Biology 110
Exam 3 Study Guide
Evolution and its genetic basis
Assignment
Audesirk, Audesirk & Byers Selections from Chapters 14-16 & 18
Background and review
Figure 14-7
Homology Limb
Comparative anatomy, embryology, biochemistry, molecular biology
Homology - common descent
forelimbs:
bat (also pterodactyl, bird - fly)
dolphin (also seal - swim)
dog (also sheep - run)
human (also shrew - grasp)
Figure 18-6
Divergent (vs. convergent evolution)
Phylogenetic tree
Eukaryote evolution
isolating mechanisms
Remember, species can reproduce
Figure 16-10
speciation in the same area (sympatric)
Figure 16-9
and in different areas (allopatric). There are also other .
STORY
Moths use sex attractant pheromones from female sensed by big feathery antennae in males.
These may be molecules like acetates, chains10 to 15 carbons long.
Two similar moths in same place (sympatric) do not mate, thus seem to be 2 species (Roelofs and Comeau, Science 165, 398-
400, 1969).
One uses molecule cis around one double bond, the other trans.
For that to happen, one female would have to change pheromone used and a male at the same place and time would have to have
a change in preference, an amazing jump (saltation).
Divergent evolution
Figure 23-1
Comparative anatomy, embryology, biochemistry, molecular biology
Figure E18-1
can use "molecular" (biochemical) data to get relationships
Figure 14-11
also (cytochrome c sequence comparison between species)
Figure 24-1
Remember (and it is so confusing that it is hard to remember) that lower on the diagram are ancestors, not "simple" organisms
that are around today.
Figure 24-2
One "left-over" that helps to confuse this issue is the old saying "Ontogeny recapitulates phylogeny." Gill pouches and tail
suggest that people and birds go through a fish stage in their development.
Need to simplify by considering one gene
Box (a closer look)
The Hardy-Weinberg principle
Figure 12-11
Hey, this looks like a punnet square for the F2 of a cross with one gene and two alleles, except here, we have added probabilities
of the two alleles (p + q = 1) to get probabilities of the "4" genotypes (actually 3 since aA is the same as Aa)
"Adaptive significance," "selection pressures" and all those favorite jargons give the false impression that everything is the way it
is because of "deliberate" outcomes of evolutionary processes. But all kinds of things got to be the way they are through
"accidental" processes. (Furthermore, evolution cannot make an overall master plan but rather has to build on the successes and
mistakes of the past.)
Figure 15-5
Genetic drift
The frequency of alleles might change by this seemingly accidental mechanism.
