- #1
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What did the spider evolve from? Just curious.
-Dan
-Dan
Spider's ancestors-Just curious
- Thread starter topsquark
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Discussion Overview
The discussion revolves around the evolutionary origins of spiders, exploring their classification within the Arthropoda phylum and their ancestral lineage. Participants touch upon the broader context of arthropod evolution and the characteristics that define spiders and their relatives.
Discussion Character
- Exploratory
- Technical explanation
- Conceptual clarification
Main Points Raised
- One participant notes that spiders belong to the group Chelicerata within the phylum Arthropoda, highlighting their exoskeleton and fused body parts.
- Another participant mentions that all arthropods evolved from early Cambrian species, with Chelicerates being distinct from other arthropods.
- A claim is made that sea spiders are primitive and may be directly descended from the ancestors of modern terrestrial spiders.
- One participant shares links to external resources regarding spider evolution, expressing uncertainty about the reliability of the information.
- The same participant humorously mentions their phobia of spiders, indicating a personal interest in understanding them better.
Areas of Agreement / Disagreement
Participants present various points regarding spider evolution, but there is no consensus on specific details or interpretations of the evolutionary lineage. The discussion remains open-ended with differing perspectives on the reliability of external sources.
Contextual Notes
Some claims depend on the definitions of evolutionary terms and classifications, and there are unresolved questions regarding the specifics of spider ancestry and the reliability of the referenced resources.
- #2
jim mcnamara
Mentor
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Spiders are Arthropods - meaning mostly that they they have an exoskeleton. Chelicerata is the group they are in. Their main cousins are horseshoe crabs, scorpions, trilobites.
All of the Arthropoda evolved from early Cambrian species. Chelicerates have their body parts (head, thorax, abdomen all fused), other arthropods don't. Trilobites dominated the the late Cambrian seas, along with sea scorpions.
Sea spiders (pycnogonids) are very primitive (meaning unchanged from a beginning ancestor ~500 million YA) and are probably descended directly from the ancestors of all modern terrestrial spiders.
All of the Arthropoda evolved from early Cambrian species. Chelicerates have their body parts (head, thorax, abdomen all fused), other arthropods don't. Trilobites dominated the the late Cambrian seas, along with sea scorpions.
Sea spiders (pycnogonids) are very primitive (meaning unchanged from a beginning ancestor ~500 million YA) and are probably descended directly from the ancestors of all modern terrestrial spiders.
- #3
Phobos
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Science Advisor
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I'm going to stick my neck out here (spider bite!) and offer a couple promising-looking sites I came across from a quick Google search. I haven't read it thoroughly, and I'm no spider expert, so I don't know how reliable they are...
http://www.earthlife.net/chelicerata/web-evolve.html
http://www.arachnology.be/pages/Paleontology.html
http://www.earthlife.net/chelicerata/web-evolve.html
http://www.arachnology.be/pages/Paleontology.html
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- #4
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Phobos said:
Thanks all! For the record, I'm phobic and I like to know my enemy...
-Dan
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