CH 21 (Ch 3)

Question 1

Phylogeny

Answer 1

a description of the evolutionary history of relationships among organisms (or their parts)

Question 2

Phylogenetic tree

Answer 2

diagram that portrays a reconstruction of history (species, populations or genes). Can trace evolutionary histories

x axis is always time

Question 3

root

Answer 3

earliest common ancestor

start point of phylogenetic tree

Question 4

Taxon

Answer 4

any group of species that has been designated or named (humans, primates, mammals)

Question 5

clade

Answer 5

any taxon that consists of all the evolutionary descendants of a common ancestor

node to newest species you are looking at

Question 6

Sister species

Answer 6

two species that each other’s closest relatives

Question 7

Sister clades

Answer 7

two clades that are each other’s closest relatives

Question 8

Homologous trait

Answer 8

• any feature shared by two or more species that has been inherited from a common ancestor
  ex. DNA sequences, protein structures, anatomical structures, behavior patterns

Question 9

Derived trait

Answer 9

ancestor whose descendent that has evolved or adapted a new trait that was from the ancestor
Arise due to a selective pressure

Question 10

Ancestral trait

Answer 10

has undergone little change from ancestral trait

Question 11

Synaptomorphies

Answer 11

derived traits that are shared among a group of organisms
Evidence of a common ancestry
Vertebral column is a synaptomorphy of all vertebrates

Question 12

Convergent evolution

Answer 12

independently evolved traits subjected to similar selection pressures become superficially similar
- don’t share a common ancestor
usually traits are different like wings, bats are skin and birds are made of feathers

Question 13

Evolutionary reversal

Answer 13

characteristic from a derived state back to an ancestral state
traits appear that appear and then disappear due to some selection pressure

Question 14

Generate homoplasies

Answer 14

the traits developed through Convergent or Evolutionary reversal that are similar for reasons other than a common ancestor

Not indicative of common ancestor, just common evolutionary paths

Question 15

see the tree diagrams for in-group and outgrip terms

Answer 15

!!!

Question 16

Parsimony principle to explain how phylogenetic trees are made

Answer 16

the preferred explanation of observed data is the simplest explanation
Minimize number of evolutionary events assumed
“the best explanation is the one that fits the data best while making the fewest assumptions”

Question 17

Morphology (source to make the tree)

Answer 17

the presence, size, shape, or other attributes of a body part
Important source of phylogenetic information

Limits: some taxa exibit very little morphological differences despite great species diversity
There are very few morphological traits that can be compared between very
distant species

Question 18

Development (source to make the tree)

Answer 18

similarities in developmental patterns reveal evolutionary relationships
Early developmental similarities may be lost during later development (notochord)

Question 19

paleontology (source to make the tree)

Answer 19

fossil record as a source of evolutionary history
When and where species lifed, what they looked like
Evidence for extinct species
Limits: few or no fossils may be present for groups of animals, info may be fragmented
Only fossils that are preserved can be seen

Question 20

behavior (source to make the tree)

Answer 20

• behavioural traits like bird songs Can’t be tracked as they are learned, while frog calls are genetically programmed

Question 21

Molecular data (source to make the tree)

Answer 21

heritable variation that is encoded in DNA
Comparing DNA sequences

limit is that we don’t have all data on all mutations

Question 22

how do biologists use phylogenetic trees?

Answer 22

help reconstruct the past, compare and contrast organisms and predict the future (IE new flu vaccine)

Question 23

binomial nomenclature

Answer 23

Kingdom - Phylum - Class - Order - Family - Genus - Species

“keep pushing cookies or fail girl scouts”

Question 24

monophyletic

Answer 24

taxa in biological classifications are expected to be this

• contain an ancestor and all descendants of that ancestor only

Question 25

polyphyletic group

Answer 25

no common ancestor is considered, just comparing branches/species on the tree (black dotted box)

Question 26

paraphyletic:

Answer 26

some descendants are examined but not all (red circles). A group that does not include every descendent.