Consider the following animals:
Earthworm
Flatworm.
Frog.
Jellyfish.
Lamprey.
Tuna.
Create a table of fundamental traits for these six animals as a basis for building a cladogram. Use traits that are either present or absent in a given organism. Use the jellyfish as an outgroup and construct a cladogram that accurately depicts the branching of the evolutionary lines of descent of these animals.
Where do I even start creating a cladogram? I know what it is, but my book nor anyone can explain where I start.
Creating a cladogram involves analyzing the shared and derived traits among different organisms to determine their evolutionary relationships. Here's a step-by-step guide to help you get started in constructing a cladogram:
1. List the organisms: First, list the six organisms you want to include in the cladogram: earthworm, flatworm, frog, jellyfish, lamprey, and tuna.
2. Identify shared and derived traits: Look for traits that are either present or absent in each organism. A shared trait is one that is found in two or more organisms, while a derived trait is a trait that is unique to one organism or a group of closely related organisms.
For example, some traits that you can consider for the animals mentioned are:
- Presence or absence of a backbone (vertebrae)
- Type of reproduction (sexual or asexual)
- Type of body symmetry (bilateral or radial)
- Presence or absence of fins or limbs
- Method of respiration (gills or lungs)
- Type of body covering (scales, fur, or none)
3. Determine the outgroup: The outgroup is a species that is not closely related to the other organisms in your table but helps identify ancestral traits. In this case, the jellyfish can serve as the outgroup because it is the most distantly related organism among the six.
4. Build the cladogram: Start by placing the jellyfish at the base of the cladogram since it is the outgroup. Then, consider the presence or absence of traits among the remaining organisms and establish the order of branching for each trait.
For example, if the presence of a backbone is a shared trait among earthworm, frog, lamprey, and tuna, but absent in flatworm and jellyfish, you would place these four organisms in one branch, indicating a common ancestor with a backbone.
Continue this process for each trait, branching out accordingly. Consider both shared and derived traits, making sure to group organisms based on their most closely related features.
5. Fine-tune the cladogram: Once you have finished placing organisms based on their shared and derived traits, review the cladogram to ensure it accurately represents the evolutionary relationships and maintains consistency with the data you gathered.
Remember, constructing a cladogram is an analytical process, and the final cladogram may vary depending on the specific traits you choose and your interpretation.