A 45-70 shoots like a rainbow, the further away a target is the higher you need to aim. For any of the animals that you listed except for the brown bear I would have to say that 150 yards would be max. For the bear I would keep it under 100 yards just for the simple fact that you don't want to make him mad.
A lot of brown and black bears have fallen to that round and I would figure that most of them have been under 100 yards.
I totally agree with you critter on the 150 yds with the 45-70. Like you mentioned they have a trajectory like a rainbow. Definetly would'nt be my 1st choice for an open area where shots could surpass 200 yds
Has enough omph to do the grizzly but I'd limit the rangs to 100yds or less. not that it won't do it farther but you shoot better at 100yds than ay 150! If you are innharms way, and if you wound a grizzly, that is where you may well be, you need to make the best most accurate shot you can!
A perk of majoring in wildlife biology in college is the plethora of hunting knowledge that you collect throughout your course load. One of the most important factors in whether an area can hold large quantities of animals or produce large antlers is forage.
Most universities, state schools and even community colleges offer basic botany courses and plant ID courses. Although it might not be feasable for the average middle age hunter to pay tuition and go back to college to learn hunting...