The first agricultural revolution was when the human species went from hunting to gathering and farming about 11,000 years ago. This occurred in the Middle East and humans started to domesticate animals for easy meat and as pets.
This is a picture of one of the first crops grown by humans, wheat.
The second agricultural revolution started in Western Europe from 1700 to 1900 and invented the plow, horse collar, seed drill, crop rotation, and the 4 course system. This improved efficiency for farmers more than the 1st agricultural revolution. So now it is a lot easier to farm food and we can produce more to start feeding the masses.
The above picture is a old tractor from the 2nd agricultural revolution.
The 3rd agricultural revolution is the most recent revolution. It began in the late 19th century. This started scientific farming methods, chemicals on crops, biotechnology, gas and diesel tractors, increased land with less people working, pollution, resistance to petroleum and GMOs.
This is a recent picture of a combine harvester used by farmers right now in the 3rd agricultural revolution.
In more recent times, scientists have made GMOs. GMOs are genetically modified organisms, which are plants and animals changed as a result of biotechnology. The GMOs are more resistant to weeds, pests and diseases, they are bigger, they grow faster, which is better for farmers to plant, and in some cases, they are better for you. But they are mixing genes of different organisms, the GM foods are being marketed without labeling and some long term consequences are still under research.
This tomato is a product of biotechnology, and was made to be bigger.