Exponential Growth - Schurz High School

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Transcript Exponential Growth - Schurz High School

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A student grew a yeast culture on sterilized nutrient medium in a
closed dish for 5 days. Each day, she took the same size sample from
the dish and placed it on a special slide used for counting
microorganisms. She examined the samples under a microscope and
drew the following illustrations of her observations over the course of
the investigation. Each dot represents 10 yeast cells.
1. Why did the student use sterilized medium and keep the dish
closed?
Sterilized medium and closed dish were used to minimize
contamination.
2. During which two-day period was population growth most rapid?
From Day 2 to Day 3
POPULATION DYNAMICS
Objectives:
• Compare and contrast
exponential, logistic and
linear growth.
PRINCIPLES OF POPULATION GROWTH
A population is a group of organisms, all of the same species, that
live in a specific area.
A healthy population will grow and die at a steady rate unless it
runs out of food or space, or is attacked in some way by disease
or predators.
Characteristics of a Population
• Geographic distribution or range (the area inhabited by a population)
• Density (the number of individuals per unit area)
• Growth rate (how slow or how fast a population grows)
POPULATION GROWTH
Factors that Affect Population Growth
• Number of birth
• Number of death
• Number of individuals that enter or leave a population
# of Birth > # of Death
Population will grow
# of Birth < # of Death
Population will shrink
# of Birth = # of Death
Population will stay the same
Immigration: The movement of individuals into an area (Causes
populations to grow)
Emigration: The movement of individuals out (Exit) an area (Causes
populations to shirk)
PATTERNS OF POPULATION GROWTH
Linear
Growth
Exponential
Growth
Linear Growth: A steady growth over time
Logistic
Growth
Exponential Growth: When a population reproduces at a constant
rate. Initially the population grows slowly, but as it get larger it grows
at a faster rate.
Logistic Growth: When a population’s growth slows or stops following
a period of exponential growth
Carrying capacity: The maximum number of organisms that a
population can support.