obj 19 and 20

Question 1

2 definitions for evolution

Answer 1

• descent with modification
• change in genetics of a population from generation to generation

Question 2

describe how Hutton and Lyell’s ideas influenced Darwin’s thinking about evolution

Answer 2

• Hutton: uniformitarianism: Earth’s geology formed by slow gradual processes
• shows Darwin how small changes can occur over large amount of time, instead of sudden events
  Lyell: present geological processes explain past changes

Question 3

Contrast the role of Darwin’s ideas on evolution thought vs. previous thinkers

Answer 3

He proposed natural selection as the mechanism of change

Question 4

adaptation

Answer 4

a heritable trait that aids survival and reproduction

Question 5

natural selection

Answer 5

differential survival and reproduction based on inherited traits

Question 6

Wallace’s role and why he is not main architect for natural selection

Answer 6

• developed theory of natural selection nearly identical to Darwin’s
• Darwin had developed idea more thoroughly

Question 7

process of artificial selection and how it is evidence for evolution

Answer 7

• selective breeding by humans for desired traits
• demonstrates that selection can change species

Question 8

Darwin’s two observations and 2 inferences

Answer 8

observations
- individuals within species vary
- organisms produce more offspring than will survive to adulthood
inferences
- not all offspring survive to reproduce
- favorable variations are preserved

Question 9

how did Thomas Malthus’ work influence Darwin

Answer 9

it helped explain population regulation

Question 10

relationship btwn natural selection and adaptation

Answer 10

adaptation results from natural selection

Question 11

how can evolutionary change be directly measured

Answer 11

• superposition of strata
• fossils
• molecular DNA

Question 12

anatomical homologies

Answer 12

• similar anatomical structures found in different species
• suggest different species evolved independently

Question 13

molecular homologies

Answer 13

• similarities in DNA sequences
• suggest common ancestor and inherited genetic material

Question 14

vestigial structures

Answer 14

• structures that have no apparent function
• indicate past evolutionary history
• tailbone, wisdom teeth, appendix, ear muscles

Question 15

analogous structures and convergent evolution

Answer 15

• similar traits in species that serve same function from different evolutionary origins
• suggest similar environmental pressures
• convergent evolution: organisms not closely related evolve similar traits(bat and bird wings)

Question 16

whale evolution is supported by

Answer 16

• presence of leg bones
• nostril position changes
• skull structure modifications

Question 17

determining relative fossil age

Answer 17

position of strata; lower=older

Question 18

biogeography

Answer 18

• how the geographical distribution of species in a region reflect evolutionary history
• predicts that isolated regions have unique species

Question 19

what does a phylogenetic tree represent

Answer 19

illustrates evolutionary relationships between organisms over time

Question 20

branch points + branch length

Answer 20

• nodes
• represent common ancestor from which 2+ groups diverge
• branch length could represent amount of genetic change

Question 21

sister taxa

Answer 21

groups that share the most recent common ancestor

Question 22

polytomy

Answer 22

• 3+ taxa from a branch point
• uncertainty about branching order

Question 23

basal taxon

Answer 23

• the group that diverged earliest from others
• farthest away from others on tree

Question 24

what can and cannot phylogenetic trees tell us

Answer 24

can
- common ancestry between species
- order of branching events
- presence of shared derived traits
cannot
- absolute time of divergence without additional data

Question 25

challenge of DNA sequencing

Answer 25

- insertion and deletion

Question 26

homologous vs analogous structures

Answer 26

- only homologous structures share common evolutionary origin

Question 27

monophyletic group

Answer 27

a common ancestor and all its descendants - a clade

Question 28

paraphyletic group

Answer 28

- a part of a clade, not all of it - includes ancestral species and some, but not all, of its descendants

Question 29

polyphyletic group

Answer 29

- includes distantly related species but not the most recent common ancestor - from different clades - don't reflect evolutionary relationships

Question 30

principle of maximum parsimony

Answer 30

simplest explanation is preferred - tree with fewest evolutionary changes is often correct

Question 31

shared ancestral traits

Answer 31

- a feature inherited from a distant common ancestor - trait that predates clade - older, more widely shared evolution

Question 32

shared derived traits

Answer 32

- novel characteristics shared by related species from a recent common ancestor - trait unique to clade - newer evolution

Question 33

molecule clocks

Answer 33

- tools that use comparative data on mutations to estimate times of evolutionary changes + divergence events - rough estimated that can be made more reliable with data

Question 34

limitation of molecular clocks

Answer 34

- assume constant mutation rates over time - most accurate for closely related species + estimating relative divergence times

Question 35

charachter tables in phylogenetic analysis

Answer 35

- show distribution of traits across different species - most useful traits are traits that vary among species

Question 36

making better phylogenetic trees

Answer 36

- combining multiple lines of evidence - best evidence for close evolutionary relationships come from shared derived traits