Interdependence of Life: Population Balance in Biomes

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Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the third of four Science Objects in the Interdependence of Life SciPack. It explores population balance in biomes.

Interdependent and fluctuating interactions among living organisms and populations and the abiotic components of their environment cause cyclical changes in the overall ecosystem resource equilibrium.

Interactions among living organisms within a population and among organisms of different populations take place on an ever-changing environmental stage. The nonliving environment—including land and water, solar radiation, rainfall, mineral concentrations, temperature and topography—shapes Earth’s ecosystems. Because each species can tolerate a limited range of physical conditions, the diversity of physical conditions creates a wide variety of ecosystems. In all these environments organisms use vital, yet limited, resources; each seeking its share in specific ways that are limited by biotic and abiotic factors.

Learning Outcomes:

  • Explain why there are such diverse ecosystems on Earth.
  • Given a description of changes in abiotic factors defining an ecosystem (i.e. temperature, precipitation, soil composition, atmospheric composition, amount of available solar energy) and the tolerance of a few species to these factors, identify graphs that accurately predict their effects on size and growth rate of these species.
  • Identify and explain graphs that accurately represent examples of dynamic equilibrium.
  • Explain how the population sizes of predators and their prey maintain a balance over many generations.

  • Elementary
  • Middle
  • High

Community ActivitySaved in 3799 Libraries

Reviews (8)
  • on Fri Nov 03, 2017 8:31 AM

This has great visuals and simulations.

Courtney Johannssen  (Springboro, OH)
Courtney Johannssen (Springboro, OH)

  • on Thu Apr 28, 2016 10:33 AM

it’s main purpose is to explain living and non-living things and how they interact with the surroundings in your ecosystem. It was a good activity to go through because it tests you after everything you read and it allows you to make sure you are understanding everything that is being taught.

Carolina Lopez
Carolina Lopez

  • on Sun Mar 08, 2015 5:38 PM

Great photos, simulations, and assessments.

Robin Willig  (Rye Brook, NY)
Robin Willig (Rye Brook, NY)

  • on Tue Sep 02, 2014 7:32 AM

I really enjoy Science Objects. In 1-3 hours, the Interdependence of Life: Population Balance in Biomes Science Object will help me re-learn, refresh, or learn for the first time some critical science concepts I will have to know to obtain my Science Educator credentials. I appreciate that I can complete them at my own pace, and that, if used as park of a SciPack, I have access to a content expert to go to for help. The NSTA Learning Center Science Objects are very beneficial!

Naomi Beverly  (Marietta, GA)
Naomi Beverly (Marietta, GA)

  • on Thu Nov 28, 2013 3:41 PM

Just used this last week with great results. Sometimes it's a little difficult to get the kids interested in population and communities but the chunking of the concepts and the interactive activities kept their interest great, especially considering it was the day before Thanksgiving vacation. Great job!

James Johnson  (Custer City, PA)
James Johnson (Custer City, PA)

  • on Mon May 05, 2014 5:26 PM

This science object moved me in the direction of introducing human population into the ecology unit. Then it stemmed into including a discussion of animal populations in an ecosystem. I searched a link that gave me a rabbit and fox population simulator for students to use.

Hazel Robateau
Hazel Robateau

  • on Tue Mar 03, 2015 4:41 PM

This science object was a little bit boring; however, it had very important information. I think studying biomes may be more interesting through videos that show just how different plant and animal species thrive in the environment. The activities did make it a little easier to understand and interesting.


  • on Mon Mar 18, 2013 7:59 PM

I expected this sci-object to focus on population balance and how populations maintain equilibrium. These areas were addressed. However, a large majority of the material seemed to focus on environmental reasons for the emergence of different biomes across the planet. In fact, it went into great detail regarding rain patterns and biome descriptions. The core material, regarding population balances, almost seemed an afterthought.

Cory Williams
Cory Williams

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