5AB Flashcards
Patterns in nature
* Nature displays ______ patterns of ______all around us
* _______produces two distinct, but related patterns:
* _______ similarities found among ________ (living) species
* ______ pattern recorded by ______
* Phylogeny:
* Much like the _______ in our own family _______
* Way of organizing our knowledge of __________
Patterns in nature
* Nature displays nested patterns of similarity all around us
* Evolution produces two distinct, but related patterns:
* Nested similarities found among extant (living) species
* Historical pattern recorded by fossils
* Phylogeny: history of descent with branching
* Much like the genealogy in our own family history
* Way of organizing our knowledge of biodiversity
Phylogenetic trees/Phylogenies
* A ________ diagram that shows the _________ between species,
often according to the time since a _________ _______
* for each species/group of species, shows which other species/group of
species it shares its ______ _____ ________ancestor with
* Provides __________ of ________relationship
* Phylogenetic Trees:
- A branching diagram that shows the relationships between species,
often according to the time since a common ancestor - for each species/group of species, shows which other species/group of
species it shares its most recent common ancestor with - Provides hypotheses of evolutionary relationship
- Phylogenetic Trees: represent the best model of the relatedness of
organisms on the basis of data
Relationship between speciation and a
phylogenetic tree
Tips (terminal node)
Branches
Nodes
Root
Tim
SISTER GROUPS
- Species A and B share a more common ancestor with each other than
either shares with C or D
A B C D - Sister groups: Two species (or groups
of species) that share a common
ancestor not shared by any other
species or group
Equivalent trees -
The four trees are equivalent because ….
Equivalent trees - these trees are all the same
The four trees are equivalent because nodes can be rotated without changing
evolutionary relationships
Phylogenetic trees/Phylogenies
* Phylogram:
* Cladogram:
* We can construct evolutionary trees to show the branching patterns of many
kinds of _______ , not just _______(e.g. ______ lineages and ________ etc.
Phylogenetic trees/Phylogenies
* Phylogram: a phylogenetic tree where the branch lengths represent the
amount of inferred evolutionary change/time. (branching + evolutionary time)
* Cladogram: a phylogenetic tree where all branches are of equal length. (just
branching)
* We can construct evolutionary trees to show the branching patterns of many
kinds of lineages, not just species (e.g. viral lineages and variants etc.
Monophyletic-
Paraphyletic-
polyphyletic-
Monophyletic, Paraphyletic, and polyphyletic
Monophyletic group (clade, blue) includes a
common ancestor and all of its descendants
Paraphyletic group (green) includes a
common ancestor and some, but not all, of
its descendants
A polyphyletic group (red) does not include
the common ancestor
- Phylogenies _______ using ___________ that are shared between
species - Characters used: vary among, but not within species and have a
_______ _____ - _________(e.g., ____patterns)
- ________(e.g., number of ____)
- ________(e.g., __)
- Phylogenies inferred using characters that are shared between
species - Characters used: vary among, but not within species and have a
genetic basis - morphological (e.g., wing patterns)
- chromosomal (e.g., number of chromosomes)
- molecular (e.g., DNA sequences
Characters: Morphological or DNA
- Referring broadly to ______ traits of the ______ organism
- Evidence consists of a number of characters, each with a number of ________
character ______ - Flower colour: ____, _____
- Wings: _____, _____
- Referring broadly to observable traits of the whole organism
- Evidence consists of a number of characters, each with a number of discrete
character states - Flower colour: blue, yellow
- Wings: present, absen
________ _____can be similar for one
of two reasons:
* ___________ characters (________)
* shared because of _______ _______
* shared _________ and ________ characters
* __________characters (________)
* Homoplasy means similarity in ___________but not in _________
* shared because of __________ _________
Character States can be similar for one
of two reasons:
* Homologous characters (homologies)
* shared because of common ancestry
* shared ancestral and derived characters
* Analogous characters (homoplasies)
* Homoplasy means similarity in appearance but not in origin
* shared because of convergent evolution
Phylogeny reconstruction
Homologies are recognized by:
- structural similarity
- relations between parts
- embryonic development
Character States can be similar for one of
two reasons:
Amniotic Egg:
Wings (in birds and bats):
Character States can be similar for one of
two reasons:
Amniotic Egg: Homology
(evolved once in the
common ancestor)
Wings (in birds and bats): Analagous (wings evolved
independently in birds and bats = homoplasy
Shared derived characters :
Shared derived characters :
-Unique character states
uninformative for sister group
-Need homologies shared by
some, but not all à
synapomorphie
Phylogeny reconstruction from shared
derived traits
Strongest hypothesis of evolutionary relationships is the tree with the fewest number
of changes required
Minimizes the total number of independent origins of character state
Possible phylogenetic trees: most likely?
Fewest number of changes required
Principle of parsimony
The phylogeny requiring the _______ _________ _______is the best estimate
of the true _________= most __________
Principle of parsimony
The phylogeny requiring the fewest evolutionary changes is the best estimate
of the true phylogeny = most parsimonious
_______ ____ often favored
4 changes :
Comparison to an “outgroup (OG)” –
… : e.g., evolution of pupae
Simplest tree,
4 changes : Phylogeny of hexapoda (insects)
Comparison to an “outgroup (OG)” – earlier branch of tree
Examine potential synapomorphs : e.g., evolution of pupae
Molecular data complement comparative
morphology
* Each _________ in the DNA sequence (A, T, G, C) can act as a _____
* ______ ___ sequence (alanine, leucine, etc) of ______ can work in the
same way
* underlying logic of phylogenetic inference is identical for _________
and ______ character
Molecular data complement comparative
morphology
* Each nucleotide in the DNA sequence (A, T, G, C) can act as a trait
* Amino acid sequence (alanine, leucine, etc) of proteins can work in the
same way
* underlying logic of phylogenetic inference is identical for morphological
and molecular character
-Distance methods:
* Infer relationships from actual data – ….
* DNA sequence differences reflect time since …
* Therefore, can estimate …
Distance methods: an alternative method of
reconstruction
* Infer relationships from actual data – descendants of recent common
ancestor will have had little time to evolve differences, descendants of
ancient common ancestor = more time
* DNA sequence differences reflect time since common ancestor
* Therefore, can estimate degrees of relatedness from comparisons of DNA
sequence
Phylogeny meets taxonomy
* Linnaeus classification system was implicitly based
on presumed “______” ________
* members of these groups (e.g., a genus) assumed
to share a more _____ _________ancestor with
each other than with members of other group
Phylogeny meets taxonomy
* Linnaeus classification system was implicitly based
on presumed “rough” phylogenies
* members of these groups (e.g., a genus) assumed
to share a more recent common ancestor with
each other than with members of other group
Macroevolutionary patterns
31
* _____________ _________
* __________
* ____________
-Macroevolution: …
Macroevolutionary patterns
31
* adaptive radiations
* anagenesis
* cladogenesis
Macroevolution: evolution
above the species level, e.g.,
assess the diversity of an entire
clade and its position on the
Adaptive radiation
s
- the rapid evolution of new
species occupying new niche
Anagenesis versus Cladogenesis
Anagenesis: speciation wherein the ancestor species is wholly replaced by
new species (evolution w/in lineage).
Cladogenesis: parent species splits into two species
Graduated versus Punctuated
Graduated: slow and steady gradual evolution (results in more anagenesis)
Punctuated: rare and rapid (on a geologic time scale) events of branching
speciation (results in more cladogenesis
