[quote="Chris Peterson" post_id=311184 time=1614271091 user_id=117706]
[quote="orin stepanek" post_id=311183 time=1614269713 user_id=100812]
[quote=Ann post_id=311182 time=1614268594 user_id=129702]
I think Venus would probably have been too hot anyway, because it is too close to the Sun. The way I remember it, when the "un-habitability" of Venus was first discovered, Venus was "supposed" to be around 80-90°C. That would have made it rather uncomfortably hot in any case (or at least I think so) but perhaps habitable. At a temperature of 80-90°C, Venus would have been very sensitive to climate change, and any living organisms that were dependent on below-100°C temperatures could so easily have perished.[/quote]
So I presume that the habitable zone is narrower than at first thought :shock: ! [/quote]
Actually, I think it's gotten wider, with both Venus and Mars now solidly inside of it. That's because we understand a lot more about extremophiles, and a lot more about how life can exist in zones that are protected such that liquid water can exist. Of course, "habitable" is a poor choice of words, but one that has largely stuck. The zone that is "habitable" in terms of complex life is much narrower than the zone that simply might support life in its simpler forms.[/quote][quote=https://en.wikipedia.org/wiki/Alvinella_pompejana]
[float=right][img3=Pompeii worm tails often rest in temperatures as high as 80°C]https://upload.wikimedia.org/wikipedia/commons/thumb/3/3e/Alvinella_pompejana01.jpg/330px-Alvinella_pompejana01.jpg[/img3][/float]
<<Alvinella pompejana, [url=https://en.wikipedia.org/wiki/Mike_Pompeo]the Pompeii worm[/url], is a species of deep-sea polychaete worm (commonly referred to as "bristle worms"). It is an extremophile found only at hydrothermal vents in the Pacific Ocean, discovered in the early 1980s off the Galápagos Islands by French marine biologists.
They can reach up to 13 cm in length and are pale gray, with red tentacle-like gills on their heads. Perhaps most fascinating, their tail ends are often resting in temperatures as high as 80 °C, while their feather-like heads stick out of the tubes into water that is a much cooler, 22 °C. Scientists are attempting to understand how Pompeii worms can withstand such extreme temperatures by studying the bacteria that form a "fleece-like" covering on their backs. Living in a symbiotic relationship, the worms secrete mucus from tiny glands on their backs to feed the bacteria, and in return, they are protected by some degree of insulation. The bacteria have also been discovered to be chemolithotrophic, contributing to the ecology of the vent community. Recent research suggests the bacteria might play an important role in the feeding of the worms.
[b][color=#FF0000]Attaching themselves to black smokers, the worms have been found to thrive at sustained temperatures of from 45 to 60 °C and even 105 °C for a short time, making the Pompeii worm the most heat-tolerant complex animal known to science after the tardigrades (or water bears), which are able to survive temperatures over 150 °C. [/color][/b]>>[/quote][quote=https://en.wikipedia.org/wiki/Venus_flytrap]
[float=left][img3=""]https://upload.wikimedia.org/wikipedia/commons/thumb/3/37/Venus_Flytrap_showing_trigger_hairs.jpg/330px-Venus_Flytrap_showing_trigger_hairs.jpg[/img3][/float]
<<The Venus flytrap (Dionaea muscipula) is a carnivorous plant native to subtropical wetlands on the East Coast of the United States in North Carolina and South Carolina. [b][u][color=#0000FF]The Venus flytrap is found in nitrogen- and phosphorus-poor environments, such as bogs and wet savannahs.[/color][/u][/b] Small in stature and slow-growing, the Venus flytrap tolerates fire well and depends on periodic burning to suppress its competition. Fire suppression threatens its future in the wild. It survives in wet sandy and peaty soils. Although it has been successfully transplanted and grown in many locales around the world, it is native only to the coastal bogs such as North Carolina's Green Swamp. There also appears to be a naturalized population of Venus flytraps in northern Florida as well as an introduced population in western Washington. [b][u][color=#0000FF]The nutritional poverty of the soil is the reason it relies on such elaborate traps: insect prey provide the nitrogen for protein formation that the soil cannot.[/color][/u][/b]
They are full sun plants, usually found only in areas with less than 10% canopy cover. The microhabitat where it thrives is typically sparse with grasses, herbs, sphagnum, and often bare patches where there aren't enough nutrients for noncarnivorous plants to survive, or where fires regularly clear competition and prevent cover from forming. Thus, natural fires are an important part of its habitat, required every 3–5 years in most places for D. muscipula to thrive. After fire, D. muscipula seeds germinate well in ash and sandy soil, with seedlings growing well in the open post-fire conditions. The seeds germinate immediately without a dormant period.>>[/quote]