Whom did cnidarians arm agains?

  • Thread starter haael
  • Start date
  • Tags
    Arm
In summary: According to this study, ctenophores are the most basal animals and are not related to sponges or cnidarians. The study also suggests that the evolution of animals may require re-evaluation.
  • #1
haael
539
35
Hey. I'm not a biologist, but I love to read about the evolutionary origins of different species. I also realized that the current knowledge on this matter is still incomplete.

Now, when reading Wikipedia about cnidarians, ctenophora and other primitive types, I started to wonder. Cnidaria and ctenophora are very similar, so they are likely related, but it is still not known which type came first.

I suddenly came up with a theory. We know that cnidaria have the poisonous cells filled with neurotoxins. They are rarely used as an offensive weapon, rather as a defense. Doesn't it mean that they evolved from an evolutionary pressure of some predators that had must have had neurons?

Defensive weapon implies existence of some predator. The target of the poison (neurons) means that the predator must have had neurons.

So, that means that cnidaria are more advanced than ctenophora and their predecessor more likely resembled ctenophora than the other way.

We could also approximate the time when it all happened. The apperance of cnidaria must have occurred shortly after the apperance of predators with neurons.

Does this chain of thought have any probability of being true?
 
Biology news on Phys.org
  • #2
Ctenophora came first according to:
The Base of the Animal Tree?

The identity of the most basal lineages of the animal kingdom evolutionary tree has long been contested. Ryan et al. (p. 10.1126/science.1242592; see the Perspective by Rokas) sequenced the genome of the ctenophore the warty comb jelly or sea walnut, Mnemiopsis leidyi, and conclude that ctenophores alone, not sponges or the clade consisting of both ctenophores and cnidarians, are the most basal extant animals. The results suggest a specific evolutionary process that likely occurred—including repeated gains and loss of mesoderm, expansion of genes associated with the cell cycle, growth signaling, apoptosis, and epithelial and neural cell types. Furthermore, previous hypotheses regarding the evolution of animals may require re-evaluation.
http://www.sciencemag.org/content/342/6164/1242592
(Editor's summary)
 

1. Whom did cnidarians arm against?

Cnidarians arm against their prey and any potential predators.

2. What type of arms do cnidarians have?

Cnidarians have specialized stinging cells called cnidocytes that they use for defense and capturing prey.

3. How do cnidarians use their arms?

Cnidarians use their arms, or tentacles, to sting and immobilize their prey, and also for defense against predators.

4. Can cnidarians arm against each other?

Yes, cnidarians can arm against each other in territorial disputes or competition for resources.

5. Are cnidarians always armed?

No, cnidarians only arm themselves when they are in danger or need to capture prey. Otherwise, their tentacles are often retracted and hidden.

Similar threads

  • Sci-Fi Writing and World Building
Replies
9
Views
2K
Replies
10
Views
2K
  • Art, Music, History, and Linguistics
Replies
1
Views
1K
  • Sci-Fi Writing and World Building
Replies
15
Views
3K
  • Electrical Engineering
Replies
2
Views
2K
  • General Discussion
3
Replies
71
Views
14K
  • General Discussion
2
Replies
42
Views
5K
  • STEM Academic Advising
Replies
6
Views
1K
  • General Discussion
Replies
27
Views
12K
  • General Discussion
3
Replies
78
Views
9K
Back
Top