Learning Objectives - Linn–Benton Community Collegecf.linnbenton.edu/mathsci/bio/bienekr/upload/BI...
Transcript of Learning Objectives - Linn–Benton Community Collegecf.linnbenton.edu/mathsci/bio/bienekr/upload/BI...
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Biology 101
Lecture 3: Populations
Learning Objectives
1. Understand the differences between population size,
density, age structure, and distribution.
2. How does age structure affect population growth?
3. Recognize the different dispersion/distribution patterns
found in nature.
4. What factors affect population growth? What limits it?
5. What is the difference between exponential and
logistic growth?
6. Compare/contrast density dependent and
independent controls.
7. Differentiate between the three survivorship curves.
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Salmon in California
Data from Peter Moyle, UC Davis
Less than 1% of original populations remain
Outline
Populations
1. Size and growth
a. Exponential
b. Logistic
2. Age structure
3. Distribution
a. Clumped
b. Uniform
c. Random
4. Density
5. Survivorship
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Age Structure Diagrams
Shows age distribution of a population
Rapid
Growth
Slow
Growth
Zero
Growth
Negative
Growth
Otter age structure
Otters released in Oklahoma in 1960s & 1990s
BARRETT, D. A., & LESLIE JR., D. M. (2012). Spatio-Temporal
Variations in Age Structures of a Partially Re-established
Population of Northern River Otters (Lontra canadensis).
American Midland Naturalist, 168(2), 302-314.
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Discuss: Western populations had more young
otters than eastern populations. What does this mean?
Distribution
clumped • Clumped populations:
– Suitable physical, chemical, and biological conditions are patchy, not uniform.
– Resources patchy
– Social groups
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Distribution
• Rare in nature
• Result of fierce
competition for very
limited resources
uniform
45.1
Distribution
• Uniform environmental
conditions
• Members are neither
attracting nor repelling
each other
random
45.1
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Human Population Growth
• What kind of growth?
Life Table for the US Human
Population in 2001
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Survivorship Curves
• represent age-specific patterns of death for a
given pop in a given environment
• Each species has a characteristic curve.
• Three types of curves are common in nature.
45.5
Figure 45.11
Page 809
•Type I: low death rates early in life and through midlife,
with a sharp increase in death rate among older-age
groups (e.g., humans).
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Fig. 45-11a, p.809
Figure 45.11
Page 809
•Type I: low death rates early in life and through midlife,
with a sharp increase in death rate among older-age
groups (e.g., humans).
•Type II: fairly even mortality rate throughout life of
organism (e.g., birds).
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Fig. 45-11b, p.809
Figure 45.11
Page 809
•Type I: low death rates early in life and through midlife,
with a sharp increase in death rate among older-age
groups (e.g., humans).
•Type II: fairly even mortality rate throughout life of
organism (e.g., birds).
•Type III: high death rates early in life followed by a sharp
decline of death rates for the survivors (e.g., fish and
many insect populations).
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Fig. 45-11c, p.809
Homework
• Study for Quiz #1 Wed
– Scientific method
– Evolution
• Pre-lab: due at the beginning of lab
– Lab packet this week