State Standard: Standard V: Students will understand that biological diversity is a result of evolutionary processes.

Transcription

1 Course: Biology Agricultural Science & Technology Unit: Changes through time (Evolution) Unit Home State Standard: Standard V: Students will understand that biological diversity is a result of evolutionary processes. Utah Core Objectives: Objective 1: Relate principles of evolution to biological diversity a. Describe the effects of environmental factors on natural selection. b. Relate genetic variability to a species potential for adaptation to a changing environment. c. Relate reproductive isolation to speciation. d. Compare selective breeding to natural selection and relate the differences to agricultural practices. Objective 2: Cite evidence for changes in populations over time and use concepts of evolution to explain these changes. a. Cite evidence that supports biological evolution over time (e.g., geologic and fossil records, chemical mechanisms, DNA structural similarities, homologous and vestigial structures). b. Identify the role of mutation and recombination in evolution. Unit Objectives: At the conclusion of this unit, students will be able to: A. Cite evidence that supports biological evolution over time; B. Describe the historical process through which the theory of natural selection was proposed; C. Describe the modern theory and mechanisms of natural selection, including variation, isolation, mutation, and recombination; D. Define terms related to natural selection including species, population, variation, sexual selection, speciation, isolation, extinction, gene pool, and genetic equilibrium; E. Describe the three types of selection and explain how each contributes to changes in a population; and, F. Compare and contrast natural selection to selective breeding (artificial selection) practices used in agriculture.

2 Materials Needed (Equipment): 1. Antibiotic resistance Tag a. Clothespins (enough for 2 per student one painted red, the other left plain) b. 2 antibiotic signs (cardstock or heavy paper with the word antibiotic written across landscape on the paper, a string or yarn attached to each upper corner so it can be draped around the neck of a student and worn as a sign) 2. Fossils (molds of fossils available all over Utah or through scientific supply catalogs) 3. Fossil Layering a. Cake pan b. Soil of different types (sand, silt, clay) c. Swedish Fish (1 small package) or similar item 4. Geologic Timescale a. Copies of the Geologic Timescale (1 per student) b. 3x5 cards (1 per student) 5. Muskox Maneuvers a. Cards or slips of paper for students to draw out what they will be (muskox calf, cow, bull, or wolf) b. Rag Flags to be used as tails (two different colors one for calves, one for wolves). An old sheet or t-shirt can be ripped into these rags. 6. Competitive Interaction (for a group of 30 students) a. paper cups (1 for each student) b. plastic spoons (6) c. tongue depressors or popsicle sticks (6 pairs) d. scissors (6 pairs) e. tweezers (6 pairs) f. clothespins spring type (6) g. round toothpicks (500) h. ¼ inch washers (400) i. Marbles or pea gravel (400 pieces) 7. Graphing activity graph paper, rulers, pencils (regular and colored) 8. $10,000 pyramid 3x5 cards 9. Camouflaged butterflies 1 butterfly sheet for every 6 students (cut into squares); scissors; pens; pencils; colored pencils; masking tape; scotch tape Facilities: Classroom PowerPoint Projector (if available); slides may also be printed onto overhead transparencies Large area for tag -like games: Antibiotic Tag and Muskox Maneuvers School football field

3 Interest Approach: Antibiotic resistance tag : Materials needed: 1 plain clothespin for each student in the class, 1 clothespin painted red for each student in the class, two pieces of paper with the word Antibiotic written plainly across one side with string attached to two corners so student can wear it around their neck. An area outside or in a large inside area where students can run around is also needed. Procedure: Give two students (one if class is less than 20) the Antibiotic signs and ask them to wear them around their necks. All other students in the class will be bacteria. Clothespins represent the genetic material (DNA) of the bacteria. Give one student a clothespin painted red. Ask the student to clip it to his/her sleeve. The red clothespin represents a mutation in the genetic information allowing it to be resistant to the antibiotics. This student should also be given a sandwich bag containing all of the remaining red clothespins. All other students in the class receive clothespins which have not been painted. Explain to the class that the antibiotics are to kill the bacteria. In this role play, it will be similar to tag. Antibiotics will chase the bacteria within a given area (there should be out-of-bounds set) to unclip their clothespins (Be sure to put these on a sleeve or other part of the clothing that will maintain appropriateness). When a clothespin has been removed, that individual bacterium is dead. Antibiotics will continue to chase and unclip clothespins until all bacteria are dead. The antibiotics cannot kill the bacteria with red clothespins because of the mutation. Also, the bacteria with the red clothespin can reproduce. As bacteria reproduce asexually, it only takes one individual bacterium to divide into two. As bacteria without the mutation are killed by the antibiotics, their parts can be recycled and converted into new bacteria. When a bacterium is killed by an antibiotic they can go over to the original mutated bacterium become a new bacterium this time with the mutated DNA preventing him/her from being killed by the antibiotics. Play the game until all non-mutated bacteria are killed. Return to the classroom. Ask the following questions to engage students in a discussion: How effective were the antibiotics in killing the bacteria? What would have happened if there were no mutation? What could be the effects of a mutation such as this one? [ superbugs, staff infection that can t be controlled, etc.] What is a theory? [Best explanation possible based on available scientific evidence facts that are observed repeatedly]

4 Can a theory be disproved? If so, how? [yes, new evidence] State something like the following: We are going to talk about a theory in this unit that is based on available scientific evidence. Just like all science, it is subject to change and has changed as new evidence is observed. This theory has to do with how populations change over time just as the population of bacteria changed in our activity. Objective A: Cite evidence that supports biological evolution over time Curriculum (Content) (What to teach) Instruction (Methodology) (How to teach) What is a fossil? What can a fossil tell us about things that have lived in the past? Evidence that life has changed and is now changing A1. Fossil Record Fossils are remains or traces of organisms that lived in the past. Fossils are usually found in sedimentary rock. Organisms are buried soon after death and the hard parts become fossilized. Fossils indicate a great deal about the actual structure of the organisms and their environment. Types of fossils o Petrified Bones o Imprints o Molds/Casts o Fossils preserved in tar, amber, or ice A2. Relative Age of Fossils Layering of fossils: o Older fossils are found in the lower levels of sediment o Newer fossils deposited on top of older fossils and sediment o Sometimes flipped by earthquakes, etc. o Fossils in each layer usually of those A1. PowerPoint Slides 3-5 Discussion about fossils how they are formed, where they are found in Utah. NOTE: Most photos of fossils in this section were found in Utah. Read the Notes section of the PowerPoint slides for details. Pass around fossils (if available) A2. PowerPoint Slides 6-13 Discussion about how older fossils are deposited first with more recent fossils in upper layers. Demonstration: For a more visual approach, this can be demonstrated for students with

5 organisms that lived at the time the layer was formed. o Fossils in lower layers represent species that lived earlier than those found in the upper layers. o Relative position only tells which are older and which younger. Swedish Fish and different soil types in a cake pan. Make one layer of sediment and place one color of fish in that layer. Then add the next layer with a different color fish noting that these are more recent. A3. Evolution of the Horse Over time (higher layers of sediment) horse fossils became larger Separate toes became a single-toed hoof Teeth became adapted to grinding grasses A3. PowerPoint Slide 14 Discuss how artificial selection is now used to make changes in horses. A4. Radiometric Dating Some elements, such as uranium, undergo radioactive decay to produce other elements. Scientists have observed that radioactive elements (isotopes) decay at a constant rate over time The amount of radioactive elements remaining in a rock can help scientists determine how much time has elapsed since the rock was formed and cooled. Common isotopes used for long-term dating (old rocks) include uranium as it decays to lead, and potassium as it decays to argon. The carbon-14 isotope can be used for dating of more recent fossils and artifacts Radiocarbon Dating o Carbon-14 is a radioactive isotope found in all living organisms. o It decays at a known rate. o Carbon-12 does not decay. o By comparing the ratio of C-12 to C-14 scientists believe they can determine the age of a fossil A5. A timescale Based on radiometric data, scientists have proposed a timeline for the history of the A4. PowerPoint Slides For additional information on Radiometric Dating, see the following URLs: A5. PowerPoint Slides 19-23

6 earth. Composed of four primary eras o Archeozoic (oldest) [aka Precambrian period] o Paleozoic o Mesozoic o Cenozoic (most recent) Archeozoic Era o Oldest known rocks and fossils o Animals without backbones o Jelly-fish, worms, sponges o Bacteria and blue-green algae Paleozoic Era o Estimated from million years ago o Animals: Fish, amphibians, and insects o Plants: Algae and simple plants; first conifers Mesozoic Era o Estimated from million years ago o Age of the Dinosaurs o Animals: Reptiles and birds o Plants: Conifers and first flowering plants Cenozoic Era o Estimated from present to 65 million years ago o Age of the Mammals o Animals: Mammals and birds o Plants: Flowering plants Activity See Geologic Timescale activity described at the end of this objective. A6. Contemporary Changes Evidences we can observe within our lifetime o Pesticide resistance in insects o Antibiotic resistant bacteria A6. PowerPoint Slides Refer to antibiotic tag activity. Bring in articles, news clips, and Internet citations related to super bugs. A7. Indirect evidences Scientists cite these indirect evidences as evidence of common ancestry o Homologous structures o Embryonic development patterns o Biochemical evidence o Vestigial organs A7. PowerPoint Slides 26-30

7 They at least demonstrate a common pattern of development Parts of the body with similar structure (homologous structures) Similar patterns of embryonic development (homologous development) Biochemical similarities DNA and Proteins o The ability to analyze individual biological molecules (DNA and proteins) has provided evidence for biochemical similarities Activity: Geologic timescale Print copies of the geologic timescale for students. Distribute copies of timescale along with a 3x5 card. Assign each student one of the events from the Biological Record (if there are more than 18 students in the class, students can work in pairs or some of the biological record events can be divided into separate items). Ask the students to write their assigned event from the biological record on a 3x5 along with how many million years ago the event occurred. Tell students you will be going to the school s football field and that one yard on the football field will represent 50 million years. Start with the end zone nearest the classroom. Have students determine at which yard line their card should be placed. Then move to the football field and have them place the cards in the appropriate place. Students should get a feeling for the rapid changes in the more recent geologic record. Alternative: Print out the geologic timescale and provide to students. Ask specific questions for which students must find the answer based on the table. For example, ask during which period did the dinosaurs die out? Approximately how many million years ago do scientists estimate that occurred? One benefit of using the timescale in this way is that the Utah Core Criterion Referenced Test includes many tables, graphs, charts, etc. for which students are asked to answer questions.

8 Objective B: Describe the historical process through which the theory of natural selection was proposed Curriculum (Content) (What to teach) Instruction (Methodology) (How to teach) Can a person change their height by stretching? If so, will the person s offspring be taller because of it? If you learn to play the piano, will your children know how to play the piano automatically? Methods of Change B1. Jean Baptiste Larmarck French naturalist and evolutionary theorist Proposed the inheritance of acquired characteristics Based on an inner need to change Larmarck s theory was disproved B1. PowerPoint Slides Discuss Larmarck s theory about how the giraffe s neck become longer because it stretched to reach the leave on the higher branches then passed this trait on to it s offspring. Refer back to the two questions in the box above. B2. Charles Darwin and Natural Selection (1859) Naturalist on the HMS Beagle Charles Darwin and Natural Selection (1859) Exploration of South America (3 ½ years) Visited the Galapagos Islands Darwin s theory of Natural Selection o Living things increase in number geometrically (overproduction) o There is no net increase in the number of individuals over a long period of time o A struggle for existence since not all individuals can survive o No two individuals exactly alike (variation) o In the struggle for existence, those variations which are better adapted to their environment leave behind them proportionately more offspring than those less adapted Survival of the Fittest B2. PowerPoint Slides Activity: Muskox Maneuvers

9 Activity: Muskox Maneuvers To emphasize principles of natural selection and show how predator prey relationships contribute to natural selection, conduct the Project Wild activity Muskox Maneuvers. This is a fun tag-like simulation of the interaction between wolves and muskoxen in the arctic. This activity is found on page 130 of the Project Wild K-12 Activity Guide and can be obtained by attending one of the Project Wild training sessions. This is highly encouraged. For more information on training sessions, go to After conducting the activity, show students the following video of the struggle between muskoxen and wolves in the arctic: Emphasize the concept that the weaker animals are those most easily killed by the predators. If those weaknesses are genetic, and the animal is killed before it reproduces, those genetic traits are not past on. This extends to coyotes and rabbits. The faster, more agile, and/or more camouflaged rabbits survive while others are killed. Overtime this results in faster, more agile, and/or more camouflaged rabbits. At the same time, in times of scarcity (when less food is available) those coyotes that are not fast, smart, and/or see well do not eat and therefore die this results in a stronger population of coyotes. Objective C: Describe the modern theory and mechanisms of natural selection, including variation, isolation, mutation, and recombination. Curriculum (Content) (What to teach) A Modern Perspective C1. Mutation a sudden change in the genetic material (a source of variation) Example: The DNA of one bacteria changes (becomes mutated), allowing it to become resistant to an antibiotic. It survives long enough to reproduce. Each succeeding generation has the mutated copy and is resistant to the antibiotic. C2. Recombination of genes within a population (sexual reproduction) Provides new combinations for natural selection to try. Shows how the percentage of a gene in a Instruction (Methodology) (How to teach) C1. PowerPoint Slide 39 Refer back to bacteria activity at the beginning of the unit. C2. PowerPoint Slide 40

10 population can change. C3. Isolation separation of a population from others of the same kind (species) Prevents recombination of genes Species become different overtime Example: A species of primrose existed together where the Promontory Range (Northern Utah) now exists. When the range lifted up, it isolated two groups. Both became different as they adapted to the different environments on either side of the range. They have become so different they can no longer reproduce. C4. Natural Selection certain traits give an adaptive advantage to organisms and they leave behind more offspring They survive long enough to reproduce and pass on their genetic information INDIVIDUALS DO NOT EVOLVE... POPULATIONS EVOLVE OVER TIME C3. PowerPoint Slide 41 C4. PowerPoint Slide 42 Activity: Competitive Interaction Activity: Competitive Interaction To emphasize how variability and competition lead to natural selection, conduct the competitive interaction activity. This is a highly interactive activity. Click on the above link for instructions, student sheets, etc.

11 Objective D: Define terms related to natural selection including species, population, variation, sexual selection, speciation, isolation, extinction, gene pool, and genetic equilibrium. Curriculum (Content) (What to teach) Instruction (Methodology) (How to teach) What is a population? What is a species? D1. Species A group of individuals that LOOK similar and are capable of producing FERTILE offspring in the natural environment. D2. Population All of the members of the same SPECIES that live in particular AREA at the same TIME. D1. PowerPoint Slide 43 D2. PowerPoint Slide 44 What does variation mean? In what ways is there variation in the population in this classroom? D3. Variation in a population Bell Curve - The distribution of traits (Average is the middle.) Mode - The number that occurs most often (High pt.) Range - The lowest number to the highest number D3. PowerPoint Slides Graphing Activity: Supply students with graph paper. Select one characteristic (height, arm span, finger spread, etc.). Measure each student in the class and record measurements on the board. Have students graph the entire class. See how close it comes to a bell curve. D4. Sexual Selection D4. PowerPoint Slide 47 Preferential choice of a MATE based on the presence of a specific trait D5. Speciation D5. PowerPoint Slide 48 The formation of new SPECIES

12 D6. Isolation Separation of a formerly successful BREEDING population Geographic Isolation Separated PHYSICALLY from each other Reproductive Isolation Can no longer produce FERTILE offspring What does it mean to D6. be PowerPoint isolated? Slides Refer back to the example of the primrose and the promontory range. What are some animals that are extinct or close to extinction? D7. Extinction When an entire SPECIES dies off. D7. PowerPoint Slide 52 Have students think of examples of extinct species D8. Gene pool D8. PowerPoint Slide 53 The collection of GENES for all of the traits in a POPULATION D9. Genetic Equilibrium Hardy-Weinberg Principle Genetic Equilibrium no CHANGE in the gene pool Conditions that must exist for genetic equilibrium 1. No MUTATION 2. No MIGRATION 3. Large POPULATION 4. Random MATING 5. No NATURAL SELECTION D9. PowerPoint Slides Emphasize that because there is always at least one of the five conditions occurring at any given time in a population, there is no genetic equilibrium. Mutations occur, individuals migrate, some populations are isolated, and there is sexual selection (preferential mating). Therefore, changes do occur. Review concepts with $10,000 Pyramid Moment

13 Activity: $10,000 Pyramid Moment: Based on the game show $10,000 Pyramid, this strategy is one fun, fast-paced way for your students to seek patterns, make meaning, and detect purpose in learning the terms and concepts of natural selection. 1. Teach the above objective. 2. Select key words and phrases. Comb through your lesson or unit and extract the important information facts, dates, people, formulas, places, concepts students must know well. 3. Create fact cards. Place each item of importance on its own 4 x 6 card. (Note: 3 x 5 cards work also, but the larger sized index cards are easier to handle and provide more room to write the information.) You ll need one set of these fact cards for every three to five students. For example, a class of 30 students would require 6 to 10 sets of fact cards. The number is determined by the number of students in each group (three or five). 4. Explain the game show roles. There are three roles in this activity the Player, the Clue Giver, and the Teleprompter. The Player sits facing the Clue Giver and with his or her back toward the Teleprompter. The Player guesses the facts through clues given by the Clue Giver. The Clue Giver faces the Player and the Teleprompter. He or she will receive the facts from the Teleprompter and give clues to the Player. The Teleprompter stands behind the Player and faces the Clue Giver. He or she will reveal the fact cards one at a time to the Clue Giver. 5. Play the game. If there are more than three people in the group, have them decide who will be the first to play each of the roles. As the game continues everyone gets a chance to play each role. The game is played in rounds of 60 seconds each. After each round, the groups count the number of correct answers given by the Player. Then, people switch seats and roles. Play as many rounds as needed for each student to play each role. It s fine if they go through the stack of fact cards more than once.

14 Objective E: Describe the three types of selection and explain how each contributes to changes in a population. Curriculum (Content) (What to teach) E1. Natural Selection Three types of selection 1. Stabilizing Selection 2. Directional Selection 3. Disruptive Selection Instruction (Methodology) (How to teach) E1. PowerPoint Slides Stabilizing Selection Individuals with the AVERAGE form have the ADVANTAGE Example lizards that are small are not fast enough to avoid predators; lizards that are large cannot hide easily from predators; those of average size are both fast enough to get away from predators and small enough to hide giving them the selective advantage. Directional Selection Individuals with one of the EXTREME forms have the ADVANTAGE Example Peppermoth in Great Britain during the industrial revolution melanistic (dark colored) moths had the selective advantage after trees where covered in coal soot. After air quality improved, the selection advantage returned to the lighter colored moths. Slide 60 See if students can find two pepper moths in all three pictures. Activity: Camouflaged butterflies Disruptive Selection Individuals with either of the EXTREME forms have the ADVANTAGE Example: a shellfish living in shallow ocean water is preyed upon by a bird. Originally those with the neutral color (sand colored) had the advantage because they were camouflaged in the sand. As the birds fed on the shellfish and left their feces behind in the water, the ocean floor became white in color.

15 Those shellfish that were sand colored are now easily found while the lighter colored shellfish are able to blend in, as are the darker colored shellfish if they are found on the darker rocks. Activity: Camouflaged Butterflies Materials needed: Butterfly sheets (1 sheet for every 6 students); scissors; pens, pencils, colored pencils, etc.; masking tape and/or scotch tape. Preparation: Prior to class, print off copies of the butterfly sheets on regular white paper. Cut the butterflies apart (just in squares students will trim them to the edges). Procedures: Explain to the students that they will have an opportunity to create the most fit butterfly in the class. The predator of the butterflies is the teacher and they are selected by sight. The goal is to create the butterfly that is the most camouflaged in the classroom. The person whose butterfly is found last, if all rules are followed, will receive (a candy bar, extra points on test, a free homework assignment, etc.) Give them until the next class period to create their butterflies (they may take them home). At the beginning of class, give them time to hide their butterflies The rules are as follows (any butterfly not created or hidden within the rules will not be eligible for the prize): 1. Butterflies must have the ability to be viewed while standing on the floor of the classroom and without moving any object (i.e., cannot be hidden inside or underneath something). 2. Butterflies must be attached without damaging the surface of object to which it is affixed. 3. Butterflies must remain in the classroom when the student leaves the room (i.e., not on a notebook, clothing, backpack of student). 4. Butterflies can be made out of another material, but must be of the same size and outline as the paper butterfly pattern. 5. Students may take butterfly patterns home to create their butterfly, but must be hidden in the classroom by the date specified. No late entries accepted.

16 Objective F: Compare and contrast natural selection to selective breeding (artificial selection) practices used in agriculture. Curriculum (Content) (What to teach) Instruction (Methodology) (How to teach) In producing better livestock or crops, what are some examples of traits for which producers select? F1. Selective Breeding How have crops and livestock changed over the last 50 years? Then and Now F1. PowerPoint Slides List responses on the board. Go through the then and now slides. Ask students to list traits for which breeders have selected and those selected against in livestock and crop production. List additional traits identified on the board. Natural Selection an organisms ability to SURVIVE and pass on its GENETIC information to its offspring. Review Natural Selection definition and concepts Selective Breeding Also known as Artificial Selection Human control over organisms passing on their genetic information. Human determination of those crops and livestock allowed to reproduce Based on desired traits Define Selective Breeding (artificial selection) for students For more information on selective breeding from the Agricultural Research Service, see: cid=769&pf=1&cg_id=0 In what ways is selective breeding similar to natural selection? In what ways is it different? Ask students to compare and contrast natural selection and selective breeding.

17 Activity: Gene Pool Genetics Evaluation: Evolution Test and Key References: Prentice Hall Biology by Kenneth R, Miller and Joseph S. Levine. 2002, Pearson Education, Upper Saddle River, New Jersey. Strategies for Great Teaching by Mark Reardon and Seth Derner, 2004, Zeyphry Press, Chicago, Illinois ProjectWILD K-12 Activity Guide, by the Council for Environmental Education, ProjectWILD, Bethesda, MD. Unit Home