Convincing Aliens

I just uploaded a new picture, so according to the rules I made up, I get to play on DevArt a little.  (I'm trying to encourage myself to spend more time on art by rewarding myself with DevArt whenever I produce something)

Today's topic is convincing aliens.  Here are some ideas I've had for aliens recently, but haven't been able to illustrate.  Does anyone out there want to try?

1) I had an idea at one point for a colonial organism that uses silicates to build shells around itself (perhaps on a hot, geologically active world). Chemo-synthetic microbe colonies in deep-sea vents secrete hard protective coats of glass as they burrow into the crust in search of metabolites. They form the basis for a rich ecosystem on the sea floor, and free up a lot of silicates for other organisms to use. When life conquers land, it does so in a glassy fish bowl filled with sea water. That one I actually used in a story, but it isn't real silicon-based biochemistry.

2) This is.  Silicon-life utilizes solar power by focusing sunlight to produce thermal expansion---thermal expansion stresses piezo-electric crystals, which produce electric current, which can be stored. Electric current can then be used on other piezo-electric "muscles" to produce movement (probably in defense or to move solar collectors). Reproduction...how about this?
Stored energy or sunlight focused on pressurized chambers inside the organism turns water into superheated steam. Minerals are dissolved into the steam, and as the steam cools, seed crystals are introduced to grow the appropriate crystals.
Genetic information is stored as imperfections in the crystal.

I am envisioning a single, giant organism here. It would not reproduce copies of itself, but rather incorporate resources from the environment into itself as it spreads. "Speciation" would occur as mutations build up in the genetic crystals in different areas of the spread. When mutant areas are too different, different regions no longer recognize each other as "self" and attempt to cannibalize each other for raw materials. Competition ensues.
The end result? A crystal maze that covers the continent, spreading mirrored spires, dishes, and panels to collect and focus sunlight, filled with a complicated system of water-carrying tubes, the whole thing extending deep under ground to trap geothermal energy and minerals. Movement and growth are glacially slow, but communication takes place nearly instantaneously as electricity and light are channeled from one region to another. As regions compete, signals are intercepted, scrambled, encrypted, decrypted, and allowed to evolve as their crystal hardware becomes more sophisticated. As the crystal cities fight one an other, intelligence is advantageous.

3)Radio-synthesis.  There is a supernova near an earthlike world, bathing it in ionizing radiation (or alternately, the core stops spinning and the ionosphere collapses).  The basic producers in this new environment use melanin to generate energy from radiation, like the molds growing in the reactors of Chernobyl.  

4)Competition.  An endogenous retroviral plague hits the colonists of a new planet.  Jumping genes scramble their chromosomes, making some people unable to breed with others.  There are no outward signs, but these people are now several distinct species.  Natural selection for mate-discrimination and the founder effect cause rapid divergence among different species.  Niche partitioning?

5)Chimeras.
Fact: mothers and fetuses share somatic cells with eachother.  These cells can take root and form colonies that replace native cells, microchimersim.
Imagine a somatic cell line that evolves the ability to reliably traverse the uteral wall and form colonies in fetuses.  Imagine further developments—encysted seeds that infect and form colonies inside individuals who do not share placentas, or are not related.  Across species?  Transmissible cancer.
Imagine trans-cancer diversity.  Multiple varieties may infect the same individual.  Competition ensues.  Symbiosis?  (I actually wrote a short story about humans using these trans-cancers.  Let me know if you want to read it).
Moving on: Life evolves to take advantage of transmissible cancers.  A basic chassis is formed through normal germ-line reproduction, but elaborated upon by trans-cancers (transmissible somatic cell lines) (sideline: perhaps some of these lines re-evolve miosys and start the pattern over again).  Intelligence evolves in one cell line, but only if those cells form the brain.  (there would be some system in place to segregate developing colonies to grow into the organs that they produce best).  Thus, a species evolves genetic manipulation before fire.  They can choose which transmissible somatic lines to expose themselves and their offspring to.  

6) Larvicians: Larvicians are sea creatures related to sea squirts (and all other chordates).  The animals are small, but use mucus to build large feeding structures around themselves.  The larvician (which looks like a tadpole) builds a sort of funnel, which it pumps water through to collect food and move around.  Larvicians can reproduce sexually or by pudding, and asexual colonies can grow very large.  Imagine that early animals like this build more complicated structures out of shells, rocks, and other materials they glue onto their mucus houses.  "fish" evolve as complicated armatures built and piloted by colonies of worm-like animals.  They conquer land in reverse-scuba-suits made of found materials and diversify.  Predatory behavior may consist of either breaking the suit to eat the worms inside or by stripping and cannibalizing materials from suits.  Intelligence evolves quickly as an elaboration of suit-building behaviors, which allows worm colonies to produce more creative designs for their suits.  Soon, all animals on the planet are intelligent worm colonies in a variety of suits.  But civilization only emerges when one colony learns to talk with another.

7) and finally.  I can't see aliens and humans living together without trying to exterminate each other.  Unless there is niche-partitioning and symbiosis going on.  What qualities would the aliens have to make them useful enough for us not to kill them?  What qualities do we have to make the aliens not want to kill us?

Okay, that's all for now.  Let me know your responses.  I'm going to try to illustrate some of these concepts, but feel free to beat me to it!

Now how do I tag people?