contestada

On a field trip to two local ponds, a group of students observed a difference between the two ponds in the diversity of worms and insect larvae living in the mud and debris near the edges of the ponds. Numerous factors, both biotic and abiotic, influence the distribution of aquatic organisms. The students decided that they would investigate some of the abiotic factors. List three water-quality tests that could be conducted and explain what information each test provides. Include in your answers a description of the impact of each factor on the distribution of aquatic organisms. Larvae of a certain insect are found in pond A but not in pond B. Design a controlled experiment that would help explain the observed distribution of these insect larvae. Be sure to include the following in your design. Formulate a hypothesis. Identify the variable that will be manipulated. Outline the field and/or laboratory procedures that will be followed. Describe what data you will collect. Discuss the possible results and relate them to the distribution of the insect. What are indicator species and how are they used to assess environmental quality

Respuesta :

hopemichael95

Answer: seen below.

Explanation:

1) 3 water quality test and their impact includes;

A) Carbon dioxide test: this process tests the amount of carbon dioxide in water.

The impact of carbon dioxide test is that increased CO2 will decrease pH while decreased CO2 will decrease photosynthesis.

B) Dissolved oxygen test: this process tests the amount of dissolved oxygen.

The impact of dissolved oxygen test is required for the use of oxygen (aerobic respiration) decomposition.

C) Ammonia test: this process tests the level of ammonia and it's impact leads to the blooms of algal.

2) Formulated hypothesis: pond A insect larvae can only survive in water with a dissolved oxygen level of 8 ppm (parts per million) or higher.

•Variable that will be manipulated is the level of dissolved oxygen.

•Procedures :

a) set up 30 petri dishes for the growing of the larvae found in pond. Use 3 petri dishes for every level of dissolved oxygen up to 10, for example 3 petri dishes of 1 ppm dissolved oxygen, 3 petri dishes of 2 ppm dissolved oxygen, 3 petri dishes of 3ppm dissolved oxygen and so on...

b) cultivate the larvae in the same room, the same amount of time, the same temperature, the same amount of light and the same amount of food. Keep all variables the same, to ensure validity of data

c) measure how many larvae lived in each dish then graph and interpret the data

Result : larvae only grows in water with dissolved oxygen of 8 ppm and above as stated in the hypothesis. Pond A has a dissolved oxygen of at least 8 ppm, pond B has less than 8 ppm, also this hypothesis could be wrong and the larvae grow just as well in all of them. Meaning that there is a different variable that causes the difference in pond A and pond B.

3) indicator species are species that are used to indicate the health of their environment that is the presence, absence or abundance of this species reflects a specific environmental condition.

example. Tubifex worms.

Tubifex worms indicate oxygen-poor and stagnant water unfit to drink.