Taxonomy and phylogenetics! Flashcards
(137 cards)
1
Q
What does taxonomy underlie?
A
Medicine genetics biochem ecology ethology botany zoology
2
Q
Why is taxonomic identification important?
A
Misidentification can affect economy food security and health
3
Q
How can pathogen misidentification impact health?
A
Prevents accurate identification of disease strains and vectors
4
Q
What’s an example of misidentification in agriculture?
A
Cassava mealybug misidentified in Africa delaying control programs
5
Q
How was taxonomy used in the covid-19 response?
A
Viral strain classification influenced vaccine and policy decisions
6
Q
What is taxonomy?
A
Identifying describing classifying organisms and preserving collections
7
Q
What are early examples of classification?
A
Indigenous populations independently developed rudimentary systems
8
Q
What survival value does classification have?
A
Helps distinguish edible from poisonous and harmless from dangerous
9
Q
What was Aristotle’s classification based on?
A
Land dwellers water dwellers air dwellers
10
Q
What proportion of species are currently catalogued?
A
About 10 percent
11
Q
How long might it take to record all species?
A
Estimated 260 to 2000 years
12
Q
Which group includes the majority of species?
A
Insects
13
Q
What other group has many uncatalogued species?
A
Fungi
14
Q
Where are many unknown species likely to be found?
A
Threatened areas
15
Q
What is the first step of classification?
A
Delimiting populations into species
16
Q
Who is the father of modern taxonomy?
A
Linnaeus
17
Q
What is the taxonomic hierarchy?
A
Domain kingdom phylum class order family genus species
18
Q
What is binomial nomenclature?
A
Genus species italicised with Genus capitalised
19
Q
What happens after a genus is first mentioned?
A
It can be abbreviated to its first letter
20
Q
What scientific advances occurred in the 1700s and 1800s?
A
Theories of evolution and extinction fossilisation anatomical studies
21
Q
What did Lamarck believe?
A
Organs increase in complexity and environment drives evolutionary change
22
Q
Why was Lamarck wrong?
A
He misunderstood change as lack of selective pressure not a positive force
23
Q
What did Darwin observe in finches?
A
Variation in beak morphology related to environment
24
Q
What key ideas did Darwin develop?
A
Common descent and natural selection
25
Why are taxonomic groups similar?
They reflect evolutionary history from common ancestors
26
What did Wallace propose?
Species share common ancestors and show descent patterns
27
Who had similar ideas before Darwin and Wallace?
Hunter
28
What is natural classification based on?
Evolutionary history
29
Why is defining species challenging?
Biologists disagree on what constitutes a species
30
What is the typological species concept?
Classification based on morphology or appearance
31
What is a limitation of the typological concept?
It ignores intraspecific variation
32
What is the biological species concept?
Based on genetics and reproductive isolation
33
What are criteria for the biological species concept?
Interbreeding and gene pool coadaptation
34
What is reproductive isolation?
Barriers preventing interbreeding between divergent populations
35
What are prezygotic isolation mechanisms?
Habitat morphology behaviour and gametes
36
What are postzygotic isolation mechanisms?
Hybrid sterility or inviability from gene incompatibility
37
What is the typological species concept based on?
Morphology and overall similarity including intraspecific variation
38
What is a pro of the typological species concept?
Morphology is easy to observe and communicate
39
What is a con of the typological species concept?
Ignores cryptic species and intraspecific variation and is artificial
40
What is the biological species concept based on?
Interbreeding and producing viable offspring in the wild
41
What is a pro of the biological species concept?
It is based on a biological mechanism
42
What is a con of the biological species concept?
Excludes asexual organisms and fossils and struggles with intermediacy
43
What is evolutionary intermediacy?
Populations in the process of becoming separate species
44
What is an example of evolutionary intermediacy?
Ring species and anagenesis in paleospecies
45
What defines biospecies?
Reproductive isolation and non interbreeding
46
How do taxonomists define morphospecies?
Using morphological traits as indirect evidence of reproductive isolation
47
What does distinct morphology usually indicate?
Intrinsically isolated gene pools or species
48
What is a cryptic species example?
Common pipistrelle bats with different echolocation but same morphology
49
What are ring species?
Connected populations where neighboring groups can interbreed but distant ones cannot
50
What are paleospecies?
Extinct species distinguished from others by anatomical differences in fossils
51
What are allopatric populations?
Populations that are geographically isolated and not interbreeding
52
What are sympatric populations?
Coexisting populations with no intermediate forms in the overlap zone
53
What does it mean if ruddy and whistling ducks are subspecies?
They are local populations of the same species differing taxonomically
54
What is a subspecies?
Aggregate of local populations within a species in different geographic areas
55
Can subspecies be sympatric?
No they must inhabit different areas
56
What causes reduced gene flow in subspecies?
Physical barriers causing isolation
57
What are incipient species?
Subspecies in the process of becoming biological species
58
What is a polytypic species?
A species with several subspecies each with a trinomial name
59
What is an example of a polytypic species?
Many bird species
60
What issue arises with human lice?
Two morphologically distinct forms are rarely found on the same host
61
What is the recognition species concept based on?
Recognition between allopatric populations as potential mates
62
What is a pro of the recognition species concept?
Removes uncertainty about allopatric populations
63
What is a con of the recognition species concept?
Excludes asexual organisms fossils and intermediates
64
What is the phylogenetic species concept based on?
Smallest monophyletic grouping on a phylogeny
65
What is a pro of the phylogenetic species concept?
Explicitly includes evolutionary history and uses various data types
66
What is a con of the phylogenetic species concept?
Arbitrary divisions and ignores subspecies and ring species
67
What is the genetic species concept based on?
Genetic similarity or distance
68
What is a pro of the genetic species concept?
Can uncover cryptic species and deal with asexual organisms
69
What is a con of the genetic species concept?
Relies on subjective thresholds and hard to explain to nonspecialists
70
What are the purposes of classification?
To store information and make predictions
71
What is classification based on?
Morphology
72
What is delimitation?
Grouping animals that share more features with each other than with others
73
What is ordering in classification?
Grouping similar animals into larger related groups
74
What is an example of ordering?
Indian and Javan rhinos in one group then grouped with tapirs and horses
75
What happened post Darwin in taxonomy?
Interest in phylogenetic trees increased
76
What is the danger of the tree concept?
The tips are not more evolved or better than others
77
What is phylogenetic reconstruction?
Creating trees using molecular genetic data
78
What are dendrograms?
Tree diagrams showing hierarchical relationships of groups
79
What does ranking involve in taxonomy?
Conferring status to groups above species level
80
What is topology in phylogenetics?
The arrangement of tree branches and how taxa are grouped
81
What is phenetics based on
overall phenotypic similarity
82
How are all characteristics treated in phenetics?
given equal weighting regardless of type
83
Does phenetics consider evolutionary history?
no it ignores genealogy and evolutionary history
84
What is a phenogram
a tree showing overall similarity not evolutionary relationships
85
What is a key problem with phenetics
it cannot account for convergent evolution leading to misleading similarities
86
What causes convergent evolution
similar selection pressures
87
Why do limpets and barnacles appear similar
due to phenotypic convergence from wave and current action
88
What does homologous mean
same embryonic origin
89
What does analogous mean
same function, but not origin
90
Are barnacles and crabs homologous or analogous
Homologous - they share origin of armoured covering and jointed limbs
91
What is mimicry in convergent evolution
resemblance of one species to another due to selection pressure
92
Give an example of mimicry
nonvenomous snakes resembling venomous ones
93
What is cladistics based on?
Inferred genealogy and evolutionary history
94
What are cladograms based on and what are they?
They are the trees showing clades, and are based on shared derived homologous characters
95
What type of taxa are required in cladistics
monophyletic groups
96
What does monophyletic mean
group includes all descendants of a common ancestor
97
What does paraphyletic mean
group includes some but not all descendants of a common ancestor
98
What does polyphyletic mean
group includes unrelated organisms without a recent common ancestor
99
Why are paraphyletic and polyphyletic taxa invalid in cladistics
they do not reflect true evolutionary history
100
How are monophyletic taxa recognised
by identifying new traits shared by nearest common ancestor
101
Why might taxa resemble each other due to shared primitive characters
character arose early before nearest common ancestor
102
Why might taxa resemble each other due to shared derived characters
character originated in nearest common ancestor
103
Why might taxa resemble each other due to convergence
character evolved independently due to similar pressures
104
What defines a taxon in cladistics
unshared derived characters after branching from sister group
105
What is character polarity
determining which trait state is ancestral and which is derived
106
What are methods for assessing character polarity
outgroup comparison, embryology, fossil record
107
What is a problem with cladistics
it ignores anagenesis and uses only cladogenesis
108
Why is this problematic for ranking taxa
sister taxa may be given same rank despite different evolutionary distances
109
What is orthodox classification based on
both genealogy and divergence
110
What data does orthodox classification often use
dna comparisons
111
What are phylogenies or phylograms
trees based on genetic or evolutionary relationships
112
What does orthodox classification provide
info on genealogy and divergence rates
113
Why are classifications based on dna seen as more objective
they reflect actual genetic relationships
114
What is a benefit of using dna over morphology
dna less affected by selection shows ancestral signals
115
What is junk dna
dna not subject to natural selection with highly informative mutations
116
What is a drawback of morphology based classifications
too subjective and can conflict with molecular data
117
Example of molecular classification changing tree structure
cetaceans shown to descend from artiodactyls
118
Can genetic data be misinterpreted
yes it must be considered in context
119
How similar are humans to chimps based on dna
98.4 percent
120
Define allopatric
An event or process occurring in separate, non-overlapping geographical areas.
121
Define anagenesis
Non-branching lines of descent where there are no offshoot populations.
122
Define analogous
Structures with the same function but different genetic origins.
123
Define arboreal
A tree-dwelling organism.
124
Define bootstrap value
A statistical measure of confidence (in %) that a phylogenetic tree branch is correct.
125
Define character polarity
Determines which character state is ancestral vs. derived.
126
Define clade
A cluster of individuals or branches within a phylogenetic tree.
127
Define cladistics
A method of grouping organisms based on inferred evolutionary relationships.
128
Define cladogenetic history
The history of branching in a phylogenetic tree or dendrogram.
129
Define derived characters
Traits that originated from a common ancestor but changed in descendant lineages.
130
Define extrinsic mechanisms
Environmental or geographic factors influencing species.
131
Define homoplasy
A similarity due to convergent evolution or phenotypic convergence, not common ancestry.
132
Define ontogeny
The development and physical appearance of organisms across time.
133
Define orthodox approach
Combines morphology and genetics with similarity scores (e.g. branch lengths).
134
Define phenotypic convergence
The process where unrelated groups evolve similar features due to similar environments.
135
Define Recognition Species Concept
Defines species based on mutual recognition of mates.
136
Define vestigial
A structure that is no longer fully formed or functional.
137
Explain how derived traits are different to ancestral traits
In evolutionary biology, derived characters are traits that have evolved relatively recently in a lineage and are not shared by all members of a group. Conversely, ancestral characters are traits that were present in the common ancestor of a group and are shared by all members of that group
