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POPULATION BIOLOGY
Chapter 5
Population Dynamics
• Population _________ = increase in ________ of population over time (Fig. 4.1, p. 95)
– growth of organisms is not _____________ but ______________
– as population get larger it also grows ___________
J-shaped curve
• Initially, the increase in number of organisms is _____________
– number of ____________________________ is small
– rate increases rapidly because ________________________ of organisms increases
– results in population __________________
Limits of population growth
• Populations cannot grow ____________________!
– Limiting factors will cause population to stop increasing
– results in ________________ growth curve
Carrying Capacity ______
• Number of organisms of one ________________ that an environment can support
– if population is __________ its carrying capacity, then _____________ >deaths
(until k is reached)
– if population is _____ its carrying capacity, then _____________ > births (until k is
reached)
* Thus….population levels __________________.
Patterns of population growth
• Most important factor determining population growth is organism’s _______________
________________________
–
–
–
–
how fast
how ________________
how early
how _______________
•
_____________ reproductive rates found in organisms with ___________ body size
and short _______________________
– populations increase/decrease ____________________ as conditions change
– ie. mosquitoes
• __________________ reproductive rates found in organisms with ______________
body size and longer life span
– species live in more ___________________ environments
– ie. elephants, ___________________
Environmental Limits
Two main kinds of limiting factors
1. ______________________________
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2. ______________________________
Limiting Factors
• Density-dependent
– have increased effect as population __________________
– ________________, competition, parasites, food
– ex: disease spreads more quickly in large populations
– _____________________ can also limit population
• Density-independent
– affect _______ populations regardless of size/density
– ___________________, storms, floods, drought, habitat disruption, ____________
Human Population Growth
• __________________--study of human population growth characteristics
– growth rate, _______________________, geographic distribution
– world wide human population has ________________ exponentially over past
several ___________________ years
– humans can reduce/limit environmental effects by __________________
competing organisms, increasing food production and controlling ______________
Birth/Death Rates
Growth rate of population = Birth rate - Death rate
•
In US, people are _______________ longer, waiting until their _________ to have
kids , and having fewer kids (__________________ rate is decreasing)
•
When fertility rates are high, populations grow ________________ unless death rate is
also high
Age Structure
• Proportions of population that are at different ____________ levels
• Rapid growth countries have ___________ base (lots of _________________ people)
• Stable populations have fairly _____________ categories (Fig. 4.11, p. 107)
•
_______________ of people affects population size
•
Immigration vs. Emigration
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