How to Reconcile Multiple Findings, Conclusions, or Theories on the GED Science Test

By Murray Shukyn, Achim K. Krull

On the GED Science test, you may be called on to step into the shoes of a scientist and reconcile results from two or more studies with other data, or you may be asked questions related to incidents in which scientists reconciled other theories or hypotheses. Scientists often must draw conclusions from two or more findings, conclusions, or theories to identify the cause of a certain phenomenon and answer questions.

To answer such questions successfully, examine the data and the question carefully for clues. The information you’re given points the way to the correct answer. The following reading passage and questions challenge your ability to evaluate how scientists use existing knowledge from two sources to formulate questions and arrive at a conclusion.

Questions 1−2 refer to the following passage, What connects fish and maple trees? from the National Science Foundation.

If we are what we eat, some lake fish, it turns out, are made of maple leaves. These fallen leaves play an integral role in the food webs of lakes.

It has long been thought that aquatic plants form the base of a lake’s food web. The energy they contain supports life, from invertebrates to the largest sport fish. Now, a study funded by the National Science Foundation’s (NSF) Biological Sciences Directorate shows that aquatic plants are receiving a little help from trees along the shoreline.

Scientists Michael Pace and Jonathan Cole of the Institute for Ecosystem Studies in Millbrook, New York, found that a significant part of the aquatic food chain is supported by organic matter (“food”) that originates on shore.

A building block of life, organic carbon is essential to aquatic food webs. In lakes, aquatic plants produce this carbon by harnessing the sun’s energy through photosynthesis. Some of the carbon supports the growth of fish and invertebrate populations.

In Lakes Peter and Paul at the University of Notre Dame Research Center, scientists conducted tests to determine whether lake plant production was enough to support resident aquatic life.

The short answer: It’s not. Test results show that aquatic plants don’t produce nearly enough food to support lake animals. Therefore, to survive and thrive, the lake animals are dependent on inputs from the surrounding shores.

Leaves and other organic matter that enter lakes, it turns out, are ultimately incorporated into aquatic animals. That maple leaves may eventually become perch, and that the vegetation around a lake can have profound impacts on the animal life within that lake, blurs the boundaries between aquatic and land-based ecosystems.

As naturalist John Muir once wrote, tug on one strand of nature, and you’ll find it connects to all others.

  1. Which of the following conclusions can be drawn from the evidence presented?

    • (A) Aquatic plants do not produce enough organic matter to support resident aquatic life, so fish must eat tree leaves.

    • (B) Fish cannot obtain sufficient amounts of food from aquatic plants, so they need to eat aquatic invertebrates to survive.

    • (C) Aquatic plants do not produce sufficient carbon to support resident aquatic life, so the carbon must be coming from plants along the shoreline.

    • (D) Shoreline vegetation supplies sufficient energy to support resident aquatic life without the addition of aquatic plant production.

  2. Which of the following is a fact about food chains that caused researchers to question whether aquatic plant production was sufficient to support resident aquatic life?

    • (A) All energy in a food chain comes from the sun.

    • (B) In lakes, aquatic plants produce all the food required to support resident aquatic life.

    • (C) All aquatic animals obtain their energy directly from plants.

    • (D) In food chains, secondary consumers eat primary consumers.

Check your answers:

  1. By studying the amount of aquatic plants and animals, researchers concluded that the animal population was greater than the aquatic plant life could support, so additional plant life would need to be added, and the only place it could possibly come from is around the shoreline, Choice (C).

  2. In arriving at their conclusion, scientists needed to reconcile knowledge about food chains and the photosynthetic process. Through photosynthesis, plants convert radiant energy from the sun into chemical energy that animals can eat. A population is limited by the amount of energy plants can harvest from the sun. So the fact about food chains that the researchers used to arrive at their conclusion is that all energy in a food chain comes from the sun, Choice (A).