2.1.4 Ecosystem Dynamics

Ecosystem Dynamics

2.1.4

Objectives

Learners can:

• describe how ecosystems are dynamic

• explain how changes in an ecosystem impact specific populations

• determine whether changes will benefit or harm a system

• community

• ecosystem

• habitat

Prerequisite Vocab

• dynamic

New Vocab

Vocabulary

​a process characterized by constant change

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Dynamic

Ecosystems are dynamic, meaning they are characterized by constant change. A forest may not seem to change much over time, but when you look more closely, you will see that the populations within that forest ecosystem are constantly changing. A flood could destroy habitats and lead to the decline of animal populations.

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Ecosystem Changes

An ecosystem's organisms interact with an environment's biotic and abiotic components. An animal, such as a grizzly bear, relies on other living things for food. The fish that the bear eats need the water in rivers to survive. If something happens to even one part of an ecosystem, that impact can lead to many other changes within the ecosystem.

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Ecological Connections

​The Clark's nutcracker relies on the seeds from the whitebark pine as a food source.

Clark's Nutcracker

The whitebark pine tree relies on the bird to disperse its seeds, allowing new trees to grow.

Whitebark Pine Tree

Other animals, such as the Douglas squirrel, rely on the pine trees as homes.

Douglas Squirrel

Ecosystem Connections

Open Ended

What is a possible outcome that could occur if one of the species was affected? For example, if there were fewer Clark's Nutcrackers, how would that affect the Whitebark Pine trees?

The frog relies on the grasshopper as a source of food. Also, the frog is a food source for the owl and the snake. If something happened to reduce the number of grasshoppers, this change would impact all of the other species in some way.

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Ecosystem Relationships

Hotspot

Use the diagram to determine which organisms would be impacted if the mouse population disappeared.

Select the two correct answers.

• ​drastic changes make it less likely for organism populations to survive

• humans can alter the environment or introduce invasive species

Negative

• make it more likely that organisms will survive

• populations may increase

• humans can plant more vegetation and regulate land use

​​Positive

​Positive vs. Negative Changes

Categorize

Options (6)

setting restrictions on construction to protect native birds

a region receiving rainfall after a drought

clearing land for a new housing development

an earthquake altering the landscape resulting in rivers drying up

native grasses are reintroduced into the environment

an invasive predator is introduced that only feeds on mice

Which of the following activities will lead to positive change in an ecosystem, and which activities will lead to negative change?

Positive Changes

Negative Changes

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Open Ended

What was the first type of organism that you needed to add to your ecosystem? Why?

Open Ended

When you started the secondary succession phase, why were you able to skip over adding lichen and moss, which were critical in starting an ecosystem in primary succession?

Multiple Choice

Why did it take less time for the ecosystem to come back to life in the secondary succession?

• There were already remnants of the previous plants making it easier for them to grow.

• It took the same amount of time.

• The primary succession was faster than the secondary succession.

• The fire did not burn down all of the plants so they continued to grow.