Patterns of Inheritance and Genetics

Grade 7 Science Understanding How Traits Pass from Parents to Offspring Tennessee Science Standard 7.LS3.3

I Can Statements & Success Criteria

I can identify inherited traits in living organisms I can explain the difference between dominant and recessive alleles I can use Punnett squares to predict inheritance patterns I can calculate probability ratios for genetic crosses Success Criteria: Correctly predict offspring traits 80% of the time

Bell Work: Family Trait Hunt

Look around the classroom and identify 3 traits you might have inherited Consider: eye color, hair texture, height, dimples, earlobes Write your observations in your science journal Differentiation: Visual trait cards provided for ELL students

What Are Inherited Traits?

Heredity: passing of traits from parents to offspring Traits: observable characteristics like eye color, height Genes: sections of DNA that control traits Some traits are inherited, others are learned or environmental

Dominant vs. Recessive Alleles

{"left":"Dominant alleles: Always expressed when present (represented by capital letters like 'B')\nRecessive alleles: Only expressed when two copies are present (represented by lowercase letters like 'b')","right":"Example: Brown eyes (B) are dominant over blue eyes (b)\nYou need two 'b' alleles (bb) to have blue eyes"}

Hands-On: Coin Flip Genetics

Each coin represents one parent Heads = dominant allele (B), Tails = recessive allele (b) Flip both coins 20 times and record results Calculate the ratio of dominant to recessive traits Extension: Try with three traits simultaneously

Punnett Square Basics

Check for Understanding

If brown hair (B) is dominant and blonde hair (b) is recessive, what would happen if two parents with Bb genotypes had children? Think-Pair-Share: Discuss with your partner Be ready to explain your reasoning

Real-World Application: Northern Cardinals

Male cardinals: bright red feathers (dominant trait) Female cardinals: brown feathers (different expression) Offspring show predictable color patterns This helps scientists study inheritance in wild populations

Exit Ticket Reflection

"The more we learn about genetics, the more we understand that we are all connected through the patterns of inheritance that have shaped life on Earth for millions of years." Complete: One thing I learned today about inheritance is... One question I still have is...