draw2discard2 t1_j9igmaz wrote on February 22, 2023 at 5:00 AM

This is backwards. A giant sloth or other large animal is equally good at spreading large or small seeds. What would make actual sense is that perhaps there is an advantage to having a large seed (for instance, more energy stored inside) but size is limited by the ability of animals to disperse the seeds (for instance, both a mouse and giant sloth can move raspberry seeds but only the sloth can move the avocado). So, the sloth may have allowed the evolution of a larger seed but it didn't do anything to make a larger seed to be favored in natural selection.

JainaOrgana t1_j9ikvp2 wrote on February 22, 2023 at 5:43 AM

Less likely to be digested?

More likely to propagate when dumped?

draw2discard2 t1_j9iqj4x wrote on February 22, 2023 at 6:46 AM

Evidently plants that live in shady places tend to have larger seeds because after germination there needs to be enough energy for the seedling to grow leaves and be able to reach the light (or perhaps to have enough foliage to get enough light to continue growth). On the other hand there is also danger of predation because some animals (such as rodents) will eat larger seeds, which doesn't happen with tiny seeds (e.g. a dandelion).