BIOL1003 Lecture Notes - Lecture 18: Eastern Gray Squirrel, Tropical Rainforest, Exponential Growth
Competitive Exclusion
• Grey squirrel driving red squirrel to extinction
• Red squirrel: smaller, lower mass
• Plan: increase predator number —> grey squirrels and bigger, slower, better target
Biodiversity hot spots
• >1500 species of endemic vascular plants
• Lost 70% of their original habitat
• 34 on the planet
• Generally have more niches available —> over evolutionary time, more resilient to
change
• Very productive
• Tropical rain forest species
◦ Potential anti cancer activity
◦ Several compounds mainly from edible plant species or plants used as dietary
supplements that may act as chemo preventative agents
Population Ecology
• Includes environmental influences on population density and distribution, age structure
and variations in population size.
• Range: population versus species range
• Dispersion: moving on new habitat
• Dispersal: how populations are dispersed in the space in which they are located
◦ Random neutral interactions between individuals, and between individuals and
the local environment
◦ Regular
▪ Antagonistic interactions between individuals or local depletion of
individuals
▪ Koalas—> regrowth of trees in regular pattern
◦ Clumped
▪ Attraction between individuals or attraction of individuals to a common
source
Population growth
Factors that affect population growth
• Sources of increase:
◦ Birth
◦ Immigration
• Sources of decrease:
◦ Death
◦ Emigration
Growth rates
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• Growth rate (r) is determined by birth rates (b) and mortality rates (m)
• b–m=r
• If r = 0 : no growth r > 0 : population increase r < 0 : population decrease
• Intrinsic rate of growth (rmax) is the rate of growth with no extrinsic (external –
limiting-) factors
◦ rmax is characteristic of the species
Exponential
Number of births (B) - Number of deaths
find more resources at oneclass.com
find more resources at oneclass.com
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Competitive exclusion: grey squirrel driving red squirrel to extinction, red squirrel: smaller, lower mass, plan: increase predator number > grey squirrels and bigger, slower, better target. Biodiversity hot spots: >1500 species of endemic vascular plants, lost 70% of their original habitat, 34 on the planet, generally have more niches available > over evolutionary time, more resilient to change, very productive, tropical rain forest species. Several compounds mainly from edible plant species or plants used as dietary supplements that may act as chemo preventative agents. Random neutral interactions between individuals, and between individuals and the local environment. Antagonistic interactions between individuals or local depletion of individuals. Attraction between individuals or attraction of individuals to a common source. Factors that affect population growth: sources of increase: Number of births (b) - number of deaths. Population peaks at an intermediate level, when n=k/2: factors preventing exponential growth. Logistic growth is sometimes a good model, but not always.
