Chapter 26 Flashcards Preview

AP Biology Semester 1 > Chapter 26 > Flashcards

Flashcards in Chapter 26 Deck (50):
1

phylogeny

the evolutionary history of a species or group of related species

2

systematics

classifies organisms and determines their evolutionary relationships
-use fossil, molecular, and genetic data to infer evolutionary relationships

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taxonomy

the ordered division and naming of organisms

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binomial

the two part scientific name of a species

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genus

first part of the name of species

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specific epithet

second part of name of species

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the taxonomic groups from broad to narrow are ... (8)

1. domain
2. kingdom
3. phylum
4. class
5. order
6. family
7. genus
8. species

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taxon

a taxonomic unit at any level of hierarchy

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phylogenetic trees

systematists depict evolutionary relationships

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phylocode

which recognizes only groups that include a common ancestor and all its descendents

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a phylogenetic tree represents ...

a hypothesis about evolutionary relationships

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branch point

represents the divergence of two species

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sister taxa

groups that share an immediate common ancestor

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rooted tree

includes a branch to represent the last common ancestor of all taxa in the tree

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basal taxon

diverges early in the history of a group and originates near the common ancestor of the group

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polytomy

a branch from which more than two groups emerge

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phylogenetic trees show patterns of ____

descent, not phenotypic similarity

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do phylogenetic trees indicate when species evolve or how much change occurred in a lineage?

no

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to infer phylogenies systematists gather _____, ______, and ____

1. information about morphologies
2. genes
3. biochemistry of living organisms

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phenotypic and genetic similarities due to shared ancestry are ____

homologies

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similarity due to convergent evolution

analogy

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similarity due to shared ancestry

homology

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convergent evolution

occurs when similar environmental pressures and natural selection produce similar (analogous) adaptations in organisms from different evolutionary lineage

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homoplasies

Analogous structures or molecular sequences that evolved independently are also called
homoplasies

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homology can be distinguished form analogy by....

comparing fossil evidence and the degree of complexity

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the more complex two similar structures are, the more likely it is that they are ______

homologous

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molecular systematics

uses DNA and other molecular data to determine evolutionary relationships

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cladistics

groups organisms by common descent

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clade

a group of species that include an ancestral species and all its descendants

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do all groupings of organisms qualify as clades?

no

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monophyletic

signifying that it consists of the ancestor species and all its descendants

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paraphyletic grouping

consists of an ancestral species and some, but not all, of the descendants

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polyphyletic grouping

consists of various species with different ancestors

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in comparison with its ancestor, an organism has both ____ and ______

shared and different characteristics

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shared ancestral character

a character that originated in an ancestor of the taxo

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shared derived character

an evolutionary novelty unique to a particular clade

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outgroup

a species or group of species that is closely related to the ingroup, the various species being studied
-outgroup is a group that has diverged before the ingroup

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ingroup

the various species being studied

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characteristics shared by the outgroup and ingroup are ....

ancestral characters that predate the divergence of both groups from a common ancestor

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maximum parsimony

assumes that the tree that requires the fewest evolutionary events (appearances of shared derived characters) is the most likely

41

maximum likelihood

states that, given certain rules about how DNA changes over time, a tree can be found that reflects the most likely sequence of evolutionary events

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gene duplications increases the number of genes in the genome, providing....

more opportunities for evolutionary changes

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repeated gene duplications result in

gene families

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like homologous genes, duplicated genes can be traced to ....

common ancestor

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orthologous genes

found in a single copy in the genome and are homologous between species
-they can diverge only after speciation occurs

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paralogous genes

result from gene duplication, so are found in more than one copy in the genome
-they can diverge within the clade that carries them and often evolve new functions

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_____ genes are widespread and extend across many widely varied species

orthologous

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molecular clock

uses constant rates of evolution in some genes to estimate the absolute time of evolutionary change

49

natural theary

states that much evolutionary change in genes and proteins has no effect on fitness and is not influenced by natural selection
• It states that the rate of molecular change in these genes and proteins should be regular like a clock

50

horizontal gene transfer

the movement of genes from one genome to another
- occurs by exchange of transposable elements and plasmids, viral infection, and fusion of organisms
-complicates efforts to build a tree of life