course: biology agricultural science &...

Course: Biology Agricultural Science & Technology

Unit: Changes through time (Evolution)

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 diversitya. 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.

Unit Home

Materials Needed (Equipment):

1. Antibiotic resistance Taga. 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 panb. Soil of different types (sand, silt, clay)c. Swedish Fish (1 small package) or similar item

4. Geologic Timescalea. Copies of the Geologic Timescale (1 per student)b. 3x5 cards (1 per student)

5. Muskox Maneuversa. 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 cards9. 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

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]

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)

Evidence that life has changed and is now changingA1. 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 fossilso Petrified Boneso Imprintso Molds/Castso 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.

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)


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

What is a fossil?What can a fossil tell us about things that have lived in the

past?

o Fossils in each layer usually of those 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.

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

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 Datingo 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

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. PowerPoint Slide 14

Discuss how artificial

selection is now used to

make changes in horses.


For additional information on Radiometric

Dating, see the following URLs: http://en.wikipedia.org/wiki/Radiometric_dating

http://pubs.usgs.gov/gip/geotime/radiometric.html

http://www.gpc.edu/~pgore/geology/geo102/radio.htm

http://www.talkorigins.org/faqs/dating.html


http://www.talkorigins.org/faqs/dating.html

http://www.gpc.edu/~pgore/geology/geo102/radio.htm

http://pubs.usgs.gov/gip/geotime/radiometric.html

http://en.wikipedia.org/wiki/Radiometric_dating

proposed a timeline for the history of the earth.

Composed of four primary “eras”o Archeozoic (oldest) [aka Precambrian

period]o Paleozoico Mesozoico Cenozoic (most recent)

Archeozoic Erao Oldest known rocks and fossilso Animals without backboneso Jelly-fish, worms, spongeso Bacteria and blue-green algae

Paleozoic Erao Estimated from 248-550 million years

agoo Animals: Fish, amphibians, and insectso Plants: Algae and simple plants; first

conifers Mesozoic Erao Estimated from 65-248 million years

agoo Age of the Dinosaurso Animals: Reptiles and birdso Plants: Conifers and first flowering

plants Cenozoic Erao Estimated from present to 65 million

years agoo Age of the Mammalso Animals: Mammals and birdso Plants: Flowering plants

A6. Contemporary Changes Evidences we can observe within our

lifetimeo Pesticide resistance in insectso Antibiotic resistant bacteria

A7. Indirect evidences Scientists cite these indirect evidences as

evidence of common ancestry o Homologous structureso Embryonic development patterns

Activity – See Geologic Timescale activity

described at the end of this objective.


Refer to antibiotic “tag” activity.

Bring in articles, news clips, and Internet

citations related to “super bugs.”


o Biochemical evidenceo Vestigial organs

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 Proteinso 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.

Objective B: Describe the historical process through which the theory of natural selection was proposed



Methods of ChangeB1. Jean Baptiste Larmarck French naturalist and evolutionary theorist 1744-1829 Proposed the inheritance of acquired characteristics Based on an “inner need” to change Larmarck’s theory was disproved

B2. Charles Darwin and Natural Selection (1859) Naturalist on the HMS BeagleCharles 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”

B1. PowerPoint Slides 32-33

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. PowerPoint Slides 34-38

Activity: Muskox Maneuvers

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?

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 http://wildlife.utah.gov/projectwild/.

After conducting the activity, show students the following video of the struggle between muskoxen and wolves in the arctic:http://video.nationalgeographic.com/video/player/animals/mammals-animals/cattle-sheep-and-goats/musk_ox.html

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.



A Modern PerspectiveC1. 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.

C1. PowerPoint Slide 39

Refer back to bacteria activity at the beginning

of the unit.


http://video.nationalgeographic.com/video/player/animals/mammals-animals/cattle-sheep-and-goats/musk_ox.html

http://video.nationalgeographic.com/video/player/animals/mammals-animals/cattle-sheep-and-goats/musk_ox.html

http://wildlife.utah.gov/projectwild/

Shows how the percentage of a gene in a 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



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.

Objective D: Define terms related to natural selection including species, population, variation, sexual selection, speciation, isolation, extinction, gene pool, and genetic equilibrium.



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.

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

D4. Sexual Selection Preferential choice of a MATE based on the presence of a specific trait

D5. Speciation The formation of new SPECIES

D1. PowerPoint Slide 43


D3. PowerPoint Slides 45-46

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.



What is a population?What is a species?

What does “variation” mean?In what ways is there variation in the population in this

classroom?

D6. Isolation Separation of a formerly successful BREEDING population Geographic Isolation

Separated PHYSICALLY from each other

Reproductive Isolation

Can no longer produce FERTILE offspring

D7. Extinction When an entire SPECIES dies off.

D8. Gene pool 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 MIGRATION3. Large POPULATION 4. Random MATING 5. No NATURAL SELECTION


Refer back to the example of the primrose and

the promontory range.


Have students think of examples of extinct

species



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

What are some animals that are extinct or close to extinction?

What does it mean to be isolated?

Moment

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.

Objective E: Describe the three types of selection and explain how each contributes to changes in a population.



E1. Natural SelectionThree types of selection

1. Stabilizing Selection2. Directional Selection3. Disruptive Selection

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.

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. Those shellfish that were sand colored

E1. PowerPoint Slides 56-63

Slide 60 – See if students can find two pepper

moths in all three pictures.

Activity: Camouflaged butterflies

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.

Objective F: Compare and contrast natural selection to selective breeding (artificial selection) practices used in agriculture.



F1. Selective Breeding

How have crops and livestock changed over the last 50 years?

Then and Now

Natural Selection an organisms’ ability to SURVIVE and

pass on its GENETIC information to its offspring.

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

In what ways is selective breeding similar to natural selection?

In what ways is it different?

F1. PowerPoint Slides 64-79

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.

Review Natural Selection definition and

concepts

Define Selective Breeding (artificial selection)

for students

For more information on selective breeding

from the Agricultural Research Service, see:

http://www.ars.usda.gov/business/docs.htm?

docid=769&pf=1&cg_id=0

Ask students to compare and contrast natural

selection and selective breeding.

In producing better livestock or crops, what are some examples of traits for which producers select?

http://www.ars.usda.gov/business/docs.htm?docid=769&pf=1&cg_id=0

http://www.ars.usda.gov/business/docs.htm?docid=769&pf=1&cg_id=0

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, 1992. ProjectWILD, Bethesda, MD.

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