Darwin came across two big ideas from geology. (1) Since Earth could change over time, it was possible that life could change too. (2) This also means that it would take a lot of years for life to change. Therefore, the Earth is extremely old.

Lamarck explained that due to the involvement of natural selection in the way animals use their organs or body parts, organisms have altered, acquired and lost particular traits in their entire lifetime. Those traits that are well-adapted to the environment are passed down to the next generation. As a result, evolution in the species occurs.

According to Malthus, the continuous unchecked population growth would leave insufficient living space and food for everyone. He observed that war, famine, and disease worked against population growth. These were limiting factors to population growth.

Lyell helped Darwin to grasp the idea behind geology by letting the scientists know the importance of observation. He stressed that processes that shaped the Earth continue until the present time and observing these events may be the key to understanding our world even better. This idea influenced Darwin and led him to ponder about some ideas about geology. (1) Since Earth could change over time, it was possible that life could change too. (2) This also means that it would take a lot of years for life to change in the way he actually thought and suggested. In that case, the Earth is extremely old.

The human population is growing unchecked; people are being born faster than they are dying. If this constant growth continues, at some point there will be insufficient living space and food for everyone. Humans need land for shelter, growing crops, hospitals and many other things. Eventually, there will be too many people and not enough land for everyone. There won’t be enough crops in the field to feed every person on Earth. Examples of famine and the result of exponential growth can be seen already in streets. Poor families cannot afford shelter and food, so they live in the alleys bundled up against the cold. It is these people who die more often of famine, cold, or disease. Giving these families money will only have a ripple effect and hasten our demise. Once they are well fed and survive through famine, they will only have more children whom will continue to increase our population. These offspring will take land and food. The only forces that work against the continued growth of our human population are war, disease, and famine. It is only when one or more of these three strike against the human race that people die and the birth-death rate is stabilized. Famine is caused by insufficient food for everyone. Disease accelerates through larger populations and war is often caused by the fight for land or resources. Overall, each factor limiting population growth is intensified in greater populations. The human condition will put everyone on the streets, without food or land. Society will crumble under the burden of an overpopulated Earth. Although clearing more land for farming may bring a larger harvest, the food cannot last forever. A certain amount of food an only sustain a certain population. Our population is constantly increasing, and the harvests will be unable to keep up with the growing demand. Food increases more slowly than population, and humans will eventually exceed Earth’s carrying capacity. If moral restraints are not enforced and population is not checked, society will be stripped of all its resources. Natural checks or catastrophes such as disease, famine, and war will become inevitable.