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EVOLUTION. DARWIN’S THEORY OF EVOLUTION Chapter 15. Mr. V. M. Galdo Science Department BOOKER T. WASHINGTON S.H.S. The Puzzle of Life’s Diversity (p. 369 – 372).
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DARWIN’S THEORY OF EVOLUTIONChapter 15 Mr. V. M. Galdo Science Department BOOKER T. WASHINGTON S.H.S.
The Puzzle of Life’s Diversity (p. 369 – 372) • During his travels, Charles Darwin made numerous observations and collected evidence that led him to propose a revolutionary hypothesis about the way life changes over time. • Darwin noticed that the characteristics of many animals and plants varied noticeably among the different islands of the Galapagos in Ecuador. • Key Words: evolution, theory, fossil.
The Puzzle of Life’s Diversity (cont. p. 369 – 372) • Fossils vs. living organisms: Many of the fossils that Darwin discovered resembled living organisms but were not identical to them. Read and discuss: page 370, fig. 15-2. • Habitats and shapes: Darwin observed that the characteristics of many animals and plants varied noticeably among the different Galapagos Islands. Their shapes seem to adapt to their habitat. Read and discuss: page 371, fig. 15-3.
The Puzzle of Life’s Diversity (cont. p. 369 – 372)The Warbler Data • The warbler finch (top) boasts a thin, sharp beak best suited for spearing insects. Ground finches' shorter, more robust beaks (center) are adapted for eating seeds found on the ground. Those of cactus finches (bottom) are shaped for getting seeds from cacti. (Harvard Medical School and Margaret Bowman)
The Puzzle of Life’s Diversity - Video • VIDEO: Biomes: Islands and Evolution (Call # NP 577.5 – ISL) • Copy the questions that appear on the video in the Questions section of your notebook. • Answer the questions while you watch the video in the notes section of your notebook
QUESTIONS & SUMMARY • Read pages 368 through 372 create your own notes, at least a full page of notes. • Using the High School Question Task Cards write at least 5 questions about today’s notes. • Write your summary.
Output • Copy and answer the 15-1 Section Assessment on page 372, all questions 1 through 5. • GIZMO http://www.explorelearning.com/index.cfm?method=cResource.dspView&ResourceID=447&ClassID=802401 • Lab: Finch Beak Evolution/Adaptation Demo (see next slide)
Ideas that Shaped Darwin’s Thinking 1785 – James Hutton Earth is shaped by geological forces over extremely long periods of time. Earth is million of years old. Essay on the Principle Of Population. Limited Resources. 1798 – Thomas Malthus Predicts that the human population will grow faster than the space and food supplies needed to sustain it. Hypothesis of the inheritance of acquired traits. It was wrong. 1809 – Jean-Baptiste Lamarck First to propose a mechanism explaining how organisms change over time.
Ideas that Shaped Darwin’s Thinking 1831 – Charles Darwin Sets sail on the H.M.S. Beagle. A trip around the world that lasts 5 years. Evidence and data is collected. Principles of Geology 2nd and final volume. Earth changes. 1833 – Charles Lyell Explains that processes occurring now have shaped Earth’s geological features over long periods of time. Based on his studies of the distribution of plants and animals 1858 – Alfred Wallace Writes to Darwin speculating on evolution by natural selection
Ideas that Shaped Darwin’s Thinking 1859 – Charles Darwin publishes On the Origin of Species
The Evolution of the Universe, Earth and Life • A HUGE TIMELINE OF EVOLUTION: http://www.johnkyrk.com/evolution.html
QUESTIONS & SUMMARY • Using the High School Question Task Cards write at least 5 questions about today’s notes. • Write your summary.
Output • Lab – Moth or Butterfly Adaptation and Natural Selection
Studying Living Organisms - Protective Coloration: A Model of Natural Selection (LAB) Richard Filson -1995 Woodrow Wilson Biology Institute Introduction Natural selection operates on the principle of survival of the fittest. Fitness can be defined as the suitability of an organism to a given environment. One might ask if one set of features favorable in one environment might prove unfavorable in another environment. In this experimental model, the features studied will be the adaptations of protective coloration in two very different environments. You will act as the predator and your prey will be three types of paper squares, each with a different color. Their environment will be either a sheet of light colored paper or a sheet of dark paper. Procedure Work in groups of three partners (a predator, an experimenter, and a data collector). One of you must always be the predator while the others will supervise the experiment so as not to introduce an uncontrolled variable. The experimenter's job is to spread out the prey * randomly for each trial making sure they are not piled up and that they thoroughly cover the sheet of paper. The data collector will time each trial, count and record the data. The predator's role here is to pick up as many preys (squares) as possible in 30 second trials and take them to the nest (Petri dish). With the predator standing with his back to the hunting area, the data collector will give a signal, the predator then quickly turns around and begins to hunt until the data collector tells him to stop (at 30 seconds). The data collector writes down the total for each colored pray that was catch. This trial is repeated two more times and then the environmental background will be changed to a different color. Again three trials will be made attempting to spot and catch as many prays (squares) as possible in 30 seconds trials. * The experiment will start with 45 preys – colored squares, 15 of each color. Once picked the prey is dead, and it is removed from the environment. You must stop and wait for the teacher between trials. Important Notes: The particular predator in this problem only hunts for prey just before sunrise and just after sunset, therefore, the light in the room will be very subdued. After each trial, the experimenter should rearrange all paper circles on the paper to make sure the population is randomly distributed. When all data is recorded, compute your average and report the results to your teacher. Before starting, make a prediction. Hypothesis / Prediction: Which square on which background will get the lowest count? Why? Interpretations and Conclusions In natural selection, selective pressure is the factor that reduces the frequency of a particular phenotype more than another phenotype. In this model the phenotypes are white, red, and black. What was the selective pressure on this population? Some circles went uncatched and thus escaped predation. Why did some escape? Is survival equal for each phenotype? Explain why, or why not. From results of this experiment, what can you conclude about the relative nature of fitness with respect to the environment?
LAB REPORT • Read pages 380 – 381, 397 – 398 and 400. • Use the Lab Report Format to Write your lab report about Natural Selection.
Darwin Presents His case (p. 378 – 386) • In artificial selection, nature provides the variation among different organisms, and humans select those variations that they find useful. For example, ______________. • Over time, natural selection results in changes in the inherited characteristics of a population. These changes increase a species’ fitness in its environment. For example, __________________________. • Key Concepts: artificial selection, struggle for existence, fitness, adaptation, survival of the fittest, natural selection, descent with modification, common descent, homologous structure, vestigial organ.
Darwin Presents His case (p. 378 – 386) • Darwin argued that living things have been evolving on Earth for millions of years. • Evidence for this process could be found in the fossil record (fig.15-13), the geographical distribution of living species (fig. 15-14), homologous structures of living organisms (fig. 15-15), and similarities in early development, or embryology (fig. 15-17).
QUESTIONS & SUMMARY • Using the High School Question Task Cards write at least 5 questions about today’s notes. • Write your summary.
Output • Read pages 373 – 377. Copy and answer the 15-2 Section Assessment on page 377, all questions 1 through 5. • Read pages 378 - 386. Copy and answer the 15-3 Section Assessment on page 386, all questions 1 through 4.
The Fossil Record (Sect 17-1, P. 416 - 422) • The fossil record provides evidence about the history of life on Earth. It also shows how different groups of organisms, including species, have changed over time. • Relative dating allows paleontologists to estimate a fossil’s age compared with that of other fossils. • Vocabulary: paleontologist, fossil record, extinct, relative dating, index fossil.
The Fossil Record (Sect 17-1, P. 416 - 422) • In radioactive dating, scientists calculate the age of a sample based on the amount of remaining radioactive isotopes it contains. What is a Half-Life? • After the Precambrian Time, the basic divisions of the geologic time scale are eras and periods. • Vocabulary: half-life, radioactive dating, geologic time scale, era, period.
What is a Half-Life? • Every radioactive element has a half-life • Half-life is the time it takes for half of its atoms to decay. • Half-lives range from a fraction of a second to billions of years – 4.5 billion for uranium 238. • The longer the half-life, the less intense the radiation. • After 10 half-lives, an element is usually harmless
QUESTIONS & SUMMARY • Using the High School Question Task Cards write at least 5 questions about today’s notes. • Write your summary.
Output • Read pages 417 – 422. • Using the vocabulary words, write a letter to a friend explaining how fossils are use to support the theory of evolution: paleontologist, fossil record, extinct, relative dating, index fossil, half-life, radioactive dating, geologic time scale, era, period. UNDERLINE THE VOCABULARY WORDS IN THE LETTER
Earth’s Early History • Earth’s early atmosphere probably contained hydrogen cyanide, CO2, carbon monoxide, hydrogen sulfide, and H2O. • 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 (proteinoids microspheres)
Earth’s Early History • The rise of O in the atmosphere drove some life forms to extinction, while other life forms evolved new, more efficient metabolic pathways that used O for respiration. • The endosymbiotic theory proposes that eukaryotic cells arose from living communities formed by prokaryotic organisms. • Vocabulary - proteinoid microsphere, microfossil, endosymbiotic theory
QUESTIONS & SUMMARY • Using the High School Question Task Cards write at least 5 questions about today’s notes. • Write your summary.
Output • Read pages 423 – 428. • Write two or three paragraphs explaining what was the main factor the help life develop the way we know it? Use at least 3 key words from the notes. UNDERLINE THE VOCABULARY WORDS IN THE LETTER