Mod 9 Laboratory 1 PDF

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Mod 9 Laboratory 1...

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Barnacle Competition In this computer simulation lab, you will visit a hypothetical seashore to investigate the role of the environment on barnacle survival. Barnacles are shelled animals that attach themselves to solid objects (rocks, docks, etc.) at the seashore. They feed on small organisms that they catch by raking the water with the setae on their legs. Thais is a snail that feeds on barnacles.

Procedure Part 1. The effect of competition and predation 1. Go to www.virtualbiologylab.org 2. At the home screen, go to Ecology and then community Ecology. 3. Read about Model 1 – Barnacle Competition 4. Click on “Launch Model,” then on Background Information. Use this information to answer the first three questions on the data and observation sheet. 5. Return to Home and click on “Run Experiments.” 6. General information for running experiments. A. Use the “Controls” arrows to change the variables for your experiment. B. To start an experiment remove all the Balanus and Chthamalus by clicking on the red circles with slashes. C. Then click the “To Data” arrow. D. On the Data page click the “Reset” bottom to start you experiment on day 1. E. You can click the fast forward button at the bottom to speed up your experiment. F. When you get to day 21 of the experiment click the pause button to stop the experiment and collect your data. G. Click the arrow “To Design” to change the variables for your next experiment. 7. Use the instructions in step 6 to run the following experiments, leave the sea level and tide change at the default conditions. For each experiment, let the experiment run for 20 days and record the resulting population size in Data Table 1 on the data and observation sheet. Use default values of 2.5 larvae/ml and 3 predators when the barnacle species or predator is present. A. Experiment 1: Balanus only no predators

B. Experiment 2: Chthamalus only no predators C. Experiment 3: Balanus only with predators D. Experiment 4: Chthamalus only with predators E. Experiment 5: Balanus and Chthamalus no predators F. Experiment 6: Balanus and Chthamalus with predators 8. Answer questions 4-6 on the data and observation sheet.

Part 2. The effect of abiotic environmental conditions. 1. Tide change. Explore the effect different magnitudes of tide change has on each species and on the competition between the species. Record the changes you make and results on the worksheet and answer the question. 2. Sea level change. One of the consequences of global warming is a rise in sea level. Explore the effect of rising sea level on the barnacles and barnacle competition. Record the changes you make and results on the worksheet and answer the question.

Barnacle Competition Data and observation

Name _______________

Part 1. Effect of competition and predation. Use the Background Information to answer the following questions: 1. Differentiate between a fundamental and realized niche. Fundamental - All the habitats the organism can live in and the available resources Niches - All the habitats where it actually lives and the resources it consumes

2. What are the advantages and disadvantages of living in the intertidal zone? Some animals don’t have the capability of moving from the tides, but the species that are capable have a higher chance of getting away from predators

3. Describe the life cycle of a barnacle. Eggs are released in the water which hatch into tiny nauplius larvae, feed on phytoplankton and then change into cyprid larvae, find a spot to settle and change to adult, they reproduce sexually

Data Table 1. Abundance values after 20 days for barnacles under various experimental conditions. Treatment Balanus abundance Chthamalus abundance One species of barnacle without predators

A 391

B 537

One species of barnacle with predators

C 170

D 412

Both species of barnacle without predators

E 363

E 217

Both species of barnacle with predators

F 189

F 148

4. In which area(s) is each species generally found during the simulations? (High to mid-tide, mid-tide to low tide, below low tide) Balanus - high Chthamalus – high to mid Thais – low 5. Did predation or competition have more impact on Balanus? (Compare C and E to A.) Why? Predation because it significantly decreased the species 6. Did predation or competition have more impact on Chthamalus? (Compare D and E to B.) Why? Neither had an impact because the species stayed around the same amount

Part 2. The effect of abiotic environmental conditions. 1. Tide Change. a. Record your parameters and results of your experiments below. Tide @ 0m - Balanus stays towards the top, Chthamalus stays towards the bottom, both species have a large amount at the very top causing a lot of competition Tide @ 1m - During high tide there is a lot of competition, both species stay towards the top Tide @ 2m - Chthamalus spends a long time out of the water, not much competiton as Balanus is lower than Chthamalus

b. How does changing the magnitude of tide level change affect the population of barnacles? Is it the same effect on both species? Increasing the tide level increased Balanus but decreased Chthamalus

2. Sea level change. a. Record your parameters and results of your experiments below. Sea level 1m - abundance of Cthamalus, still not much competition. Sea level 1.5m - abundance of Cthamalus, more competition than previously because both species are under water

b. How does increasing sea level affect the population of barnacles? Is it the same effect on both species? Increasing the sea level increases the population of Chthamalus, and Balanus stays relatively the same throughout...