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What is the biggest single-celled organism? - Murry Gans

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The elephant is a creature of epic proportions — and yet, it owes its enormity to more than 1,000 trillion microscopic cells. And on the epically small end of things, there are likely millions of unicellular species, yet there are very few we can see with the naked eye. Why is that? Why don’t we get unicellular elephants? Or blue whales? Or brown bears? Murry Gans explains.

Additional Resources for you to Explore

When we try to imagine the largest cell, ostrich eggs might come to mind first. These are indeed single cells. Ostrich eggs use another biological hack to be unusually large: the overwhelming majority of the egg is stored food and only a small part of it is biologically active. At first this is a single fertilized egg cell. The developing, multicellular ostrich will use up all of that food before it hatches. If you want to find out more about ostriches and their eggs, naturall you can head straight to the American Ostrich Association.

How do you calculate the number of cells in a human, given that they come in all sizes and shapes? Find out here! Still inquisitive? Cell Biology By The Numbers has even more answers. 

Ever wonder how many gut bacteria we humans have? If you compare the number of genes our resident bacteria contain to our cellular genes, we are outnumbered 10 to 1. This Nature article sums it all up: Gut bacteria gene complement dwarfs human genome.

Here is an article about the giant coenocyte algae Caulerpa taxifolia published in PLOS|Genetics in January, 2015. This TED-Ed lesson also has lots of information about this invasive algae and why it is so successful: Attack of the killer algae - Eric Noel Muñoz.

Considering the largest unicellular organism leads to wondering what the smallest multicellular organism might be. Here are some interesting links on the subject. Smallest multicellular organism, Dicopomorpha echmepterygis, and Dicyemida.

Interested in learning more about cells? Take a look at these TED-Ed lessons:

How we think complex cells evolved - Adam Jacobson

Insights into cell membranes via dish detergent - Ethan Perlstein

The wacky history of cell theory - Lauren Royal-Woods

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Meet The Creators

  • Educator Murry Gans
  • Script Editor Emma Bryce
  • Producer Zedem Media
  • Director Michael Kalopaidis
  • Animator Andria Pourouti
  • Illustrator Amanda Kafandari
  • Sound Designer Andreas Trachonitis
  • Narrator Addison Anderson

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