Dichotomous Keys
What is the purpose of a dichotomous key?
To identify organisms based on their characteristics.
What is the broadest group in the Linnaean system?
Kingdom
What do we call all the living and non-living parts of an environment?
An ecosystem.
What do arrows in a food chain represent?
The flow of energy.
Which group has the most energy: producers, herbivores, or carnivores?
Producers.
How many choices are given at each step in a dichotomous key?
Two
What is the correct order of classification: Kingdom, ____, Class?
Phylum
Which is a biotic factor: sunlight, grass, or rocks?
Grass
What is the name for organisms that eat producers in a food chain?
Primary consumers.
What percent of energy is usually passed to the next level?
10%.
What does a dichotomous key mainly use: behaviours or physical features?
Physical features.
In Panthera leo, what does Panthera represent?
The genus.
What would happen if all the plants died in an ecosystem? (Pick one) A) Nothing, B) All animals would thrive, C) Many animals would die
C) Many animals would die.
In a food chain, what type of organism always comes first?
Producer
If plants have 1,000 kJ of energy, how much would herbivores get?
100 kJ.
Which characteristic would be most useful in a dichotomous key: number of legs or how fast an animal moves?
Number of legs.
True or false: All organisms in the same species can reproduce and have fertile offspring.
True
Which organism breaks down dead things?
Decomposer.
Which is more realistic in nature: a food chain or a food web?
A food web.
If plants have 20,000 kJ of energy, how much would tertiary consumers receive?
20 kJ.
You are using a dichotomous key and reach a point where neither option fits. What should you do?
Go back to the previous step and check your observations.
What level of classification comes directly before genus in the Linnaean system?
Family
A large factory pollutes a river, killing many aquatic plants. What is the most likely effect on the rest of the ecosystem?
Herbivores will lose food, leading to fewer animals overall and disrupted food chains.
In the chain: Grass → Mouse → Snake → Hawk, what would happen if all the mice disappeared?
Grass would increase, snakes would decrease from lack of food, and hawks might also decrease because there are fewer snakes to eat.
Why are there usually only 3–4 levels in an energy pyramid?
Because energy decreases at each level.