Interdependence of Life: Species Relationships

Science ObjectDigital resources are stored online in your NSTA Library.

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 second of four Science Objects in the Interdependence of Life SciPack. It explores species relationships.

All organisms, both land-based and aquatic, are interrelated by their need for resources. One example of a network of interconnections is called a food web; it is a model of the interdependence among the organisms in populations of different species. Predator-prey and parasitic relationships are examples of interspecies relationships, interdependence that occurs among organisms in different species in a food web.

Interspecies relationships can be categorized as positive, negative, or neutral for the fitness of the individuals and their populations who are involved. A change in the population of one species can affect the population of another species. Intra-species relationships, or interdependence among organisms of the same species, can also affect a population.

Learning Outcomes:

  • Given the specific nature of an interspecies relationship, categorize the relationship between two interrelated populations as positive, negative or neutral for each population.
  • Given a description of a change to one population depicted in a food web, predict changes that might occur in the size and rate of growth for other populations depicted in the food web.
  • Given a line graph displaying changes in population sizes and rates of growth for a number of populations in a community, along with a description of the trophic relationships among populations, generate plausible hypotheses about causes of the changes depicted in the graph.

  • Elementary
  • Middle
  • High

Community ActivitySaved in 3466 Libraries

Reviews (8)
  • on Mon Jul 25, 2016 10:44 PM

This is my first Science Object and I am very impressed with the information here! While some of the concepts were familiar to me, I really appreciated having a refresher for the things I had forgotten, as well as the knowledge to be able to teach this to my students. The interactive aspects were also really helpful and enhanced my understanding of the concepts.

Katheryne A
Katheryne A

  • on Sun Jul 03, 2016 2:12 PM

The food chain is an important concept for children to learn about. It shows them how everything is linked to each other and helps them see the bigger picture. This resource has wonderful information about the food web that will help children be more responsible and increase their understanding of the environment.

Jennifer Pierre
Jennifer Pierre

  • on Mon Jan 11, 2016 12:01 AM

This is a wonderful addition to my unit on food chains and food webs.

Jamie Walsh  (Poway, CA)
Jamie Walsh (Poway, CA)

  • on Sun Mar 08, 2015 12:32 PM

The simulations are excellent learning and teaching tools!

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: Species Relationships 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 Mon Apr 08, 2013 3:14 PM

This lesson had good interactive tools and questions asked throughout.

Ashley Bax
Ashley Bax

  • on Fri Mar 08, 2013 10:41 AM

This object targeted all relevant standards on this topic. It provided an excellent illustration of the interdependence of predator and prey in graphical form.

Roselle Leone
Roselle Leone

  • on Mon Feb 04, 2013 12:21 PM

I never tire of hearing about the different ways that species interact with one another. This Science Object was full of wonderful examples of all of the different types of relationships that plants and animals have with one another, including mutualism, commensalism, ammensalism, neutralism, and parasitism. While I was familiar with most of these terms, the Science Object presented them in such a way that I’m pretty sure I have got them all down pat. They repeated the concepts several times, gave a lot of different examples, and gave me plenty of opportunities to practice what I had learned, through questioning and also through an interactive game. I thoroughly enjoyed being a snowshoe hare and making decisions about where I should go in order to escape predation and get plenty to eat. This Science Object also helped me solidify my understanding of trophic levels and biomass pyramids. The graphics were very helpful, and I appreciated the interactive element in which you change the amount of hawks, snakes, kangaroo rats, and creosote bushes to see how other species are affected when there is a change in the population of one species. I would highly recommend this Science Object to anyone. I took a few ecology classes in college, and I have taught many of these ideas to elementary students before, so even though the concepts were not new to me, they refreshed my understanding and also gave me fresh examples of the different relationships between species. I’d like to figure out some ways to transform the interactives into hands-on classroom activities as part of an ecosystem unit for fourth grade.

Kirsten Tuhus
Kirsten Tuhus

Free - NSTA Members

$5.95 - Nonmembers

Login or Create a Free Account to add this resource to your library.