Blackberries have so many seeds! Sometimes a seed gets caught between two teeth and the person eating the biscuit and blackberry jam will complain, but mostly we eat our sweet berries and don't worry about the slight inconvenience.
Blackberry bushes when I was a kid grew in our rural spot in south Louisiana like wildfire. We picked berries in the field next door, and we picked berries along the country roads near our house. After the road expansions and more intensive maintenance of the roadside, the blackberries in our area pretty much disappeared.
Years after leaving Louisiana, we had opportunities to pick berries while visiting Bellingham, Washington. There were lengths of undisturbed land along the fences bordering the railroad tracks, area open to the public. Berries glowed in the sunshine, plump, juicy and sweet. We filled our buckets in the morning, and dined on blackberry pie in the evening.
The seeds - they are tiny and plentiful. A bird or bear dines on a ripe berry, and the juicy flesh nourishes the body. The seeds pass through, carried in the creatures' wastes that serve as fertilizer. In uncultivated areas with low human interference, these gardening geniuses' crops grow fast and plentiful.
Given rain and sunshine and fertile (living) soil, berries propagate plentifully, there to nourish and pleasure us humans and the many creatures who share the planet on which we live.
I know a little about raspberries in the wild, something about blueberries and strawberries, but nothing about gooseberries and huckleberries except their names. Salmon berries grew wild along the Washington/Canadian border north of Bellingham. They looked like raspberries, but had a fainter flavor and paler color. We were told bears along the Pacific coast up there enjoyed these. Bears eat a range of foods -berries, fruit, fish, insects, and grubs, to name a few. The last bears I've seen were at Crater Lake National Park in Oregon around 1999. A mother and two cubs gazed at us as we drove along a forest road west of the park.