Ecology Lec 10
Human population has increased, but the energy have also increase way more
Slow start, bubonic plague dip, after industrial revolution, skyrocketed
Growth rate has slowed to 1.18% per year, But rate has decreased BUT still increasing
population
Estimates of our K range from 1 billion to 1 trillion
Ecological footprint: total area of productive ecosystems required to support a population
- estimate how much space a person takes up based on resources, pollution etc etc
Remember ecological maxim: no population can grow in size forever
Life table: summary of how survival and reproductive rates vary with age
- Sx (survival rate)- chance that an individual will survive from age x to age x+1
- Lx (survivorship)- proportion of individuals that survive from birth to age x
- Fx (fecundity)- average # offspring a female will have at age x
Birth & death rates can vary greatly with different ages
Gambian survival depends on the season of birth- if born in the hungry season, lower
survivorship,
In some species, age doesn’t matter, SIZE matter, at a certain size, reproduction can occur
Survivorship curve:
Type I: most individuals survive to old age (sheep, humans)
Type II: the chance if surviving remains constant throughout life (some birds)
Type III: high death rates for young, ones that reach adulthood, survive well (species that
produce lots of offspring) Age structure: tells you how a population will grow… many people at reproductive age, will
grow, if most at post reproductive age, then will not grow
To predict population size next year:
1. Calculate number of people surviving to the next year
2. # of offspring these survivors will produce
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