During this experiment, tests are performed to determine whether or not various
temperatures change the population density of the green algae, Chlamydomonas
To correctly perform Equal amounts of
were placed in one of
three environments (4, 22, and 30º C), and their growth was monitored for 14 days.
at 22º C had the greatest increase in population density after each week.
The algae at 4º C had the least increase in population density after each week.
comparing the population densities, it is concluded that the alternative hypothesis is
rejected for the populations grown at 30º C because the readings from day 14 do not
show a significant difference in growth between 22º C and 30º C.
alternative hypothesis is accepted for 4º C.
In extreme temperatures, growth of
is restricted because the flagella are inhibited, decreasing motility.
exposure to extreme temperatures results in loss of flagella and, eventually, cell death
(Huang, Rifkin, and Luck, 1977). The results from day 14 signify that 30º C is not an
extreme enough temperature to inhibit growth in the populations of
is a unicellular green algae that is capable of self-
movement and has eyespots that detect light.
It is found in fresh water as well as in soil.
is a common choice for studies involving biology and ecology because of
its short life span, ability to reproduce both sexually and asexually, and ability to be both
a heterotroph as well as a facultative autotroph (“
The objective of this experiment was to find out what effect the temperatures, 4 º C, 22 º
C, and 30 º C, have on the population density of
course of 14 days.
In accordance to a similar study, an extreme cold or hot temperature
lowers the production rate of
(Spreitzer, 1988). These results show that a
grows the quickest in a lake at a point below the surface that
is not on the immediate surface or in the depths.
The deeper or shallower the depth, the
slower the rate of growth is going to be because these depths receive the most and least
amount of sunlight, reaching the highest and lowest temperatures (Janssen, 1999).