Chapter 23

Front 1

Evolution produces two distinct but related patterns, both evident in nature:

Back 1

1. nested pattern of similarities found among species

2. historical pattern of evolution recorded by fossils

Front 2

phylogeny

Back 2

history of descent with branching

Front 3

node

Back 3

the point where a branch splits

represents the common ancestor from which the descendant species diverged

Front 4

Phylogenetic trees provide ...

Back 4

hypotheses of evolutionary relationships

Front 5

Phylogenetics

Back 5

study of evolutionary and genetic relationships among organisms by comparing their anatomical or molecular features

Front 6

Taxonomy

Back 6

classification of organisms

Front 7

Two related disciplines in systematics:

Back 7

1. phylogenetics

2. taxonomy

Front 8

The aim of taxanomy:

Back 8

classify species in more and more hierarchical inclusive groups

Front 9

phylogenetic tree

Back 9

hypothesis about the evolutionary history of the species

Front 10

What lies at the heart of phylogenetics?

Back 10

search for sister groups

Front 11

sister groups

Back 11

groups that are more closely related to each other than either of them is to any other group

Front 12

An important aspect of a node is that:

Back 12

it can be rotated without changing the evolutionary relationships of the groups

Front 13

Information about evolutionary relationships lies in the order of ____ over time, not the order of ______ along the tips.

Back 13

1. nodes

2. groups

Front 14

monophyletic group

Back 14

common ancestor and all its descendants

Front 15

taxon

Back 15

technical word for group

Front 16

monophyletic

Back 16

all members share a single common ancestor not shared with any other species or group of species

*one cut to separate group

*clade

Front 17

paraphyletic

Back 17

includes some, but not all, of the descendants of a common ancestor

*two cuts to separate group

Front 18

polyphyletic

Back 18

groupings that do not include the last common ancestor

Front 19

taxonomic classifications

Back 19

information storage and retrieval systems

Front 20

taxonomic levels

Back 20

1. genus

2. family

3. order

4. class

5. phylum

6. kingdom

7. domain

Front 21

Phylogenies can show similarity and differences in:

Back 21

1. phenotype

2. genetics

Front 22

Length of the branch indicates

Back 22

evolutionary distance

Front 23

homology

Back 23

similarity by common descent

Front 24

Phylogenetic trees are inferred by ...

Back 24

comparison of character states shared among different groups of organisms

Front 25

characters

Back 25

anatomical, physiological, or molecular features that make up organisms

Front 26

character states

Back 26

several observed conditions

Front 27

Character states can be similar for one of two reasons:

Back 27

1. the character state was present in the common ancestor of the two groups and retained over time (common ancestry)

2. independently evolved in the two groups as an adaptation to similar environments (convergent evolution)

Front 28

analogy

Back 28

similarity that results from convergent evolution

Front 29

homologous

Back 29

characters that are similar because of descent from a common ancestor

Front 30

analogous

Back 30

similarities due to independent adaptation by different species

*result of convergent species

Front 31

Shared derived characters enable biologists to ...

Back 31

reconstruct evolutionary history

Front 32

synapomorphies

Back 32

shared derived character trait

Front 33

cladistics

Back 33

phylogenetic reconstruction on the basis of synapomorphies

Front 34

Among multiple possible trees, which is favored?

Back 34

the simplest tree

Front 35

parsimony

Back 35

choosing the simpler of two or more hypotheses to account for a given set of observations

Front 36

__________ complements ___________ in reconstructing phylogenetic history.

Back 36

1. Molecular data

2. comparative morphology

Front 37

homoplasy

Back 37

same form

Front 38

An alternative method of reconstruction is based on _________ rather than synapomorphies

Back 38

distance

Front 39

The total distance between two taxa is ...

Back 39

the sum of the differences along all the branches that connect the taxa

Front 40

What does the fossil record do?

Back 40

1. enable us to calibrate phylogenies in terms of time

2. provide our only record of extinct species

3. place evolutionary events in the context of Earth's dynamic environmental history

Front 41

fossils

Back 41

remains of once-living organisms, preserved through time in sedimentary rocks

Front 42

Fossilization requires

Back 42

burial

Front 43

Why is the marine life fossil record more complete than that for land-dwelling creatures?

Back 43

Marine habitats are more likely than those on land to be places where sediments accumulate and become rock

Front 44

What contributes to the incompleteness of the fossil record?

Back 44

biological factors

Front 45

What determines the probability that an ancient species will be represented in the fossil record?

Back 45

1. properties of organisms

2. environment

Front 46

Organisms that lack hard parts can leave a fossil record in two other, distinctive ways:

Back 46

1. trace fossils: tracks and trails left from movement

2. molecular fossils

Front 47

Burgess Shale

Back 47

Cambrian Period

sedimentary rock formation that accumulated on a relatively deep seafloor covering what is now British Columbia

*waters just above the basin floor contained little or no oxygen, so that when mud swept into the basin, entombed animals were sealed off from scavengers, disruptive burrowing activity, and bacterial decay

Front 48

Messel Shale

Back 48

German lake

Release of toxic gases from deep within the Messel Lake suffocated local animals, and their carcasses settled into oxygen-poor muds on the lake floor

Front 49

Geological data indicates:

Back 49

1. age

2. environmental settings

of fossils

Front 50

geologic timescale

Back 50

series of time divisions that mark Earth's long history

Front 51

half-life

Back 51

half of the 14C in a given sample will decay to nitrogen in 5730 years

Front 52

Radioactive decay of what isotope is used to date wood and bone?

Back 52

14 Carbon

Front 53

Steps of 14C Decay

Back 53

1. Neutrons generated by the sun collide with 14N to create 14C

2. 14C that ends up in carbon dioxide can be incrorporated in plants through photosynthesis

3. 14C is next incorporated into animals when they eat the plants

4. After the plant or animal dies and is buried, its 14C decays to the more stable 14N

5. Half of the 14C in a fossil turns to 14N in 537- years, half of the remaining 14C decays to 14N and so on

Front 54

Archaeopteryx and Tiktaalik are two fossil organisms that document, respectively, the ___________ transition and the ______________ transition.

Back 54

1. bird-dinosaur

2. fish-tetrapod

Front 55

All land vertebrates, from amphibians to mammals, are descended from ...

Back 55

fish

Front 56

mass extinctions

Back 56

spelled the end of many previously important groups of species

*adaptive radiation

Front 57

Best known mass extinction

Back 57

end of Cretaceous Period

dinosaurs disappeared abruptly, ammonities (predators) became extinct due to impact of a giant meteorite

Front 58

Main causes of mass extinction during Permian Period:

Back 58

1. lack of oxygen

2. ocean acidification

3. global warming

Front 59

Permian Period extinction

Back 59

Most genera in late Permian oceans disappeared due to volcanic eruptions

Front 60

______ and _____ complement each other

Back 60

1. phylogeny

2. fossils

Front 61

The disadvantage of using comparative biology is that we lack:

Back 61

1. evidence of extinct species

2. time dimension

3. environmental context

Front 62

Agreement between phylogenies and the fossil record provides:

Back 62

strong evidence of evolution

Front 63

Bias in the Fossil Record

Back 63

1. habitat

2. taxonomic & tissue

3. temporal

4. abundance

Front 64

vestigial traits

Back 64

1. incompletely developed

2. little or no function

3. not adaptive