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Biology > chapter twenty-five > Flashcards

chapter twenty-five Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what types of changes does the fossil record show?

A

macroevolutionary changes
1. emergence of terrestrial vertebrates
2. impact of mass extinctions
3. origin of flight of birds

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2
Q

what did earth’s early atmosphere likely contain?

A

water vapor and chemicals released by volcanic eruoptions

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3
Q

what did chemical/physical processes on earth potentially produce?

A

simple cells

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4
Q

how were simple cells maybe produced?

A
  1. abiotic synthesis off small organic molecules
  2. joining of these small molecules into macromolecules
  3. packaging of molecules into protocols
  4. origin of self-replicating molecules
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5
Q

what did Oparin and Haldane hypothesize in the 1920s?

A

that the early atmosphere was a reducing environment

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6
Q

Miller and Urey 1953

A
  • conducted lab experiments that showed the abiotic synthesis of organic molecules in a reducing environment (with pond and clay) is possible
  • evidence not yet convincing there was reducing atmosphere
  • organic molecules could have been formed with various possible atmospheres
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7
Q

where might the first organic compounds have been synthesized?

A

near volcanoes and deep sea vents

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8
Q

what have been found in meteorites?

A

amino acids

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9
Q

what were produced spontaneously from simple molecules

A

RNA monomers

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10
Q

when do small organic molecules polymerize

A

when concentrated on hot sand, clay, or rock

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11
Q

protocells - simple cells

A

fluid-filled vesicles with membrane-like strcuture

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12
Q

what are key properties of life that may have appeared together?

A

replication and metabolism

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13
Q

how are vesicles formed?

A

in water, lipids and other organic molecules can spontaneously form vesicles with a lipid bilayer
- adding clay can increase rate of vesicle formation

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14
Q

first genetic material

A

most likely RNA

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15
Q

ribozymes

A

RNA molecules that have been found to catalyze many different reactions
- can make complementary copies of short pieces of RNA

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16
Q

what has natural selection produced?

A

self-replicating RNA molecules

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17
Q

what types of RNA would have left the most descendent RNA molecules

A

RNA molecules that were more stable or replicated more quickly

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18
Q

RNA world

A

small RNA molecules able to replicate and store genetic info about vesicles that carried them

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19
Q

vesicles with RNA capable of replication would have been _____________

A

protocells

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20
Q

RNA could have provided the template for what?

A

DNA - more stable genetic material

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21
Q

richest source of fossils

A

sedimentary rock, deposited into layers called strata

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22
Q

fossil record is biased in favor of species that:

A
  1. existed for long time
  2. were abundant and widespread
  3. had hard parts
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23
Q

relative age of fossils

A

revealed by strata

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24
Q

absolute age of fossils

A

determined by radiometric dating
- parent isotope decays to daughter isotope at constant rate
- can be used for fossils up to 75,000 years old

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25
Q

half-life

A

time required for half of parent isotope to decay

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26
Q

if fossils are older than 75,000, how can they be dated?

A

isotopes can date the sedimentary rock layers above and below the fossil

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27
Q

what group to mammals belong to?

A

tetrapods

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28
Q

what is the geologic record divided into?

A

Hadean, Archaean, Proterozoic, Phanerozoic

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29
Q

which eon encompasses most multicellular eukaryotic life?

A

Phanerozoic

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30
Q

3 eras of phanerozoic

A

Paleozoic, Mesozoic, Cenozoic

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31
Q

what do major boundaries between geological divisions represent?

A

extinction events

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32
Q

stromatolites

A

oldest known fossils
- rocks formed by the accumulation of sedimentary layers on bacterial mats

33
Q

when were stromatolites dated back to?

A

Archaean eon

34
Q

when were prokaryotes earth’s sole inhabitants?

A

2.1-3.5 billion years ago

35
Q

most atmospheric oxygen is of what?

A

biological origin

36
Q

O2 was produced by what?

A

oxygenic photosynthesis, which reacted with dissolved iron and precipitated out to form banded iron formations

37
Q

oxygen revolution

A
  • caused extinction of many prokaryotic groups
  • some groups survived/adapted using cellular respiration
38
Q

what was the early rise in O2 likely caused by?

A

ancient cyanobacteria

39
Q

what was the later increase of O2 maybe caused by?

A

evolution of eukaryotic cells containing chloroplasts

40
Q

when were the oldest fossils of eukaryotic cells dated back to?

A

Proterozoic eon

41
Q

what do eukaryotic cells have

A

nuclear envelope, mitochondria, endoplasmic reticulum, cytoskeleton

42
Q

endosymbiont theory

A

mitochondrion and plastids (chloroplasts and related organelles) were formerly small prokaryotes living within larger host cells

43
Q

endosymbiont definition

A

cell that lives within a host cell

44
Q

key evidence for endosymbiont theory:

A
  • inner membranes similar to plasma membranes of prokaryotes
  • division similar to prokaryotes
  • transcribe and translate their own DNA
  • ribosomes more similar to prokaryotic ribosomes
45
Q

oldest known fossils of multicellular eukaryotes

A

small algae

46
Q

snowball earth hypothesis

A

periods of extreme glaciation confined life to equatorial region or deep sea vents

47
Q

Cambrian explosion

A

sudden appearance of fossils resembling modern animal phyla in Cambrian period

48
Q

what phyla appeared before the Cambrian explosion?

A

sponges, cnidarians, molluscs

49
Q

what does the Cambrian explosion provide the first evidence of?

A

predator/prey interactions

50
Q

vascular tissues in plants

A

transport material internally

51
Q

what did plant and fungi form?

A

mutuals beneficial associations
- likely colonized together

52
Q

most widespread and diverse animals

A

anthropoids and tetrapods

53
Q

what did tetrapods evolve from?

A

lobe-finned fish

54
Q

supercontinent

A

Pangea - could have been formed in 3 points in time

55
Q

plate tectonics

A

earth’s crust is composed of plates floating on earth’s mantle

56
Q

continental drift

A

tectonic plates moving slowly

57
Q

what do interactions between plates cause?

A

formation of mountains, islands, and earthquakes

58
Q

possible effects of Pangea

A
  • deepening ocean basins
  • reduction in shallow-water habitat
  • colder/drier climate inland
59
Q

what did the separation of land masses lead to?

A

speciation

60
Q

mass extinction

A

where global environmental changes lead to increased rate of extinction

61
Q

how many mass extinctions have there been

A

5
- in each one, more than 50% of species became extinct

62
Q

Permian mass extinction

A
  • boundary between Paleozoic and Mesozoic
  • 96% of marine animal species
63
Q

factors contributing to Permian extinctions

A
  1. intense volcanism in now Siberia
  2. global warming resulting from emission of large amounts of CO2 from volcanoes
  3. reduced temperature gradient from equator to poles
  4. oceanic anoxia from reduced mixing of ocean waters
64
Q

Cretaceous mass extinction

A
  • separates Mesozoic/Cenozoic
  • half of marine species, plants/animals, dinosaurs
65
Q

what evidence suggests a meteorite impact?

A

presence of iridium in sedimentary rocks

66
Q

what can mass extinctions alter?

A
  • ecological communities/niches
  • percent of marine predators increased
67
Q

adaptive radiation

A

evolution of diversely adapted species from common ancestor
- can occur when organisms colonize new environments with little competition

68
Q

what might adaptive radiations follow?

A
  1. mass extinctions
  2. evolution of novel characteristics
  3. colonization of new regions
69
Q

what did the disappearance in dinosaurs lead to?

A

expansion of mammals in diversity and size

70
Q

development genes

A

control rate, timing, and spatial pattern of changes in an organism’s form as it develops into an adult

71
Q

heterochrony

A

evolutionary change in rate/timing of developmental events
- can have impact on body shape

72
Q

paedomorphosis

A

rate of reproductive development accelerates compared with somatic development
- sexually mature species may retain body features that were juvenile structures in ancestral species

73
Q

homeotic genes

A

determine basic features
- where wings/legs develop on bird, or how flower’s parts are arranged

74
Q

Hox genes

A

class of homeotic genes that provide positional info during development
- if expressed in wrong location, body parts can be produced in wrong location or alter timing

75
Q

what do new morphological forms likely come from?

A

gene duplication events that produce new developmental genes

76
Q

what do changes in morphological forms likely come from?

A

changes in REGULATION of developmental genes rather than changes in sequence of developmental genes

77
Q

evolution is like what?

A

tinkering

78
Q

how have complex eyes evolved?

A

from simple photosensitive cells independently many times

79
Q

exaptations

A

structures that evolve in one context but become co-opted for a different function

Biology (35 decks)

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