Some snow hare in that sunbeam just became the Main Character.

The Y Chromosome is mostly non-coding DNA. We know that it has been losing genes for millions of years. The reason it shrinks while others don't is that it has no duplicate partner to repair itself from, like every other chromosome has including the X chromosome, though X only has a partner in women. We also know that it has been lost in other mammals. Some of them found alternative ways to keep producing males. We don't know for sure, but it is a reasonable hypothesis that others did not and went extinct.

It's SRY that gets lost, and it would probably not get lost all at once, but instead get a mutation that makes it work less well and shifts the chances of being born male lower. That will create selective pressure for the mutation near SOX9 (or another that substitutes for SRY) to spread through the population.

That is happening right now. The Y chromosome used to be bigger and is shrinking and will be gone in a few million years. Most mammals have a similar situation to humans, who have an X chromosome with 900 genes and a Y chromosome with 55 genes. One of those 55 genes is the one that causes male sex characteristics to start to develop - don't tell your right wing friends, but everyone is female at first and the males TRANSform at about 9 weeks.

The platypus has 2 equal sized sex chromosomes, and we diverged from them evolutionarily 166 million years ago. We have lost 845 Y chromosome genes in that time, which means we will lose the rest in about 11 million years. All is not lost, though.

We know of a couple of other mammals that lost their Y chromosome and still produce males. In most mammals, a gene called SRY on the Y chromosome (sex region y) triggers another gene on another chromosome called SOX9 to start the process of developing into a male. In a couple of spiny rat species from Japan, the y chromosome has disappeared. The males have a duplication mutation near the SOX9 gene that turns it on and the females don't have that mutation. Humans could evolve (or splice in) a similar mutation to keep producing males once we have lost SRY.

Np. The various fungal pathogens that cause tree cankers and other plant diseases are mostly carried around the world by the nursery trade. Plant local grown native plants!

No the lichens dont hurt the trees. Lots of trees have fungal diseases called x canker. They develop a sore that leaks sap at the infection site.

The trees atop that cliff are Monterey Cypress trees. This stand and another in Pebble Beach are the only two remaining natural stands in the world. It is a Pleistocene relict species that is being pushed into the sea by the changing climate of the past 12k years. There is a fungal disease that affects new world cypresses called cypress canker, caused by Seiridium cardinale. Monterey Cypress are the most vulnerable to it, but the salt spray from the sea protects them from the fungus, so they don't grow that well elsewhere, despite being a popular landscape tree.

All new world cypress trees are beautiful and smell fantastic, but Monterey Cypress is one of the most hauntingly beautiful. Because of its growth on sea cliffs exposed to heavy winds, they are Krummholz trees. Krummholz means they are stunted and twisted by exposure to harsh, salty wind. Combined with the varied lichens and mosses in the grove, it makes hiking through there feel like something from a fantasy movie.

There is a prison on San Francisco Bay that has a giant wall on the bay side so the prisoners don't have a nice view. I think about that a lot.

It is very very close to consistent, but days are very slowly getting longer. Thanks to tidal interactions, the moon steals a little of Earth's angular momentum every year and gets a little further away. That makes the day a tiny bit longer and the tilt of the orbit a tiny bit bigger. At the start of the Triassic 252 million years ago, there were about 400 days per year, and the moon was about 6000 miles closer.

That is Orion right above the palm tree. The 3 stars in a row are his belt and the stars forming a line to the right of it is his sword. The sword has the Orion nebula in it which is a stellar nursery about 5000 light years away and the only stellar nursery visible with the naked eye.

Not really true. In the 19th century people in Congress believe that" rain followed the plow" and God would bring rain to the west if people turned it into farms. They let people homestead places like Arizona and it went terribly for the homesteaders. Later they spent lots of money on water projects to bring water to the places that needed it. But by that time the holdings have been consolidated and the homesteaders who survived had sold their holdings for next to nothing.

Nobody wants a salt water well.

The guy you are responding to is joking, but the whole planet is kind of made of water with land floating on it. It's not just water though; it's rock that is saturated with water. There is a lot of water in the crust, then the upper mantle is pretty dry, but 400 km deep there is a lot of water, possibly more than in all the oceans combined. It's the boundary between the outer mantle and the inner mantle. That transition zone is about 7% of the Earth's mass and probably between 1 and 3% of it is water. That puts it at 1.5 to 4.5 times as much water as there is in the crust.

There are toooooons of places where you hit bedrock before water. You can dig a well anywhere and get to water but it's not economical to do it in places that you have to drill through hundreds of feet of rock.

I feel like you have to close with "So long, and thanks for all the fish."

Those are some awfully short cutoffs your dad is rocking.

Most gem quality rubies and sapphires come from metamorphic rock with igneous intrusions, so you would be real unlikely to be able to get big clean crystals this way. On top of that, you can't really get them out of the metamorphic rock really because you'll break them with the surrounding rock. We mostly get them from sedimentary deposits (placer deposits) when the softer rock around them weathers away and the hard gemstones get picked up by water and moved downstream.

The first ones will probably be set up at the south pole with solar panels on the rims of craters that get sunlight all year except during a lunar eclipse, but there are stable orbits at Lagrange points. Since the moon has no atmosphere microwave power transmission would be pretty effective.

It doesn't have much hydrogen which you need to make water and hydrocarbons.

With it's low gravity and lack of atmosphere, the moon screams for orbital solar.

It smells a little like cheese. This is native to California deserts, but there is another non-native moderately invasive plant called cheese weed. That one can be cooked like okra and the fruits are these little nutty-flavored things that look like wheels of cheese, which is where the name comes from. The fruits are good on salads.

This would go great with milk steak.

One of the ways we know is that we have detected galaxies that underwent a normal matter interaction that caused the normal matter to be displaced from the dark matter like this one. The collision of 2 galaxies exerted gravitational forces on both regular and dark matter, but other forces on just the normal matter make it get displaced from the dark matter.

The CMB is light that was emitted, but not until about 380k years after the big bang. Before that matter was so dense in the universe that any light that was emitted was reabsorbed by other matter. There were also other elementary particles in the early universe ~1 second after the big bang like quarks and electrons. By 3 minutes after the big bang, quarks we're forming neutrons and protons. Around 24k years after the big bang, there was more matter than energy in the universe. At 380k years after the big bang, things had cooled Enough for electrons to get captured by hydrogen and helium nuclei, throwing off photons that we still see some of today, the CMB. The CMB doesn't dominate the energy in the universe. It's about 10 orders of magnitude lower than the average matter/energy density of the universe.

1. A lot. California has more biodiversity than the northeast US and Canada combined. Texas scores so high because they have a lot of rivers with endangered species. Deserts have a lot of biodiversity actually. Generally speaking, the closer you get to the equator the more biodiversity you have, and the zone where we get deserts is mostly between 30 and 50 degrees north and south.

2. None. California has it's own law and a species that is protected under it is called "a species of special interest to the state of California." The Endangered Species Act is federal law. There is also an international organization called IUCN that designates species as endangered.