Question

final exam review packet (study guide) 2026

1. identify the following from the food web shown. producer(s), primary consumer(s), secondary consumer(s), herbivore(s), carnivore(s), omnivore(s).

producers:
primary consumers:
secondary consumers:
herbivores:
carnivores:
omnivores:

1. what is an energy pyramid?

final exam review packet (study guide) 2026

1. explain the 10% rule.

1. what are the three types of symbiosis? describe and give an example of each.

1. explain the process of ecological succession and compare and contrast primary and secondary succession.

unit 9: evolution review choose the best answer.

1. the theory of natural selection was a hypothesis first proposed by:

a. gregor mendel
b. francis crick
c. charles darwin
d. robert hooke

1. the ability of an organism to survive and reproduce is known as

a. fitness
b. evolution
c. diversity
d. adaptation

1. fitness arises through a process called

a. common descent
c. half-life
b. homologous change
d. adaptation

1. which statement best describes evolution?

a. evolution is a predictable change from simple to complex organisms.
b. evolution is a process of change through time.

Explanation:

🆕 New Concept Discovered: Trophic Levels and Food Web Dynamics
*How energy flows and organisms interact in an ecosystem*

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Step 1: Analyze the Food Web (Question 3)

To classify each organism, we trace the arrows in the food web. Remember: arrows point in the direction of energy flow (from the organism being eaten to the organism that eats it).

* **Grass**: Has arrows pointing away from it to Cow, Mouse, and Cricket. It makes its own food.
* *Classification*: Producer.
* **Cow**: Eats Grass.
* *Classification*: Primary Consumer, Herbivore.
* **Cricket**: Eats Grass.
* *Classification*: Primary Consumer, Herbivore.
* **Mouse**: Eats Grass and Cricket.
* *Classification*: Because it eats both a producer (Grass) and a consumer (Cricket), it is both a Primary and Secondary Consumer, making it an Omnivore.
* **Bird**: Eats Cricket.
* *Classification*: Secondary Consumer, Carnivore.
* **Snake**: Eats Mouse.
* *Classification*: Secondary/Tertiary Consumer, Carnivore.
* **Kookaburra**: Eats Snake.
* *Classification*: Tertiary/Quaternary Consumer, Carnivore.

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Step 2: Define an Energy Pyramid (Question 4)

An energy pyramid is a graphical representation designed to show the biomass or bio-productivity at each trophic level in a given ecosystem. It shows how energy is lost as it flows upwards through the trophic levels.

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Step 3: Explain the 10% Rule (Question 5)

The 10% Rule states that when energy is passed in an ecosystem from one trophic level to the next, only about \(10\%\) of the energy is stored as biomass to be passed on to the next level. The other \(90\%\) of the energy is lost as heat during metabolic processes (like respiration) or excreted as waste.

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Step 4: Describe the Three Types of Symbiosis (Question 6)

Symbiosis describes close, long-term interactions between different biological species:

1. **Mutualism**: Both species benefit from the interaction.
* *Example*: Bees and flowers (bees get nectar, flowers get pollinated).
2. **Commensalism**: One species benefits, while the other is neither helped nor harmed.
* *Example*: Barnacles on a whale (barnacles get a ride to nutrient-rich waters; the whale is unaffected).
3. **Parasitism**: One species benefits (the parasite) at the expense of the other (the host).
* *Example*: A tick feeding on a dog.

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Step 5: Explain Ecological Succession (Question 7)

Ecological succession is the gradual process by which ecosystems change and develop over time.

* **Primary Succession**: Occurs in essentially lifeless areas—regions in which the soil is incapable of sustaining life (e.g., after a volcanic eruption or retreating glacier). It begins with pioneer species like lichens or mosses that break down rock into soil.
* **Secondary Succession**: Occurs in areas where an existing community has been cleared by a disturbance (e.g., a forest fire or abandoned farm), but the soil remains intact. It occurs much faster than primary succession because soil is already present.

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Step 6: Solve the Evolution Review Multiple Choice (Unit 9)

1. **The theory of natural selection was a hypothesis first proposed by:**
* *Answer*: **C. Charles Darwin** (He famously proposed natural selection in *On the Origin of Species*).
2. **The ability of an organism to survive and reproduce is known as:**
* *Answer*: **a. fitness** (In evolutionary biology, fitness is defined by reproductive success).
3. **Fitness arises through a process called:**
* *Answer*: **d. adaptation** (Adaptations are heritable traits that increase an organism's fitness in its environment).
4. **Which statement best describes evolution?**
* *Answer*: **B. Evolution is a process of change through time.** (Evolution is not necessarily a predictable march from simple to complex, but rather genetic change in populations over generations).

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Answer:

Question 3: Food Web Identification

• Producers: Grass
• Primary Consumers: Cow, Cricket, Mouse
• Secondary Consumers: Mouse, Bird, Snake
• Herbivores: Cow, Cricket
• Carnivores: Bird, Snake, Kookaburra
• Omnivores: Mouse

Question 4: Energy Pyramid

An energy pyramid is a diagram that shows the amount of energy available at each trophic level of an ecosystem, illustrating how energy decreases as you move up the food chain.

Question 5: The 10% Rule

The 10% rule states that only about \(10\%\) of the energy at one trophic level is transferred to the next level. The remaining \(90\%\) is lost as heat or used by the organisms for life processes.

Question 6: Three Types of Symbiosis

1. Mutualism: Both organisms benefit. (Example: Bees and flowers)
2. Commensalism: One organism benefits, the other is unaffected. (Example: Barnacles on a whale)
3. Parasitism: One organism benefits, the other is harmed. (Example: Ticks on a dog)

Question 7: Ecological Succession

• Ecological Succession is the gradual process of ecosystem recovery and change over time.
• Primary Succession starts in an environment with no soil (e.g., bare rock after a volcano).
• Secondary Succession occurs after a disturbance in an environment that already has soil (e.g., forest regrowth after a fire).

Unit 9: Evolution Review

1. C (Charles Darwin)
2. a (fitness)
3. d (adaptation)
4. B (Evolution is a process of change through time.)