Question 25 of 25
2 Points
A biologist began studying a population of bullfrogs. In 1998,
she found that most of the male frogs croaked, but some did
not. A bat species known to prey on male frogs migrated to
the area in 2005. The biologist returned to the area in 2008
and repeated population counts of male frogs. The table
shows her data.
1998
2002
2004
2008
Number of
noncroaking males
244
368
298
1086
Number of croaking
males
742
1165
791
305
What factor most likely caused the noncroaking male
population to increase after 2004?
O
A. Learning to avoid the new predator
O
B. Adaptation of the croakers in the presence of a new predator
O
C. Extinction of the croakers because of the new predator
O
D. Selective pressure in the form of a new predator
SUBMIT

With the description of the different cell walls, membranes, and associated proteins set in the students' minds, you now need to introduce them to the idea that the cell wall can also act as a foundation to build things upon. bacterial appendages require a strong foundation that will offer the support needed to move and function in a dynamic world. for example, flagella are long, whiplike protein structures that are used by many gram-positive and gram-negative bacteria for locomotion. in order to function effectively, a flagellum must be firmly anchored to the cell wall. how will you be able to get across the idea that the peptidoglycan cell wall is strong enough to support such a mechanism? with a protein rod that passes through the cell wall and protein rings used to anchor it in the membranes, these basal bodies are the rudimentary biological motors that use atp power to spin the hook and the flagella attached to it. bacterial flagella have a biological motor that spins within the cell wall and is powered by atp. this allows the flagella to spin in a whiplike motion to propel the bacterium.

The human genome project is devoted to mapping the general dna sequence of our species. this could lead to the development of new medicines, as well as the possibility of using gene therapy to treat certain diseases. however, there are some ethical issues surrounding the mapping of individual genomes. one concern is a) that your genes may change over time, making the project useless. b) that insurance companies could discriminate based on genetic make-up. c) that since this has never been done before, we should probably not do it now. d) that sequencing our individual genomes is so expensive, it is a counter-productive strategy.

What condition is kept close to its set point in osmoregulation? a. body temperature b.platelet count c.blood glucose level d.water balance