Hi deegee,
I am working for Forbes, hence familiar with what is going on in the world, and aware of all those things you mentioned--they are all exceptions, and also things have not been so from the beginning. If humans divert the time for accumulating things which they seldom use, all those perversions can be reversed.
For example, dogs that happen to be with vegetarian masters complete their life-span eating vegetarian food. (http://www.realfoodforlife.com/vegetarian-dog-lives/) There have been cases of little lamb being saved by lion from chasing cheetah, and lamb continued to grow with the lion. (Discovery Channel) Romans have a coin made in memory of a lion that refused to eat Androcles when he was thrown into hungry lion because Androcles was recognized by the lion as one who helped a thorn to be removed from its leg years back when it was a baby in the forest. (https://www.cointalk.com/threads/papal-medal-alexander-vii-androcles-and-the-lion.288161/) Even I have been saved by dolphins when I had an unexpected accident while surfing. All these show things can change if humans want.
Sometimes our own body shake while we are asleep like earthquake—there could be some reason we don’t know. If we are not careful about what to eat, how much to eat …. and what to feed our mind … etc our body would behave like turbulent climate. If thinking of humans collectively become negative and hurtful it would have its corresponding changes in the environment too. Though account of Cain and Abel symbolizes two type of people, aftereffects of spilling blood on earth is symbolically described in Genesis 4 saying earth would retaliate. No disease occurs without any reason—some reasons are discernible and some are not. Even when some know certain habits (such as smoking, drinking alcohol …etc) invite diseases they still continue with it. Everyone should know what to eat, and how much to eat ...etc. But people often choose to go by convenience rather than conviction. For example, everyone knows exploiting the weak is wrong. Yet many humans kill lesser beings, eat their flesh and make a celebration out of their suffering. Even though fondly called non-vegetarian, in reality it is corpse; and killing and eating corpse are violation of the very first law found in the first book of the Bible (Genesis 1:29) which is the scripture for three major religions—Jews, Christians and Muslims. Like any other violation of law, this too will have its consequence in the form of diseases. (“Poisons in Your Body,” by Mary and Steven Null). Look at the damage just this one human habit causes besides health hazards: It is “an area 1.5 times the size of the European Union” that is being wasted for animal farming, according to the World Wildlife Fund (WWF). (http://www.independent.co.uk/news/science/meat-eating-destroying-planet-report-warning-a7985071.html dt 4.10.2017). When a part of human family suffers from poverty, about 5.5 billion people—up to 76% of the world's population—are `overfat', which invite various diseases. What you feed your mind also matters—every time you are negative having ego, lust, anger, greed, hatred … etc, you create a biochemical reaction in your physical body, which progressively destroys your immune system and your health.
Only when all humans live like a family, then only we will know what could be the real condition of our earth, environment, animals …etc.