Evolutionary Science And Its Implications

[Chinahand]

Nice video from the Royal Society with David Attenborough and Brian Cox discussing Charles Darwin.

[Chinahand]

Where did Turtles come from?

 

[Chinahand]

A discussion of breasts.

Sorry, Woody, it doesn't contain any breasts, it's a monologue, so it may be quicker to read it here.

[Chinahand]

Why sex exists is one of the great questions that science has been attempting to answer.  Read the Red Queen and Dr Tatiana's Sex Advice to All Creation: Definitive Guide to the Evolutionary Biology of Sex for just some of the details.

However there is another fascinating question that needs answering as well - how does nature determine whether something is male or female in the first place; and as you'd expect in an evolutionary environment there are lots of ways to do it.

In mammals (and beetles (coleoptera) if you have two different sex chromosomes XY you're male, if they are the same XX you're female, in birds (and butterflies (Lepidoptera)) it is the other way round - if the sex chromosomes are the same ZZ you're male if different ZW female.

For the rest of the web of life it can get really complicated with all sorts of evolutionary niches producing all sorts of ways of deciding if something is male or female - think crocodiles and temperature, but that is just the start of it!

If you want to get an overview of all the technical details try this paper from the Public Library of Science: Sex Determination: Why So Many Ways of Doing It?

But if not just enjoy the graphic.  Biology is really really complicated - life is sloppy, changes, makes mistakes, but if it works it works and life carries on.  The result: the wonderful world that we see.

 

[Chinahand]

Nice video on the Evo-Devo of whales and dolphins:

 

[Chinahand]

Great World Service science program on the earliest animal life back in the Ediacaran many millions of years prior to the Cambrian Explosion.

[Chinahand]

I love fossils.  You head to a beach or cliff or rock field and wander around often with a hammer and try cracking open the odd rock which takes your fancy, and if you are very very luck something really special appears giving you a window on life many millions of years ago.

Back in 2012, two people  (interestingly with the same surname - Berndt - one from Dortmund and one from Berlin (a parent and child? a separated couple? a coincidence?)) were exploring an area about midway between Munich and Nuremberg and found a quite wonderful fossil:

It's a squid and it has been dated to somewhere between 149 to 152 million years old.

It is one unique squid.  You might call it lucky, you might call it unlucky, because some time before it died it was very nearly lunch for a pterosaur, but managed to avoid been eaten!

 

How do we know this?  Because a pterosaur tooth is embedded in its mantle. 

The squid was able to escape the reptile's jaws, pulling out a tooth in the struggle and get away.

Whether it died soon afterwards, or lived long with the tooth embedded isn't clear, but when it died it sank to the bottom of the sea and was buried to be uncovered millions upon millions of years later.

A tiny insight into pterosaur behaviour!  Read all the details here.  Open source science for the win.

[Chinahand]

Great video from a hugely knowledgable garrulous yank going 20 to the dozen through the mammal radiations that followed the end of the dinosaurs.

 

[Chinahand]

Tiny tiny fossil bird from a 100 million years ago trapped in some tree sap and now preserved in amber:

 

[Chinahand]

Fantastic lecture by Professor Peter Holland FRS on the diversity (and evolution) of animals.

https://www.merton.ox.ac.uk/event/diversity-animals-darwin-dna

[quilp]

That's a huge project, sequencing the genomes of every living species in the UK. The knowledge gained would be phenomenal. Imagine the wonderment of Darwin or Wallace were they alive to see it today. Excellent stuff... 

[Chinahand]

I really like Prof Mathew Cobb, he's an expert on the olfactory system of maggots, but also a huge polymath authoring multiple books.

Here he's giving a talk on human evolution.  It's an amazing story.

 

 

[Chinahand]

Really great enthusiastic talk on Homo Naledi.

 

[Chinahand]

Two videos on the complexities chromosomes bring to bodies and our classifications of them:

 

The second link is in some ways a bit of a hard watch - it goes into details on foetal abnormalities. PZ Myers is very aware of the complexities of these issues, but even I found at time the language he uses over-medicalised people struggling with terrible conditions.

He also challenged my understanding of the word viable.  At one point he says people with Down's Syndrome are the only viable trisomal condition, but he then discusses Edward's and Patau syndromes, both conditions where new borns suffer cruelly.  For me non-viability means development ceases in the womb, not months or even years later (and in fact people with both Edward's and Patau syndromes have lived multiple years).

[Chinahand]

On 11/27/2017 at 8:04 PM, Chinahand said:

Great lecture looking at how sequencing DNA from ancient bones has improved and improved and hence given us deep insights into our ancestry with Neanderthals and Denisovians.

 

Really cool - Prof Paabo has been awarded the Nobel Prize for this work.

https://www.bbc.co.uk/news/health-63116304

Understanding our convoluted origins via our DNA - and the fragments of it surviving in ancient bones and sediments - is one of the most incredible achievements of science.