Biodiversity Classwork Classwork #1

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1 Biodiversity Classwork Classwork #1 1. What is biodiversity? 2. In the boxes below, create two ecosystems: one with low biodiversity and one with high biodiversity. Explain the difference.

2 Biodiversity Homework Homework #1 Source: 1. Describe how the diagram above shows the relationship between biodiversity and resilience.

3 Disturbance Classwork Classwork #2 Biotic and abiotic factors in ecosystems are interrelated. This means that, if one factor changes, it will affect all the other factors in that ecosystem. The marine Arctic ecosystem is a good example of this concept. Sea ice floats above the water in the Arctic Ocean. This sea ice is an essential component of the ecosystem. Ice algae are a type of algae that lives within nutrient-rich pockets of the sea ice. The ice algae are eaten by zooplankton, which are microscopic invertebrates in the water. The zooplankton are eaten by a variety of fish, including the Arctic cod, which is a favorite food of the ringed seal. Polar bears are also dependent on the sea ice. The majority of a polar bear s diet is ringed seals. Because polar bears live on the land, they use the sea ice as a platform from which to hunt seals. 1. Draw a food chain below that describes the energy relationships in the marine Arctic ecosystem. 2. As global climate warms, sea ice melts. This causes the ice algae population to decrease. Describe how a decrease in the ice algae population affects the polar bear.

4 Disturbance Homework Homework #2 Pacific salmon are migratory fish. They hatch and mature in freshwater and then travel to the ocean as adults. When it is time to spawn, the salmon return to the same freshwater stream from where they were born. After making the strenuous journey back to freshwater and then spawning, the Pacific salmon dies. Pacific salmon are greatly affected by climate change. As the climate warms, glaciers and snowpacks become smaller. This means that there is reduced stream flow in the summer and fall. This makes it difficult for salmon to travel to and from the ocean. As the climate warms, the water temperature also warms. Warm water temperatures make the salmon more susceptible to predators and disease. Climate change produces frequent strong storms, which creates runoff that carries toxins into the streams. As the salmon population is affected, many other populations are affected as well. Young salmon eat insects and plankton. Some species exclusively eat plankton. In turn, salmon are preyed upon by bears, eagles and orcas. 1. Describe two ways that climate change disturbs the salmon population. 2. A change in one part of an ecosystem will inevitably create changes in other parts of the ecosystem. Describe how a decrease in the salmon population would affect the following populations: a. Plankton b. Bears

5 Succession Classwork Classwork #3 After the eruption of Mount St. Helens, it took many years for vegetation to cover the landscape again. After three years, vegetation covered only 1% of the landscape. After 14 years, 38% of the landscape showed vegetation. After 20 years, vegetation coverage was 66%. One plant that played an important role in the succession of the ecosystem was the prairie lupine. The prairie lupine has small, light seeds that blew into the area via the wind. Although there was no nutritional value in the volcanic ash, the lupine was able to grow because it has the ability to obtain nitrogen directly from the atmosphere. This ability enabled the lupine to create healthy soil around each individual plant. Each lupine plant became a microhabitat, enabling several other plants to grow. This, in turn, attracted insects. Source: 1. Describe how soil is created during the process of succession. Use the prairie lupine as an example. 2. Create a graph of % vegetation coverage versus time, using the information given. Remember to label your axes and give a title to your graph.

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7 Succession Homework Homework #3 1. Prairie dogs often create disturbances in an ecosystem by tunneling through the ground and disrupting vegetation. How would vegetation biodiversity differ in areas that experience low, medium and high levels of prairie dog disturbance? Refer to the intermediate disturbance hypothesis in your explanation. 2. Compare and contrast primary succession and secondary succession. (Include the terms pioneer species and climax community in your answer.)

8 Answer Key Biodiversity Classwork Classwork #1 1. Biodiversity is the variety of species in an area. 2. Answers will vary. Biodiversity Homework Homework #1 1. In an ecosystem with low biodiversity, a disturbance will automatically lower the number of individuals present. In an ecosystem with high biodiversity, a disturbance will affect some species and not others. The unaffected species can increase in population while the affected species decrease in population. Overall, the ecosystem can retain the same health as before the disturbance. This is called resilience. As biodiversity increases, resilience also increases. Disturbance Classwork Classwork #2 1. Ice algae zooplankton Arctic cod ringed seal polar bear 2. Since ice algae is the base of the food chain, if that population decreases, all other populations will decrease. Since zooplankton no longer have a food source, their population will decrease, followed by a decrease in Arctic cod, ringed seal and then the polar bear. Disturbance Homework Homework #2 1. There is reduced stream flow making migration difficult. Warmer water temperatures increase risk of disease. Storms wash toxins into the water. 2. a. The plankton population would increase, since salmon eat plankton. b. The bear population would decrease, since bear preys on salmon. Succession Classwork Classwork #3 1. The prairie lupine was able to grow despite the lack of nutrients. The lupine was able to add nitrogen to the soil. As each plant and animal died in the microhabitat, it decomposed and added nutrients to the soil.

9 % Vegetation Coverage Vegetation Coverage After Eruption Time (years) Succession Homework Homework #3 1. The intermediate disturbance hypothesis states that biodiversity will be highest in areas that receive intermediate levels of disturbance. In areas of low disturbance, the vegetation biodiversity would be low because only the best competitors will survive. In areas of high disturbance, biodiversity would be low because only hardy, fast growing species would survive. In areas of intermediate disturbance, biodiversity would be high. In these areas, disturbance would be high enough to prevent competitors from getting rid of other species. At the same time, disturbance would be low enough to allow a variety of species, not just hardy plants, to thrive. 2. Primary succession occurs in areas which have no life, such as a volcanic eruption. In these areas, pioneer species are the first species to thrive. As these species die, they decompose to create soil. Eventually, a fully functioning climax community forms. In contrast, secondary succession occurs where a disturbance has destroyed habitat but preserved soil. In these areas, recovery is faster. As plants and animals return to the area and then die, the soil health is increased. Eventually, just like in primary succession, a climax community forms.