Dude... This one is fucking wild.

First off, keep in mind that the numbers are arbitrary. They were decided by early scholars who we now know spent 50 years misclassifying it as a Gnostic text.

Then consider that the very next line is the only one in the entire work preceeded by a numbered saying but beginning with a conjunction.

So take the two together (and let's throw in the one after for good measure):

Jesus said, "Lucky is the lion that the human will eat, so that the lion becomes human. And foul is the human that the lion will eat, and the lion still will become human."

And he said, "The person is like a wise fisherman who cast his net into the sea and drew it up from the sea full of little fish. Among them the wise fisherman discovered a fine large fish. He threw all the little fish back into the sea, and easily chose the large fish. Anyone here with two good ears had better listen!"

Jesus said, "Look, the sower went out, took a handful (of seeds), and scattered (them). Some fell on the road, and the birds came and gathered them. Others fell on rock, and they didn't take root in the soil and didn't produce heads of grain. Others fell on thorns, and they choked the seeds and worms ate them. And others fell on good soil, and it produced a good crop: it yielded sixty per measure and one hundred twenty per measure."

So first you have a saying about how no matter if man eats lion or the other way around man will be the inevitable result.

The part about the net mirrors Habakkuk 1:14-17 with a metaphor of man like a fish caught up in a net, but here "the human being" is like a big fish selected from small fish.

Then the next saying is about how with randomly scattered seeds it is only the seeds that survive to reproduce which multiply.

The only group recorded following the Gospel of Thomas had this to say about the sower parable:

For the ends, he says, are the seeds scattered from the unportrayable one upon the world, through which the whole cosmical system is completed; for through these also it began to exist. And this, he says, is what has been declared: "The sower went forth to sow...

• Pseudo-Hippolytus Refutations 5.3

Elsewhere this group describes these seeds as "indivisible, like a point as if from nothing," and "making up all things."

See, 50 years before Jesus was born the poet Lucretius writes a poem in Latin about the Epicurean philosophy, and instead of using the Greek atomos to describe indivisible parts of matter, he refers to them as 'seeds'.

For example:

Especially since this world is the product of Nature, the happenstance Of the seeds of things colliding into each other by pure chance In every possible way, no aim in view, at random, blind, Till sooner or later certain seeds suddenly combined So that they lay the warp to weave the cloth of mighty things: Of earth, of sea, of sky, of all the species of living beings.

• Lucretius, De Rerum Natura book 2

In fact, Lucretius used the metaphor of "seed falling by the wayside of a path" to describe failed human reproduction. This is how it is phrased in both the version of the sower parable quoted in Pseudo-Hippolytus and in all the canonical gospels - "on the path" in Thomas may have been an attempt to correct the translation as it made it's way into Coptic.

See, Lucretius's De Rerum Natura is the only extant work from antiquity that explicitly described what is basically evolution from the idea that it is a doubled seed with one part from each parent that passed on traits to the idea there were intermediate mutants that didn't survive because they weren't as adaptive as others in order to survive and reproduce. We tend to think these ideas are only as old as Darwin, but they predated Jesus by decades.

And the Epicureans were known to Judea where one of the sects (the Sadducees) had similar perspectives about no afterlife and where the Talmud has a Rabbi in the first century saying "Why do we study the Torah? To know how to answer the Epicurean."

Lucretius even explicitly described man as originating from nature as well:

I cannot hold The race of mortal beings was lowered on a rope of gold To the fields down from the lofty heavens, nor that mortals came From the sea, nor from the waves that smash the rocks. It's from the same Earth that feeds them from her body now that they were born.

• Lucretius De Rerum Natura book 2

And many of the ideas in Lucretius we see paralleled in Thomas.

For example, in terms of if intelligent design was the origin or evolution, you have saying 29 where the spirit arising from flesh is the greater wonder over flesh arising from spirit.

In response to Lucretius's points about there not being an afterlife because the soul depends on bodies, you have sayings 87 and 112 bemoaning a soul which depends on a body.

In response to Lucretius's claim about the notion the cosmos was like a body that would one day die, you have saying 56 about how the cosmos is already a dead body.

While outside the scope of this comment, effectively most of the Gospel of Thomas seems to be a rebuttal to Epicurean philosophy by incorporating ideas from Plato such that it claims this is a non-physical copy of an original physical universe, and because of that there actually is an afterlife as opposed to the Epicurean ideas.

So back to saying 7, in combination with 8 and 9.

TL;DR: These seem to be, in this broader context, an embrace of Lucretius's views of survival of the fittest but applied to humanity, as in that the human being is like a big fish selected from small fish, so no matter if lion ate man or man ate lion, man was was going to be the inevitable result.

It also goes a long way to explaining why in Mark the sower parable was so dangerous it is the only parable given a "secret explanation" at odds with John 18:20's "I said nothing in secret" and Papias describing the parables as "up to each person to interpret as best they could." The net parable also ends up with a secret explanation later on in Matthew, where in one of his other secret explanations he tips his hand that he had a copy of the Gospel of Thomas (or an earlier version of it) in front of him.