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BI158 > Chapter 26- Progeny > Flashcards

Chapter 26- Progeny Flashcards

1
Q

Phylogeny

A

the evolutionary history of a species or group of species

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2
Q

Systematics

A

a discipline focused on classifying organisms and determining their evolutionary relationships

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3
Q

Taxonomy

A

the discipline of naming and classifying organisms

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4
Q

Common names (2)

A

convey meaning in casual usage

Can refer to more than one species

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5
Q

Latin scientific name origin

A

Instituted by Carolus Linnaeus

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6
Q

Latin scientific name parts (3)

A

two-part format of the scientific name

The first part is the genus of the species

The second part is the specific epithet, which is unique to each species in a genus

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7
Q

Why is the latin scientific name used?

A

Avoids ambiguity

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8
Q

What is the linnaean system? (2)

A

Species > genus > family > order > Class > phylum > kingdom > domain

Does not reflect evolutionary history

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9
Q

What is taxon? (2)

A

named taxonomic unit

Taxa broader than genus isn’t italicized

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10
Q

Examples of taxon (2)

A

taxon of leopard at the genus level is Panthera

Mammalia is a taxon at the class level of mammals

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11
Q

What is a phylogenic tree? (2)

A

the evolutionary history of a group of organisms using a branching diagram

Matches how taxonomists grouped organisms

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12
Q

What does a phylogenic tree represent?

A

Represents a hypothesis about evolutionary relationships

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13
Q

Why do some species belong in the same genus even though they aren’t closely related?

A

Due to evolution, a key feature is lost that was once shared with the genus

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14
Q

What is an issue of a phylogenic tree?

A

it tells nothing about the group’s evolutionary relationships with anotherW

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15
Q

What is used to create accurate phylogenic trees?

A

DNA and new evidence

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16
Q

How do systematists create a classification system?

A

recognizing only groups that include a common ancestor and all its descendants

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17
Q

What are branch points?

A

divergence of two evolutionary lineages from a common ancestor

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18
Q

What is a sister taxa?

A

groups of organisms that share an immediate common ancestor

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19
Q

What does rooted mean?

A

a branch point represents the most recent common ancestor of all taxa in the tree

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20
Q

What is a basal taxon?

A

a lineage that diverges early in the history of a group

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21
Q

Wha is polytomy? (2)

A

a branch point from which more than two descendant groups emerge

Evolutionary relationships among the taxa are not yet clear

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22
Q

What are the three key points of a phylogenetic tree?

A

Show patterns of descent, not phenotypic similarity

The sequence of branching does not indicate the actual age of a species

Should not assume that a taxon on a phylogenetic tree evolved from the taxon next to it

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23
Q

What are reservoirs?

A

close relatives of a specific species possessing beneficial alleles that can be transferred and cross breed

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24
Q

How is phylogeny applied? (2)

A

Provides important info about similar characteristics in closely related species

Identifies species by analyzing the relatedness of DNA sequences from different organisms

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25
How is phylogeny inferred? (2)
Must gather info about morphology, genes, and biochemistry of relevant organisms Focus on features that result from common ancestry- reflects evolutionary relationships
26
What are homologies?
phenotypic and genetic similarities due to shared ancestry
27
What increases the likely hood of species being closely related?
similar morphologies or similar DNA sequences
28
What is an analogy?
similarity between organisms due to convergent evolution
29
What causes analogies?
Occurs when environmental pressures and natural selection produce similar adaptations in organisms from different evolutionary lineages
30
What are homoplasies?
analogous structures that arose independently
31
How are homologies and analogies distinguished? (4)
Corroborative similarities Fossil evidence Complexity of characters The more similarities in a complex structure, the more likely they share a common ancestor Comparison of gene level If two characters share the same sequence of nucleotides, the genes are homologous
32
Example of homology and analogy
Bats and birds Forelimbs are homologous Wings are analogous
33
How is DNA compared between similar species?
Closely related species differ bases at a few sites
34
How is DNA compared in distantly related species? (2)
Similar sequences can have a different origin Those distantly related differ and can have different lengths
35
How are computers used to compare DNA?
align this to compare it more easily They can also identify molecular homoplasies
36
What is cladistics?
Systematics where common ancestry is the primary criterion used to classify organisms
37
What are clades?
a group that includes an ancestral species and all of its descendants
38
What is monophyletic? (2)
consists of an ancestral species and all of its descendants Taxon is equivalent to a clade
39
What is paraphyletic?
consists of an ancestral species and some of its descendants
40
What is polyphyletic? (2)
distantly related species but does not include their most common ancestor Avoided by biologists, and reclassifies groups if it is polyphyletic
41
What is a shared ancestral character, and an example?
a character that originates in an ancestor of the taxon Ex- backbones in mammals
42
What is a shared derived character, and an example?
an evolutionary novelty unique to a clade, not found in their ancestors Ex- hair in mammals
43
What is an outgroup?
species from an evolutionary lineage that is known to have diverged before the lineage that includes the species we are studying (ingroup)
44
What are outgroups based on, and what is it used for?
Based on evidence from morphology, paleontology, embryonic development, and gene sequences Used to compare ingroup and outgroup to differentiate between shared derived and shared ancestral characteristics
45
What are branch lengths?
the longer the branch lengths, the more genetic changes have occurred
46
What is maximum parsimony? (3)
first investigate the simplest explanation that is consistent with the facts Requires the fewest evolutionary events Fewest base changes
47
What is maximum likelihood?
tree most likely to have produced a given set of DNA data, based on certain probability rules about how DNA sequences change over time
48
What is phylogenetic bracketing?
predicting features shared by two groups of closely related organisms are present in their common ancestor and all of its descendants unless independent data indicate otherwise
49
How are genes used to study evolution? (4)
Genes evolve at different rates Duplication of genes provides more opportunities for evolutionary changes Duplicated genes can be traced to a common ancestor Nucleic acids and other molecules are used to compare organisms’ evolution
50
How is rRNA used to study evolution?
DNA for rRNA changes slowly Useful for investigating relationships from a long time ago
51
How is mitochondrial DNA used to study evolution?
Mitochondrial DNA evolves rapidly Used to capture recent events
52
What are gene families?
groups of related genes within an organism’s genome
53
What are orthologous genes? (3)
homology is the result of a speciation event and hence occurs between genes found in different species Single copy in the genome Diverges in separate gene pools
54
What are paralogous genes? (3)
homology results from gene duplication Multiple copies of these genes have diverged from one another within a species Diverges within a species
55
What is genome evolution? (3)
Lineages that diverged long ago often share many orthologous genes The number of genes a species has doesn’t increase through duplication at the same rate as phenotypic complexity One gene can code for multiple proteins
56
Molecular clock
approach or measuring the absolute time of evolutionary change based on the observation that some genes and other regions of genomes appear to evolve at constant rates
57
What is molecular clock used for? (2)
Used to study prior to fossil record The older it is, he higher the degree of uncertainty Using multiple genes can improve estimates
58
Orthologous genes for molecular clocks
nucleotide substitutions are assumed to be proportional to the time since they last shared a common ancestor
59
Paralogous genes for molecular clocks
nucleotide substitutions are proportional to the time since the genes became duplicated
60
Neutral mutations and molecular clocks (2)
Neutral mutations occur more quickly Molecular change is regular
61
Irregular burst in molecular clocks (2)
cause changes in important functions Can also result from natural selection
62
First taxonomy classification
Plants and animals
63
First five kingdoms
Monera (prokaryotes), Protista, Plantae, Fungi, and Animalia
64
What are the current domains?
Domain Bacteria Prokaryotes Domain archaea Prokaryotic organisms that inhabit a wide variety of environments Domain eukarya Groups of single-celled organisms and multicellular organisms
65
Why is Kingdom Monera not used?
because it has members in two different domains
66
Why isn't Kingdom Protista used?
because it includes members related to plants and fungi rather than other protists
67
What is the first split?
when bacteria diverged from other organisms
68
What is horizontal gene transfer, and what does it lead to?
genes are transferred from one genome to another through mechanisms such as the exchange of transposable elements and plasmids, viral infections, and fusion of organisms This can lead to inconsistent results of trees built using different genes

BI158 (16 decks)

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