QQuestionBiology
QuestionBiology
1. How many pairs of appendages does a human have?
2. 1001
3. Crayfish?
4. Grasshopper?
5. Bird?
6. Frog?
7. Sea anemone?
# EXERCISE II: IDENTIFICATION OF ANIMALS USING A KEY
A dichotomous key is a tool to help you identify the animal you are looking at. In order to use the key, always start at step 1. Each step will give you two options 1A or 1B and you will choose the option that best describes the animal. Follow the directions from there to the next step and choose the best option for your specimen until you end with a choice that names the phylum of your animal.
Using the key provided, identify the 9 animals we have been studying. List the phylum for each in the latest provided below. If you key an organism to either the phylum Arthropoda or Chordata, proceed to the appropriate key to classes and determine the class for the specimen.
1. Sea Star:
2. Clam:
3. Frog:
4. Crayfish:
5. Ascans:
6. Grasshopper:
7. Sea anemone:
8. Fish:
9. Earthworm:
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Answer
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Step 1:I'll solve this problem in 3 parts:
Part 1: Identifying the number of appendage pairs in humans and various animals. Part 2: Creating a simplified dichotomous key for the given animals. Part 3: Using the key to identify the phylum of each animal. **Part 1: Appendage pairs in humans and animals**
Step 2:
Humans have 2 pairs of appendages: 2 arms and 2 legs.
Step 3:
Crayfish have 5 pairs of appendages: 2 pereiopods (walking legs), 3 pereiopods with claws (pincers), and 1 pair of antennae.
Step 4:
Grasshoppers have 6 pairs of appendages: 3 pairs of legs, 1 pair of antennae, and 2 pairs of wings.
Step 5:
Birds typically have 2 pairs of appendages: 2 wings and 2 legs, but some birds, like the ostrich, don't have wings capable of flight.
Step 6:
Frog appendages include 4 pairs: 4 legs (2 hind legs and 2 front legs or arms).
Step 7:
Sea anemones do not have appendages. **Part 2: Simplified dichotomous key** (Note: This key is a simplified version of the actual key provided in the question.)
Step 8::
A) Has a hard exoskeleton? - If yes, proceed to Step 2A. - If no, proceed to Step 2B.
Step 9:A:
A) Has jointed appendages? - If yes, the animal belongs to the Phylum Arthropoda. Proceed to the Arthropoda key. - If no, the animal does not belong to the Phylum Arthropoda.
Step 10:B:
A) Has a notochord (a flexible rod) at some point in life? - If yes, the animal belongs to the Phylum Chordata. Proceed to the Chordata key. - If no, the animal does not belong to the Phylum Chordata. **Part 3: Identifying the phylum of each animal**
Step 11:
Sea Star: Belongs to Phylum Echinodermata.
Step 12:
Clam: Belongs to Phylum Mollusca.
Step 13:
Frog: Belongs to Phylum Chordata. Class: Amphibia.
Step 14:
Crayfish: Belongs to Phylum Arthropoda. Class: Malacostraca.
Step 15:
Ascidians (Sea squirts): Belongs to Phylum Chordata. Class: Ascidiacea.
Step 16:
Grasshopper: Belongs to Phylum Arthropoda. Class: Insecta.
Step 17:
Sea anemone: Belongs to Phylum Cnidaria.
Step 18:
Fish: Belongs to Phylum Chordata. Class: Actinopterygii (ray-finned fish) or Chondrichthyes (cartilaginous fish).
Step 19:
Earthworm: Belongs to Phylum Annelida. **
Final Answer
1. Sea Star: Phylum Echinodermata 2. Clam: Phylum Mollusca 3. Frog: Phylum Chordata, Class Amphibia 4. Crayfish: Phylum Arthropoda, Class Malacostraca 5. Ascidians: Phylum Chordata, Class Ascidiacea 6. Grasshopper: Phylum Arthropoda, Class Insecta 7. Sea anemone: Phylum Cnidaria 8. Fish: Phylum Chordata, Class Actinopterygii or Chondrichthyes 9. Earthworm: Phylum Annelida
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