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Evolution Honors Biology Ms. Pagodin. Evolutionary Views of 19 th Century  Catastrophism - George Cuvier (anatomist)  Earth unchanging except rare catastrophes.

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Presentation on theme: "Evolution Honors Biology Ms. Pagodin. Evolutionary Views of 19 th Century  Catastrophism - George Cuvier (anatomist)  Earth unchanging except rare catastrophes."— Presentation transcript:

1 Evolution Honors Biology Ms. Pagodin

2 Evolutionary Views of 19 th Century  Catastrophism - George Cuvier (anatomist)  Earth unchanging except rare catastrophes  Recognized mass extinctions  Survivors repopulated  Never any new species, just fossils not yet found  Inheritance of Acquired Characteristics - Jean Lamarck  Environmental pressure & internal needs induced permanent changes in an organisms form and function, then passed to offspring  Ex. Giraffes  Easily disproved

3 Darwin’s Influences  Erasmus Darwin  All life was “produced by a simple life filament”  Organisms change over time  Artificial Selection AKA Selective Breeding  Domestication of crops, dogs, horses, etc  Charles Lyell – Theory of uniformity  “Principles of Geology”  Erosion, earthquakes, floods, etc, slowly and gradually shaped and changed the earth over millions of years (not 6,000 years)  Thomas Malthus  “Essay on the principle of population”  Population – a group of individuals that belong to the same species, live in a defined area, and breed with others in the group  Populations have the potential to increase faster than the available food supply…but this doesn’t occur because of death by disease, war, and famine

4 Charles Darwin & The Beagle  British Naturalist (attempted med school, and theology)  1831 at 22 yrs old went on a 5 year voyage around the world  Made observations, took notes, collected thousands of specimens, consulted with other naturalists  Alfred Wallace independently developed the same theory of natural selection  1859: Darwin Published “On the Origin of Species”  Fiercely Debated

5 Darwin’s Observations  Argentina  extinct glyptodonts – large, similar to armadillo and same region  Descent with modification?  Galapagos  Populations - variations in traits (size, color, etc)  Environmental Influence  Ex. Finches

6 Natural Selection 1. Overpopulation  Populations have ability to reproduce more individuals than can survive 2. Genetic Variation  Mutations are sources of different traits 3. Competition  Some traits give a selective advantage 4. Successful Reproduction  Over successive generations, see an increase of certain traits within a population

7 Lamarck's vision of evolution differs from Darwin's in that Lamarck believed 1. Living things evolved upwards 2. Behavioral changes modified heritable ones 3. Genetic differences allowed for evolution

8 Which Scientist influenced Darwin on population Growth? 1. Cuvier 2. Malthus 3. Lyell 4. Wallace

9 Artificial Selection is the process by which 1. Natural selection fails to act on wild populations 2. Humans prevent natural selection 3. Humans allow only organisms with specific characteristics to breed

10 Darwin Awards  Ski Theft Backfires 1998 Darwin Award Nominee Confirmed by Darwin  (February 1998) Matthew and his friends were sliding down a Mammoth Mountain ski run on a foam pad at 3am, when he crashed into a lift tower and died. His makeshift sledge of yellow foam had been stolen from the legs of a lift tower on Stump Alley. The cushion is meant to protect skiers who hit the tower, and the tower Matthew ran into was the one from which he had created his sledge. There's a moral in there somewhere.  DarwinAwards.com © Submitted by: Blink and Grech Reference: The Guardian, Sacramento Bee DarwinAwards.com © Blink

11 Individuals do not evolve – Populations do  Microevolution – small scale changes within a population  Morphological – body structures  Physiological - functionality  Behavioral – ex. mating ritual  Arise from  Mutations  Lethal, neutral, or beneficial  Natural selection  Gene flow – immigration and emigration between 2+ populations  Genetic drift – small populations affected by random changes  Bottle Neck or Founder’s Effect – rebuild a population or start a new one  Inbreeding – ex. Polydactylism in Amish population, PA (1/200)

12 Patterns of Microevolution  Directional Selection  Changes in environmental conditions that lead to a phenotypic shift in one direction  Ex. Antibiotic resistance, Pesticide resistance  Stabilizing (balancing) Selection  Intermediate forms of the trait are favored  Preserves common phenotypes  Disruptive Selection  Intermediate forms of the trait are selected against

13 Industrial Melanism of Biston betularia a. In the last 150 years, the relative preponderance of the two morphs has changed dramatically. b. Old collections from the early 1800's show that the pepper morph was far and away the most abundant morph. Melanic morph was collected only very rarely. c. Beginning in the early to mid 1800's, however, melanic form increased in abundance dramatically, until today, in some areas virtually all moths are melanic. d. There has thus clearly been a dramatic change in gene frequencies

14 Reproductive Isolation  A new species may emerge as a result of accumulations of microevolutionary changes in which one population can no longer successfully reproduce with initial population  Mechanical Isolation  Bodies are incompatible for sexual reproduction  Behavioral Isolation  Differing courtship displays prevent gene flow  Temporal Isolation  Differences in timing of reproduction  Ecological Isolation  Habitats separated  Gamete Mortality  Molecular incompatibilities  Postzygotic isolation  Early death, sterility, or low survival rates of hybrids

15 Evidence of Macroevolution: Fossils  Fossils formed by pressure and mineralization  Radiometric Dating – measures proportions of parent and daughter isotopes, known half-life’s are used to calculate approximate age

16 Fossil Record

17

18 C-14 has a half-life of 5,730 years. If an anthropologist has a hominid skull with a C-14 to C-12 ratio 1/16 th of a living organism what is the age of the skull? yrs 2. 5,730 yrs 3. 11, 460 yrs 4. 17,190 yrs 5. 22,920 yrs

19 Carbon 14 had a half-life of 5730 years. Scientists found a fossilized bone from an organism in a deep layer of rock. When they took the bone back to the lab they realized that the bone had only 12.5% of the total carbon 14 left. Based on the amount of carbon 14 left in the bone how old is the bone? yrs 2. 1,910 yrs 3. 5,730 yrs 4. 11,460 yrs 5. 17, 190 yrs 6. 71, 625 yrs

20 The half-life of potassium is 1.3 billion years. If a rock was determined to be around 5.2 billion years old how much potassium 40 would be left in that rock sample? % 2. 50% 3. 25% % % % %

21 Evidence of Macroevolution: Morphology  Homologous Structures – similar body structures suggests common ancestry  Vestigial Structures – structure reduced in size or function  Analogous Structures – adapted individually, different structures with similar function  Embryonic Development

22 Evidence of Macroevolution: Biogeography  Pangea disproves theory of uniformity  Continental drift due to shifts in plate tectonics  Accounts for distribution of fossils

23 Evidence of macroevolution - Biochemistry  Nucleic Acid Comparisons  Nuclear DNA  Mitochondrial DNA  Protein Comparisons  Highly Conserved = functionally important  Utilized as Molecular Clocks  Evolutionary divergence based upon number of differences between species

24 Vestigial structures are anatomical structures that 1. Have multiple functions 2. Are no longer functional 3. Look similar in different species but have a different function 4. Have the same function in different species, but different appearance

25 Which of the following is an example of developmental homologies seen in human embryonic development? 1. Gill slits 2. Tail 3. Spinal chord 4. All of the above

26 Fossil record shows the first mammals evolved about 220 million years ago. Pangea began to break apart 200 million years ago. Therefore fossils of the first mammals should be found. 1. Most or all of the current continents 2. Only Antarctica 3. Only one or a few continents

27 Patterns of Speciation & Extinction  Evolutionary Trees  Each branch represents a line of decent from common ancestor  Graduated Equilibrium – accumulation of small changes over long spans of time  Punctuated Equilibrium – long periods of stability followed by abrupt change  Adaptive radiation – burst of divergence from one linage or branch  Mass Extinctions – catastrophic losses of major groups of organisms

28 How did cells originate?  Big Bang Theory – instantaneous distribution of all matter and energy throughout the universe  Sun approx. 5 billion years old  Early Earth 4.5 byo  Abiotic Synthesis of Organic compounds  Stanly Miller Experiment  Proto-cells – simple self replicating sacs with early metabolic reactions occuring  Spontaneous Organization  3.5 bya – Anaerobic prokaryotes diverged by metabolic pathways  Chemosynthesis vs. photosynthesis  Endosymbiosis – eukarytoes emerged from prokaryotes

29 Stanley Miller Exp


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