What causes the birthrate to decrease?

Answer 1

lack of mystyrbytion. ha ha. no. well maybe. actually probably. but over population happens when demand overcomes supply. when there is to many of a species for there to be room for their food supply. lack of predation, and lack of competion are the causes.

Answer 2

With the discovery of agriculture roughly 10,000 years ago, our ancestors diverted streams, plowed fields, and began maintaining large herds of cattle. This knowledge was spread from continent to continent and helped allow our ancestors to safely survive every winter from then on. What was not expected from this knowledge however was that the human race would experience a boost in population growth and that this number would substantially increase as time passed.

By the early 1800's, the human population that occupied the planet was roughly around 1 billion than doubled to 2 billion by the 1930's with the discovery of mass production. Mass production made it possible for products such as food, liquids, chemicals, and mined minerals to be ready and available in bulk for families.

With large amounts of food and other survival needs always being readily available thanks to mass production, the human populous grew than from 2 billion in the 1930's to 4 billion by 1975 and then to 6.8 billion today. Mass production made it possible for humans throughout the world to no longer have to survive independently with family farms or gathering, instead it is more common to purchase all of your needs from a grocery store or market. Our population numbers have been predicted to reach 7 billion by the end of 2011, 8 billion by 2020, and 15 billion by 2050.

But what does this mean for Earth's Natural Resources? In the 1700's only 7% of the planets land was used for food production, today over 40% of land is used for farming and production to feed the world. Humans annually absorb 42% of the Earths terrestrial primary productivity, 30% of all primary marine productivity, and over 50% of the Earths fresh water. As the years progress, the Earth's finite natural resources become more scarce at the same time that human population becomes more robust. Without finding an alternative, the human population as we know it will be doomed to an extinction like many other species before us, but this will be our own undoing with no one else to blame.

Answer 3

It can be caused by many things. Among them are war, disease, natural disasters, etc. The effects are borderline nice. It can lead to more land for humans, less issues with "going green" since there are less people mucking about with it, things like that. However, it can also result in the breaking of leagacies in clans of ancient familes or bloodlines being "tainted".

Actually, it is determined by Birth Rate, Death Rate, net migration, and maternal and infant mortality rates. Add these all up and you can tell whether or not there is negative population growth.

Answer 4

A high death rate would cause a low population growth rate. If many people are dying, or a high majority of people are of the elderly, then there would be less births the counter effect the high death rate.

Answer 5

high death rate