Ch 4: Population Biology

• Trade-offs: benefit of excelling in one thing comes at a cost of another
• Fecudity: number of offspring per individual
• Survival: ability to stay alive and grow
• Animals with low fecudity put more effort into offspring and this is why they have high survivorship rates
• r-selected species: high rate of population growth but poor competitive ability; typically die
• k-selected species: more or less stable populations adapted to exist at or near carrying capacity, low reproductive rates and highly competitive
• Type I survivorship curve: low young death and most die old
• Type II survivorship curve: uniform death rate
• Type III survivorship curve: juvenile loss high and then low loss for survivors
• The world population is increasing at a rate of 153 people every minute.
• The human population growth fits an exponential growth pattern
• There was low population until agriculture advanced and animal domestication
• Exponential growth equation: dN/dt=rN. N= population size. r= growth. d= change in time
• Logistic growth equation: dN/dt=rN(K-N)/K. K=carrying capacity
• Ecological footprint: the impact of human activities on the environment, measured in terms of the amount of land and water needed to produce the resources that people consume