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Curriculum:  Science:  Environmental Systems  [ 112.44(b)(4)]

The Texas Legacy site hosts a variety of educational curricula, lesson plans, keys and ideas, and supporting media, including video, databases, transcripts and other material.  Below you can find the TEKS standards for Environmental Systems, especially biotic and abiotic factors, as described in section 112.44(b)(4), with relevant activities drawn from this archive.

Goal:  The student knows the relationships of biotic and abiotic factors within habitats, ecosystems, and biomes:


Excerpts of TEKS Text

TexasLegacy.org  Relevance

Suggested Activities


(b)(4)(A)  identify indigenous plants and animals, assess their role within an ecosystem, and compare them to plants and animals in other ecosystems and biomes;


Indigenous plants and animals are those that are naturally and originally occurring in a site.  The TexasLegacy.org project includes numerous biologists, botanists and ecologists who have studied indigenous life, and can offer a wide variety of relevant experiences and insights.



Top predators have a key role to play in ecosystems.  Biologist Billy Pat McKinney discusses the efforts to restore the mountain lion to the Trans Pecos, while naturalist Bonnie McKinney tells about work to bring back the black bear to northern Mexico and the southwestern U.S.

Many indigenous wild plants have been removed in favor of domesticated crop species, harming the vitality and stability of the ecosystem.   Scooter Cheatham and Benito Trevino work to celebrate the many valuable uses of wild plants, and to help with their reintroduction into commerce and ecosystems.



(b)(4)(B)  make observations and compile data about fluctuations in abiotic cycles and evaluate the effects of abiotic factors on local ecosystems and biomes;


Abiotic factors are the non-living aspects of the earth that affect the ability of living organisms to survive in an environment.  Typically, they include physical and chemical factors.  The TexasLegacy.org archive includes a hydrologists, geologists, and chemists whose work has centered on these abiotic factors, and who can provide help in this area.



A key, and often limiting, abiotic factor is water, especially in a state like Texas with large dry regions.  It is essential that living organisms have sufficient, and clean, water.

To understand the importance and controversies affecting water supplies to human communities and natural systems, please watch our documentary about statewide groundwater issues, called  Echoes from a Well, and a segment on surface water supplies in Texas, entitled Ripples on a PondShorter excerpts about water supply  in the Trans-Pecos include discussions by the farmer John Carpenter, in the Edwards Plateau by the activist Ken Kramer, and in coastal estuaries by the agency offical Joe Moore, Jr.

In addition to supply questions, water quality is another critical abiotic factor.  A number of TexasLegacy.org narrators discuss this quality concern.  George Rice, a San Antonio hydrologist and Edwards Aquifer Authority board member, together with George Veni, a San Antonio geohydrologist, explain the vulnerability of the Edwards Aquifer to pollution.  Jim Earhart and Tom Vaughan, both biologists in Laredo, discuss surface water pollution in the Rio Grande.  Johnny French, a former Fish and Wildlife Service biologist, explains water pollution in the Lower Laguna Madre.



(b)(4)(C)  evaluate the impact of human activity such as methods of pest control, hydroponics, organic gardening, or farming on ecosystems;


Many TexasLegacy.org narrators have been involved in this question of human activity's impact on ecosystems, including farmers, ranchers, botanists and policy experts.


Pest control has had a harmful impact on ecosystems, as explained by Bessie Cornelius in seeing the decline of the Brown Pelican due to DDT.  Fortunately, efforts to eliminate DDT from U.S. agricultural use have been successful (see the story from state senator Don Kennard about the first discussions of such banning legislation, and from former Texas Agriculture Commissioner, Jim Hightower). 

Reform of other practices in agriculture has also benefited ecosystems, as depicted in the half-hour pieces, Sowing the Seeds (a statewide discussion about progressive horticulture and agriculture), From the Ground Up (organic grains and vegetables), and Working with Nature (organic fibers and meats).

Shorter and more focused discussions of organic farming include video excerpts with citrus farmer Dennis Holbrook and vegetable farmer Carol Ann Sayle).  Progressive grazing is discussed in detail by ranchers Alan Birkenfeld, Walt Davis, and Richard Sechrist).  More sustainable approaches to silviculture, particularly the reintroduction of fire, are laid out by forester Ike McWhorter and forest activist Pete Gunter.



(b)(4)(D)  predict how the introduction, removal, or reintroduction of an organism may alter the food chain and affect existing populations; and



The TexasLegacy.org participants include several narrators who have discussed such introductions and removals of organisms, and their related impact on the larger population.


The introduction of genetically modified organisms has generated a great deal of discussion and concern related to possible unintended effects on the food chain and existing wild populations.  Please look at the visit with attorney Reggie James, and follow up with a discussion or research project on pharmacological crops.  Another concerns about genetic alterations and introductions involves bT corn, which may harm the monarch butterflies discussed by Carol Cullar

Major efforts have been carried on to avoid the loss of several species from the food chain and general wild population.  Please watch the following videos about endangered species protection, and then explain what niche that species fills, and what the consequences would be of their loss.  Examples concerning endangered species include the bald eagle (by game warden, Jim Stinebaugh), Attwater prairie chicken (by ornithologist Kenneth Seyffert), and the piping plover (by naturalist Jesse Grantham).



(b)(4)(E)  predict changes that may occur in an ecosystem if biodiversity is increased or reduced.



Biodiversity, and its factors, fluctuations and trends, is a central topic for many TexasLegacy.org narrators.


Biologist Dede Armentrout discusses the impacts of reduced biodiversity in the whitetail deer population from managed breeding efforts.

Bob and Mickey Burleson and Jim Eidson explain their efforts to restore the highly diverse native tallgrass prairie of the central Texas blackland.



Conservation History Association of Texas
Texas Legacy Project

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