig. 13.8 Homology among vertebrate limbs • Homologous structures: have same structure, DIFFERENT function. However, the structures are derived from the same part of a common ancestor The same basic bones are present in each forelimb

  22. Analogous structures:resemble each other as a result of needed adaptations to similar environments(Different animals adapt in similar fashion when challenged by similar opportunities) • The feature has the same function but looks different.

  23. Vestigial structures: • Although the structure(s) had a purpose & function in the pastbut they are largely or entirely functionless now. • a vestigial structure may retain lesser functions or develop new ones. The blind mole rat has tiny eyes completely covered by a layer of skin. The blue whale has tiny hind leg bones under its tail.

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