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Grades 6–8. In 11 lessons, this unit helps students explore the different ways that organisms reproduce and what that means for their genetics. Students learn how traits are passed from one generation to the next as they study zebra fish, plants, protists, and humans. By the end of the unit, students create their own "creatures" with unique characteristics and follow those traits to their offspring to learn about inheritance. For a class of 32 students.

Grades 6–8. Unit Driving Question: How has human understanding of inheritance allowed us to influence change in biodiversity?
Unit Highlight—In 11 lessons and beginning at the cellular level, the Genes and Molecular Machines unit helps students explore the different ways that organisms reproduce and what that means for their genetics. Students learn how traits are passed from one generation to the next as they study zebra fish, plants, protists, and humans. By the end of the unit, students create their own "creatures" with unique characteristics and follow those traits to their offspring to learn about inheritance. Using Punnett squares, DNA, and mutations, they predict future generations.

From the STC³ Edition, Genes and Molecular Machines addresses the performance expectations, science and engineering practices, and crosscutting concepts deemed appropriate for grades 6 through 8 by the Next Generation Science Standards* (NGSS). This unit allows students to develop an understanding of phenomena that influence the many different fields of genetics. By completing the unit, students and teachers alike will develop a better understanding of how traits are inherited and how humans have influenced traits in various organisms.

Each lesson in this unit builds on the skills and concepts presented in previous lessons. As students progress through the unit, they take increasing responsibility for their own learning. Eventually, students plan and conduct their own procedures, and they analyze the results obtained. Therefore, the unit should be taught in its entirety; it should not be used as a sourcebook of occasional experiments.

To structure and scaffold the development of students' knowledge, skills, and cognitive reasoning, this unit includes 3 primary lesson types: pre-assessment, skills and knowledge building, and assessment. The pre-assessment lesson allows educators to access students' preconceptions, misconceptions, and skills. The skills and knowledge-building lessons provide multiple opportunities for students to grow and learn through formative assessment. The assessment lesson includes both performance and written assessment activities that function together as a summative assessment of student learning.

This 1-Class Unit Kit comes with a Teacher Edition, teacher access to Carolinascienceonline.com, 16 reusable hardbound Student Guides (item #513303), student eBook access, vouchers for prepaid delivery of the living organisms, and the materials needed for a teacher to teach up to 32 students per day. Note: Among the additional materials that will be needed but not supplied in the kit are 16 microscopes.

Next Generation Science Standards*
Performance Expectations

• MS-LS1-1. Conduct an investigation to provide evidence that living things are made of cells: either one cell or many different numbers and types of cells.
• MS-LS1-4. Use argument based on empirical evidence and scientific reasoning to support an explanation for how characteristic animal behaviors and specialized plant structures affect the probability of successful reproduction of animals and plants, respectively.
• MS-LS3-1. Develop and use a model to describe why structural changes to genes (mutations) located on chromosomes may affect proteins and may result in harmful, beneficial, or neutral effects to the structure and function of the organism.
• MS-LS3-2. Develop and use a model to describe why asexual reproduction results in offspring with identical genetic information and sexual reproduction results in offspring with genetic variation.
• MS-LS4-4. Construct an explanation based on evidence that describes how genetic variations of traits in a population increase some individuals' probability of surviving and reproducing in a specific environment.
• MS-LS4-5. Gather and synthesize information about the technologies that have changed the way humans influence the inheritance of desired traits in organisms.
• MS-LS4-6. Use mathematical representations to support explanations of how natural selection may lead to increases and decreases of specific traits in populations over time.

Disciplinary Core Ideas

• LS1.A: Structure and function
• LS1.B: Growth and development of organisms
• LS3.A: Inheritance of traits
• LS3.B: Variation of traits
• LS4.B: Natural selection
• LS4.C: Adaptation

Science and Engineering Practices

• Analyzing and interpreting data
• Engaging in argument from evidence
• Planning and carrying out investigations
• Constructing explanations and designing solutions
• Asking questions and defining problems
• Obtaining, evaluating, and communicating information
• Developing and using models

Crosscutting Concepts

• Cause and effect
• Scale, proportion, and quantity
• Patterns
• Systems and system models
• Structure and function
• Interdependence of engineering, technology, and applications of science
• Science addresses questions about the natural and material world

Lesson Summaries
Lesson 1: Pre-Assessment
Focus Question: What do you already know about cells, reproduction, and genetics?
Students perform short, simple investigations that evaluate their existing knowledge of one or more concepts related to genetics. Students plant Wisconsin Fast Plant® seeds, root a coleus plant, observe variations in zebrafish, examine cells, and look for similarities between parents and offspring. Students are also introduced to model organisms and their significance in life science.
Lesson 2: Cells
Focus Question: What are the building blocks of life?
Students carry out investigations relating to cells by creating wet-mount slides of various organisms that allow them to distinguish between unicellular and multicellular organisms. Next, students analyze prepared slides and attempt to interpret cell function within a multicellular organism. Finally, students consider the function of bones in an animal and design a cell whose structure would adequately meet that function.
Lesson 3: Organism Reproduction
Focus Question: What can cells tell us about how organisms reproduce?
Students cross-pollinate the flowers of their Wisconsin Fast Plants®, simulating sexual reproduction. Students then investigate various asexual methods of reproduction under the microscope by observing paramecium undergoing fission and hydras undergoing budding. Students continue to explore asexual reproduction by regenerating a blackworm segment and analyzing the results of their coleus clipping. Students then consider the advantages and disadvantages of sexual and asexual reproduction and the offspring that are created as a result.
Lesson 4: Cellular Reproduction
Focus Question: Where do cells come from?
Students explore cell division and how it relates to reproduction. Students prepare and stain a wet-mount slide of onion root cells undergoing mitosis. Students then design and construct a model of a cell and predict the behaviors of the cell during mitosis. Next, students explore plant reproductive cells undergoing meiosis. Students use their observations to design and construct a model of a cell and predict the cell behaviors that occur during meiosis. Students compare and contrast these two cellular divisions and how they both relate to reproduction.
Lesson 5: Genetics
Focus Question: Why do family members look similar but not identical to one another?
Students begin to investigate variation by observing a lady beetle population. Students then explore complete dominance by using probability to determine genotypes and phenotypes in a newly created creature. Next, students take those creatures and demonstrate heredity by using a die to randomly pass on genes to an offspring. Students then create Punnett square models that allow them to analyze and interpret the passing of traits from parents to offspring.
Lesson 6: DNA to Trait
Focus Question: How does DNA determine the traits that organisms have?
Students analyze the structure of DNA and determine the patterns that exist in the structure. Students then carry out an investigation to extract DNA from strawberries. Next, students use pop beads to model DNA transcription into RNA, and then translate the RNA into amino acids, forming proteins. Using their creatures from Lesson 5, students then explore how changes in DNA can lead to changes in a protein which leads to changes in the creature's traits.
Lesson 7: Successful Reproduction and Offspring
Focus Question: How do behaviors and structures allow plants and animals to reproduce more successfully and better survive?
Students analyze various flowers and pollinators to determine which pair relies on one another for reproductive success. Then, students plan and carry out an investigation to determine how various seeds are dispersed. Next, students plan and carry out an investigation to explore materials and ideal conditions needed for a seed to germinate. Then, students develop and present a model of a new species of flower, its pollinator, seed structure, and method of dispersal. To end the lesson, students determine the reproductive success of some animals based on parenting strategies.
Lesson 8: Variation
Focus Question: How do differences within a population help a species survive?
Students harvest and germinate the Wisconsin Fast Plant® seeds from their plants. Students then observe the variations that exist between the plants. Next, students use the phenotypes that they observe to predict the genotype of the parents by using Punnett square models. Students then use beads to investigate genetic diversity within asexual and sexual reproducing organisms.
Lesson 9: Selection
Focus Question: How do natural and artificial selection change a population over time?
Students work in groups to carry out an investigation relating to natural selection using beads and different types of habitats. Then, students intentionally hunt for certain colors of beads, modeling the process of artificial selection. Students then consider the selection pressures of both processes and how they lead to evolution.
Lesson 10: Human Manipulation
Focus Question: What are some ways that humans have influenced the inheritance of desired traits in organisms?
Students organize prior knowledge about genetics to consider reasons why humans would want to manipulate an organism's DNA. Then, students observe the different variants of zebra fish in their classroom to construct an explanation to how the different kinds of zebra fish were created. Next, students research different types of genetic modification technologies and compile a list of reliable sources of information.
Lesson 11: Assessment
The unit concludes with a two-part assessment. The first part is a performance assessment, in which students apply the knowledge and skills they have acquired during the unit to research and report on human manipulation of organisms' genetics to produce desirable traits. In the second part, students complete a written assessment covering the performance expectations, disciplinary core ideas, crosscutting concepts, and science and engineering practices covered in this unit.

Note: GloFish® fluorescent fish are licensed under 1 or more United States patents. Reproduction (breeding) of GloFish® is permitted only for educational use by teachers and students in bona fide educational institutions; however, any sale, barter, or trade of the offspring from such reproduction is strictly prohibited.

Note: The Casper Fish™ provided are intended for non-commercial, internal research and educational purposes only. The sale, lease, license, or other transfer of the Casper Fish™ to a for-profit organization, uses of the Casper Fish™ by any organization, including Recipient, to perform contract research, to screen compound libraries, to produce or manufacture products for general sale, or to conduct research activities that result in any sale, lease, license, or transfer of the Casper Fish™ to a for-profit organization are strictly prohibited. However, industrially sponsored academic research shall not be considered a use of the Casper Fish™ for commercial purposes per se, unless any of the above conditions are met. Customers seeking to use the Casper Fish™ for commercial purposes should contact the Technology and Innovation Development Office of Children's Hospital Boston.

Note: Onion bulblets are available October through June.

*Next Generation Science Standards® is a registered trademark of WestEd. Neither WestEd nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of this product, and do not endorse it.