Download presentation
Presentation is loading. Please wait.
Published byScarlett Jennings Modified over 9 years ago
1
Ch. 5: Population Structure and Changes
2
Population Models 2) Continuous time models –dN/dt=Nr max Ideal conditions…
3
Population Models 2) Continuous time models –Limiting conditions –Logistic growth.
4
Population Models 2) Continuous time models dN/dt=Nr max (K-N)/K N small: (K-N)/K almost 1 N near K: (K-N)/K very small
5
Population Models Plant Point 1: K based on density Animals: most individuals have certain size Plants: high modular growth/plasticity Crowding capacity: combine density with biomass per individual.
6
Population Models Plant Point 2: “Law” of constant yield Yield same Great Phenotypic Plasticity
7
Population Models 3) Discrete-time period models (complex): life tables BIOL 3060 Cemetery lab
8
Population Models Types: –Cohort life table: follow –Static life table: assume
9
Oldest known tree Bristlecone Pine (Pinus longaeva). High mtns. How age?
10
Oldest known tree Increment borer: extract
11
Oldest known tree Oldest was 4,950 yr (NV mountains)
12
Oldest known tree Now oldest (“Methuselah”) 4,767 yr.
13
Population Models Survivorship (l x ): proportion orig.
14
Population Models Survivorship curves: mortality Type I: Annual plants. Type II: Type III: Perennial Note log scale on Y axis!
15
Age distributions Predictive? Ex, pine/hardwood succession
16
Age distributions Often, stable pop’n L-shaped Ex, red spruce (Picea rubens)
17
Age distributions Some species: episodic establishment –Sporadic Jack…
18
Age/stage distributions Serotinous cones (closed-cone pine) –Seed
19
Population Models 3) Model: life table info + fecundity info Fecundity: age- Survivorship & fecundity give net reproductive rate (R 0 ): R 0 = ∑ l x b x
20
Population Models R 0 = ∑ l x b x Ex: Age Survivorship (l x ) Fecundity (b x ) Reproduction 0-11.00 1-20.23 2-30.15 3-400 R 0 = 1.1
21
Population Models R 0 >1, R 0 =1, R 0 <1,
22
Population Models 4) Transition matrix models Life history stages + matrix algebra Fig. 5.6 Matrix.. Trillium! SL 1L 3L
23
Population Models Matrix algebra Matrix: numbers rows/columns
24
Population Models Ex: Column matrix (vector) = pop’n status: population vector Life history stages: s=seeds, r=rosettes, f=flowering 140 16 10 # seeds # rosettes # flowering Lab 1: who am I? Rosette forming perennial
25
Population Models Transition matrix: probability transition
26
Population Models Ex: teasel (Dipsacus sylvaticus) Perennial pasture/roadside weed.
27
Population Models Transition matrix: teasel (Dipsacus sylvaticus) Note columns don’t always sum to 1.0: accounts for mortality
28
Population Models Model: pop’n vector X transition matrix New matrix: pop’n structure next time
29
Population Models Ex: 3 stages. Seed, rosette, flowering Pop’n vector 140 20 10 # seeds # rosettes # flowering
30
Population Models Ex: 3 stages. Seed, rosette, flowering Transition matrix 0.5 0.2 0 seed rosetteflowering seed rosette flowering year 1 year 2 0 0.2 0.5 20 0.2 0.1 Note: columns not summing to 1.0 includes mortality
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.