Lesson 6

Question 1

What does phylogenies provide regarding changes in time?

Answer 1

A way to measure how diversity changes over time

Question 2

What are two evolutionary patters?

Answer 2

Nested similarities found among extant (living) species nad historical patterns recorded by fossils

Question 3

What’s phylogeny

Answer 3

History of descent with branching, much like genealogy of family history, way of organizing our knowledge of biodiversity

Question 4

What do branching diagrams show??

Answer 4

Relationship b/w species often according to time since common ancestor, for each species/group of species whose which other species/group of. Species it shares its most recent common ancestors with, provides hypothesis of evolutionary relationships

Question 5

What are phylogenetic trees?

Answer 5

Rep best model of relatedness of organisms based on data

Question 6

What are the branches of a phylogenetic tree?

Answer 6

Trace lineage back in time

Question 7

What are the tips of a phylogenetic tree?

Answer 7

Terminal node, where tree ends

Question 8

What are the nodes of a phylogenetic tree?

Answer 8

Common ancestor from which the descendent species diverged

Question 9

What are the roots of a phylogenetic tree?

Answer 9

Base of phylogeny, starting point

Question 10

What are sister groups?

Answer 10

Two species (or groups of species) that share a common ancestors not shared by any other species or groups

Question 11

What’s a phylogram?

Answer 11

Phylogenetic tree where branch lengthsrep amount of inferred evolutionary change/time (branching and evolutionary time), explicit hypothesis abt evolutionary time and extinction

Question 12

What’s a cladogram?

Answer 12

Phylogenetic tree where branches are all of equal length (no time), only rep relatedness b/w species

Question 13

Why do we construct evolutionary trees?

Answer 13

Show branching patterns of many kinds of lineages, not just species (ex. Viral lineages and variants)

Question 14

What is monophyletic groups?

Answer 14

Group including a common ancestors and all of its descendants

Question 15

What’s a paraphyletic group?

Answer 15

Group including a common ancestors but not all of its descendants

Question 16

What’s a polyphyletic group?

Answer 16

Group doesn’t include common ancestor

Question 17

How are phylogenies inferred and created?

Answer 17

Using characteristics shared between species esp ones that vary b/w but not w/in and have a genetic base (morphological, chromosomal and molecular)

Question 18

What characters are used to create phylogenies?

Answer 18

Morphological (ex. Wing patterns), chromosomal (# of chromosomes) and molecular (DNA sequences)

Question 19

What are morphological/dna characteristics used for phylogenies

Answer 19

Observed discrete character states, ex pea shape, flower colour, wings, dna sequence

Question 20

What are homologous characters (homologies)

Answer 20

Shared characters due to common ancestor and shared ancestral and derived characters, good for phylogenies

Question 21

What are analogous characters (homoplasies)?

Answer 21

Similarity in appearance or function but not in origin, shared bc of convergent evolution

Question 22

What are the two reason characters states can be similar?

Answer 22

Homologous or analogous characters

Question 23

Ex of homology?

Answer 23

Amniotic egg, evolved from common ancestor, wing bones of birds and bats

Question 24

Ex of homoplasy?

Answer 24

Wing evolvement in birds and bats

Question 25

What do you need for phylogeny reconstruction?

Answer 25

Shared derived characters, unique character states uninfrmative for sister group, need homologies shared by some but not all (synapomorphism)

Question 26

How do you recognize homology?

Answer 26

Structural similarities, relation b/w parts and embryonic developemnt, similar join connectivity and bone arrangements

Question 27

What is synamorphisim?

Answer 27

Shared derived character traits found in two or more taxable that were inherited from most recent common ancestor, essential for reconstructing evolutionary relationships

Question 28

What’s the principle of parsimony?

Answer 28

Occams razor, among competing hypothesis one with fewest assumption should be selected so strongest hypothesis of evolutionary relationship is the tree w fewest number of changes required, most simple, minimized total numbers of idependt origins of character traits

Question 29

How does molecular data complement comparative morphology?

Answer 29

Each nucleotide/gene difference in the DNA sequence can act as a “trait”, AA sequence of proteins can work the same way, underlying logic of phylogenetic inference is identical for morphological and molecular characters

Question 30

What’s the distance methods?

Answer 30

Alternative method of reconstruction, infer relationships from actual data, descendant of recent common ancestors have had little time to evolve differences, descents of ancient common ancestor = more time, dna sequence difference reflect time since common ancestor therefor can estimate degrees of relatedness for comparison of DNA sequences, Less difference percent when comparing DNA sequence means closer degree of relatedness, allows u to infer divegance bacackwards in time to common ancestors to draw phylogeny

Question 31

Phylogeny and its relation with taxonomy?

Answer 31

Linnaeus classification system was based on presumed “rough” phylogenies, members of these groups (ex. Genus) assumed to share a more recent common ancestors with each other than with members of other groups

Question 32

What’s macroevolution?

Answer 32

Evolution above species eleven, ex asses the diversity of an antire clause and its position on the tree

Question 33

What does the rapidity of character and lineage speciation in macroevoluion depend on?

Answer 33

Envormental factors which change rapidity of characters which affect lineage speciation

Question 34

What’s adaptive radiation?

Answer 34

Rapid evolution of new species occupying new niches

Question 35

What’s anagenesis?

Answer 35

Speciation wherein the ancestor species is wholly replaced by new species (evolution w/in a lineage), gradual, slow, net neutral for biodiversity

Question 36

What’s cladogensis?

Answer 36

Parent species splits into two species, impacts biodiversity by increasing it

Question 37

What’s graduated speciation?

Answer 37

Slow and steady evolution that often result is more anagenesis

Question 38

What’s punctuated evolution?

Answer 38

Rare and repaid (on a geological time scale) events of branching speciation (results in more cladogenesis)

Question 39

Why would evolution occur by a gradual pattern?

Answer 39

Intense competition with other species -> few avalibl niches Low genetic diversity and evolvability Small pop size and limited exposure to alt niches High specialization (ex. Obligate parasites -> tend to pseciate at the rate of host speciation)

Question 40

Why would evolution occur by a punctuated pattern?

Answer 40

Colonization of a new area (post glacial, new volcanic island, ex mammals) Diversification following a mass extinction event Evolution of a new trait (ex. Wings which opens up a whole new avenue for diversification) that opens up a new niche Something in the genome?? We dont know yet!

Question 41

What’s tempo and mode related to?

Answer 41

How rapidly do characters evolve (tempo) -> gradual or punctuated How rapidly do lineages speciation (mode) -> cladogensis or anagenesis

Question 42

How does adaptation drive speciation?

Answer 42

Possibly: divergent adaptation to different pressure-> different change Convergent adaptation to similar pressure -> homoplasy (same change) Genetic drift with no selective pressure-> random chance Limited evidence for divergent adaptation driving speciation, may explain why we frequently see convergent evolution 38/130 traits fit adaptive model and most of those fit single-optimum model best (convergent evolution)

Question 43

Summery of topics 4-6?

Answer 43

Nat selec can cause changes over short timescale but not selection causes adaptation Speciation a process involving both drift and selection and progresses w accumulation f reproductive isolating mechanisms Macro-evolution characterized by incredible variation in rates of diversification, both chance events and predictable responses to selection can be imp in shaping big patterns

Question 44

What causes adaptation

Answer 44

Only selection not genetic drift