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45 Cards in this Set
- Front
- Back
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What is a phylogenetic history?
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diagram showing history of descent of a group of taxa from common ancestors, including order of branching
-sometimes absolute times of divergence |
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What types of traits can be used to infer phylogenetic relationships?
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-independent, not linked
-homologous, similar ancestry -conservative, not easily reversed |
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What is a homologous trait?
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found in a group of species, from common ancestor
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What is a synapomorphy?
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from common ancestor and modified in common ancestor
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Why are synapomorphies important?
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identify evolutionary branch points
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What is a cladogram?
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phylogenetic tree deduced by clustering synapomorphies
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Trait “little d” is a synapomorphy for which species or species?
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s3 |
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How are synapomorphies represented in the figure above?
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a bar across the branch in the cladogram
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What is an outgroup?
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therapod dinosaurs, closest relative to entire group of birds |
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Why do scientists often use both mitochondrial and nuclear genes to reconstruct phylogenies?
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mitocondrial genes are maternalnuclear are both parents , independent
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Why is the use of multiple independent traits necessary when conducting a phylogenetic analysis?
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can sort through the noise to accurately reconstruct the phylogeny |
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What is convergence?
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2 species with similar trait but no common ancestor, similar selection pressure
-sugar glider and flying squirrel |
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How did two genetically unrelated species (sugar gliders and flying squirrels) end up withvery similar thin pieces of skin between their legs that allow them to glide between trees?
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similar selection pressure
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What is a phylogenetic reversal?
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derived trait reverts to ancestral trait
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What reversal is there in the evolution of the yucca moth?
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egg laying flower
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Describe the reversal depicted in the slide above.
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amino acid adinine changes to tymine
- changes back to adinine |
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Why is it important that traits are “conservative”?
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not easily reversed or conserved
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What is parsimony?
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simplest answer is usually correct one
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Which of the two scenarios above is the most parsimonious? Why?
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the bottom tree. all traits arising independently is unlikely
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Describe how the presence/absence of teeth, flight, fur and live offspring are used to group bats, mice and sparrows in a phylogenetic tree.
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since mice and bats share live offspring, fur, and teeth they can be grouped together. flight arose independently in bats and birds |
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Why of the three phylogenies above is the most parsimonious? Why?
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bottom, because only has 5 evolutionary transitions |
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There are two hypotheses regarding the origin of whales. What are they?
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morphological characters, DNA sequences -sister species to hippos -outgroup of hooved mammals |
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Why is the astragalus in hooved mammals important to our discussion of the origin ofwhales?
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present in hooved mammals whales either never had it OR was gained and lost over evolution |
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What other characteristics do hooved mammals have in common?
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skull and dental characteristics |
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Which of the two phylogenetic trees incorporating the astragalus trait is most parsimonious?18
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left figure, whales are out group
-only 1 character change |
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Which of the molecular markers above are informative? Why? |
162, C ancestral trait, T derived
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Based on the molecular markers, which of the phylogenetic trees above is the mostparsimonious?
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right |
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When scientists have to choose between multiple trees, what methods can they use?
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What bootstrap value is there for the relationship between whales and hippos?
bootstrap greater than_____ is statistically significant |
99 70 |
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What are LINES and SINES? Why are they reliable characters?
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-short/ long interspersed elements
-can be used as a character -minimzes convergence and reversals |
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What fossil evidence was found that supports the hypothesis that whales and hippos weresister species?
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4 species of terrestrial long tail whales, with astragalus - |
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How can the distance method be used to build phylogenetic trees?
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looking at difference in nucleotide bases |
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What is a monophyletic group?
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What is a paraphyletic group?
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Why are fish a paraphyletic group?
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include reptiles and mammals as descendants
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What examples of convergence are illustrated in this slide?
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- wings birds bats
-eyes in crocodiles and hippos -thin skin in sugar gliders and flying squirrels |
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What is phylogeography?
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geographic distribution of species over time
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There are 134 species of chameleons. Where are they found and what supercontinent were their ancestors found on?
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africa, madagascar, india, indian ocean islands-gandwano
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The Gondwanan breakup hypothesis argues that the chameleons did not disperse between islands after the initial break-up of the landmass, what evidence did C.J. Raxworthy and colleagues find for or not for this hypothesis?
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continued to move between landmasses after break up of gondwana
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What is cospeciation?
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extreme form of coevolution
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Aphids have bacteria in their cells that produce _____________ that aphids are unable to produce themselves. Female aphids pass these bacteria to their offspring through their _____________.
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honeydew, gametes |
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What evidence is there that aphids and bacteria cospeciated?
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DNA sequence data |
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When and where were the three major outbreaks of the plague?
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541-767AD
-1346- early 19th century Asia and Europe -1800s china |
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Where do the three different strains of the plague exist today?
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all from one of the 3 great historical plagues
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What did Dr. Achtman learn about the evolutionary history of the three different strains?
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sequences multiple Representatives of 3 plagues
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