种群数量增长的s型曲线中增长率和增长速率的区分（The distinction between growth rate and growth rate in the S type curve of population growth）.doc

种群数量增长的s型曲线中增长率和增长速率的区分（The distinction between growth rate and growth rate in the S type curve of population growth） The distinction between growth rate and growth rate in the S type curve of population growth In July 18, 2009 Wang Caixia 16:55 Views: 133 | comment number: 1 growth curve in the number of study population, many students do not understand the growth rate and growth rate, and in the exercise of the two are often confused, in fact, the two are different, the difference between the two total nodes are as follows. 1. growth rate: growth rate refers to the number of population growth per unit time, [growth rate = birth rate - mortality = birth number - death) / (unit time, unit number). Growth rates remained constant in the growth of the J - shaped population, while growth rates were smaller in the S - shaped growth curve. 2. growth rate: growth rate is the rate of population change per unit time, [growth rate = (birth death number) / unit time]. The rate of population growth is the slope of the curve through each point, and the slope on either the J curve or the S curve always varies. In the growth of J - shaped curves, the rate of increase is increasing. In the growth of S curves, the growth rate is the slope of the tangent of the point on the curve. The greater the slope, the greater the rate of increase, and when the slope is the maximum, it is 1/2K. Then the growth slows down and the rate of growth decreases gradually. When the S curve reaches the K value, the growth rate is 0. In the J growth curve, the annual growth rate remains unchanged; because the slope of the J growth curve is changing, increasing gradually until infinity, so its growth rate is also increasing. Growth in the S curve, the annual growth rate of the initial maximum value in environmental resistance (space pressure, lack of food etc.) under the action of lead to declining birth rates, increased mortality, the population reached the maximum value (K value), the growth rate declined