Thanos' plan to solve resource scarcity by killing half the population is logically flawed because a smaller workforce would still face proportional resource production issues.

“So if you have a farm that requires 100 people to run, and you kill half the people, the remaining 50 can't now run the farm at all, 'cause everybody has their job. You'd need farms half the size, so yeah, I think Thanos really didn't think this through.”

Reducing an animal population by half would likely lead to a population spike and subsequent overshoot of the environment's carrying capacity due to reduced competition.

“So if you think about if you have a small population of deer or some kind of herbivore, and a huge meadow full of food, full of plant food for them to graze in, they're gonna get bigger and fatter, and in the ecological world that means more fit. And so when they're more fit, they're better able to ”