What makes an ecosystem unbalanced

Often, after a major disturbance, you can observe an ecosystem move through several stages of succession. Discuss the successional stages that occur after one or two of the examples students listed. Build background on shifting baselines and succession in marine ecosystems. Ask them to pay attention to how Dr. Show students the first 3 minutes, 30 seconds of the video. After viewing, ask students to summarize what they saw. Elicit from students that the video uses coral reefs with varying degrees of human habitation and impacts to show how the composition of reef species changes over time.

Ask students to provide examples of disturbances that occur in marine ecosystems. Add their ideas on the table from Step 2. Elicit examples such as hurricanes, ocean warming, dead zones anoxia , overfishing, habitat destruction trawling, coastal development , and pollution toxic waste, oil spill. Using the example of coral reefs from the video to provide context, ask: What is a baseline? Elicit from students that a baseline is a point of reference against which significant change can be measured.

Ask: Why is it important to have an accurate baseline for marine ecosystems like coral reefs? Elicit from students that if we know the baseline for an ecosystem in decline, we can work to restore it to that level.

If the baseline has shifted, we may be accepting a degraded system as normal. Divide students into small groups and have them start the worksheet. Distribute a copy of the Shifting Baselines and Succession worksheet to each student.

Divide students into small groups and read aloud the directions. Ask each group to provide at least one example of each item in column 1. Use the examples generated from Steps , including the video, to correct any misconceptions students have about each of the items in the list.

For example, students may think that a pristine ecosystem is an ecosystem to which humans have no access. Clarify that the ocean and atmosphere connect humans to all marine ecosystems. Also clarify that sustainability can be defined in different ways, but for this activity they need to think about it in terms of ocean resources and ecology.

After the video, have groups work together to discuss and refine their examples and explanations. Use the provided answer key to facilitate the discussion.

Ask: Do you think coral reefs can recover from natural disturbances at the same time that anthropogenic disturbances are increasing? Why or why not? Use the provided answer key to facilitate discussion and check for completeness. Ask: How did the scientists describe the initial stages of coral reef succession?

What stages do you think might follow? Elicit from students that the scientists stated that a hard or rocky substrate free of algae was needed so that the small coral recruits, or polyps, could attach and begin to multiply into a coral colony. The coral colonies would then provide food, space, and shelter for other reef creatures, including herbivores. Then, carnivorous fish and invertebrates would multiply and feed on the herbivores. As biodiversity increased, additional niches would develop.

And in the case of the more pristine Line Islands, the reef supported more predators than herbivores and showed signs of stability and resilience. Have students reflect on what they have learned. Lead a class discussion about how the terms shifting baseline, disturbance, succession, and sustainability are all interconnected. Have students use their worksheets to share examples of these ecological principles in coral reef ecosystems.

Ask students to brainstorm about how these principles are applicable in other marine or terrestrial ecosystems. Assess students' worksheets for completeness and accuracy.

Check students' understanding by asking them to restate their examples and explanations of the key terms. Have students use Google Earth: Oceans to explore the Ocean Now Line Islands Expedition Log and reflect upon the current state of the research and how it could impact the establishment and design of coral reef marine protected areas.

Students make predictions about marine ecosystems based on combined impacts of anthropogenic and natural disturbances. They evaluate others' predictions and create concept maps to identify cause-and-effect relationships. Elicit students' prior knowledge. Remind students of their previous learning about marine ecosystems, food webs, interdependent relationships, and impacts.

Ask students to work in pairs to recall as many different types of marine ecosystems as they can. Have them record their answers. Discuss student responses as a class and any questions students may have.

Remind them of the interdependent relationships symbioses, food webs that exist within and among marine ecosystems. Have students work in groups to predict combined impacts. Divide students into small groups.

Distribute a copy of the blank Four-Column Chart to each group. Have each group select one of the ecosystems and its two associated impacts—either natural or anthropogenic—listed below. Necessary Necessary. Necessary cookies are absolutely essential for the website to function properly. These cookies ensure basic functionalities and security features of the website, anonymously. The cookie is used to store the user consent for the cookies in the category "Analytics".

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It has interesting articles and facts. There are features such as the Environmental Timeline that shows how there were different concerns about the environment throughout history. The environmental impact of war is an interesting article on how preparation of war and warfare leads to environmental losses.

The carpet bombing of the lush green forests during the Vietnam war led to the loss of habitat of many species. Special features on population and the environment show how population has increased from the industrial age and how it will affect the environment.

There are additional resources for higher classes. In the name of development, we remove trees and vegetation, change how we use land, and keep expanding paved areas.

All these not only affect the soil ecology, but also the water balance. Increased urbanization also requires more water to feed the city's population and industry, often requiring deeper and deeper wells to be drilled or water to be moved from even more distant locations. Increase of pavement area not lonely lessens the amount of water vapour that transpires back from the vegetation but also contributes to groundwater pollution if the salt used to melt road ice were allowed to runoff into the natural drainage system.

Visit this site for a detailed look at water as a precious resource and how human development affects water and its ecosystem.