My basic question is could life 'as we know it' (carbon DNA/RNA based, using water as the main solvent in metabolic processes) evolve on a planet where the temperature ranges from 16 degrees Celsius (at the equator in summer), to -120 Deg. C at the poles in Winter.
For anyone wanting more elaborate details:
The absolute average temperature is approximately -20 Deg C, the prior values representing the record high and low values.
Liquid water at the surface is primarily available from geothermal vents and snow melted by volcanic activity - both of which are spatially frequent and temporally consistent.
Water at the equator also remains liquid at the equator virtually year round, with the annual low of -4 Deg C.
The planet has an solar orbital period of 1,050 hours (44 days), and negligible axial precession (IE the 'wobble' that causes Earth's seasons)
The planet has a rotational period, however, of 4,800 hours (200 days), and it's rotation counters it's solar orbit. This gives it an effective day of 3750 hours (156 days on Earth). The planet's day/night cycle consequentially defines its 'seasons.'
It spends 78 days in the winter/night where the lack of sunlight leads to rapid cooling, then 78 days in the summer/day where the planet again warms.
The planet's chemistry is Earth-like, mostly. The atmosphere is 68% nitrogen, 25% oxygen, 5% xenon, 1% argon, and trace gasses.
The planet itself is composed of 77% Silicon and silicates, 13% Iron, 5% carbon, carbides, and organic compounds, 3% Titanium, 2% Lanthanides, .07% ground water and perma-ice, and trace compounds.
The biology of the story
Or does it make sense?
The evolution I currently have starts with proteins boding into DNA/RNA slop and then single cell organisms in lakes and rivers, where geothermal activity creates temperatures as high 120+ Deg C (in places). It eventually evolves into complex land based organisms.
Owing to the relative scarcity of energy (for metabolic purposes) on the planet, biodiversity is significantly lower than earth. Perhaps 100 plant and animal species, plus an additional 1,000 bacteria species compromise the entire biosphere about five billion years after life first emerges. Cold climate adaptions can be assumed.
Intense competition for resources causes frequent evolutionary arms races and extensions, leading to most extant species occupying a particular niche very well, and having either innate weaponry or symbiotic properties.
Under the circumstances, does that story work an a biological front?