Hacker News Reader

Comment by jjcon | Hacker News Reader

> A new study suggests that all living snakes evolved from a handful of species that survived the giant asteroid impact that wiped out the dinosaurs and most other living things at the end of the Cretaceous.

I mean... didnt everything that is around today evolve from species that weren't wiped out?

View on HN

I tell my kids that if they don't give me grandchildren, they'll be breaking a 4 billion year record of 100% reproductive success. Every single one of their ancestors, back to the first DNA molecule succeeded at having offspring. Let's not break that record.

No pressure.

Have you tried to forbid them to have kids?

Reverse psychology works great when they're toddlers, but they soon catch on to it.

Try telling them that youre indifferent. Maybe a lateral angle will work

Huh! Well, I'm going to try it anyway!

Which is why reverse-reverse psychology is used.

It’s even more specific!

You can tell a son that all their male ancestors had a son!

And you can tell a daughter that all their female ancestors had a daughter!

No pressure indeed!

> You can tell a son that all their male ancestors had a son

This seems off... by counterexample, my grandfather had no sons, but three daughters (one being my mother).

Your mother is not a male ancestor. Parent was just saying there is a line of all males for men and all females for women.

I agree that's what he probably intended, but that's definitely not what he said.

Yes that is what I intended. The line up the father side for the boys and the mother side for the girls.

No, but the maternal grandfather is still a male ancestor. Parent said "all male ancestors had a son", which is not true. The true statement is that, for any generation of ancestors, at least one had a son.

There is an unbroken line of males having males and females having females, but not every male ancestor had a son and not every female had a daughter. Every ancestor had a father and mother, but it doesn't work in reverse.

Reference: https://dailyreckoning.com/the-demographic-time-bomb/

A few decades ago humans were going to smother the planet with people. Now we're dying out. Come on, there are billions of us. Demographic trends will come and go, but for now shedding a few billion people organically over the next century or so would be no bad thing.

well, the ancestor lineage also was able to take steps to accomplish that goal.

Your kids can tell you that if you don't provide an arranged marriage partner for them, it'd be your fault that they couldn't find a partner and thus reproduce!

I think the question is more did a "handful" of snake species survive or did "many" survive?

That is, when did the diversification we see in modern snakes start?

From the paper:

> Historically, squamates were believed to have experienced minimal extinction at the K-Pg boundary ... So far, molecular divergence time analyses of snakes recover conflicting patterns ... Given this uncertainty, we attempted to improve our understanding of the timescale of crown snake diversification and the methodological factors that affect these inferences. ... Our results suggest a potential diversification of snakes near the time of the K-Pg transition.

Is this possible evidence for a food chain collapse at this time?

I don't think there's any question that the food chain collapsed and that's what caused most of the animal extinctions.

Bacteria species, sure, but having full on land animals survive an event like that is worthy of note.

This discovery channel video might help put things in perspective:

https://youtu.be/bU1QPtOZQZU

Reply on news.ycombinator.com