Evidence for Evolution - Biogeography

Sources:

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Viced Rhino
PO Box 343
Fort Erie, Ontario, Canada
L2A 5N1

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[godlessrecovery]

HAHAHA. That single frame of Mitch in the Galapagos bit was just... Perfect.

[marcocappelli]

Bigeography is my favourite piece of evidence for evolution, along with ERVs, because they are so easy to understand.
For throwing it at creationists, of course.

[notgoldrat]

We here before Viced adds the - dash in the title

[Halomusik]

This reminded me of a documentary I watched about some animals separated by the wall the communists built in eastern Europe. Once the wall came down and the animals were able to mingle they had profoundly changed. So diversity can occur in a relatively short period of time. Sorry I can't recall the title. I really am enjoying this series. I may rewatch them again as some of the science goes over my head. My science and math classes were limited back in the sixties, mainly due to our huge class sizes and girls weren't encouraged to take such classes including language and limited history. The opportunities for young women today are so much greater. Did you know only males speak German? Yep so I had a class in French. By the way I get compliments on the tee shirt, can't wait for the baby rhino one.

[highlyvurgultis]

Why does everyone always talk about extinct animals when referring to island dwarfism? There are dwarf Red Deer in the Mediterranean and dwarf water buffaloes in the Philippines & Indonesia for frick's sake!

[Sparkbomber]

Great episode~! Its amazing how our understanding of the world continues to branch out, and what the implications of this field of study are.

[richardblazer]

In 1933 a film crew discovered a large species of ape on an island near Indonesia, very cool example of island gigantism.

[joseph-thewatcher]

I'm going to be watching the next episode of Cosmos tonight. I love these series.

[John.z]

I can almost hear Ken Ham having a coronary listening to this!

[MrGrumblier]

Who else had to google "cecal valve" before the opening?

[OmegaWolf]

Camels in Africa and Asia, camelids in S. and Central America.

[michaelsommers]

It is about 35 years old, but it is basic enough that it hasn't been outdated. The nice thing about it is that it has a bunch of computer project aimed at simulating various aspects of the subject.

[gaellafond]

7:00 This is an opossum (family of Didelphidae). Possums are from a different family (Phalangeridae) and are endemic to Australia. They are now found in New Zealand because we messed up once again (introduction by human). Opossums are very often refered to as "Possums" because people things one is short for the other, but it is about as wrong as calling a spider an insect.

[theosib]

I’d heard that one of the innovations necessary for a placenta came from an ERV.

[Rocco_Kurokawa]

Nice system of showing the source you base the arguments on live in the video 👍

[PurpleRhymesWithOrange]

Quite interesting. I was not aware of examples of such rapid evolutions as you talked about in the lizards.

[MarkC]

In reference to the cecal valves, I recall reading up on this some time ago. I'd be curious to know your answer to the "go to" creationist complaint with this example. As far as I can see it seems like a fairly reasonable complaint too.

I'll try to summarise it as briefly as I can.

A dietary shift has been demonstrated to cause a loss of the cecal valves in the adult lizards (a kind of phenotypic plasticity at work, I think). As the lizards from the original population are already exposed to this kind of diet then any who had the potential for expressing this phenotype would not be obvious.

I don't think any exhaustive testing has been carried out to rule out the possibility that a small percentage of the original population carried genes to express cecal valves the same as this new population does (mainly because it would probably require extensive sampling, breeding and then autopsies and that's a bit intensive and cruel).

So the proposal from a creationist point of view would be that this cecal valve was "created" as part of the original populations genotype and we just notice it when the diet was changed. Therefore nothing "new" needs to have arisen or evolved.

I'm not sure if there is any good data out there that could reasonably rule this out (within the confines of this particular example). I guess you can explain that this kind of phenotypic plasticity can still be selected on and cause genetic changes like that black caterpillar example I saw from PZ Meyers YouTube channel. But I don't think you will convince creationists it happened in this particular case without specific proof of that occurring to these lizards.

The other morphological changes like the head shape etc aren't really addressed but from what I recall there is enough ambiguity over the genetics to allow for the plausible explanation that no new mutations needed to occur for these cecal valves to suddenly appear. I can dig up references if you need me to but I imagine you are probably better read up on this that I am.

I think maybe epigenetic inheritance was used to explain the traits being passed on to new generations.

Anyway in summary I think the example of cecal valves does show a change in the population but mutations weren't necessarily required to explain it. In that case it fits the narrative of "fixed kinds" because presumably this phenotypic plasticity does have a kind of boundary if you pretend mutations never really happen. So without any further explanation I think this example will be easily dismissed and in some cases even used as evidence against evolution.

Side note, you might want to address the mistaken assumption about the lizards being "genetically indistinguishable" from the original population. It's a silly mistake but it's used deceptively to imply a confirmation that the two populations have not undergone any genetic changes at all. It doesn't even make sense as it implies all the lizards are clones!? Clearly not what the author was saying (they were indistinguishable as a species, thats all), but it is commonly repeatedly lie from creationist sources that might be worth preempting.

[Vandalia]

Just wondering if you are going to include ERV in your series as well?

[megagrey]

Oh, I've hit creationists with the lizard/cecal valve example before. Their response? Invariably, Hovind-ish whining that they're still lizards.

[AndrayTheDutchman]

The ability to evolve under environmental pressure looks like a good design feature.