GEOB 102 Lecture Notes - Lecture 15: Exponential Growth
2 Nov 2016
School
Department
Course
Professor
Dispersal & Population Dynamics
GEOB 102
October 26, 2016
Objectives:
- Contrast geographical and ecological dispersal
- Discuss factors that facilitate or inhibit dispersal
- Define population and list factors contributing to change in population size
- Draw graphs of exponential and logistic population growth and describe when to expect
each to occur
- Define carrying capacity
- Apply the above concepts to exotic species
Some Definitions
- Habitat: biophysical factors where a species lives that match its niche requirements
- Geographical range: entire extent of species distribution
Dispersal
- Ability to move from birth site to a new site
1. Ecological dispersal: within the geographic range
2. Geographical dispersal: expansion of range
a. Jump dispersal: long-distance dispersal, infrequent
b. Diffusion: slow extension of range over time
- Barriers: inhibit species from dispersing
- Geographic barriers: physical barriers
o E.g.:
▪ Mountain ranges
▪ Oceans
▪ Deserts, forests
▪ Climate
▪ Scale important—linked to size of organism
- Ecological barriers: biotic interactions
o E.g.:
▪ Disease organisms/parasites
▪ Predators
▪ Lack of prey
- Corridor: regions of similar climate and vegetation structure that facilitate dispersal
Exotic species: species that were directly or indirectly introduced to a new region by humans,
where they were not present before
Subset of these become invasive species →spread (via diffusion) in the new region
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GEOB 102 Full Course Notes
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Document Summary
Discuss factors that facilitate or inhibit dispersal. Define population and list factors contributing to change in population size. Draw graphs of exponential and logistic population growth and describe when to expect each to occur. Apply the above concepts to exotic species. Habitat: biophysical factors where a species lives that match its niche requirements. Geographical range: entire extent of species distribution. Ability to move from birth site to a new site: ecological dispersal: within the geographic range, geographical dispersal: expansion of range, jump dispersal: long-distance dispersal, infrequent, diffusion: slow extension of range over time. Geographic barriers: physical barriers: e. g, mountain ranges, oceans, deserts, forests, climate, scale important linked to size of organism. Ecological barriers: biotic interactions: e. g, disease organisms/parasites, predators, lack of prey. Corridor: regions of similar climate and vegetation structure that facilitate dispersal. Exotic species: species that were directly or indirectly introduced to a new region by humans, where they were not present before.
