Lab4_population

Lab4_population - Population Growth How population grow?...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Population Growth •A population's growth rate is the change in the number of individuals in the population ( Δ N ) per unit time ( Δ t ). • If no immigration or emigration is occurring, Δ N / Δ t=N ( b - d ) N is the number of individuals in the population b is the birth rate per individual; d is the death rate per individual • per-capita (“per individual”) rate of increase ( r ) is the difference between b and d . – Per capita = >, =. < 0 – When b is as high as possible and d is as low as possible, r reaches a maximum value called intrinsic rate of increase r max How population grow? The effects of resource and environmental conditions on population growth. Exponential Growth Exponential growth (logarithmic) occurs when r does not change over time. • It does not depend on the number of individuals in the population. population density is the number of individuals per unit area. • When increases in the size of a population do not affect r , growth is density independent .
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Logistic Growth • When population density gets very high, we would expect the population’s per-capita birth rate to decrease and the per-capita death rate to increase, causing r to decline.
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/25/2011 for the course BIO 138 taught by Professor Wu during the Summer '08 term at Staten Island.

Page1 / 7

Lab4_population - Population Growth How population grow?...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online