Exponential growth

To correctly mange the population we need to-

how populations grow. This is a fundamental process in ecology

Exponential growth and bacteria

Bacteria can divide every 20 minutes. if the mass of one bacterium is 1x10^-15 kg and the earth weighs 5.98x10^24 kg. After 44 hours, the E. coli colony would be the mass of the earth

why hasn’t E. coli got to the weight of the earth

It is mainly down to resources and competition

Population growth equation

N_t+1 = λN_t

how to calculate λ ((fraction that survived) + ((fraction that survived)(surviving births per female)(fraction female))

((fraction that survived) + ((fraction that survived)(surviving births per female)(fraction female))

Higher 𝝀

= faster population growth and this difference is greater at higher population sizes 

Fast and slow population growth

Higher 𝝀 = faster population growth and this difference is greater at higher population sizes 
At all growth rates, the population only grows fast when it gets big. Thus, exponential growth can be both slow and fast 
Slow when there aren’t many adults to have babies and fast when enough babies become adults and start to have babies 

Larger N0

= faster population growth, even with a low(ish) λ  
You need lots of adults to have lots of babies. But even if you have a lot of babies per adult if there are not many adults, the population grows slowly