1. Octopus Evolution 7-7-2018 10 am CST Scientistmel.com
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2. Octopus Evolution What are they? What are their ancestors?
How do they evolve?
What evolutionary traits are unique to them?
What evidence do we have on their intelligence?

3. Octopus Evolution 289 species of octopus - octopoda
Cephalopoda = head feet
Mollusks who lost their shells
Brain/body ratio similar to other intelligent animals

4. Octopus Evolution Complex nervous system
Same amount of neurons as dogs
2/3 of neurons are in its arms
3 hearts
Extremely intelligent

5. Octopus Evolution Range in size (2.5 cm – 5 meters)
Range in weight (1 gram – 50 kg)
Carnivores
Sex is a death sentence
Blue blood

6. Octopus Evolution 500 million yrs ago – first cephalopod
Cambrian rock layers
17,000 named species of fossil cephalopods
Extremely diverse extinct taxa
3 distinct fossil clades

7. Octopus Evolution
This information comes to us from the university of California museum of paleontology. Scientists are not certain where to place these three distinct clades
Endoceratoidea, Actinoceratoidea, and Bactritoidea (cladogram A pictured here) on the family tree. There are so much diversity in the fossils of these cephalopods that scientists are still working out which species are most related in placing them on the tree. These 2 clades were squid-like, but had straight external shells called orthocones. They are found primarily in Paleozoic oceans between  Ordovician (488 mya) and Triassic periods (200 mya). For some species, their shells reached a length of nearly 10 meters (32 feet).

8. Octopus Evolution Nautiloids are earliest cephalopods
Appear in late Cambrian
Started with straight shells
Coiled shells in Ordovician
Similar to ammonoids in Devonian
Nautiloids and ammonoids may look the same, you can differentiate them by finding the siphuncle and analyze the shapes of their sutures.

9. Octopus Evolution Siphuncle – internal tube connecting chambers
Runs through the center in nautiloids
Along the exterior in ammonoids
The pic shows the siphuncle in ammonoids. The other two pics are nautiloids showing their typical simple sutures.

10. Octopus Evolution Belemnites – earliest cephalopod ancestor
The fossil record for the earliest cephalopods is mostly poor due to the small sizes of the ancestors and the lack of calcification. There is little calcification due to tlack of shells. Belmemnites are the exception in this case. They are considered the earliest cephalopods in the clade Coloidea ( octopus, squid, cuttlefish). Belemnites had internal shells made of 3 parts we see in this pic from the university of California. The largest amount of these species can be found in the Mesozoic marine sediments.
Belemnites – earliest cephalopod ancestor
Exception to

11. Octopus Evolution
Three main clades within the Cephalopoda cladogram B : the Ammonoidea (an extinct and shelled clade), Nautiloidea (with only one living shelled genus, Nautilus) and Coleoidea (squids, cuttlefish, octopuses, the Ram's Horn Squid, the "paper nautilus," the extinct belemnites). Ammonoids survived for 300 million years in the Paleozoic and Mesozoic periods. Most had planar (flat) coiled/spiral external shells. Throughout their evolutionary history, ammonoids shared the seas with the nautiloids. By the end of the Cretaceous Period, the ammonoids were wiped out and left the nautiloid clade, the genus Nautilus. The last of the shelled cephalopods are a few species of Nautilus living today.

12. Octopus Evolution
How exactly does the octopus evolve? The best we have is looking at the modern octopus, comparing to the fossil record, looking at other species that are similar, how those particular species are represented in the fossil record, and see what lines up! Evolution is based on natural selection. Triggers in the environment can shift genetic expression. Octopuses, octopodes, octopi…whatever plural you prefer have inherently unusual evolutionary characteristics that we do not see so readily in other animals. Something that we are learning that is incredible is the ability of the octopus to alter it’s RNA. Usually in the evidence of evolution, DNA is altered…and thus the genetic expression changes. Here’s the thing, the octopus doesn’t necessarily have it’s DNA changed, it can edit the RNA. Why is this important?

13. Octopus Evolution RNA drives protein expression
Altering RNA alters proteins
Octopus can edit RNA

14. Octopus Evolution
Most organisms who have altered RNA tend to not do so well. Yet the octopus can alter the RNA without changing their base DNA. They haven’t changed so much in regard to their base genetic code (DNA)…but the ability to alter their proteins through RNA has shown to be inherently valuable especially when faced with rising sea temperatures and human interference.

15. Octopus Evolution Veined octopus uses tools
Octopus digs out the coconut shells, empty the shells with jets of water, stakc them hollow side up, and carry them to build their shelter.
Veined octopus uses tools
Humans supply coconut shells
Octopus uses them to build shelter

16. Octopus Evolution
The octopus not only is an expert escape artist, but it can also take photographs of people. Scientists think the RNA editing capabilities of the octopus has caused it to retain much of its DNA without an increase of mutations…and there is some link to this ability of RNA editing and the intelligence of the octopus…let’s have a look at the video of the octopus in the New Zealand zoo photographing people…

17. Octopus
Sources!
Images via Google Search

18. Octopus Evolution What are they? What are their ancestors?
How do they evolve?
What evolutionary traits are unique to them?
What evidence do we have on their intelligence?

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21. Octopus Evolution 7-7-2018 10 am CST Scientistmel.com
Twitter.com/scientistmel
Patreon.com/scientistmel
am CST