Have you ever wondered how we can count things we don’t know about? Imagine trying to figure out how many candies are hidden in your couch cushions or how many undiscovered life forms exist on Earth. If you’re curious about the candies in your couch, you might start by reaching between the cushions and collecting what you find.
As you search, you might discover some candies and identify a few different types. However, since you can’t find every single piece, you won’t know exactly how many types you missed. Luckily, you can estimate how many you haven’t found by observing how often you encounter new types before you stop searching.
If most of the types you find are ones you’ve already seen, it suggests that there aren’t many types you missed. But if you’re still finding new types regularly when you stop, it indicates that there are likely many more types you haven’t seen yet.
By knowing how many types of candies you’ve seen once and how many you’ve seen twice, you can estimate how many types you haven’t found. For example, if there are 5 types of candies you’ve only seen once and 2 you’ve seen twice, you can use these numbers in an equation along with other information about how many candies you’ve found overall. This might suggest that there are probably 3 types still hidden away.
While this candy example might seem simple, a similar method can be used to discover hidden things on our planet. Recently, a team of researchers, including expert Peter Reich, used this method to estimate how many undiscovered tree species exist on Earth. Instead of collecting candies, they gathered data on every individual tree cataloged by scientists—about 44 million trees across approximately 64,000 different species—and calculated how many species had been seen once versus twice.
Using these numbers in their equations, the researchers estimated that there are about 9,200 tree species that we have yet to discover. This number is quite significant. In the centuries we’ve spent studying plants around the world, we’ve identified around 64,000 tree species. Could we have really overlooked an eighth of what exists? The couch candy protocol suggests that this might be the case.
Considering all the biodiverse tropical regions that haven’t been thoroughly explored, our lack of knowledge about the natural world isn’t entirely surprising. While we still have much to learn, we now have a better understanding of how much is likely out there, waiting to be discovered.
This research was conducted in association with the ASCEND project, a National Science Foundation-funded Biological Integration Institute led by Jeannine Cavender-Bares, Phil Townsend, and Peter Reich. The ASCEND team, based at the Universities of Minnesota and Wisconsin, aims to understand the causes and consequences of plant biodiversity in an era of rapid global change. They use reflected sunlight to study biological variation and model how variation at one biological scale influences the next, from individual organisms to ecological communities. In addition to advancing knowledge, ASCEND is training the next generation of integrative biologists to understand how life’s variation is interconnected across scales and affected by global change.
Start by searching your own couch for hidden candies or small objects. As you find them, keep track of how many different types you discover. Use this hands-on activity to understand the concept of estimating unknown quantities based on the types you find. Reflect on how this relates to discovering new species in the wild.
Create a simulation using a bag filled with different colored beads representing different species. Draw beads one at a time, recording how many new colors you find. Use this data to estimate how many colors (species) might still be in the bag. Discuss how this activity mirrors the methods used by scientists to estimate undiscovered species.
Choose a biodiverse region of the world and research its known species. Present your findings to the class, including an estimation of undiscovered species based on the couch candy protocol. This will help you understand the vastness of biodiversity and the importance of scientific estimation.
Engage in a workshop where you learn the mathematical equations used in the couch candy protocol. Apply these equations to different scenarios, such as estimating the number of undiscovered species in a fictional ecosystem. This will enhance your mathematical skills and understanding of scientific estimation.
Participate in a class discussion about how global change affects biodiversity. Consider how the discovery of new species can impact our understanding of ecosystems. This activity will help you connect the couch candy protocol to real-world environmental issues and the importance of biodiversity conservation.
Here’s a sanitized version of the provided YouTube transcript:
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How do we count things we don’t know about? For example, how many forgotten candies might be hiding in your couch cushions, or how many unknown life forms exist on Earth that we have yet to discover? If you’re curious about the different kinds of candy lurking in your couch, you could start reaching between the cushions and collecting what you find.
By the time you stop searching, you may have discovered some candies and identified a few different types. However, since you didn’t find every single piece, you can’t know how many types you missed. Fortunately, you can estimate how many you haven’t found based on a simple piece of information: how often you encounter new types before you stop searching.
One possibility is that most of the types you find are ones you’ve already seen before, which would suggest that there aren’t many types you missed. On the other hand, if you’re still discovering new types regularly by the time you give up, it indicates that there are likely many more types that remain unseen.
If you know how many types of candies you’ve seen once and how many you’ve seen twice, you can estimate how many types you haven’t found. For instance, if there are 5 types of candies you’ve only seen once and 2 you’ve seen twice, you can use these numbers in an equation along with other information about how many candies you’ve found overall. This could suggest that there are probably 3 types still hidden away.
While this example may seem trivial, many things are also hidden in the nooks and crannies of our planet. Recently, a team of researchers, including our own expert Peter Reich, applied this method to estimate how many undiscovered tree species exist on Earth. Instead of collecting every candy they could reach, they gathered data on every individual tree cataloged by scientists—about 44 million trees across approximately 64,000 different species—and calculated how many species had been seen once versus twice.
Using these numbers in their equations, the researchers estimated that there are about 9,200 tree species that we have yet to discover. This number is quite significant. In the centuries we’ve spent studying plants around the world, we’ve identified around 64,000 tree species. Have we really overlooked an eighth of what exists? The couch candy protocol suggests that this might be the case.
Considering all the biodiverse tropical regions that haven’t been thoroughly cataloged, our lack of knowledge about the natural world isn’t entirely surprising. While we still have much to learn, we now have a better understanding of how much is likely out there, waiting to be discovered.
This video was made in association with the ASCEND project, a National Science Foundation-funded Biological Integration Institute led by Jeannine Cavender-Bares, Phil Townsend, and Peter Reich. The ASCEND team, based at the Universities of Minnesota and Wisconsin, aims to understand the causes and consequences of plant biodiversity in an era of rapid global change. They utilize reflected sunlight to study biological variation and model how variation at one biological scale influences the next, from individual organisms to ecological communities. In addition to advancing knowledge, ASCEND is training the next generation of integrative biologists to understand how life’s variation is interconnected across scales and affected by global change.
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This version maintains the core ideas while removing informal language and ensuring clarity.
Candy – A sweet treat often used in experiments to study taste preferences and behavior in biology. – In our biology class, we used candy to estimate how different flavors affect taste preferences.
Estimate – A rough calculation or judgment of the value, number, quantity, or extent of something. – Scientists estimate the population size of a species by counting individuals in a small area and multiplying by the total habitat size.
Species – A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding. – The giant panda is a species that is native to China and is known for its distinctive black and white coloring.
Biodiversity – The variety of life in the world or in a particular habitat or ecosystem. – The Amazon rainforest is known for its incredible biodiversity, hosting thousands of different species of plants and animals.
Research – The systematic investigation into and study of materials and sources in order to establish facts and reach new conclusions. – Our research project focused on the effects of pollution on local aquatic species.
Data – Facts and statistics collected together for reference or analysis. – We collected data on plant growth under different light conditions to understand how light affects photosynthesis.
Types – Categories or classes of things that share common characteristics. – There are different types of cells in the human body, each with a specific function.
Discover – To find something unexpectedly or during a search. – Scientists discover new species in the ocean every year, expanding our understanding of marine life.
Biological – Relating to biology or living organisms. – The biological processes of photosynthesis and respiration are essential for plant and animal life.
Variation – A change or difference in condition, amount, or level, typically within certain limits. – Genetic variation within a species is important for adaptation and survival in changing environments.
