Download Chapter 25 Reading Guide

AP Biology Reading Guide
CHAPTER 25: Phylogeny & Systematics
Directions
1) Before you read the chapter, decide whether you think each statement is true or false. Circle your
choice. If you are uncertain, write in a question mark and circle it.
2) As you read the chapter, identify whether each statement is true or false according to what you have
read. Circle the answer and note the evidence in complete sentences.
3) Was your thinking changed or reinforced by what you read? If so, in what way?
4) Be prepared to share your answers with the class.
Before
Reading
True
False
Statement
True
False
2. Organisms that share very similar morphologies or DNA sequences are likely to
be less closely related than organisms with very different structures and genetic
sequences. But analogy (similarity due to shared ancestry) must be sorted from
homology (similarity due to convergent evolution).
Evidence:
True
False
True
False
3. Linnaeus’s system gives organisms two-part names: a genus plus a specific
epithet.
Evidence:
True
False
True
False
4. Linnaeus introduced a system for grouping species in increasingly broad
categories.
True
False
1. The fossil record is based on fossil organisms preserved in geologic strata of
different ages and reveals ancestral characteristics that may have been lost.
Evidence:
Evidence:
After
Reading
True
False
True
False
5. Systematists depict evolutionary relationships as branching Phylogenetic trees,
which may be based on one type of evidence.
Evidence:
True
False
True
False
6. A clade is a monophyletic grouping of species that includes an ancestral species
and all its descendants. In cladistic analysis, clades are defined by their evolutionary
novelties, or shared derived characters. These are identified by comparing outgroup
species with an ingroup species that does not have the shared derived character.
Evidence:
True
False
True
False
7. In ultrametric trees, the length of a branch reflects the number of evolutionary
changes in that lineage. Phylograms place evolutionary branch points in the context
of geologic time.
Evidence:
True
False
True
False
8. Among Phylogenetic hypotheses, the most parsimonious tree is the one that
requires the fewest evolutionary changes, and the most likely tree is the one based
on the most likely pattern of changes.
Evidence:
True
False
True
False
9. The best Phylogenetic hypotheses are those that are consistent with the most data:
morphological, molecular, and fossil.
Evidence:
True
False
True
False
10. Paralogous genes, found in a single copy in the genome, can diverge only after
speciation has taken place. Orthologous genes arise through duplication within a
True
False
genome and can diverge within a clade, often adding new functions.
Evidence:
True
False
11. Orthologous genes are often shared by distantly related species. The relatively
small variation in total gene number in organisms of varying complexity indicates
that genes in complex organisms are extremely versatile and that each gene can
perform many functions.
Evidence:
True
False
True
False
12. The base sequences of some regions of DNA change at a rate consistent enough
to allow dating of episodes in past evolution. These molecular clocks may result
from the fixation of neutral mutations, but even when selection plays a role, many
genes have tended to change in clocklike fashion over long periods of time.
Researchers have measured some molecular clocks and shown that they are
remarkably constant. Other genes, however, change in a less predictable fashion.
Evidence:
True
False
True
False
13. The tree of life has three great clades (domains): Bacteria, Archaea and Eukarya.
Evidence:
True
False