MIDTERM

control variables

are all of the variables that you keep the same in each experimental treatment while you are manipulating the independent variable

control treatments

is the experimental treatment in which you do not manipulate the independent variable

**Population decreasing, death rate very low and birth rate lower than death rate**

stage 5

**High and stable birth rate, stable population size**

stage one

**Population size increasing exponentially, birth rates decreasing rapidly, death rates decreasing at a slowing rate**

stage 3

**Stable population with a high death rate**

stage 1

**Stabilizing population, decreasing birth rates and stabilized death rates**

stage 4

**The first stage in which family planning is a real aspect of life**

stage 4

**Population growing exponentially, death rates decreasing rapdily, birth rates stable**

stage 2

percent water by weight =

((moist weight - dry weight)/dry weight\*100)

(mass of water os soil/mass of dry soil)\*100

bulk of soil

(mass of soil/volume of soil)

volume of cylinder

pi(3.13159) r squared

particle density

dry mass of soil/ dry volume of soil

soil porosity percentage

(1-(bulk density/particle density))\*100

how to determine percentage of soil component

divide by height of layer by the total height of soil

percent water by mass

((volume of water)/(mass of soil)\*100)

density

number found/area searched

determining population size

density\*habitat size

population w/ mark and recapture

N = first time(second time/ ones marked found second time)

doubling time

70/ annual growth tate

exponential growth

r (how many produce per unit of time) \* the size of the population