theme 5ab- Evolutionary Patterns, Phylogeny and Macroevolution

Question 1

what are the two patterns produced by evolution?

Answer 1

1. nested similarities found among extant species
2. historical pattern recorded by fossils

Question 2

what is phylogeny?

Answer 2

a branching diagram that shows the relationships between species according to the time since a common ancestor?

Question 3

what does phylogeny do?

Answer 3

organize our knowledge of biodiversity

Question 4

what does phylogeny provide a hypotheses for?

Answer 4

evolutionary relationship

Question 5

what is a phylogram?

Answer 5

a phylogenic tree where the branch lengths represent the amount of inferred evolutionary change/time

Question 6

what is a cladogram?

Answer 6

a phylogenic tree where all branches are of equal length

Question 7

what are sister groups?

Answer 7

two species that share a common ancestor not shared by any other species or group

Question 8

how can different trees be equivalent?

Answer 8

nodes can be rotated without changing evolutionary relationships

Question 9

what are shared characters?

Answer 9

characters that are shared between species and have a genetic basis (morphological, chromosomal, molecular)

Question 10

what does morphological characters refer to?

Answer 10

observable traits of the whole organism

Question 11

what are homologous characters (homologies)

Answer 11

similar due to common ancestry, has shared sncestral and derived characters

Question 12

what are analogous characters (homoplasies)?

Answer 12

similarity in appearance but not in origin , shared due to convergent evolution

Question 13

what are the two reasons character states can be similar?

Answer 13

1. amniotic egg (homology)
2. wings (analagous)

Question 14

how did characters evolve from homology?

Answer 14

something evolved once in the common ancestor

Question 15

how did characters evolve from analagy?

Answer 15

something evolved independantly (ancestor didnt have wings)

Question 16

how are homologies recognized?

Answer 16

structural similiarity
relations between parts
embryonic development

Question 17

what are synapomorphies?

Answer 17

homologies shared by some but not all

Question 18

what are shared derived characters?

Answer 18

unique character states uniformative for sister group

Question 19

what is the strongest hypothesis of evolutionary relationships?

Answer 19

the tree with the fewest number of change required

Question 20

why is the tree with less changes the strongest hypothesis for evolutionary relationships?

Answer 20

because it minimizes the total number of independant origins of character states

Question 21

when given options of possible phylogenic trees which is most likely true?

Answer 21

the one with the fewest number of changes

Question 22

which phylogenic tree is often favoured?

Answer 22

the simplest

Question 23

what is the principle of parsimony?

Answer 23

the phylogeny requiring the fewest evolutionary change is the best estimate of the true phylogeny is the most parsimonious

Question 24

what is the molecular data complement comparative morphology?

Answer 24

-each nucleaotide in the dna sequence can act as a trait
-amino acid sequence of proteins act as traits
-underlying logic of phylogenetic inference is identical for morphological and molecular characters

Question 25

what is distance methods

Answer 25

an alternative method of reconstruction

Question 26

how does distance method work?

Answer 26

more time = more differences

Question 27

how do recent common ancestors affect evolution?

Answer 27

less time to evolve differences = less differences

Question 28

how do ancient common ancestors affect evolution?

Answer 28

more time = more differences

Question 29

what does distance methods estimate?

Answer 29

degrees of relatedness from comparisons of DNA sequences

Question 30

what are character states?

Answer 30

DNA nucleotides that exhibit variation

Question 31

what does a monophyletic group indicate?

Answer 31

a common ancestor and its descendants

Question 32

what does a paraphyletic group include?

Answer 32

a common ancestor and some but not all of its descendants

Question 33

what does a polyphyletic group include?

Answer 33

no common ancestor

Question 34

what is macroevolution?

Answer 34

evolution above the species level (diversity of an entire clade and its position)

Question 35

what does macroevolution include?

Answer 35

1. adaptive radiations
2. anagenesis
3. cladogenesis

Question 36

what is adaptive radiation?

Answer 36

the rapid evolution of new species occupying new niches

Question 37

what is anagenisis?

Answer 37

speciation where in the ancestor species is wholly replaced by new species (evolution within lineage)

Question 38

what is cladogenesis?

Answer 38

parent species splits into two species

Question 39

what does graduated mean?

Answer 39

slow and steady gradual evolution

Question 40

what is the result of graduated?

Answer 40

anagenesis

Question 41

what does punctuated mean?

Answer 41

rare and rapid (on a geologic time scale) events of branching speciation

Question 42

what does punctuated result in?

Answer 42

cladogenesis

Question 43

what do sequences of changes in a tree document?

Answer 43

evolutionary changes that have accumulated through time