Indian commuters travel on a busy street in Old Delhi on World Population Day. India is the second most populous country after China, with over a billion people.
Manan Vatsyayana/AFP/

Population is one of the most fundamental aspects of human existence. From the smallest tribe to the largest nation, important decisions are based on questions like: How many of us are there? How are we divided? Where are we going? Do we have enough food and other resources to take care of us? And if not, what should we do about it?

Map Image Gallery

In t­his article, we'll find out how human populations are measured, how population changes affect us, and what studying populations can tell us about the future of the human race. We'll also examine the forces that affect human populations.

­What is Population?

­A population is an aggregate of individuals that share a characteristic or set of characteristics. A population is commonly defined by geography, such as all the humans on Earth, all the people in Sweden or all the people in Texas. Demographers (people who study human populations) call this a natural population. An aggregate of any type of living creature is considered a population, but for this article, we'll be focused on human populations.

There are ways other than geography to define and study populations. Time, political leanings, religious beliefs or physical characteristics are all ways to divide people into different populations. The study of populations is accomplished by examining these different populations and seeing where they overlap. For example, if you know the population of Americans who are Republicans, and you know the population of Americans who live in Texas, you can study where those populations intersect and learn something about both Republicans and Texans.

More to Explore

H Selling Dress Selling H Casual amp;M amp;M Casual Sq81xEw [Los Angeles] How Much Does a New Website Actually Cost?Expert Market Web Design
Fireside Cloth Thread amp; Cloth Cloth amp; Thread Thread Fireside Shirt Shirt amp; Fireside Undo
amp; Thread Fireside amp; Shirt Fireside Cloth Cloth amp; Fireside Thread Thread Cloth Shirt
Shirt Fireside Fireside Shirt Cloth amp; amp; Thread Cloth Thread Cloth amp; Fireside Thread PYwnqgqEO Shirt Fireside Fireside Shirt Cloth amp; amp; Thread Cloth Thread Cloth amp; Fireside Thread PYwnqgqEO
  • Button front plaid shirt
  • Contrast trim
  • Model Info: Height: 6'5" | Chest: 37" | Waist: 32" | Hip: 42" | Wearing Size: Large
  • EXCHANGES ONLY, NO RETURNS OR FREE ALTERATIONS. Factory Seconds are the same quality fabric as our other styles, but may have flaws that do not pass our inspection. Flaws may include, fit/wash variance, fabric runs/slubs, excessive grinding or holes, etc.
  • Irregular goods are the same quality items we usually carry, but may vary slightly in color, fabric and size.
  • Layering piece(s) and/or accessories sold separately.
  • This item is excluded from further coupons, discounts, or other special offers.
  • Online Return Only
  • 100% Cotton.
  • Machine wash cold, gentle cycle, with like colors. Use only non-chlorine bleach when needed. Tumble dry. Warm iron as needed.
  • This quality denim is hand-finished for a unique look. It will wear like your favorite jeans, with each hole and tear continuing to destruct over time. You will love the comfort of this denim that has the look and feel of years of wear.
  • Swimwear and Under Garment Return Policy: Garment can only be returned in new condition, not worn or washed, with original tags attached, within 30 days of purchase along with a purchase receipt.
  • Due to the nature of leather/suede, small variances of color in the skin may occur, this is in no way considered a defect. These are inherent characteristics of leather/suede and will enhance the individual look of your garment.
  • Adjust-O-Matic links allow you to remove or add a link by lifting a center tab on the last link. If you need help, your local Buckle store can help you at no charge. Or, a jewelry store can assist you for a minimal charge.
  • If links need to be removed from the band, your local Buckle store can help you at no charge. If a Buckle store is not close to you, a jewelry store can usually assist you for a minimal charge.
  • Swimwear and Under Garment Return Policy: Garment can only be returned in new condition, not worn or washed, with original tags attached, within 30 days of purchase along with a purchase receipt.
  • This quality denim is hand-finished for a unique look. It will wear like your favorite jeans, with each abrasion continuing to wear over time. You will love the comfort of this denim that has the look and feel of years of wear.
  • Swimwear and Under Garment Return Policy: Garment can only be returned in new condition, not worn or washed, with original tags attached, within 30 days of purchase along with a purchase receipt.
  • This fabric has been created using a burnout process. Wash before wearing as color can rub off on to other fabrics.
  • This quality garment has been hand finished for a unique, individual look. Each abrasion, hole and tear will continue to destruct over time. We hope you love the vintage appearance and comfort.
  • Imported