3/23/12- Document what you did on your DoNow Sheet for today. Copy & answer on a separate sheet of paper. • How do you think you did on yesterday’s test? • How long did you study (outside of class)? • Did you fully complete the review sheet? • What could YOU do to improve your grade? • What could we do to help you? Study over Week 11 Vocab/Copy down Week 12 *Take out EOCT- p9 &10
3/26/12— Take out “Lorenzo’s Oil” Handout & EOCT p9-10, from Friday. Turn to pp417-422; 382-386 Read the following pages… Be on task when the bell rings, so we can listen to announcements & finish the movie…
3/27/12—Continue to define Evolution Vocab. Take out EOCT p9 & 10 • Spontaneous generation • Endosymbiotic theory • Biogenesis • Directional selection • Stabilizing selection • Disruptive selection • Natural Selection After you have finished, read the following pages 417-422; 382-386, quietly
Essential Question: What are some theories about the origin of life on earth?
EVOLUTION Today’s principle… • BIOGENESIS-all living things come from other living things
17th Century beliefs… Spontaneous generation- living things could arise from nonliving things
Experiments by Francesco Redi, Lazzara Spallanzani, & Pasteur led to the modern day idea of biogenesis Redi
Lazzaro Spallanzani demonstrated that sealing off the flask would keep microrganisms from forming in the broth.
Alexander Oparin hypothesized that the gases in the primitive atmosphere lead to the formations of organic molecules and finally living things.
Early Earth • Approximately 4.6 bya • Primitive atmosphere Earth's early atmosphere probably contained hydrogen cyanide, carbon dioxide, carbon monoxide, nitrogen, hydrogen sulfide, and water. • Probably no O2
Conditions on the Early Earth • 4.5 billion years ago • “Cloud” began to condense = rain • 4 billion years ago • Crust and mantle formed • Primitive atmosphere • H2, N2, CO, CO2 , probably no O2 • Hot temperatures
Miller and Urey’s experiment tested Oparin’s hypothesis. It recreated the conditions of early Earth.
Miller and Urey's experiments suggested how mixtures of the organic compounds necessary for life could have arisen from simpler compounds present on a primitive Earth. • Evidence suggests that 200–300 million years after Earth had liquid water, cells similar to modern bacteria arose.
The Puzzle of Life's Origins • Formation of Microspheres • In certain conditions, large organic molecules form tiny bubbles called proteinoid microspheres. • Microspheres are not cells, but they have selectively permeable membranes and can store and release energy. • Hypotheses suggest that structures similar to microspheres might have acquired more characteristics of living cells.
The Puzzle of Life's Origins • Evolution of RNA and DNA • How could DNA and RNA have evolved? Several hypotheses suggest: • Some RNA sequences can help DNA replicate under the right conditions. • Some RNA molecules can even grow and duplicate themselves suggesting RNA might have existed before DNA. • Microscopic fossils, or microfossils, of unicellular prokaryotic organisms resembling modern bacteria have been found in rocks over 3.5 billion years old. • These first life-forms evolved without oxygen.
Free Oxygen • About 2.2 billion years ago, photosynthetic bacteria began to pump oxygen into the oceans. • Next, oxygen gas accumulated in the atmosphere. • The rise of oxygen in the atmosphere drove some life forms to extinction, while other life forms evolved new, more efficient metabolic pathways that used oxygen for respiration.
Origin of Eukaryotic Cells • The Endosymbiotic Theory • The endosymbiotic theory proposes that eukaryotic cells arose from living communities formed by prokaryotic organisms. • About 2 billion years ago, prokaryotic cells began evolving internal cell membranes. • The result was the ancestor of all eukaryotic cells. • According to the endosymbiotic theory, eukaryotic cells formed from a symbiosis among several different prokaryotes.
Origin of Eukaryotic Cells • Endosymbiotic Theory Ancient Prokaryotes Chloroplast Plants and plantlike protists Aerobic bacteria Photosynthetic bacteria Nuclear envelope evolving Mitochondrion Primitive Photosynthetic Eukaryote Animals, fungi, and non-plantlike protists Primitive Aerobic Eukaryote Ancient Anaerobic Prokaryote
Origin of Eukaryotic Cells Aerobic bacteria Ancient Prokaryotes Nuclear envelope evolving Ancient Anaerobic Prokaryote
Origin of Eukaryotic Cells Mitochondrion • Prokaryotes that use oxygen to generate energy-rich molecules of ATP evolved into mitochondria. Primitive Aerobic Eukaryote
Origin of Eukaryotic Cells Prokaryotes that carried out photosynthesis evolved into chloroplasts. Chloroplast Photosynthetic bacteria Primitive Photosynthetic Eukaryote
Reading Assignment • Read p. 423-428 & p. 8-14.
Evidence of Evolution 1. Fossils- The remains of any past life Types of fossils (1) imprint (2) mold (3) cast (4) petrified (5) frozen
2. Radioactive dating • Half-life - Time it takes for one half of a given quantity of a radioisotope to decay
3. Comparative Anatomy a. Homologous structures - parts of the body that are similar in structure show evidence of common origin
b. Analogous structures – parts of the body that are similar in function but not structure – does not show common origin. Bird’s wing and bee’s wing are analogous structures
c. Vestigial structure – structures that no longer function in the body – may show relationship with other organisms, indicate common origin. Examples: appendix or a whale’s pelvis
4.Comparative Embryology • Early vertebrate embryos strongly resemble one another • Same plan of development
5.Comparative Biochemistry • The More similar the DNA & protein structure of 2 organisms, the more closely they are related. Pointing to a recent common ancestor.
3/28/12--Take out Your “Evidence for Evolution” Graphic Organizer • Contrast biogenesis & spontaneous generation. Which is believed today? • Briefly describe the experiments of each of these scientists. a. Redi b. Spallanzani c. Pasteur d. Miller&Urey 3. ____ hypothesized that the gases of Earth’s primitive atmosphere led to the formation of organic molecules & living things. 4. What was early Earth like? 5. _____ proposes that eukaryotic cells arose from communities of prokaryotic organisms.
Read p. 416-422 & p. 382-386. • Find & cut out pictures/letters to illustrate the 5 pieces of evidence for evolution. Model your paper after the diagram on the board. • On the back of your paper: • –Answer questions #1 & 2 only on p. 422. • –Answer question #3 on p. 386.
3/29/12- Take out your Evol. Poster Do-Now:On the back of your Evol. Poster: • –Answer questions #1 & 2 only on p. 422. • –Answer question #3 on p. 386. Turn in Evol. Poster on top of overhead & Complete the Evolution Vocab Word Search. Letters punched out: S, M Words punched out: Endosymbiotic Theory & Half-life
Two theories of Evolution Jean Baptist Lamarck – Theory of Acquired Characteristics Traits you develop you pass on---ACQUIRED TRAITS
Charles Darwin – Theory of Natural Selection Survival of the fittest. Fig. 17.5a, p. 274
Darwin Wolf Pinta Genovesa Marchena Santiago Bartolomé Seymour Råbida Baltra Pin zon Fernandia Santa Cruz Santa Fe Tortuga San Cristobal Española Floreana EQUATOR Galåpagos Islands Isabela Fig. 17.5b, p. 275
Darwin’s Finches • Darwin saw many of the islands in the Galapagos had their own species of finch. • Each bird had a unique beak and well adapted body for the type of food found in its area. • The birds were all similar, but were different species. • Darwin realized they must have evolved from a common ancestor.
1 A few individuals of a species on the mainland reach isolated island 1. Speciation follows genetic divergence in a new habitat. 3 2 4 Later in time, a few individuals of the new species colonize nearby island 2. In this new habitat, speciation follows genetic divergence. 1 2 Speciation may also follow colonization of islands 3 and 4. And it may follow invasion of island a by genetically different descendants of the ancestral species. 1 3 2 4 Fig. 19.11 p. 303
KONA FINCH extinct KAUAI AKIALAOA AMAKIHI LAYSAN FINCH IIWI AKIAPOLAAU APAPANE MAUI PARROTBILL fruit and seed eaters insect and nectar eaters Fig. 19.12 p. 303 FOUNDER SPECIES
Theory of Natural Selection 1. Overproduction- - populations increase at a higher rate than their food supply and the size of a population is limited by the availability of food
Theory of Natural Selection 1. Overproduction 2. Struggle for Existence – results from the competition between organisms for available food, shelter and living space.
Theory of Natural Selection 1. Overproduction 2. Struggle for Existence 3. Variations – differences make every individual different from every other individual
Theory of Natural Selection 1. Overproduction 2. Struggle for Existence 3. Variations 4. Natural selection–- those members best adapted will survive longer and reproduce
Theory of Natural Selection 1. Overproduction 2. Struggle for Existence 3. Variations 4. Natural selection 5. New Species – accumulated variations in an isolated population will eventually produce a new species = Speciation
How Natural Selection Works Example: The Peppered Moth The peppered Moth, Biston beularis, lives in England. There are two colors of this moth.