Interactions in Marine Ecosystems: Parasitism, Commensalism, Mutualism

Chapter 3 Interactions in Marine Ecosystems Day#1. Lesson plan

Enhancing AICE Marine Science Teaching: Understanding Feeding Relationships and Ecological Interactions

As an AICE Marine Science teacher, it’s crucial to ensure your students grasp the complexities of feeding relationships and ecological interactions. These concepts are fundamental to marine ecology and are essential for success in the AICE exams. This blog post will provide strategies for effectively teaching the meanings of parasitism, commensalism, and mutualism, as well as key terms related to feeding relationships, such as consumers, producers, and trophic levels. Additionally, we’ll explore how to represent and interpret food chains and food webs to deepen students’ understanding.

Lesson Outline

Hook

• Begin with a brief overview of today’s objectives: understanding feeding relationships and ecological interactions in marine ecosystems.

Instruction

• Lecture/Notes (PPT – slides 1-5)
  • this part of the lesson covers symbiotic relationships which are close and long-term interactions between different species. These interactions are vital for many organisms and can significantly influence the structure and dynamics of ecosystems. The three main types of symbiotic relationships are:
    • Parasitism: Parasitism is a type of symbiotic relationship where one organism, the parasite, benefits at the expense of another organism, the host. The parasite derives nutrients and protection from the host, often causing harm in the process.
      • Examples:
        • Barnacles attaching to whales, where the barnacles benefit by gaining access to nutrient-rich waters while the whale may experience reduced efficiency in swimming.
        • Copepods (Sea Lice) and marine fish: These parasites attach to fish, feeding on their blood and potentially causing infections.
    • Commensalism: Commensalism is a type of symbiotic relationship where one organism benefits, and the other organism is neither harmed nor helped. The benefiting organism often gains shelter, transportation, or nutrients from the host.
      • Examples:
        • Remoras and Sharks/ manta ray: Remoras attach to sharks/ manta ray using a sucker-like organ. They benefit by eating scraps of food left by the shark/manta ray and gaining transportation, while the shark/manta ray is unaffected.
    • Mutualism: Mutualism is a type of symbiotic relationship where both organisms benefit. These relationships often involve cooperation and can be essential for the survival and reproduction of the species involved.
      • Examples:
        • Coral and Zooxanthellae: Coral polyps and zooxanthellae algae live in a mutualistic relationship where the algae provide the coral with nutrients through photosynthesis, and the coral provides the algae with a protected environment and access to sunlight.
        • Boxer crabs and anemones: boxer crab hold anemones in their claws, which look like boxing gloves or pom-poms, anemones have stinging cells – cnidocytes – on their tentacles, and the crab uses them for defense and the anemone get easy access to food.
        • Cleaner Fish and Larger Fish: Cleaner fish remove parasites and dead skin from larger fish, benefiting from a steady food source while the larger fish benefit from reduced parasite loads.

• Small group activity (10 min)
  • Test yourself – page 66, questions 1-3 (Coursebook)
  • Students work with a partner
  • Students share answers with the class

• Lecture/Notes (PPT – slides 6 – 9)
  • The concept of feeding relationships is well-known and does not require extensive time to cover the basics.
  • Review the terms:
    • Primary Consumers: Herbivores that eat producers (plants or algae).
    • Secondary Consumers: Carnivores that eat primary consumers.
    • Tertiary Consumers: Carnivores that eat secondary consumers.
    • Quaternary Consumers: Top predators that eat tertiary consumers.
    • Herbivores: Animals that eat plants or algae.
    • Carnivores: Animals that eat other animals.
    • Omnivores: Animals that eat both plants and animals
    • Predators: Organisms that hunt and consume other organisms.
    • Prey: Organisms that are hunted and consumed by predators.
    • Food Chain: A linear sequence of organisms where each is eaten by the next one in the chain.
    • Food Web: A complex network of interconnected food chains.
    • Trophic Levels: The hierarchical levels in an ecosystem, based on the organism’s source of energy.

• Small group activity
  • Objective: To build and analyze food webs based on marine organisms from different ecosystems, emphasizing species interactions and trophic levels.
  • Divide students into small groups (2-3 students)
  • Provide each group with multiple lists of organisms
  • Students use devices with internet connection to research the organisms (my students can use their personal phones).
  • Instruct students to choose two ecosystems from the list provided and construct a food web for each ecosystem by drawing and connecting organisms based on their feeding relationships.
  • Encourage students to include at least three trophic levels (e.g., producers, primary consumers, secondary consumers) and label each organism accordingly.
  • Emphasize the interconnectedness of species and the direction of energy flow in their diagrams.
  • After completing their food webs, ask each group to present their diagrams to the class.
  • Facilitate a discussion on the similarities and differences between the food webs of different ecosystems. (use the analysis questions)

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By incorporating these strategies into your teaching, you can help your AICE Marine Science students gain a thorough understanding of feeding relationships and ecological interactions. This comprehensive approach will enhance their knowledge and improve their performance on exams, leading to higher passing rates. Using real-world examples, interactive activities, and clear explanations will make these complex topics more accessible and engaging for your students.

Homework

• The sole homework task assigned to my students revolves around meticulously transcribing notes in the Student Guided Notes format. They meticulously replicate content by hand from the Lecture/Notes (PPT – slides 10 – 17 ) presentation.
• This approach ensures that during class time, while I continue to deliver lectures and expound on topics, students have their notes already compiled. Consequently, they can actively engage, ask questions, and delve deeper into understanding rather than merely being preoccupied with note-taking. This strategy efficiently liberates valuable class time, allowing for engaging activities and practice Cambridge style questions.