Download Study Guide for Exam III

BIL 107 – Introduction to Evolution
Krempels – Fall 2010
STUDY GUIDE FOR EXAM III
The History in Our Genes
Know the meaning/significance of: restriction enzyme, restriction fragment
Know the definition of parsimony/parsimonious, and how we apply this to
phylogenetic trees.
Understand how an allele of a gene can arise, and then go extinct in a
particular lineage of descendants (e.g., the ones in the ape phylogenetic
trees in Lecture 12). How can this complicate the job of determining
phylogenetic relationships when comparing alleles of this gene?
Know what is meant by congruent phylogenetic trees: Do multiple
congruent trees (made from different data sets) strengthen a hypothetical
evolutionary relationship? If you know what congruent trees are, you should
be able to answer this.
Know what a transposable genetic element (same as mobile genetic
element) is, and how it can be useful to biologists trying to determine
evolutionary relationships. What usually happens to a gene when a TGE
pops into it (during DNA replication)? What can happen when it pops back
out?
How do molecular data come into the picture when biologists try to
determine evolutionary relationships? Is comparing DNA the same as
comparing physical appearance/morphology? Can both types of data be
used and/or compared to construct phylogenetic relationships?
Study the Galapagos finches and their evolution. Did they evolve from one
ancestor or many? What explains the diversity of their bill shapes? (HINT:
Once again, the link to the UC Berkeley site is helpful.)
How do we know when and how many times HIV jumped from monkeys or
chimpanzees to humans? What is the most likely cause of this jump?
(HINT: read the link to the UC Berkeley site at the bottom of Lecture 12)
The Secret World of Bats: Video
Know these basic facts about bats. If you didn’t see the video, you
can still look up these facts at .edu and other reliable sites. But be
cautious! Just because it’s on the internet doesn’t mean it’s correct.
What is the function of the bat’s ornate nose “leaf” and large ears?
What is “echolocation”?
About what percentage of the world’s mammals are bats?
How many babies does a female bat usually produce per year?
When are most bats most active?
What is the significance of certain bat-pollinated flowers opening only at
night?
What ecologically beneficial functions do bats perform?
In areas where bats are hunted, why are they hunted?
What animals, besides humans, eat bats?
What are types of food are eaten by various species of bats? (Think of all
the foods you saw in the movie!)
Do all bats hibernate? (What about tropical species?)
Natural Selection vs. Neutral Evolution
Know the meaning/significance of: silent mutation, synonymous mutation,
DNA triplet code (i.e., three “letters” of the DNA that represent a single
amino acid), neutral mutation, Darwinian fitness,
Know the subtle but important distinction between silent/synonymous
mutation vs. neutral mutation.
Understand why the DNA of species that share a more recent common
ancestor with each other should be more similar than the DNA of two species
who share a relatively distant ancestor.
Know the basic things that a gene can encode (proteins, different types of
functional RNA such as tRNA and rRNA).
Know the meaning/significance of: functional RNA, pseudogene, proteome,
purifying selection, neutral evolution (=genetic drift), natural selection (=
positive selection).
Understand why a pseudogene should be expected to carry more silent
mutations than a gene under natural selective pressure.
Understand why a gene undergoing neutral evolution (genetic drift) should
have about equal numbers of silent and non-silent mutations.
Finally, Understand how the previous two statements can be used by
scientists to determine whether a gene is evolving due to natural selection,
genetic drift, or neither. (Remember the NS/S ratios!)
Study the story and understand the significance of the FOXP2 gene in great
ape evolution. (What does it control? What’s different about this gene in
humans? What happens to individuals who inherit a faulty copy of this
gene?)
Recall what is meant by: DNA replication, gene duplication (not the same
thing!), gene recruitment, mutations (be able to recognize examples of
deletions, duplications, substitutions)
What is the significance of the citrate-feeding E. coli and the PCP-feeding
Sphingobium bacteria we discussed in class? Be familiar with these two
stories and the evolution of these features.
Irreducible Complexity?
Know who Michael Behe and William Paley are/were, and what they said
about complex structures found in nature.
Understand how enzymes originally evolved to perform a particular in one
tissue can duplicate, mutate, and end up performing a different function.
For example, what did the protein that gave rise to the snake venom
crotamine originally do in the ancestral vertebrate?
Know the very basic structure of the vertebrate eye, and its main
components such as: lens, pupil, iris, retina, optic nerve, rod and cone
photoreceptors, cornea. What is the function of each of these structures?
Understand the progression of complexity that led to the vertebrate eye.
What were the precursors of the vertebrate eye like?
What was the original, most primitive function of the “serpentine” proteins
(G-protein coupled receptors, or GPCRs)? Into what did they evolve?
What is an opsin? What does it do? What is rhodopsin? Retinal?
Which type of photoreceptor (rod or cone) confers high resolution, color
vision, and day vision? Which one confers lower resolution, but higher
sensitivity to light (no color vision) and night vision? Do all animals perceive
visual stimuli, such as color, the same way?
What is the significance of crystalline proteins to the evolution of the
vertebrate eye?
Know the meaning/evolutionary significance of: genetic toolkit, Hox genes,
animal body segmentation (and identity), homology, duplication and
recruitment of Hox and other genes
What do Hox genes code for?
Know the main differences between a protostome and a deuterostome
animal, and be able to recognize common examples of each type of
creature. Carefully read this in your textbook.
Great Transformations: Video
Links to this video on YouTube are now linked to the lecture notes
site. But as you watch, here are a few notes to help you anticipate
what I might ask and to think about evolution.
Which came first: fish? Tetrapods? Whales? Understand the progression of
complexity.
What was special about the “wolflike” fossil’s skull that identified it as a
whale?
How long has life been on earth?
In the “hour” of life on earth, how long has human history taken?
What characteristics mark a whale as a mammal?
Are there transitional whale fossils? What were they like?
What’s the significance of the Sahara desert, and why are there whale fossils
in the “Valley of the Whales”?
What is different about the way tetrapods move as compared to fish?
(especially the spinal column)
Which came first: fish out of water, or fingers on fish?
Why might early limbs on aquatic tetrapods been an advantage?
What was the Cambrian explosion, and what is the evidence of it found
today?
What is the significance of the Burgess Shale (and where is it found?)
Does evolution change bodies, or the recipes for making bodies? What does
this mean?
What was the significance of the antennapedia gene in fruit flies?
Do all animals share the same basic genetic toolkit genes, or are they very
different across species? What evidence do we have for this?
What do lemurs tell us about the evolution of the human ability to walk
upright?
Are the locomotory methods used by lemurs and chimpanzees more
primitive than ours? More advanced? Equally advanced, but different?
What is knuckle walking? What is bipedalism?