AP Bio—Unit 8 Evolution
Review Station Answers
Station 1
1. Conditions “right” on early Earth for life.
a. Reducing environment—without oxygen gas and other oxidizing molecules
b. Energy from…UV Light and Lightning
2. Simple Organic Molecules
a. Examples—amino acids, sugars, nitrogenous bases
3. Polymerization
a. Water turns into gas—dehydration by vaporization=dehydration synthesis
(making bond) by vaporizing water from the building block molecules
4. RNA World (Or Lipid Membranes)
a. Self-replicating—can make copies of itself
5. Lipid Membranes (Or RNA World)
a. Lipids form spheres because they are hydrophobic.
6. Prokaryotic Cells
a. Archaea and Bacteria—see chart for differences….
7. Eukaryotic Cells
a. Membrane enfolding—membranes folded in to make ER, Golgi apparatus,
Nuclear Membranes
b. Endosymbiosis—small prokaryotes engulfed by larger prokaryotes—mutualistic
relationship. Applies to mitochondria and plastids.
Station 2—Hardy Weinberg
a. ww= 490 individuals
q2 = .49
q = .7
p = .3
p2 = .09
2pq = .42
WW = 90 individuals
Ww = 420 individuals
b. No selection, no gene flow (migration), no mutations, mating is random, breeding
population is large
c. Probably so…whether a person has a widow’s peak or not does not necessarily determine
sexual selection??? Also depends, though, on the size of the population, though!
Station 3
a. Temporal Isolation-- Timing of reproduction is not compatible.
b. Behavioral Isolation-- Mating, social, hunting, etc., ways of acting do not match.
c. Mechanical Isolation-- Reproductive anatomy does not match.
d. Gametic Isolation-- Egg and Sperm do not recognize each other.
e. Habitat Isolation-- Organisms do not have access to where each other live.
f. Hybrid Inviability-- Zygotes do not mature.
g. Hybrid Sterility-- Offspring do not produce functional gametes.
h. Hybrid Breakdown-- Offspring are weak- or offspring of offspring are weak/ infertile.
Station 4
Mutation
A change in a gene results in a new variety of color in wildflowers. This variation may/or may
not become an adaption.
Gene Flow
ABO blood groups give evidence to human migration patterns.
Natural Selection
Historically horses were smaller, but as the environment changes and conditions grew dryer
(food more scarce) horses with longer legs are found in the fossil record. (Note! How did the
horses get longer legs?)
Genetic Drift
A high degree of albinism exists among Hopi Indians compared with other tribes in the area.
An earthquake wipes out the salamanders on one side of a mt. pond. The resulting population has
a change in gene frequency of size of salamanders. (Used to be 50% small and 50% large. Now
more small ones remain)
Non-random Mating
Station 5—What do the following have to do with evolution?
a. Wallace—Through his studies, he developed the idea of natural selection separate from
Darwin. He thought all evolution occurred this way, though. Consequently, he didn’t
think natural selection and evolution applied to humans.
b. Biogeography—Allows us to observe similarities among different organisms in the same
area versus different organisms in different geographic locations. Helps show patterns in
evolution
c. Stabilizing Natural Selection—it’s natural selection in which not much evolution occurs.
There is no change in environmental pressures, therefore, no drastic change in gene
frequencies.
d. Fossils—provide evidence of large changes that have occurred over time.
e. Sexual Dimorphism—frequencies of certain traits are different for males vs females in a
specific population. For example, male birds tend to be much more colorful than female
birds. (Often results from sexual selection.)
Station 6
Type of
Evolution
Explanation
Example
Conditions necessary in
environment.
Divergent
Branching of one
lineage into two
Any speciation event
Adaptive
Radiation
Lineages branch into
many lineages that
disperse away from
another
Mammals rapidly
Environmental change is drastic
evolved after
and/or ecological niches open
extinction of dinosaurs because of mass extinctions
Convergent
Morphologically
distinct lineages that
were only distantly
related evolve in such
ways that they end up
resembling each other
Marsupials /
Eutherians
1. Competition is increased
by an environmental
change
2. Population is
geographically separated
and in 2 different env.
Same niche but geographically
isolated
Station 7
1. No. They are still considered the same species because they can interbreed.
2. They need to become reproductively isolated. Most likely scenario…
a. Population is geographically split.
b. Natural selection / evolution occurs in different environments
c. If brought together, they can no longer reproduce together and / or have viable
offspring.
3. No.
4. Natural selection is occurring.
5. 33% dominant allele.
Station 8
2. White
3. Share a common ancestor
4. Wing and arm—same bone structure
1.
Dophin
Black / Gray
Bat
White Bat
Newly Discovered Bat