Unit 44: Ecosystems and Environmental Science

Day 3 of 30

Biotic vs. abiotic factors

6-8Science

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Learning Objective

Students will explore biotic vs. abiotic factors through guided practice and application.

Today's Lesson

In this lesson, we'll explore biotic vs. abiotic factors. Scientific inquiry allows us to investigate and explain natural phenomena.

Ecology studies interactions among organisms and between organisms and their environment. Biotic factors are living components (plants, animals, fungi, bacteria); abiotic factors are non-living (sunlight, temperature, water, soil). Populations grow exponentially when resources are unlimited but logistically (S-curve) as they approach carrying capacity. Limiting factors (food, space, predators, disease) prevent unlimited growth. Predator-prey relationships oscillate: more prey → more predators → fewer prey → fewer predators → prey recovers. Community interactions: competition (both harmed), predation (one benefits, one harmed), mutualism (both benefit—bees and flowers), commensalism (one benefits, other unaffected), parasitism (one benefits, one harmed). Biogeochemical cycles move elements through ecosystems: carbon cycle (photosynthesis, respiration, decomposition, combustion), nitrogen cycle (fixation by bacteria converts N₂ to usable form). Each organism occupies a niche—its functional role in the ecosystem.

As you work through today's material, pay attention to the examples and try to identify the patterns or strategies being used. This will help you apply these concepts to new problems.

Take notes on key points and make connections to what you've already learned in previous lessons.

Key Terms
Investigate

To examine systematically through observation and experiment

Evidence

Observable facts that support or refute a claim

Activities
Instructions
1. Read the background information on biotic vs. abiotic factors. 2. Form a hypothesis before beginning. 3. Conduct the investigation following procedures. 4. Record observations and analyze results.
Materials Needed
  • Lab notebook
  • Investigation materials
  • Safety equipment if needed
Practice Problems
1

Based on today's lesson, what is one thing you observed or learned?

Hint: Think about the main topic.
2

How could you test or investigate this topic further?

Hint: What experiment could you do?
3

Why is this topic important in the real world?

Hint: Think about everyday applications.

Teaching Tip

For advanced learners: Encourage deeper analysis and real-world connections. Consider extension activities that allow students to apply biotic vs. abiotic factors to novel situations.

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