Question

identify five resources in the freshwater ecosystem that organisms compete for.
circle each identified resource on the food web.
an example has been started for you.
resources
1 sunlight 2
3 4
5
circle five organisms on the freshwater food web. describe how they compete for the resources you identified.
competition between organisms
1 jabirus compete with humans and alligators over dourado fish
2
3
4
5
check your understanding
learning goal 1
i can label organisms as a predator or prey in a food web
i can define the terms predator and prey
i can predict what would happen to the population numbers of different organisms in another food web if a predator was removed
learning goal 2
i can list reasons why organisms might be in competition with one another
i can define the term competition
i can explain why competition occurs between organisms of the same species and organisms of different species

Explanation:

Resources:

1. Sunlight is provided as an example; the other resources are critical limiting factors in freshwater ecosystems that organisms compete for.
2. Food (prey organisms) is a core resource for heterotrophs.
3. Dissolved oxygen is essential for aquatic organisms' respiration.
4. Nutrients (like nitrogen/phosphorus) support producer growth.
5. Habitat space (e.g., shelter, nesting sites) is needed for survival/reproduction.

Competition Examples:

Each example describes interspecific competition for the identified resources in a freshwater food web.

1. Provided example: Jabirus compete with humans and alligators over dourado fish.
2. Small fish (e.g., minnows) compete with tadpoles for algae (food resource).
3. Freshwater mussels compete with crayfish for dissolved oxygen in shallow waters.
4. Phytoplankton species compete with each other for sunlight and dissolved nutrients.
5. Frogs and water snakes compete for sheltered shoreline habitat space.

Check Your Understanding:

These are self-assessment items tied to learning goals about food web dynamics and competition. All statements are valid, measurable learning objectives for this topic.

Answer:

Resources

1. Sunlight
2. Food (prey organisms)
3. Dissolved Oxygen
4. Aquatic Nutrients (N/P)
5. Habitat/Shelter Space

Competition between organisms

1. Jabirus compete with humans and alligators over dourado fish
2. Minnows compete with tadpoles for algae
3. Freshwater mussels compete with crayfish for dissolved oxygen
4. Phytoplankton species compete for sunlight and nutrients
5. Frogs compete with water snakes for shoreline habitat

Check your understanding (self-assessment):

Learning goal 1

• [ ] I can label organisms as a predator or prey in a food web
• [ ] I can define the terms predator and prey
• [ ] I can predict what would happen to the population numbers of different organisms in another food web if a predator was removed

Learning goal 2

• [ ] I can list reasons why organisms might be in competition with one another
• [ ] I can define the term competition
• [ ] I can explain why competition occurs between organisms of the same species and organisms of different species