Dichotomous Keys worksheet - Free Printable

Problem Overview:

The task involves using a dichotomous key to identify the organisms depicted in the images. A dichotomous key is a tool used for identifying unknown organisms by making a series of choices between two options at each step.

Step-by-Step Solution:

#### 1. Identify the Organisms Using the Dichotomous Key:

We will analyze each image and use the dichotomous key to determine which organism it represents.

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#### Image 1 (Dog):
- Step 1: The organism has 2 or 4 legs. → Go to Step 2.
- Step 2: The organism has no wings. → Dog.

Answer for Image 1 (Dog): Dog

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#### Image 2 (Plant with Flowers):
- Step 1: The organism does not have 2 or 4 legs. → Go to Step 3.
- Step 3: The organism is multicellular. → Go to Step 5.
- Step 5: The organism is autotrophic (photosynthetic). → Go to Step 7.
- Step 7: The organism is short and non-woody. → Dandelion.

Answer for Image 2 (Plant with Flowers): Dandelion

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#### Image 3 (Bird):
- Step 1: The organism has 2 or 4 legs. → Go to Step 2.
- Step 2: The organism has wings. → House sparrow.

Answer for Image 3 (Bird): House sparrow

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#### Image 4 (Fish):
- Step 1: The organism does not have 2 or 4 legs. → Go to Step 3.
- Step 3: The organism is unicellular. → Go to Step 4.
- Step 4: The organism freely swims in water. → Balantidium.

Answer for Image 4 (Fish): Balantidium

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#### Image 5 (Tree):
- Step 1: The organism does not have 2 or 4 legs. → Go to Step 3.
- Step 3: The organism is multicellular. → Go to Step 5.
- Step 5: The organism is autotrophic (photosynthetic). → Go to Step 7.
- Step 7: The organism is tall and woody. → Ponderosa pine.

Answer for Image 5 (Tree): Ponderosa pine

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#### Image 6 (Single-Celled Organism):
- Step 1: The organism does not have 2 or 4 legs. → Go to Step 3.
- Step 3: The organism is unicellular. → Go to Step 4.
- Step 4: The organism is anchored to a substrate. → Stentor.

Answer for Image 6 (Single-Celled Organism): Stentor

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#### Image 7 (Snake):
- Step 1: The organism has 2 or 4 legs. → Go to Step 2.
- Step 2: The organism has no wings. → Go to Step 5.
- Step 5: The organism is heterotrophic (eats other organisms). → Go to Step 6.
- Step 6: The organism lives on land. → King cobra.

Answer for Image 7 (Snake): King cobra

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#### Image 8 (Fungus/Mushroom):
- Step 1: The organism does not have 2 or 4 legs. → Go to Step 3.
- Step 3: The organism is multicellular. → Go to Step 5.
- Step 5: The organism is autotrophic (photosynthetic). → Go to Step 7.
- Step 7: The organism is short and non-woody. → Dandelion.

However, this organism is not a plant but a fungus. The key does not explicitly account for fungi, so we must infer based on the structure. Since it is not a plant, it cannot be "Dandelion." Instead, it should be classified as a fungus, such as a mushroom.

Answer for Image 8 (Fungus/Mushroom): Mushroom

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Final Answers:

1. Dog → Dog
2. Plant with flowers → Dandelion
3. Bird → House sparrow
4. Fish → Balantidium
5. Tree → Ponderosa pine
6. Single-celled organism → Stentor
7. Snake → King cobra
8. Fungus/Mushroom → Mushroom

Boxed Final Answer:

\[
\boxed{
\text{Dog, Dandelion, House sparrow, Balantidium, Ponderosa pine, Stentor, King cobra, Mushroom}
}
\]