Quick Lab
GUIDED INQUIRY
How Do Different Types of Consumers Interact? 
Place a potted bean seedling in each of two jars.
Add 20 aphids to one jar and cover the jar with screening to prevent the aphids from escaping. Use a rubber band to attach the screening to the jar.
Add 20 aphids and 4 ladybird beetles to the second jar. Cover the second jar as you did the first one.
Place both jars in a sunny location. Observe the jars each day for one week and record your observations each day. Water the seedlings as needed.
Observe What happened to the aphids and the seedling in the jar without the ladybird beetles? What happened in the jar with the ladybird beetles? How can you explain this difference?
Classify Identify each organism in the jars as a producer or a consumer. If the organism is a consumer, what kind of consumer is it?
Analyze and Conclude
MYSTERY CLUE
Bacteria are important members of the living community in Narragansett Bay. How do you think the bacterial communities on the floor of the bay might be linked to its producers and consumers?
Beyond Consumer Categories Categorizing consumers is important, but these simple categories often don't express the real complexity of nature. Take herbivores, for instance. Seeds and fruits are usually rich in energy and nutrients, and they are often easy to digest. Leaves are generally poor in nutrients and are usually very difficult to digest. For that reason, herbivores that eat different plant parts often differ greatly in the ways they obtain and digest their food. In fact, only a handful of birds eat leaves, because the kind of digestive system needed to handle leaves efficiently is heavy and difficult to fly around with!
Moreover, organisms in nature often do not stay inside the tidy categories ecologists place them in. For example, some animals often described as carnivores, such as hyenas, will scavenge if they get a chance. Many aquatic animals eat a mixture of algae, bits of animal carcasses, and detritus particles—including the feces of other animals! So, these categories make a nice place to start talking about ecosystems, but it is important to expand on this topic by discussing the way that energy and nutrients move through ecosystems.
3.2 Assessment
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Review What are the two primary sources of energy that power living systems?
Pose Questions Propose a question that a scientist might ask about the variety of organisms found around deep-sea vents.
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Review Explain how consumers obtain energy.
Compare and Contrast How are detritivores different from decomposers? Provide an example of each.
BUILD VOCABULARY
The word autotroph comes from the Greek words autos, meaning “self,” and trophe, meaning “food or nourishment.” Knowing this, what do you think the Greek word heteros, as in heterotroph, means?
Table of Contents
- Formulas and Equations
- Applying Formulas and Equations
- Mean, Median, and Mode
- Estimation
- Using Measurements in Calculations
- Effects of Measurement Errors
- Accuracy
- Precision
- Comparing Accuracy and Precision
- Significant Figures
- Calculating With Significant Figures
- Scientific Notation
- Calculating With Scientific Notation
- Dimensional Analysis
- Applying Dimensional Analysis