Authentic Lessons for 21st Century Learning

How EGG-ceptional Are We? (Biology)

Evolution: Embryonic Development

K20 Center, Shayna Pond, Alexandra Parsons, Mariah Warren | Published: May 26th, 2022 by K20 Center

  • Grade Level Grade Level 9th, 10th, 11th, 12th
  • Subject Subject
  • Course Course Biology I, Biology II
  • Time Frame Time Frame 150 minutes
  • Duration More 2-3 class periods


Students will investigate the similarity of reproduction, embryonic development, and DNA sequences to illustrate the indirect evidence for evolution. "How EGG-ceptional Are We?" is written for a general biology course.

Essential Question(s)

How do we decide what to believe about evolutionary claims?



Students listen to the storybook An Egg Is Quiet then discuss observations from the book.


Students sort embryo images into similar groups.


Students use a second card sort and claims to draw conclusions.


Students analyze data and charts to draw conclusions about similarities between organisms.


Students answer open response questions to collect their thoughts and ideas.


  • An Egg Is Quiet by Dianna Aston

  • Lesson Slides (attached)

  • Student Version Embryo Card Sort (attached, one per group of two or three, cut out)

  • Teacher Version Embryo Card Sort (attached)

  • Explain Card Sort (attached; one per group of two or three, cut out)

  • Claim Cards (attached; 1 per group of four)

  • Nucleotide Sequence Handout (attached; one per student)

  • I Used to Think, but Now I Know worksheet (attached; one half sheet per student)

  • Colored pens or markers


Use slide 3 from the attached Lesson Slides to introduce the essential questions and slide 4 to introduce the objectives to students.

Go to slide 5. If you have a copy of An Egg is Quiet by Dianna Aston, read it to students. If you do not have access to the book, show students the following "An Egg Is Quiet" read-aloud video on YouTube. Instruct students to use the I Notice/I Wonder strategy to write down observations, important details, and questions they think about as they hear the story.

Afterwards, allow students to look back through the book if they need to revisit it. In pairs, have students share what they've written and revisit the book (or copies of pages of the book) to either reinforce the observations they made or to revise them. Also use this time for students to discuss the questions they wrote and see if rereading the book answers the questions or if further investigation is needed.


Go to slide 6 and introduce Set A of the Card Sort (letters at the bottom) from the attached Student Version Embryo Cards. Pass out sets to groups of 2-3 students. Prompt students to group together the embryos that are similar. There are no duplicates, so each is a unique animal, but possible categories could be mammals, reptiles, amphibians, etc. Some students may think these are similar animals, but in different developmental stages. Try to leave it open-ended as 'group what you think is similar together.' When students are done, have them do a modified Gallery Walk, where students write why their group decided the card groupings on "Post-it" Notes as category headings. The groups should rotate and read the other groups' ideas. When a full rotation through has happened, give time for students to decide if they want to change their original groupings or not.

Taking the idea further, pass out Set B (numbers at the bottom) from the same document, so that both Set A and Set B are together, to each group. Give the prompt for students to sort the cards. Students will probably understand that the idea is to pair the embryo with the developed animal, but try not to give it away.


Let students keep the card sorts for reference during the Explain and Extend sections. Go to slide 16 and pass out the attached Explain Card Sort, which features a few stages of a chicken embryo and a mouse embryo. Display or verbally share the prompt: "There are two sets. Separate the two sets, then put each set in order." Allow students to work on this in pairs, then have each pair find another. Next, pass out slides 2-5 of the Embryo Claim Cards slide deck to each group of four. Have students use the Claim Cards strategy. Give each student a claim. Instruct them to take turns with their group members reading their claim and either supporting or refuting it based on the evidence from their card sorts in the Explore section. Have them next share responses with the whole group. There are answers and explanations for each claim on slides 17-20.


Go to slide 21 and distribute the attached Nucleotide Sequence Extend document. Offer colored pens or markers and prompt students to look through and sequence the data with a partner. There are questions on the back that can provide inspiration for students, but allow students to explore the nucleotide sequences on their own.