Life in a Nebula Evolves to Maneuver into It

"Tell me what happened!"

"The tree came apart.

"Why?"

"Maybe the fire set it off, but it was ready. Clave, everythiiing in the Smoke Ring has some way of getting around. Some way to stay near the median... middle, where there's warater and air. Where do you think jet pods come from?" The hanand relaxed a little, and the Grad kept talking. "It's a plant's way of gettmg around. If a plant wanders out of the median, t too far into the gas torus region--"

"The what?"

Alfin asked, "What on Earth is going on?"

'Clave wants to know what happened. Alfin, can you steer this thing and pick up some more of us? Here—" He passed across his store of jet pods.

Alfin took them. He took his time deciding what to do with them, and the Grad ignored him while he lectured. "The Smoke Ring runs down the median of a much bigger region. That's the gas torus, where the molecules... the bits of air have long meanfree-paths. The air is very thin in the gas torus, but there's some. It gets thicker along the median. That's where you find all the water and the soil and the plants. That's what the Smoke Ring IS living thing wants to stay."

"Where it can breathe. All right, go on."

"Everything in the Smoke Ring can maneuver somehow. An¬ imals mostly have wings. Plants, well, some plants grow jet pods. They spit seeds back toward the median where they can grow and breed, or they spit sterile seeds farther into the gas torus, and the reaction pushes the plant back toward the median. Then there are plants that send out a long root to grab anything that's passing. There are kites—"

"What about the jungles?"

"I... I don't know. The Scientist never—"

"Skip it. What about the trees?"

"Now, that's really interesting. The Scientist came up with this, but he couldn't prove it—"

The hand tightened. The Grad babbled, "If an integral tree falls too far out of the median, it starts to die. It dies in the center. The insects eat it out. They're symbiotes, not parasites. When the center rots, the tree comes apart. See, half of it falls further away, and half of it drops back toward the median. Half lives, half dies, and it's better than nothing."

The integral tree has just broken in half, and the scientist explains this is a survival mechanism because it was moving to far out of the nebula to survive.