Warm-up / EOC Prep- only write # 1 1. The process of DNA replication is necessary before a cell — A.makes a protein B. codes for RNA molecules C. divides into two cells D. modifies lysosome enzymes 2. In order to form recombinant DNA, scientists have found a way to cut a DNA segment using an enzyme named EcoRI. This enzyme cuts DNA wherever the sequence C-T-T-A-A-G occurs between the A and the G base. Which of these would result if EcoRI were used on the DNA in the diagram to the right? Agenda • • • • • • • Warm-up Notes Darwin & Natural Selection Worksheet Natural Selection Fish Lab Whiteboards Clean-up Cool-down Evolution is the core theme of biology “Nothing in biology makes sense except in the light of evolution” Theodosius Dobzhansky Evolution Day 1 Darwin and the Theory of Evolution Historical Background to Darwin's Theory of Evolution • The theory of evolution has developed through a lot of scientific observation and experimentation and most scientists today accept that evolution is the basis for the diversity of life on Earth. • Charles Darwin, who later on developed the idea of natural selection, was born in England in 1809. He struggled in school and his father wanted him to be a doctor or a minister. •In 1831 Charles Darwin left on a 5 year voyage on board the HMS Beagle to survey the coast of South America. •He stopped off in the Galapagos Islands where the diversity of tortoises and birds amazed him •In 1836 he returned to England • He specifically studied finches, a type of bird with different sized beaks on the islands. Each type of beak was special for eating a different type of food. The birds adapted or changed so they could eat their food. One bird could have a long beak to get in holes to eat insects, and another might have a big beak to crush nuts. Galapagos Islands Darwin’s Finches Darwin saw variation (difference) within species on the different Islands, but didn’t fully understand what he saw till he returned to England • Another scientist, Jean Baptiste Lamarck, believed that physical features increased in size because of use or decreased in size because of disuse. His theories suggested that the organism’s life determined what traits got passed onto offspring. • Giraffes • No Evidence Ex: mice tails • If a mouse has its tail cut-off, the mouse will not have tailless offspring • A heavy influence on Darwin’s theories was the book Principles of Geology by Charles Lyell, which explained that the surface of the Earth changed slowly over many years. • Another influence was the work of Thomas Malthus, who wrote that human populations can increase faster than the food supply. •Geologists Hutton and Lyell explained that the Earth was old, and the economist Thomas Malthus explained population growth • Populations breed rapidly, but populations don’t grow uncheckedMost organisms in a population die without breeding • In 1859 Darwin published his book, On the Origin of Species • Darwin did not want to be criticized for his ideas. However, he did not want to lose credit for his ideas either, so when a competing scientist, Alfred Russel Wallace was about to come out with a very similar idea Darwin had his ideas along with Wallace’s presented at a scientific meeting. EVOLUTION the process by which modern organisms have descended from ancient organisms. EVOLUTION the change over time (in a gene pool or set of genes) FITNESS the physical traits and behaviors that enable organisms to survive and reproduce in their environment COMMON DESCENT all species have common ancestors ADAPTATION process that enables organisms to become better suited to their environments HOW DOES ADAPTATION WORK??? Over time? In a single generation? ADAPTATION •TAKE PLACE OVER LONG PERIODS OF TIME!!! •Only surviving (well adapted) organisms pass on their traits. • The process by which new species form is called speciation. Geographic isolation plays a large role in speciation. Each environment is different with different pressures and challenges. • Organisms adapt and change in response to their specific environment. If these populations become different enough they may even form separate species-which cannot interbreed. REVIEW • Who came up with the theory of natural selection? • Charles Darwin • What was the name of his ship? • HMS Beagle • What islands did Darwin visit? • Galapagos • Change over time is called… • Evolution • What types of birds did he study and what was different about them? • Finches-their beaks • All species have a common ancestor is known as … • Common descent • Species: group of genetically similar organisms that can interbreed, and produce FERTILE offspring. • Population: group of organisms of the same species living in the same place at the same time. • Adaptation: changing of a given species to become better suited to its environment • Natural selection: is process by which populations change in response to their environment • Adaptation occurs as a result of adaptation • Complete the Darwin & Natural Selection worksheet. • Remember, if it’s FALSE, make it TRUE! Natural Selection Fish Lab • RULE # 1- DO NOT EAT THE FISH UNTIL MS. GORNEY TELLS YOU TO! • Each table needs – One bag of fish – One ocean (a paper plate) Remember- hunt, mate, and then count – BE NEAT WITH THE FISH! DO NOT DROP THEM ON THE FLOOR! Pick them up if you do. • Listen up, this will be graded! Clean-up • Dispose of the fish “properly.” Do not leave ANY on the floor. • Throw away the paper plates and bags. • TURN YOUR FISH LAB PAPER WITH THE QUESTIONS ANSWERED INTO YOUR PERIOD’STRAY! • Clean up this room!! • That means… • No paper or trash on the floor • Chairs tucked under the desks • Desks straight • THANK YOU!! Warm-Up / EOC Prep 1. Natural selection states that individuals A with adaptive traits are more likely to survive B on the bottom level of a hierarchy have the greatest reproductive success C demonstrating altruistic behavior are the ones with the most mutations D remain unchanged over a period of time 2. Which of the following best defines common descent? A All organisms came from the same ancestor. B All organisms have certain traits in common. C All organisms descended from organisms that have traits in common with them. D All organisms have similar body parts and organs in common. Agenda • • • • • • • Warm-Up Notes Evidence of Evolution Worksheet Evolution Vocabulary Table Whiteboards Clean-up Cool-Down Evolution-Day 3 Age of the Earth and Evidence for Evolution Organic Soup Theory • No oxygen in the air • Organic molecules accumulated • A spark of lightning created amino acids which over time produced organisms What was the first life like? • Anaerobic organisms…why? • Single celled prokaryotes • Asexual Reproduction • Heterotrophs…why? What came next? • Autotrophs…why? • Probably used H2S instead of H2O…why? • Then they made the switch to H2O…what happened? • Sexual Reproduction--how would this influence evolution? THE AGE OF THE EARTH How did scientists figure out how old the earth is? 2 ways to date the earth: •Relative Dating—lower levels of rock are older than higher levels (not exact) •Absolute Dating—the actual age of a sample using radiometric dating RELATIVE DATING RADIOMETRIC DATING RADIOMETRIC DATING RADIOMETRIC DATING If you start with 1000 atoms of Uranium 238, how much will be left after 4.5 billion years? 500 atoms of U 238 RADIOMETRIC DATING If you start with 1000 atoms of Uranium 238, how much will be left after 18 billion years? 62.5 atoms of U 238 According to scientists, the earth is about 4.5 billion years old. THE FOSSIL RECORD Where do we get fossils from? How do they form? PLACES TO FIND FOSSILS: • Ice • Tar Pits / quicksand / bogs • Amber / Sap • Sedimentary Rock— sediments fall on the living material and turn it to rock Fossils in Amber Are fossils a perfect record of evolution? Why or why not? No… but they are a convincing window to the past Fossils are an incomplete record of evolution because: • Fossil record is incomplete. Some organisms leave fossils, but most do not • Quality is variable. Some are perfect, some are not…missing details FOSSIL RECORD represents the preserved collective history of the earth’s organisms. The fossil record shows that changes in organisms followed changes on earth. Example: Shark teeth in Arizona EVIDENCE FOR EVOLUTION FROM LIVING ORGANISMS Present-Day Evidence for Evolution 1. DNA Similarity 2. Biogeography 3. Homologous Structures 4. Vestigial Structures 5. Embryos DNA Similarity Evidence for Evolution DNA Comparisons between Humans and other Species Species Human Chimpanzee Percent DNA Binding 100 98 Gibbon Rhesus monkey Tarsier 94 88 65 Lemur Mouse 47 21 Chicken 10 Biogeography Evidence for Evolution BIOGEOGRAPHY The study of patterns of geographical distribution of plants and animals across Earth, and the changes in those distributions over time Should species on these islands look the same? Placental Animals and their Marsupial Counterparts Placental Wolf Flying Squirrel Marsupial Tasmanian Wolf Flying Phalanger Mouse Mole Anteater Bob Cat Marsupial Mouse Marsupial Mole Numbat Tasmanian Tiger Cat Lemur Spotted Cuscus Biogeography suggests that species evolved to fit their environments Homologous Structures Evidence for Evolution HOMOLOGOUS STRUCTURES parts in different organisms that develop from the same anscestral body part HOMOLOGOUS STRUCTURES Vestigial Structures Evidence for Evolution VESTIGIAL STRUCTURES structures that have little or no purpose in the present, but did in the past Examples of Vestigial Structures • Human appendix • Tonsils • Small vertebrae in humans • Leg bones in snakes EMBRYOS Evidence for Evolution EMBRYO organisms in the early stages of development. EMBRYOS • Similar body structures / parts / organs • Similar embryonic development Embryo Similarity • What do you notice about the first row? • What happens as you move down each column? • Clean up this room!! • That means… • No paper or trash on the floor • Chairs tucked under the desks • Desks straight • THANK YOU!! Warm-Up / EOC Prep 1. When Charles Darwin went to the Galapagos Islands he saw various species of finches with different size beaks. The finches got their different beaks as a result of… A passing on acquired characteristics B adapting to different types of food in the separate environments C adapting to different types of weather D wanting different beaks 2. In order for an organism to be biologically fit, it must: A Survive B Survive and Reproduce C Be stronger than its competitors D Be in the right spot at the right time Agenda • • • • • Warm-Up Notes Evolution Flip-flop BIO BINGO Clean-up Evolution Day 2 Natural Selection and Evolution of Populations EVOLUTION BY NATURAL SELECTION • Inherited variation exists within the genes of every population or species. This variation is the result of random mutations and sexual reproduction. • Variations provides the material for natural selection • In a particular environment, some individuals of a population or species are better suited to survive (survival of the fittest)-as a result of their variationand they can then have more offspring • These traits that help certain individuals survive and reproduce to spread in a population over time, and therefore a change in the entire population is seenevolution occurs • Each species has evolved and gathered adaptations in response to its particular environment. • Certain forms of a trait become more common in a population because more individuals in the population carry the alleles for these forms. • Natural selection causes the frequency of certain alleles in a population to increase or decrease over time, depending on if they are good (favorable) for survival or bad (not favorable for survival). • If the trait is bad and does not help them survive, the trait will become less common (organisms will die, produce less offspring, and therefore not pass on the genes for the trait). • What makes a successful variation or trait? One that makes it more likely for you to: • Get food Not get eaten • Have children • Thermal conservation NATURAL SELECTION The process in nature where the most fit organisms produce more offspring Darwin’s Theory of Natural Selection • The process of natural selection is driven by four important points that are true for all real populations: 1. All populations have genetic variation 2. The environment presents challenges to successful reproduction (If you don’t survive, you don’t pass on your genes to the next generation) Darwin’s Theory of Natural Selection 3. Individuals tend to produce more offspring than the environment can support-which results in competition • 4. Individuals that are better suited to their environment and can cope with the challenges presented by their environment tend to leave more offspring than those individuals that are less suited to the environment • Given time, natural selection will produce different groups of organisms (speciation) Example: Giraffes show variation in the length of their necks. Giraffes with longer necks get better food, have more babies (greater fitness) Longer necks give birth to longer necks (trait is passed on in genes) Results: Over time, average neck length increases Under other conditions, over longer periods of time, new species form (e.g. the Okapi) REVIEW • The process in nature where the most fit organisms produce more offspring is called… • Natural selection • What makes a successful variation? • Helps not get eaten, have babies, thermal conservation, get food