Chapter 4 Flashcards
Linnaean taxonomy and the resulting system of scientific nomenclature
was derived from evolutionary thinking*; has been used by biologists for nearly 3 centuries
*double check the first part on ppt
Charles Darwin
Inferred the patterns of common ancestry with out a mechanistic understanding of genes and hereditary; developed a hypothesis about past events that later became testable; argued that humans descended from another primate species
Carolus Linnaeus (1707-1778)
Was a Swedish botanist, zoologist and physician; wrote Systema Naturae; had the insight that organisms can be organized into a system hierarchical classification without having a theoretical explanation for why these patterns should exist
German biologist Willi Hennig (1913-1976)
Established the modern approach to classification; documented evolutionary history in his book Phylogenetic Sytematics; notes that phylogenetic trees can help us to classify organisms according to their evolutionary history
The study of phylogeny predominantly aims to
understand the branching relationships of populations as they give rise to descendant populations over time
The study of phylogeny allows us to understand the
major events in evolutionary history; history of descent; relationships among taxa of organisms
The study of phylogeny rests on our observation of traits, which may include
anatomical features; embryological processes; genetics sequences
Which of the following statements about pedigrees and phylogenies is true?
A pedigree tells us about the ancestry of individuals, whereas most phylogenies tell us about the ancestry of populations
Traits are critical in the study of phylogeny because
We use observations of traits to infer patterns of ancestry and descent among populations;
By mapping individual traits onto a phylogeny we have already created, we can study the sequence and timing of evolutionary events
A trait that is similar in one or more species even though it was not present in their common ancestor is called a
homoplasy
Although they serve no current functions, vestigial traits persists in some organisms because
the trait is not costly to the organism; natural selection does not act against the trait; there is some NS against the trait, and it is on its way out- eventually will be lost
Which of the following terms is used for a situation in which the derived trait has arisen recently and appears in only one of the two most related species or populations, while the two most distantly related groups share the same trait?
SYMPLESIOMORPHY
Suppose a population of traits splits into two descendant populations prior to the evolution of dark coloration, then splits again after the evolution of dark coloration. Which of the following terms best describes the dark coloration trait in this situation?
Synapomorphy
Convergent evolution occurs when
Two or more populations or species become more similar to each other because they are exposed to similar selective conditions
Divergent evolutions occurs when
Closely related populations or species diverge from one another because natural selection operates differently on each of them
Analogous traits are found in two or more species because
some evolutionary process (usually NS) has independently fashioned similar traits in each species
Homologous traits are found in two or more species because
those traits are from a common ancestor
By placing a given trait on a phylogenetic tree that we have already constructed using other data, we can
generate a hypothesis about when and how this trait evolved
cladogram
a tree with aligned branch tips that indicated only the evolutionary relationships among the taxa shown
Phylograms
A tree in which branch lengths represent the relative AMOUNT of evolutionary change
Chronograms
A tree in which branch lengths represent actual TIME rather than the amount of evolutionary change
Based on the figure of flower color and morphology (shape), which of the following statements are true?
NONE:
- flower shape was used to infer this phylogenetic tree
- the origin of a new flower shape evolved after the origin of dark color
- the origin of a new flower shape evolved before the origin of dark color
Based on the phylogenetic tree above, which of the following groups is most closely related to mammals?
All reptiles and birds
Based on the figure above on genetic sequence data, which of the following statements is true?
There is a one base change between the analyzed sequences of lineages 1 and 2
Based on the two phylogenetic trees (with time) figure, which statement is true?
The two phylogenies of the vertebrae shown illustrate exactly the same information
Based on the two phylogenetic trees (with time) figure, which of the following two groups are most closely related?
Birds and crocodilians
Based on the two phylogenetic trees (with time) figure, the two roots (labeled) represent which of the following?
- Ancestral populations
- A common ancestor of birds and crocodilians
- A common ancestor to all tetrapods
- The ancestral lineage from which all other lineages on the tree are derived
Based on the two phylogenetic trees (with time) figure, what does the upper dot in each figure represent?
An ancestral population; the most recent common ancestor to all tetrapods
Based on the two phylogenetic trees (with time) figure, what does the INTERIOR dot in each figure represent?
An ancestral population; common ancestor of birds and crocs
Based on the two phylogenetic trees (with time) figure, which is true?
Fish is not a monophyletic group; Tetrapod vertebrates is a monophyletic group
Vestigial traits serve as a strong test of Darwin’s theory of evolution by common ancestry. Based on the figure, which limbless organisms would you expect to find vestigial limbs?
Snakes
Based on the figure (shrublike or treelike species circled in black), which of the following is true?
For the herbaceous species, the branch lengths tend to be longer, and the rates of sequence change faster
