Download Chapter 4 * Population Ecology

Chapter 4 – Population
Ecology
Ms. Ferris
Flushing High School
Ch. 4 Objectives
• I can describe the characteristics of
populations (4-1)
• I can understand the concepts of carrying
capacity and limiting factors (4-1)
• I can describe the ways in which populations
are distributed (4-1)
• I can explain how technology has affect human
population growth (4-2)
Ch. 4-1 Population Dynamics
• What is a population?
– A group of organisms of the same species in the
same area at the same time.
• There are certain characteristics that all
populations have
– Population density
– Spatial distribution
– Growth rate
Population Density
• Population density is the number of organisms
per area.
– Example: There are 256 daisies in a sqkm.
Spatial Distribution
• Spatial distribution is the pattern of spacing of
a population within an area.
– There are 3 pattern types:
• Uniform = even/equal spacing
• Clumped = groups/clusters/clumps
• Random = no noticeable pattern
Growth Rate
• Growth rate is how fast a population grows.
– Emigration = moving AWAY from an area
– Immigration = moving INTO an area
• There are two types of growth
– Exponential = slow at first then rapidly increases
– Logistic = an “S” shaped growth pattern
Limiting Factors
• There are two types of factors that limit
populations.
– Density-independent factors = usually abiotic
(nonliving) and includes weather events – drought,
flooding, extreme heat or cold, tornadoes, and
hurricanes.
– Density-dependent factors = usually biotic (living) –
predation, disease, parasites, and competition.
• Isle Royale, U.P. Michigan
• These limiting factors define how large of a
population that a single area can support.
• The maximum number of individuals of a species
that an environment can support is called the
carrying capacity.
Reproductive Patterns
• Reproductive patterns are determined by a
species reproductive cycle – age in which it
can start to reproduce and life span.
• Species have developed these reproductive
strategies in order to effectively pass on their
DNA/genes.
• There are two types of strategists:
– Rate strategists
– Carrying-Capacity strategists
R-Strategists
Small organisms – fruit flies, mice, and locust.
Short life-spans
Produces many offspring
Little to no energy is used to take care of or
raise offspring
• Usually controlled by density-independent
factors like weather conditions
•
•
•
•
K-Strategists
• Larger organisms – elephants, humans, and
whales.
• Long life-spans
• Few offspring
• Spends a lot of time and energy caring for
offspring
• Usually controlled by density-dependent
factors like predators, competition, and
disease.
Ch. 4-2 Human Population
• The study of human population size,
distribution, movement, birth and death rates
is called demography.
• What did you notice about those graphs in
regards to human population over time?
• Why do you think the human population has
increased so much in the last 200 years?
– Technological and medical advances
– Look at pg. 102 Figure 4.13