Exercises: Identification of species

Explain what a dichotomous key is and what it is used for, indicating how the questions making it up should be phrased for it to work properly. Also name two other tools that help identify living things in the field, such as a field guide or a mobile identification app, and state one advantage of each compared to a dichotomous key.

The dichotomous key in the diagram is used to identify four animals. Follow it and write down the complete path (the questions and chosen answers) leading to the lizard.

Define the concept of species and give an example of two different species that look very similar.

Using the following dichotomous key:

1. a) Has legs .................................................... 2

b) Does not have legs ................................................. Earthworm

1. a) Has wings ..................................................... Beetle

b) Does not have wings .................................................. Rat

Identify: (a) a beetle, which has legs and wings; (b) a rat; (c) a snake. What problem arises when classifying the snake? Propose an improvement to the key to resolve it.

Construct a three-question dichotomous key to distinguish between these four living things: a dog, a palm tree, a button mushroom, and a trout. Check that it works by following it with two of them.

The scientific name of the Aleppo pine is Pinus halepensis. Explain what each of the two words indicates, who devised this system of nomenclature, and what advantages using scientific names in Latin has over common names.

In the school playground you have found five different animals: a snail, a bee, a spider, a sparrow, and a mouse. Create a complete dichotomous key to identify all five and check that it works by following it with two of them.

Two frog populations of different colors live in ponds separated by a road and never interbreed in nature. Explain the difficulty in deciding whether they belong to the same species and what test could help resolve the doubt.

A research team wants to study the feeding habits of birds around the school and proposes two methods:

• Method A: Capture individuals with mist nets, lock them in individual cages in the laboratory to weigh them, and record how many seeds they consume under continuous artificial light.

• Method B: Install feeders in the trees of the courtyard, place an automatic camera trap, and observe them with binoculars from the windows at 15 meters without interfering.

1. a) Taking into account that birds are sentient beings (capable of experiencing pain, fear, and stress), justify which of the two methods is ethically appropriate.
2. b) Predict what physiological and behavioral consequences the stress of Method A would have on the birds and how it could alter or bias the scientific data obtained about their natural feeding.
3. c) If in the laboratory you need to study the response of earthworms to humidity, design two specific measures in your experimental setup to ensure their welfare and avoid causing them dehydration or harm.