Chapter 53: Population Ecology Flashcards
Chapter 53
What is population ecology
- how biotic & abiotic factors influence abundance, dispersion & age structure of populations
Chapter 53
What is the difference between density and dispersion?
- density: # of individuals per unit area or volume (#/area)
- dispersion: pattern of spacing among indivduals wihtin boundaries of population
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What is the market capture method?
- estimates population size
- 1st capture: # of captured & tagged
- 2nd capture: ratio is set with # of tagged from 2nd capture over # of actual capture
- find “N”
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What are the three patterns of dispersion?
- Clumped: individuals gather in patches; influenced by resource availability, maitng beahvior, etc…
- Uniform: individuals are evenly distributed; influenced by territorality (defense of bounded space)
- Random: position of each individual is independent of other individuals; influenced by absence of strong attractions
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What are some factors that affect population growth?
- Birth rate - add individuals to a population
- Death rate - remove individuals from a population
- Immigration(in)/emmigration(out)
metapopulations: group of populations linked by emmigration & immigration
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What is demographics?
study of statistics of a population and how they change over time
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What is a life table?
- age specific summart of survival & reproductive rates in a population
- follows fate of cohort (individuals of the same age
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What is the relationship between a suvivorship curve and a life table?
this curve is the graphic way of representing the data of a life table
3 classifications:
1. type i: low death rate in early & middle life; high in elderly
2. type ii: constant death rate
3. type iii: high death rate early & low in survivors/elderly
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What is the mathematic expression of population growth rate?
change in N/change in T = B - D or R
N: population size
T: time interval
B: # of births
D: # of deaths
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What is exponentioal population growth?
- population growth under idealized conditions
- populations may increase in size by a constant proportion at each instant
- equation: dN/dt = rN (r: rate of exponential increase/growth)
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What is carrying capacity (K)?
max population size environment can support
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What is the logistic population growth model?
- per capita rate of population growth approaches zero as population size nears “K”
- produces S-shaped curve
- dN/dt = rN(K-N/K)
- when N=K, population stops growing
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What is an organism’s life history?
comprises traits that affect reproduction
* three main components:
1. age at first reproduction
2. how often organism reproduxed
3. # of offspring per reproductive episode
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What is the difference between semelparity & iteroparity?
- semelparity: reproduce once & die
- iteroparity: reproduce repreatedly
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What is the difference between density-independent & density-dependent populations?
- density-independent: birth & death rate do not change w/ population density
- density-dependent: birth rates fall & death rates rise w/ rising population density
