POPULATIONS, POPULATIONS EVERYWHERE

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POPULATIONS, POPULATIONS EVERYWHERE!!!
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WHAT IS A POPULATION?

• All the members of a species living in the same
  place at the same time!

Population refers to the group in general and the
of individuals it contains.
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HOW CAN WE DESCRIBE POPULATIONS?

• SIZE
• DENSITY- THE NUMBER OF INDIVIDUALS PER UNIT AREA.
• DISPERSION- THE ARRANGEMENT OF THE INDIVIDUALS
  WITHIN A CERTAIN AMOUNT OF SPACE.
• EVEN, CLUMPED, RANDOM

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BUT HOW DO POPULATIONS GROW?

• Growth rate is the change in the size of a
  population over a certain amount of time.

What happens when births increase? When deaths
increase?
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JUST HOW FAST CAN POPULATIONS GROW??

• REPRODUCTIVE POTENTIAL is the maximum number of
  offspring that each member of a population can
  produce.

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CHARLES DARWIN ONCE SAID THAT A SINGLE PAIR OF
ELEPHANTS COULD THEORETICALLY PRODUCE 19 MILLION
DECENDANTS WITHIN 750 YEARS. Bacteria can
produce 19 million descendants in a few days or
weeks.
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CAN POPULATIONS KEEP GROWING AND GROWING?

• Populations CAN grow faster and faster. This
  only occurs when there is plenty of food and
  space, and when there is no competition or
  predators. This is called exponential growth!

Example Kudzu
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WHAT KEEPS POPULATIONS FROM GROWING AND GROWING?

• Limited Resources
• Competition for food
• The maximum number of individuals of a population
  that an ecosystem can support is called the
  Carrying Capacity.