1. Unit Overview

One of the outcomes that I want students to achieve during this unit is to actually learn how to think like evolutionary biologists. Evolutionary biologists study the diversity and similarity among organisms and the characteristics and adaptations of organisms. They also study how organisms change over time. All of these studies are geared towards gaining a deeper understanding of the living world around us, as well as a deeper understanding of humankind. This lesson will tie in some of the genetics concepts students will have learned in a previous unit (e.g., mutation, sorting and recombination of genes during sexual reproduction, and inheritable characteristics). It will also provide a good foundation for the study of human evolution, which will follow this unit.

Evolution (the change in species over time) is included as Key Idea 3 of Standard 4 in the Living Environment Core Curriculum (Commencement Level), published by the New York State Education Department (a.k.a. "The State Standards"). This unit has been designed to cover nine of the 12 major understandings under Key Idea 3. It is intended for use in the 10^th grade Regents Biology (or Living Environment) classroom and is approximately two weeks in length.
 
 

2. Unit Goals

1. The learner will gain an understanding of the magnitude of changes that have occurred in living things during the long history of life on earth.
2. The learner will understand the differences between hypotheses, theories, and scientific facts.
3. The learner will gain an awareness of how evolution is central to modern biological thinking.
4. The learner will understand how more modern techniques can be used to both disprove and affirm previous scientific theories.
5. The learner will gain an understanding of the mechanisms and patterns of biological evolution.

The instructional strategies that I have chosen are intended to create a classroom climate where I am the facilitator of discussions, and not solely the conveyor of scientific facts. I envision a lot of back and forth interactions between myself and my students, where students learn about the history of life on earth and changes in organisms over time by thinking about the different problems and questions that I pose and coming up with answers and solutions. The activities students will be engaged in will vary from individual work to group work to give them practice in figuring things out on their own and in working with others. I will try as much as possible to bring real world examples of what we are learning about into the classroom. I believe that the more I can make things relevant to my students’ lives, the more likely they will be interested in what they are learning.

The following paragraphs describe the instructional strategies and activities that I have planned out for the entire 2-week unit on the history of life on earth and changes in organisms over time. An instructional strategy not described below, but that will be standard practice throughout the unit, will be to succinctly summarize the topics learned the previous day at the beginning of each class. I will also bring each day’s lesson to closure by briefly summarizing or outlining the covered topics, and providing the students with a quick overview about what they will be learning the next day.

I start the unit with the history of life timeline activity because it is important for students to gain an understanding of exactly how long a period we are talking about when we speak of "the history of life on earth". When we speak of the earliest fossil bacteria existing 3.5 billion years ago, it is extremely difficult to comprehend how long that amount of time is. Constructing a timeline helps to put this timeframe into perspective. I will keep the students’ timelines displayed around the classroom during the course of the unit, and refer back to them often.

While constructing their timelines, students will probably be wondering how we know when all of these organisms first appeared, and what evidence exists. If they don’t openly ask these questions, I will ask them. This will lead into the discussion of fossil evidence. There are strengths and weaknesses in the existing fossil record, both of which will be discussed in class. I want students to understand that scientists don’t always have all of the answers, and that a lot of what students learn in class is still actively being studied outside the classroom.

I’ve included the historical perspective on the theories of evolution to show students that some theories can be easily disproved by other scientists, while others stand the test of time and are further supported by modern research techniques or the discovery of new evidence. In the real world, scientists make their predictions or discoveries and publish a scientific paper(s) on their findings to be reviewed by their peers. I have required students to read excerpts from three scientists’ original papers on evolution so that they can get a flavor for how these scientific papers are written and how they may be received by peers. I have included the reading of Lamarck’s paper on evolution as an in-class activity because his theory is one that is commonly believed to be true (even though it has been disproved), and in order for students to gain a correct understanding of the theory of evolution, they really need to comprehend the reasons why Lamarck’s theory is not true.

I plan to spend a good portion of time on a discussion of Darwin and his theory of evolution, and there are several reasons for this (first and foremost, because of his phenomenal contributions to the field of biology):

• Many people have the misconception that Darwin’s theory of evolution is more like a hypothesis that is not well supported by evidence. This is one of the biggest misconceptions in the field of biology, and it is very important to clarify this with students from the start
• Darwin’s life work makes for a good story that I think students will be able to relate to
• Darwin wasn’t schooled in science per se, but had an unbelievable ability to comprehend a wide array of scientific disciplines including geology, botany, and plant and animal physiology
• The theory Darwin spent his life work on still holds true in most respects today, some 150 years later
• Darwin used the works and findings of a number of other scientists to help develop his theory

Since the driving force behind Darwin’s theory of evolution is natural selection, it is very important that students understand this concept. Since it is difficult to observe natural selection in action in the classroom, I have included the lab on this topic, which uses a model to show how various traits may increase the ability of organisms to survive. Since the previous class consisted mostly of direct instruction and some discussion, the lab will provide a change of pace and give students the opportunity to move around a little.

After the lab activity is complete, we will explore natural selection more deeply by learning about the role adaptations play and the different types of natural selection that exist. All of the activities and discussions we have completed to date have been designed to build upon the concept of organisms changing over time, with each activity and discussion further clarifying the process of evolution. The graphing activity of the different types of natural selection is intended to provide a visual representation of these concepts, in addition to the oral explanation.

After establishing the long history of life on earth and the theory of evolution which explains the mechanisms by which organisms are able to change over time, we will move on to the scientific evidence supporting the occurrence of evolution. Students are often preoccupied with the question "well how do scientists know this happened", and I admit that I ask the same questions when hearing about new scientific discoveries (good scientists always wonder about things!). In order for students to let themselves believe in the theory of evolution, I think that it is an absolute must to cover the all-important evidence we have that it has occurred, and still is occurring. I have structured this lesson as an inquiry-based activity. I will give students drawings of homologous structures and embryonic development (without telling them that’s what they are) and let them discuss in small groups what these things mean in terms of evolution. I am providing them with yet another opportunity to act like scientists by observing data, conferring with others, and using prior knowledge to draw scientific predictions.

In addition to providing evidence that evolution has occurred, I believe that it is also important to provide students with examples of natural selection (the driving force behind evolution) to solidify their understanding of the concept of evolution. I am using the peppered moth and Galapagos finches as examples, frankly, because one of these two often occurs on the regents examination. I then go beyond these popular examples to one of my own (the speciation of red maple and sugar maple trees) to check students’ understanding of the extremely important concept of natural selection. This activity lets students work together to come up with a probable explanation for the divergence of two species through means of natural selection. This activity will also help students understand the concept of speciation, which is a major component of the next unit on the classification of organisms.
 
 

4. Assessment Techniques

To assess students’ understandings of the definitions, relationships, processes, and concepts taught in this unit on The History of Life – Changes in Organisms Over Time, I will use a combination of formal and informal assessment practices. Since the entire unit is built around facilitated discussions between the students and me, I plan to informally assess students’ understandings every day by observing their behaviors and responses to questions. This will be done by keeping track of which students do not actively participate in the group discussions, do not volunteer answers, appear distracted, and/or have confused looks on their faces. These behaviors can be expected of any student at any time, but I will focus on those who consistently display these behavior patterns to determine who might be confused or have misconceptions about what we are learning. I will also use this method of informal assessment to determine if there are topics or concepts that I need to reteach. Evidence of understanding will be conveyed through students’ responses to my questions. If the majority of the class seems confused or can’t answer a particular question I pose, I most likely need to back up a little and cover some of the material again, in a different manner than I used the first time, to see if that’s where the problem lies.

Other standard techniques that I will use in my assessment of students’ understanding include:

• grading and returning homework assignments, quizzes, and tests by the next class period (so that feedback is provided as soon as possible after the student completes the activity)
• monitoring trends in incorrect responses on the homework assignments, quizzes, and tests to determine whether I need to reteach a particular topic, concept, etc.
• going over questions on quizzes and tests where many students provided incorrect answers
• providing review sessions (either in class or after class) for quizzes and tests

While the class is constructing their timelines of the history of the earth I will be watching for them having trouble fitting the more recent events (on their list) onto the timeline. This will be my opportunity to see if they understand the concept of scales. If the students suggest that they need to create a larger scale for the last million years or so (or even suggest that something different needs to be done for the last million years), this will provide me with an indication that they do understand the concept of scales. During the class discussion following the timeline activity, I will ask probing questions (personal communication) to determine whether students have a good grasp of the extremely enormous amount of time that has passed since the 1^st events in the history of the earth were first recorded.

In the second lesson plan I have included group work (reading and answering questions) followed by a class discussion so that students can interact firsthand with Lamarck’s theory of evolution. The group discussions are provided as an opportunity for students to be able to work their ideas and thoughts out with each other. I will informally assess their comprehension by monitoring their discussions and helping to dispel any misconceptions about the theory that I hear being discussed. I will use informal assessment (personal communication) again during the class discussion to further check their understanding and see if there are any more misconceptions that need to be dispelled.

In the same lesson, I have included a means of formal assessment (reading assignment and responses to questions about reading). This is done to check the students’ ability to distinguish between the (disproved) theory of evolution proposed by Lamarck and the theories proposed by Darwin and Wallace.

During the lab on natural selection, I will use informal assessment (personal communication and observation) to check for students following directions and completing their data tables correctly. I will also use this form of assessment via class discussion after the lab to monitor students’ comprehension of natural selection as modeled through the lab exercise. The bar graph assignment will provide an indication of how well students are able to visually represent the data they collected in the lab, and if they need more practice or instruction in graphing.

The quiz on the history of life and theories of evolution (formal assessment) will be used to assess students’ understandings of the evolutionary concepts being taught. This will provide me with the opportunity to identify and clear up any misconceptions students may have, before we move on with the unit and build upon this knowledge base.

During the discussion of adaptations, I will check for students’ understanding of the concept by evaluating the examples of adaptations they provide and asking the student (or another student) to explain why a given answer would be considered an adaptation.

In the fourth lesson plan I have included small group discussions (initiated by answering questions listed on overhead) and class discussions to review groups answers to the questions. While students are working in groups, I will walk around the room and monitor students’ discussions (informal assessment) to check their ability to compare/contrast/and reason. During class discussions about comparative anatomy and embryonic development, I will monitor students’ responses to the questions placed on the overhead to check for understanding of how comparative anatomy and embryonic development provide evidence of evolution (personal communication). I will also monitor students’ comprehension of the material during construction of the graphic organizer, by asking students to fill in the blank components of the organizer.

In the fifth lesson plan I will use class discussions of peppered moths and finches to check for any misunderstandings students may have about natural selection. Then I will see if students can apply the concepts that they have learned about natural selection to a new example (speciation of maple trees). I will monitor students’ discussions and the hypotheses they pose to determine whether they are applying the concepts correctly.

The culminating unit test will assess students’ knowledge comprehension and their ability to compare/contrast, reason, and apply concepts learned in class to new/different situations. The performance assessment I have selected will bring the unit "full circle" by having students apply many of the concepts they learned throughout the unit, as they conduct research and write their papers. The performance assessment is described in more detail in the following section.
 
 

5. Authentic/Performance Assessment (Research Paper)

Since one of my major instructional goals in this unit is to get students to think like evolutionary biologists, I plan to include a performance assessment that will demonstrate whether they are able to do this successfully. The performance assessment will involve the study of adaptive radiation in penguins. Students must use the principles of natural selection and evolution that they learned in class, and their researching skills, to answer specific questions I pose to them about the evolution of penguins. I selected penguins as the topic for the research paper because there are only about 17 species of penguins in the world (the exact number is still being debated among scientists), all except one live in the Southern Hemisphere, and they all have unique structural and behavioral adaptations. All of these characteristics combined make for a great case study of evolutionary radiation.

The rubric and the process that will be used to assess the research paper on adaptive radiation in penguins are presented on the following pages. Students will be given a copy of both the rubric and the research paper guidelines at the time the paper is assigned. I will go over both of these sheets with the students so that they know what is expected of them. Class time will be provided for students to research the Internet, periodicals, journals, newspaper articles, etc.

Students will be given two weeks to complete their research papers. To assist me in grading the papers according to the rubric, I will place a copy of the rubric side by side with the paper I am assessing and place the student’s name at the top of the rubric. While assessing each paper I will use the following procedures:

1. Check the paper for a title then circle 2 pts or 0 pts on the rubric.
2. Check the paper for a bibliography then circle 5 pts, 3 pts, or 0 pts on the rubric.
3. I will proceed by reading the "Penguin Evolution" section of each paper, and assessing this section of each paper first. Then I will divide the papers by species of penguin reported on, and read the "Species Information" and "Adaptation" sections for each group of penguin species, assessing each individual paper as I proceed.
4. After reading the Penguin Evolution section of each paper, I will check off each of the required content items on the rubric as I read. I will follow the same procedure while reading the Species Information and Adaptation sections of the papers.
5. While reading the papers for the required content, I will also note on the paper any place where there is a break in the flow of the paper, or any place where ideas may be disconnected. Then when I go back through the paper to assess organization, I can easily scan the paper for the marks I made previously. After scanning the paper, I will circle the correct bulleted assessment criteria under "organization". Then I will go back through the paper to check for an introduction and a conclusion and circle the appropriate assessment criteria (e.g., "clear introduction", "foggy conclusion").
6. The point system for the content and understanding concepts criteria is simpler than it first appears. For example, the content of the Penguin Evolution section is broken down into six bulleted items that must be addressed. Each bullet is worth 4 points for a total of 24 points. A similar point system was used for the Species Information and Adaptation sections of the paper.
7. The student’s total score will be tallied up and written on the top of the rubric. The marked up rubric will be returned to the student with his or her research paper.
8. I will encourage students with questions about their grade to see me after class.

There are at least 17 species of penguins that exist in the world. All live in the Southern Hemisphere (with the exception of one species) and all have unique structural and behavioral adaptations. The evolution of penguins is an example of adaptive radiation (divergence from a common ancestral line, within a relatively short period of time, where new lineages are adapted or modified for different ways of life).

To gain a better understanding of how organisms change over time, the class will study adaptive radiation in penguins. Each student will be assigned a particular species of penguin to research and will also be required to independently research the general evolution of penguins. The assessment criteria and scoring system for the research paper are provided on the attached page. The research paper must address the following questions/information (Remember to describe responses in evolutionary terms):

Penguin Evolution

• What common ancestor do scientists believe penguins descended from?
• During what geologic period, and approximately how many millions of years ago, did the common ancestors of penguins first appear?
• How did penguins lose their ability to fly?
• How can the inability to fly be considered an adaptive advantage in the penguin?
• Why are penguins found only in the Southern Hemisphere (with one exception)?
• How did the geographic distribution of the penguin species you are researching come to be (from an evolutionary perspective)?
• Describe three differences between penguins and birds that can fly.

• Scientific name and common name of assigned penguin species.
• Geographic Range – provide copy of map
• Habitat – including temperature, rainfall, description of physical environment
• Feeding Behavior – location and type of food eaten
• Reproductive Behavior – including mating rituals, nest types & site, length of incubation, # of eggs laid, care of young

• Describe two physical and two behavioral characteristics that allow the species of penguin you researched to survive and reproduce in its environment. Provide evidence that supports why each characteristic is considered to be adaptive.

6. Lesson Plans

This unit has been divided into five different lesson plans that span nine consecutive class periods. Specific instructional objectives, materials needed, procedures and methods, and evaluation methods are provided on each lesson plan. Space for teacher’s reflections and/or notes is also provided at the bottom of each lesson plan. The lesson plans begin on the following page.

UNIT: THE HISTORY OF LIFE ON EARTH - CHANGES IN ORGANISMS OVER TIME
 

Grade: 10 – Regents Biology Length of Lesson: 2 class periods

Objectives

1. The learner will be able to construct a model, using an appropriate scale, to represent the length of geologic time, and locate the dates of important evolutionary events (provided on a list by the teacher) on the model.
2. The learner will be able to summarize how mass extinctions have affected the evolution of life on earth.
3. The learner will be able to explain how scientists use fossil evidence and radiometric dating to determine the relative ages and absolute ages, respectively, of previous life forms.
4. The learner will be able to relate the development of the ozone layer to the adaptation of life on land.

Rolls of adding machine paper meter sticks

Tape colored pencils/markers

Procedures/Methods

• Engage students by asking them if they know how old the earth is (4.5 billion years old). Then ask them if humans have been around that long (Genus Homo evolved from Australopithecines approx. 2+ million years ago). Ask students how they might go about building a visual model to show the timeline of earth’s history. To help them visualize this, provide them with the example of building plans for a house (e.g., drawn at a scale of ¼ inch = 1 inch)

• Divide class into groups of three and hand out Student Investigation Sheet and roll of paper. Review activity/procedures with students. Walk around room and assist students with any problems. Give students ~10 minutes to develop a scale on their own. After this time, help remaining students develop reasonable scale (e.g., 1 millimeter = 1 million years).
• When students are at stage of plotting events in last million years, encourage them to develop a larger scale for this time period.
• Once student scales are complete, hand them on the walls around the room. Hang one up front to use during the following discussion.

• Use a teacher led discussion to go over several additional important events in the history of

• Origin of oxygen by cyanobacterium photosynthesis (2.5 bya)
• Origin of all major animal phyla (510 mya)
• First jawless fishes (500 mya)
• 1^st mass extinction (440 mya)
• Plants, arthropods, fungi invade land, jawed fishes appear (435 mya)
• Early amphibians (1^st vertebrates) invade land (370 mya)
• 2^nd mass extinction (360 mya)
• Early reptiles appear (350 mya)
• 3^rd mass extinction (250 mya)
• First dinosaurs and mammals appear (230 mya)
• 4^th mass extinction (200 mya)
• "Age of the dinosaurs" (180 mya)
• 5^th mass extinction (65 mya)
• Major mammal groups evolve (40 mya)
• Appearance of Australopithecus (~4 mya)
• 1^st Homo sapiens appear (0.5 mya)

• Describe how scientists use the fossil record to assign relative ages to previous life forms, and how determining the age of fossils was greatly improved by the discovery of radiometric dating. Describe how radiometric dating works, and that it can be used to assign absolute ages of fossils.
• Close lesson by explaining that fossil evidence shows that living organisms have changed over time, but it does not show how these changes occurred. In the next lesson we will learn what scientists believe to be the mechanisms for this change in organisms over time.

• Informal assessment via observation while students are constructing timeline and during discussion that follows. Check for correct scaling on timeline. Check for students’ understanding of differences between relative and absolute fossil dating during discussion.

(Write on back)
 

Grade: 10 – Regents Biology Length of Lesson: 2 class periods

Objectives

1. The learner will be able to identify the three scientists who proposed the early theories of biological evolution in the 1800s.
2. The learner will be able to define Lamarck’s principle of "the inheritance of acquired characteristics" and describe the reason why this principle fails to accurately explain how organisms change over time.
3. The learner will be able to identify and explain the six main points of Darwin’s Theory of Evolution by Means of Natural Selection.

Excerpts from original writings by Lamarck, Wallace, and Darwin

Procedures/Methods

• Start off lesson with recap of previous lesson, emphasizing that the fossil record provides evidence of changes in organisms over time, but no clues as to the mechanism for this change.
• Tell students that they are going to explore the thinking of three prominent scientists as they pondered the questions of the origin and diversity of life during the 1800s, and that we will start by reading an excerpt from Jean Lamarck’s original writing entitled "Philosophie Zoologique", published in 1809.
• Hand out above referenced excerpt and give students 5 minutes to read handout. Divide students into discussion groups of 3-4 and have them answer the 4 questions on the back of the handout (give them ~15 minutes to complete questions).
• Bring class back together and go over students’ answers. Provide example of male & female body builders. Will their children be born with large muscles? Describe experiments conducted by Weismann (cutting off tails of mice) that disproved Lamarck’s theory of "the inheritance of acquired characteristics".
• Assign reading the Wallace and Darwin excerpts as homework. Also have students answer questions on the back of the handouts. Answers to questions will be handed in for grading.

• Start off next lesson with class discussion of Wallace and Darwin excerpts (ask students for answers to the questions they answered as homework).
• Provide students with brief background on Wallace & his work. Then provide students with background on Darwin. Tell in story-like fashion. Read selected excerpts from the Origin of Species to provide examples of Darwin’s thought process, observations, experiments, & drawing of conclusions.
• Introduce the six main points of Darwin’s Theory of Evolution by Means of Natural Selection (overproduction, competition, variation, adaptations, natural selection, & speciation) by writing terms and defining them on overhead. After each point, ask students to think of examples of each. Record examples on overhead (will probably need help with last two points – let them know those two will be studied in more detail in next lesson).
• Assign reading assignment in text on Darwin’s theory of evolution and 4-5 questions about reading as homework.
• Close lesson with review of key points in three theories of evolution and highlights of what’s to come in next lesson. Remind students that there will be a quiz two days from now on the history of life and the three theories of evolution covered in the last two lessons.

• Informal assessment – listen to students’ responses during two class discussions to identify and clear up any misconceptions or confusion (especially regarding the inheritance of acquired characteristics, where many students become confused).
• Formal assessment – homework questions on Wallace and Darwin reading. Check for comprehension of author’s main points regarding evolution by means of natural selection and ability of students to distinguish between these concepts and those proposed by Lamarck.
• Informal assessment – listen to examples students provide for main points in Darwin’s theory of evolution. Check for misconceptions or student confusion.

Grade: 10 – Regents Biology Length of Lesson: 2 class periods

Objectives

1. The learner will be able to relate the process of natural selection to its outcome.
2. The learner will be able to explain the term adaptation and provide three different examples of adaptations.
3. The learner will be able to distinguish among directional selection, stabilizing selection, and disruptive selection.

(10) 18" x 18" pieces of colorful floral fabric Natural Selection Lab Sheet

1000 colored chips (or paper punches), 200 each of 5 different colors

Graph paper

Procedures/Methods

• Have students hand in homework (questions from reading assignment in text).
• Recap previous lesson, emphasizing Darwin’s theory that natural selection is the driving force behind evolution.
• Introduce Natural Selection Lab by telling students that we are going to use a model (the lab) to explain how various traits may increase the ability of organisms to survive. Hand out student lab sheets and read over introduction and instructions with students.
• Have students gather in their lab groups (3-4 students per group) and conduct the lab.
• Walk around groups and make sure students are following directions (especially that the predators have their backs turned to the table when they are not picking prey). Answer questions, make sure students are completing data sheets correctly.
• When students are done with the lab, have them return to their seats. Prepare a class results chart on the overhead by asking each group for their results after the 1^st, 2^nd, and 3^rd predations. Have students prepare 3 bar graphs of numbers of colored individuals after 1^st, 2^nd, and 3^rd predations as homework (colors placed along x-axis and numbers placed along y-axis of graph).

• Next day – Start off class with short quiz on the history of life and the three theories of evolution covered in the last two lessons. Provide students with 15 minutes for quiz.

• Have students hand in their bar graphs and labs for grading. Place colored bar graphs (prepared by teacher) on overhead. Ask students to identify any trends they see and what the causes of these trends are. Relate student answers to the process of natural selection and organisms’ adaptations to their environment. Provide definition of adaptation.
• Ask students to name some adaptations in plants or animals that they are familiar with (e.g., hibernation, camouflage coloring, venom from snakes and spiders, webbed feet in ducks, etc.).
• Introduce following terms and their definitions: structural adaptations, physiological adaptations, behavioral adaptations, combinations of adaptations, mimicry, warning coloration, camouflage. Use pictures of viceroy butterfly, poison dart frog, and walking stick to show examples of last three terms, respectively.
• Switch to new topic, different types of selection, by recalling students’ memory of Lamarck’ theories about giraffes and why his theory was wrong. Ask students what they think happened to the phenotype of the giraffe population after a long period of time (longer & longer necks). Draw bell curve of short, medium, and tall neck lengths. Define directional selection and draw new bell curve (in different color) to the right.
• Draw another bell curve with small, medium and large size mice across bottom. Ask students what they think would happen if there was a change in climate that favored the medium size mice. Draw new curve (in different color) to show stabilizing selection. Mention that this is what operates most of the time in most populations.
• Draw another bell curve showing a brown color gradient along the bottom. Define disruptive selection and draw new bell curve (in different color) using tan and brown crabs in sandy and muddy environments.
• Bring closure to lesson by recapping key points in natural selection and adaptations.

• Informal assessment – walk around room during natural selection lab to check for students following directions and completing their data tables. When assigning bar graphs as

• Formal assessment – homework on Darwin’s theory of evolution, quiz on history of life and theories of evolution, constructing bar graph for natural selection lab, and questions at end of lab. All of these methods will be used to assess students’ understandings of the evolutionary concepts being taught. These assessments will provide me with the opportunity to identify and clear up any misconceptions students may have, before we move on and build upon this knowledge.

Objectives

1. The learner will be able to describe how the fossil record supports evolution.
2. The learner will be able to summarize how biological molecules such as proteins and DNA are considered evidence of evolution.
3. Predict how comparative anatomy and comparative embryonic development of living organisms provides evidence of evolution.

Homologous Structures Handout Embryonic Development Handout

Procedures/Methods

• Assign research paper on Adaptive Radiation in Penguins. Go over guidelines sheet, assessment rubric, and due date with students.
• Start lesson by telling students that we have learned a lot about the theory of evolution, and natural selection - its driving force, but we haven’t yet seen a lot of proof, or evidence of evolution. Ask the students to name one type of evidence we have already studied (looking for fossil evidence).
• Review fossil evidence of evolution, its limitations, and radiometric dating.
• Tell students you want them to think like scientists for a few minutes. Pass out the comparative anatomy handout. Divide students into groups of 2-3. Ask the students to study the handout and discuss, as a group, possible answers to the following questions (write on the overhead): What types of structures are shown on the hand out? What types of organisms did each come from? What similarities and differences do you see among all the diagrams? What might scientists conclude (in terms of evolution) based upon their studies of these diagrams?
• Review students’ answers to the questions. Tell students they are looking at the forefeet (or hands) of different animals (name the animals). Scientists have concluded that due to the striking similarities in the anatomy of these features, these organisms have all evolved from a common ancestor.

• Present and define the term vestigial structures (provide examples: penguin’s wings, whale’s pelvis) and comparative anatomy.
• Pass out embryonic development hand out. Ask students to return to their groups and answer the same questions presented above for the homologous structures hand out.
• Review students’ answers to the questions. Name the embryos they are looking at and tell them that during early stages of development, the embryos of tortoises, chicks, dogs, man, and other vertebrates all have tails, buds that become limbs, and pharyngeal pouches.
• Tell students that a third type of evidence for evolution is at the molecular level. Refresh their memories about DNA, nucleotide sequences, the coding for proteins, and amino acid sequences. Let students know that scientists have analyzed the amino acid sequences of similar proteins found in several different species. Place hemoglobin comparison chart on overhead. Ask students what they can conclude from the data on the chart (species that share a more recent ancestor w/humans have fewer amino acid differences w/human hemoglobin).
• To summarize evidence for evolution, create a graphic organizer (p.288 in text) on overhead.

• Inform class of date of unit test (in three days, after Lesson Plan 5 is complete)

• Informal assessment – while students are working in groups, walk around the room and monitor students’ discussions to check their ability to compare/contrast/and reason. During class discussions about comparative anatomy and embryonic development, monitor students’ responses to the questions placed on the overhead to check for understanding of how comparative anatomy and embryonic development provide evidence of evolution. Also monitor students’ comprehension of material during construction of graphic organizer, by asking students to fill in the blank components of the organizer.

Grade: 10 – Regents Biology Length of Lesson: 2 class periods

Objectives

1. The learner will be able to describe how natural selection has affected the European peppered moth (Biston betularia).
2. The learner will be able to explain how natural selection affected the beak size of finches in the 1973 study conducted by Peter and Rosemary Grant.
3. The learner will be able to summarize the process of species formation.

Pictures of peppered moths Graph of finch beak size variation

Procedures/Methods

• Start lesson by telling the story of the peppered moth. Show students pictures of light and dark colored moths on light and dark colored tree bark. See if students can pick out moths. Ask students what caused the moth population in industrial areas to be dominated by the darker variety. (Check for understanding – the darkened bark of the trees did not cause the moths to change color!).
• Describe the experiment Kettlewell performed with peppered moths in the 1950s. Ask students to predict the results of his experiment. Show students the bar graph of his results on the overhead. Ask them what can be concluded from his data? (That natural selection was responsible for the coloration changes in the populations of peppered moths).
• Tell students that another popular example of evolution in action is Darwin’s finches. Show a picture of the various finches in the Galapagos (Chapter 9 in text) on the overhead. Ask students to name the similarities and differences among the finches. Then ask how these differences may have come about. Explain Darwin’s hypothesis for the variety of finches found on the islands. Describe Lack’s 5-month study of the finches in 1938. Ask students if Lack’s observations were strong enough to disprove Darwin’s hypothesis? Why or why not?

• Describe 25-year study conducted by Peter and Rosemary Grant (from Perry article). Use results of this study to lead into description of speciation.

• Refer back to Darwin’s hypothesis for the formation of the various species of finches in the Galapagos Islands. Introduce terms divergence and speciation and define on the overhead.

• Split class into groups of three and pass out field guides of eastern trees. Ask students to use the information provided in the field guide to draw a hypothesis about how red maple and sugar maple trees could have evolved from a single species into two separate species. Then introduce and define the terms reproductive isolation and geographic isolation.

• Close lesson with concept mapping activity (to summarize key terms covered in lesson). Ask students to make a concept map that shows how natural selection leads to speciation, and to include the following terms in their maps: evolution, natural selection, genetic variation, environment, divergence, speciation, extinction (see p. 295 in text).
• Ask 3 or 4 students to draw their maps on the board and review them with the class.
• Place a correct form of the concept map on the overhead so students can correct any misunderstandings they may have had.
• Remind students that unit test is the next day and review class will be held today after school.

• Informal assessment – Use class discussions of peppered moths and finches to check for any misunderstandings students may have about natural selection. Then, see if they can apply the concepts that they learned to a new example (speciation of maple trees). Monitor students’ discussions and their hypotheses to see if they are applying the concepts correctly.
• Formal assessment – unit test which will assesses students’ knowledge comprehension and their ability to compare/contrast, reason, and apply concepts learned in class to new situations.

7. Bibliography

Dobzhansky, T. 1973. Nothing in biology makes sense except in the light of evolution.

The American Biology Teacher.

Futuyma, D.J. 1998. Evolutionary biology. (3^rd ed.). Sinauer Associates. Sunderland,

Massachusetts.

Geelan, T. 1996. An interdisciplinary course in evolution. [Online]. Available:

http://www.accessexcellence.org/AE/AEC/AEF/1996/geelan_evolution.html.

[2000, November 16].

Johnson, G.B., & Raven, P.H. 2000. Biology: principals and explorations. Holt, Rinehardt and

Winston. Austin, Texas.

Karp, W., 1968. Charles Darwin and the origin of species. American Heritage Publishing Co.,

N.Y., New York.

National Academy of Sciences. 1998. Teaching about evolution and the nature of science.

[Online]. Available: http://www.nap.edu/readingroom/books/evolution98 [2000,

November 21].

Perry, R.T. 1993. Using different examples of natural selection when teaching biology. The

American Biology Teacher 55(4).
 
 

8. Accompanying Materials (handouts, readings, worksheets, etc.)

See attachment A for copies of handouts, readings, unit notes, and other documents used to design and support this unit.