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How Do Eggs Become Chickens or Other Living Things?  [v2.0]

Storyline Materials


This middle school unit on the structure of living organisms and their growth, development, and reproduction starts off with students encountering a series of news reports about the growing prevalence of backyard chicken coops across the country. Disagreements about why some chicken eggs hatch chicks and others don't, and what is going on inside an egg before it hatches, spark student questions and ideas for investigations geared toward figuring out why some eggs become chickens or other living things.

The investigations that students pursue help them answer these questions as well as explain how an organism grows and builds new body structures and how the structure of the circulatory system and the structure of cells support the movement of water, food, and gas molecules that are needed in these processes. 

This unit illustrates how we can help students explore the role of cells in the growth and development of living organisms through pursuing questions and ideas for investigations raised by the students, rather than needing to teach them about the related science ideas before they plan and conduct such investigations. 

These ideas include... 

  • Embryological development of different species reveals relationships not evident in the fully-formed anatomy.

  • All living things are made up of cells, which is the smallest unit that can be alive.  

    An organism may consist of one single cell (unicellular) or many cells (multicellular).

  • Within cells, different structures are responsible for different functions; the cell membrane forms the boundary that controls what materials enter and leave the cell.

  • In multicellular organisms, the body is a system of multiple interacting subsystems. These subsystems are groups of cells working together to form tissues and organs that are specialized for particular body functions. 

  • New cells are made from old cells, which use food as building blocks, (through a series of chemical reactions)*, to make more cell parts.

* optional connection


The development of this storyline is sponsored, in part, by a Science Education Partnership Award (SEPA) awarded to the University of Illinois Urbana-Champaign and Northwestern University. V2.0 will be released at the NSTA national conference in April 2019. Contact Barbara Hug <> for access to a pre-release of the unit, before then, or for more details.