This lesson continues the previous lesson and is aligned to:
NGSS MS-LS3 Heredity: Inheritance and Variations of Traits
Disciplinary Core Idea MS-LS3-1: Genes are located in the chromosomes of cells, with each chromosome pair containing two variants of each of many distinct genes. Each distinct gene chiefly controls the production of specific proteins, which in turn affects the traits of the individual. Changes (mutations) to genes can result in changes to proteins, which can affect the structures and functions of the organism and thereby change traits.
Science and Engineering Practice 2: Developing and Using Models - As students create their concept maps, they are "developing a (mind) model to show the relationships among variables"
Crosscutting concept - Structure and Function (XC-SF-MS-1): Complex and microscopic structures and systems can be visualized, modeled, and used to describe how their function depends on the shapes, composition, and relationships among its parts, therefore complex natural structures/systems can be analyzed to determine how they function. In this lesson, students begin to comprehend how DNA, genes and chromosomes are related and how this organizational structure leads to the passing of traits from parents to offspring.
As a quick review of the concepts taught in the previous lesson I present Genes vs. DNA vs. Chromosomes - Instant Egghead #19 video (by Scientific American) and have students complete the Genes vs DNA vs Chromosomes sheet as they are watching.
Having students answer the questions on the half sheet keeps students accountable for watching the video, but it is not collected until the end of the lesson. The students have it as a reference during the second portion of the lesson as they create a concept map.
As the students are watching, I hand back their incomplete Tour the Basics sheets, submitted the day before.
We continue with the Tour the Basics presentation from the day before. I give students time to write down their answers in their Tour the Basics XP, and to add clarifying ideas as needed. Once this is done, I tell the students to once again go over their sheets and underline/highlight/circle the words they consider as key concepts in genetics. These can be words in the questions or in their answers.
I tell the students to share with their tablemates the words or phrases they have identified in their Tour the Basics sheet as key concepts in genetics, and write each down in a post-it. I then tell them that they will be creating their own concept map using those concepts, and remind them how I did it the day before.
General steps given to students to create cooperative concept maps:
I tell the students that I will be looking specifically at the labels since that tells me what they understand about the nature of the relationship between concepts. I remind them that they have not only their Tour the Basics sheets, but they also have the DNA vs. Chromosome vs. Gene sheet they used at the beginning of the lesson. Once any question about the expectation or concept map creation has been answered, I have students get to work on their maps.
As the students are working, I am walking around the room helping struggling groups determine connecting words or phrases.
Take a peek at how the students worked through this concept mapping exercise, and then at some examples of what they created.
Note to Teachers: At this point, I expect the list of concepts to include DNA, gene, chromosome, protein, heredity, traits, allele and environment. If table groups include any of the "paired" concepts (i.e. genotype and phenotype; homozygous and heterozygous; dominant and recessive), I just make sure that they include both in their map. I make it a point to mention that I am looking at the clarity of the labels since these linkages reveal the level of sophistication of the students' ideas, the accuracy of the content knowledge gained so far and the depth and breadth of their thinking. Students will continue to add to their concept maps as the unit progresses.
As students finish their concept maps, I tell them to visit another group's, identify and document one similarity and one difference in the way they linked the concepts. I am explicit in asking that the difference go beyond semantics ("made of" = "composed of" = "are groups of"). They are looking for differences in perspectives. If they cannot find a real difference, they should document why they believe both groups reached the same conclusions.
The assessment of the lesson is in the concept maps. These closure papers are collected for participation points. I go over them as they tell me the level of sophistication in their thinking, but I do not grade them.
As you can see in the Concept Map comparisons (SW1, SW2), at this point the students overwhelmingly point out basic differences (which words were included). Although this could be due to me not being explicit enough in the expectation, I believe that it stems from students not having the knowledge base required to really think about the connections. When I give them back to the students, I include comments (like the ones you see in the samples), to encourage them to think more deeply. We revisit the concept maps several times during the unit, and students will continue to add/modify them as we explore the concepts more in depth.