POPULATIONS

POPULATION POPULATION SIZE Group of one species living in the same place, at the same time, and can interbreed POPULATION SIZE # of individuals in a population. Smaller populations have a greater chance of extinction Large populations can be wiped out by natural disasters

POPULATION DENSITY Number of individuals that live in a given area. DISPERSION The way the individuals are arranged in space. 3 types- random, even, and clumped

KILLER WHALE POPULATION

SCHOOL OF ATLANTIC SPADEFISH

GROWTH RATE When more individuals are born the population increases, when more die it decreases

BIOTIC FACTORS All living organisms that inhabit an environment Ex: fish, humans, trees

ABIOTIC FACTORS Non living parts of the environment Ex: air currents, temp, soil, water

TYPES OF POPULATION GROWTH Exponential Growth- occurs when there are no limits to the size to which a population can grow Resources are unlimited, small population Represented by the J-Curve

Carrying Capacity- maximum # of organisms that a population can have. Factors limiting the carrying capacity are food, water, space, disease, predators. Represented by the S- Curve carrying capacity

Boom & Crash- population experiences exponential growth followed by crashes

K- strategists- slow growing, small populations, don’t reproduce quickly R- strategists- short life span, large populations, reproduce a lot.

Density Dependent Factors- has an increasing effect as the population increases Ex: food, water, disease Density Independent Factors- affect all populations regardless of density Usually caused by environmental conditions- temp, storms, floods, drought, fire

Limiting Factors Any abiotic/biotic factor that restricts the existence of an organism. Water, food, sunlight etc.. Tolerance- the ability to withstand fluctuations in abiotic/biotic conditions