Test 4 Flashcards
(184 cards)
1
Q
evolution
A
accumulation of genetic changes within a population over time
2
Q
population
A
group of individuals of one species that live in the same geographic area at the same time
3
Q
how to form different species
A
two populations diverge
4
Q
species
A
group of similar organisms that are capable of interbreeding with one another
5
Q
microevolution
A
see changes over a few generations
6
Q
macroevolution
A
changes over long periods of time
7
Q
aristotles view on evolution
A
visualized organisms as “moving toward a more perfect state”
8
Q
leonardo da vincis view on evolution
A
correctly interpreted fossils as remains of animals that had existed in previous ages but had become extinct
9
Q
jean baptiste de lamarck’s view on evolution
A
event that occur to you affect the traits of your offspring
10
Q
what island did darwin see the different finches?
A
galapologos
11
Q
artificial selection
A
we intervene and pick the traits instead of it occurring naturally
12
Q
thomas malthus believed…
A
inherited variations favorable to survival tend to be preserved, while unfavorable ones are eliminated
13
Q
adaptation
A
modification that improves chances of survival and reproductive success in a given environment
14
Q
accumulations of modifications results in…
A
a new species
15
Q
natural selection
A
better adapted organisms are more likely to survive and become the parents of the new generation
16
Q
what was the situation between darwin and wallace?
A
darwin heard that wallace was about to publish on the same thing as him so he published “On the Origin of Species by Natural Selection” first while Wallace published “Contributions to the Theory of Natural Selection” in 1970.
17
Q
4 principles of natural selection
A
- variation- individuals in population show variation traits; some improve survival and reproductive success, some don’t
- overproduction-produce more offspring than are able to survive
- limits on population growth- organisms compete for limited resources, not all survive to reproduce
- differential reproductive success-individuals with most favorable combination of characteristics are more likely to survive
18
Q
darwin came to these conclusions without _____
A
understanding heredity
19
Q
genotype
A
what your genes say
20
Q
phenotype
A
what you actually express
21
Q
The modern synthesis
A
explains Darwins observation of variation among offspring in terms of mutation
22
Q
population genetics
A
study of genetic variability within a population and of the evolutionary forces that act on it
23
Q
allele
A
one of two or more alternate forms of a gene that occupy corresponding positions (loci) on homologous chromosomes
24
Q
gene pool
A
all alleles for all the loci present in the population
25
genotype frequency
proportion of genotype in population
26
sum of all genotype frequencies
1.0
27
phenotype frequency
proportion of a particular phenotype in the population
28
if 2 alleles are dominant and recessive, the dominant phenotype is _____________
the sum of 2 genotypes
29
allele frequency
twice as much- proportion of a specific allele in a particular population
30
genetic equilibrium
nothing is happening; frequencies stay the same
31
change in genetic equilibrium
evolution occurs
32
Hardy-Weinberg Principle
genotypes in a population of genetic equilibrium occur in the frequency: p^2 + 2pq + q^2=1
33
conditions of genetic equilibrium
1. random mating
2. no net mutations
3. large population size
4. no migration
5. no natural selection
34
are the conditions of equilibrium always met?
no, never actually in equilibrium
35
nonrandom mating
(inbreeding) mating with any person more closely related to you than would be at random
36
inbreeding depression
inbred individuals have lower fitness than those not inbred
37
assortative mating
individuals select mates by their phenotypes
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positive assortative mating
selection of mates with same phenotype
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negative assortative mating
selection of mates with opposite phenotypes
40
mutation
any change in DNA
source of all new alleles
only mutation in reproductive cells inherited
only place you get new variation
41
gene flow
alleles moving from one population to another
more gene flow, the more people look the same
increases genetic variability in recipient population
42
natural selection
members of population that are better adapted to the environment have greater fitness
43
genetic drift
random evolutionary changes in small populations
- results in changes in allele frequencies in a population.
- decrease in genetic variation within a population, but increases genetic differences among different populations
44
sampling error
smaller population, more error
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smaller populations driven by
drift
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larger populations driven by
selection
47
bottlenecks
rapidly decrease due to disease, exploitation, and sudden environmental change
48
founder effect
few different individuals from a large population found a new colony
-only alleles in the new population will be those of the colonizers
49
what fixes bottlenecks and founders?
migration
50
metapopulation theory
available spaces to live
51
polymorphism
genetic variation among individuals in a population
| -may or may not produce distinct phenotypes
52
SNPs
Single Nucleotide Polymorphisms
| Differ by one nucleotide
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CNVs
Copy Number Variations
- Genetic changes in which segments of DNA have been gained or lost
- can involve DNA segments from 500 to 2 million base pairs
54
stabilizing selection
selects against phenotypic extremes
favors individuals with average phenotypes
narrows bell curve
55
directional selection
when an environment changes, phenotypes at one extreme of the normal distribution are favored
-occurs only if alleles favored under new circumstances are already present in the population
56
disruptive selection
- extreme changes in the environment may favor 2 or more phenotypes
- selects against average phenotype
- occurs only if alleles favored under new circumstances are already present in the population
- results in a divergence of distinct groups of individuals within a population
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balanced polymorphism
a special type of genetic polymorphism in which 2 or more alleles persist in a population over many generations as a result of natural selection
58
mechanisms that preserve balanced polymorphism
heterozygote advantage and frequency dependent selection
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heterozygote advantage
natural selection maintains alleles that are unfavorable in the homozygous state when the heterozygote Aa has a higher degree of fitness than either homozygote AA or aa
60
frequency dependent selection
a phenotype that has a greater selective value when rare than when common in the population
-often acts to maintain genetic variation in populations of predator or prey species
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neutral variation
variation that does not alter the ability of an individual to survive and reproduce and is therefore not adaptive
-an allele that is neutral in one environment may be beneficial or harmful in another
62
we have a ________ with chimps
common ancestor
63
what did everything evolve from?
a common ancestor that was unicellular (3-4 billion years ago)
64
morphological species concept
classification of plants and other organisms into separate species based on their visible structural differences, such as feathers or number of flower parts
65
biological species concept
a species consists of one or more populations whole members interbred in nature to produce fertile offspring and do not breed with members of different species
66
short comings of biological species concept
- applies only to sexually reproducing organisms
- doesn't apply to bacteria and asexual organisms or extinct ones which are classified by structural and biochemical characteristics
- individuals assigned to different species sometimes successfully interbreed
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phylogenetic species concept
classified due to different traits because of 2 separate evolutions
- undergone evolution long enough for statistically significant differences
- testable by comparing gene sequences between groups
68
short comings of phylogenetic species concept
- requires thorough studies of DNA sequencing
| - many subspecies would become separate species under this concept
69
reproductive isolating mechanisms
prevent interbreeding between 2 different species whose ranges overlap
70
prezygotic barriers
dont even get to the point of creating a zygote
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temporal isolation
reproduce at different times of day, season, or year
72
habitat isolation
same area, but different habitats
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behavioral isolation
how you behave affects selection
| ensures they're the same species
74
mechanical isolation
structural differences in reproductive organs prevent mating between species
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gametic isolation
molecular and chemical differences between species prevent fertilization after mating
76
postzygotic barriers
when fertilization occurs between two closely related species mate
reproductive failure
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hybrid invariability
the embryo of an interspecific hybrid spontaneously aborts
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hybrid sterility
if an interspecific hybrid lives, it may not reproduce
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hybrid breakdown
more sterile as you go on
80
speciation
the evolution of a new species
| -population becomes reproductively isolated
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allopatric speciation
populations separated geographically and evolve by natural selection and/or genetic drift
82
sympatric speciation
when reproductive isolating mechanisms evolve at the start of the speciation process
- common in plants
- 2 populations in same geographic region
83
2 ways that sympatric speciation occurs
1. ploidy-number of chromosome sets
| 2. change in ecology
84
polyploidy
having more than 2 sets of chromosomes
| -major factor in plant evolution
85
2 kinds of polyploidy
1. autopolyploid- contains multiple sets of chromosomes from a single species
2. allopolyploid-contains multiple sets of chromosomes from 2 or more species
86
what occurs with hybridization?
allopolyploid
- produces a fertile interspecific hybrid because polyploidy provides the homologous chromosome pairs necessary for synapsis
- reproduces with itself or with similar individual
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outcomes of allopolyploid
1. new species cant compete & becomes extinct
2. new species assumes new role & coexists with parental species
3. has a greater fitness & replaces parents
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geographic variation
genetic differences among different populations within the same species
89
cline
gradual change in a species through geographically separate populations as a result of an environmental gradient
90
what explains the rapid appearance of many flowering plant species in the fossil record & their diversity?
allopolyploidy
91
what leads to disruptive selection?
mutation spread by sexual reproduction
92
sexual selection
choosing a mate based on color and some other characteristic
93
hybrid zone
area of overlap between 2 recently diverged populations in which interbreeding takes place and hybrid offspring are common
94
3 outcomes of hybrid zone
1. reinforcement- hybrids less fit
2. fusion- hybrids just as fit
3. stability- hybrids more fit
95
punctuated equilibrium
long periods of stasis interrupted by short periods of rapid selection
96
phyletic gradualism
evolution proceeds continuously over long periods of time
97
what explains evolutionary novelty (Large phenotypic changes such as the appearance of jointed limbs)?
macroevolution
98
preadaptations
pre-existing structures
99
evolutionary novelties
preadaptations that originally fulfilled one role but subsequently were adapted for a different one
100
allometric growth
different parts of body grow at different rate
101
regulatory genes
control hundreds of other genes during development
102
paedomorphosis
retain juvenile features during adulthood
103
adaptive radiation
evolutionary diversification of many related species from one or a few ancestral species in a relatively short period
104
adaptive zone
new or vacant ecological niches that were not used by an ancestral organism
105
extinction
when any line ends
| eventual fate of all species
106
chemical evolution
life developed from nonliving matter
107
first life
unicellular bacteria
prokaryotes---> eukaryotes
developed in water
108
sequence of evolution
soft-bodied, shelled, marine invertebrates, vertebrates, fishes, amphibians, reptiles, mammals
109
earth's early atmosphere
not much oxygen---made of carbon dioxide, water vapor, carbon monoxide, nitrogen, ammonia, hydrogen sulfide, methane
110
4 requirements for chemical evolution
1. little or no free oxygen (oxygen oxidizes the organic molecules necessary for life)
2. a source of energy (sun & no ozone layer)
3. availability of chemical building blocks
4. time
111
formation of organic molecules models
1. prebiotic soup hypothesis
- mix building blocks and add energy
2. iron-sulfur world hypothesis-organic precursors formed at cracks in the ocean's floor
112
protobionts
synthesized vesicles made by scientists with functional and structural attributes of living cells
- divide in half after they've grown
- maintain an internal chemical environment different from the external environment
- some show beginnings of metabolism
- highly organized
113
microspheres
type of protobiont formed by adding water to abiotically formed polypeptides
- some produce an electrical potential across their surfaces
- can absorb materials from their surroundings (selective permeability) and respond to changes in osmotic pressure
114
metabolism first hypothesis
chemical reactions occur between simple molecules enclosed within a boundary
- an energy source must be coupled to the chemical reaction sequence
- organization increases as pre-cells evolve
- the pre-cell system must grow and reproduce
115
RNA world hypothesis
RNA came first
- simpler (single stranded)
- code for protein
- some types serve as enzymes (ribozymes)
- self-replicate
116
when did cells first exist?
no one knows exactly but mircofossils suggest 3.5 bya
117
stromatolites
composed of many minute layers of prokaryotic cells
118
describe first photosynthetic autotrophs
used light energy to split hydrogen-rich molecules, releasing sulfur in the process
119
cyanobacteria
first photosynthetic autotrophs to obtain hydrogen electrons by splitting water
-need oxygen to produce mitochondria
120
aerobes
respiratory pathway evolved that used oxygen to increase the amount of energy from food
121
UV protection
ozone layer prevents sun's ultraviolet radiation from reaching Earth's surface
organisms could live closer to the water surface and eventually move onto land
122
serial endosymbiosis
early eukaryotic cells were assemblages of formerly free-living prokaryotes
123
chloroplasts
evolved from photosynthetic bacteria that lived inside larger heterotrophic cells
124
what did mitochondria evolve from?
aerobic bacteria that lived inside larger anaerobic cells
125
endosymbionts
live symbiotically inside host cell; could have survived and reproduced with host cell, forming a mutualistic relationship
126
how many strata are there
5 layers
127
archaean eon
life originated here
128
Proterozoic eon
2.5-542 mya
prokaryotes
first eukaryotic cells appeared 2.2 bya
129
ediacaran period
600 mya-542 mya
multicellular organisms
simple, soft invertebrates
130
6 periods of paleozoic era
542 mya-251 mya
1. cambrian
2. ordovician
3. silurian
4. devonian
5. carboniferous
6. permian
131
cambrian
evolution was rapid and sudden appearance of animal body plans (oxygen enrichment hypothesis)
132
orduvician period
land covered by shallow seas and another burst of evolutionary diversification
-giant cephalopods, coral reefs, jawless fish, terrestrial plants
133
silurian period
jaw fish and terrestrial plants
land arthopods (air breathing)
evolution of plants allowed animals to colonize on land
134
devonian period
(age of fishes)
when tiktaalik lived
-placoderms, sharks, lobe-finned fish, and ray finned
-late devonian- amphibians, wingless insects, and all major plant groups
135
carboniferous period
- lots of oxygen because of forests
- amphibians went through adaptive radiation and became dominant carnivores in terrestrial ecosystems
- 2 lines of reptiles: lizards & permians and early mesozoic mammal-like ones
- 2 groups of winged insects: cockroaches & dragonflies
136
permian period
divergence between reptiles and mammals
| therapsids- mammal-like reptiles that included the ancestor of mammals, originated in the permian to mesozoic era
137
mass extinction
occurred at end of paleozoic era, between permian and triassic (251 mya)
more than 90% of marine species & 70% of vertebrates living on land became extinct
catastrophic
138
mesozoic era
- 251-66 mya
- age of reptiles
- 3 periods:
1. triassic
2. jurassic
3. cretaceous
139
triassic period
terrestrial groups: mammal-like therapsids (insectivores & herbivores
carnivorous thecodonts (ancestors of crocs, flying reptiles, dinos, and birds)
marine groups: plesiosaurs & ichthyosaurs
pterosaurs (flying reptiles) appeared & diversified
140
jurassic and cretaceous periods
crocodiles, lizards, snakes, and birds appeared and dinos diversified dramatically
141
2 groups of dinos
1. saurischians- origin of birds; bipedal, fast, carnivores
- others huge, quadrupedal herbivores
2. omithischians- entirely herbivores; some with broad, birdlike beaks, others with great armor plates
142
archaeopteryx
oldest known bird (150 mya)
| teeth and long bony tail
143
sihornis confuciusornis
earliest known bird with toothless beak
144
what were the first feathers used for?
thermal insulation but then were modified for flight
145
microraptor gui
had feathers on forelimbs, hindlimbs, and tail
146
how much does archaeopteryx predate m. gui by?
25 million years
147
what ended the cretaceous period?
change in climate over a long period
impact at chicxulub crater in Mexico
smoke and forest fires that lowered global temperatures
148
cenozoic era
66 mya-present
flowering plant diversity
explosive radiation of birds adapted for different habitats
149
pleistocene
ice age
150
quatemary
present time
151
when did mammals emerge?
paleocene epoch
152
when did many modern families of mammals emerge?
during the oligolene epoch
153
when did humans appear?
in Africa during Late Miocene and early Pliocene epochs
| -homo appeared 2.5 mya
154
paleoanthropology
study of human evolution
155
what is the origin of primates?
came from small, shrew-like placental mammals that lived in trees and ate insects
156
when did primates appear?
early ecocene (56 mya)
157
kinds of primates?
lemurs, tarsiers, monkeys, apes, and humans
158
primate characteristics
opposable thumb
stereoscopic vision (overlapping vision fields)
relatively large brain for their size
159
what type of primates are we?
anthropoids
160
tarsiers
nocturnal primates found in rain forests of indonesia and philippines
161
anthropoidea
arose in Africa or Asia during the middle ecocene epoch (45 mya)
oldest anthropoid fossils (eosimias) were small insecting eating arboreal primates, active in day
relatively larger brain
162
new world monkeys
- south and central america
- arboreal and prehensile tails
- marmosets, capuchins, howler monkeys, squirrel monkeys, and spider monkeys
163
old world monkeys
- africa, asia, and europe
- some arboreal, none have prehensile tails
- ground dwellers, quadrupedal
- baboons, macaques, guenons, mangabeys, langurs, colobus
164
hominoids
group composed of apes and hominins (humans)
| -apes and old world monkeys diverged 25 mya-23 mya
165
proconsul
fossil with hominoid features
166
5 genera of hominoids
1. gibbons (hylobates)
2. orangutans (pongo)
3. gorillas (gorilla)
4. chimpanzees (pan)
5. humans (homo)
167
brachiate
swing from branch to branch (gibbons and orangutans)
168
knuckle walking
chimps and gorillas
169
what hemoglobin is identical to humans?
chimps and humans
170
foramen magnum
hole for brainstem in skull
| if its right under it, then they were bipedal
171
differences between ape skeleton and human
- no brow ridge
- no protruding jaw
- smaller k9s
- alignment of toes
- foramen magnum
172
human skull
- brain larger
- smaller teeth
- look like a baby primate
- modern human skulls lack prominent subraorbital ridges
173
orrorin
bipedal, early hominin
| 6 mya
174
australopithecines
ardipithecus, australopithecus, and paranthropus
bipedal
hominin
175
A. afarensis
```
lucy
ancestor to lots of autralopithecines
bipedal
3.2 million years old
found in ethiopia in 1974 by donald johanson
```
176
what did the homo genus arise from?
australopithecines
177
homo habils
used tools, larger brain
178
homo ergaster
may be direct ancestor of humans (2-1.4 mya)
179
homo erectus
larger brain
dead end
more sophisticated tools, clothing, fires, lived in shelters
180
archaic humans
descendants of homo ergaster
same size as our brains
rich, varied cultures
oldest archaic human fossils discovered in Europe as Homo antecessor
181
homo heidelbergensis
ancestors to homo sapians and neandertals
| larger brain
182
neandertals
overlap with homosapiens and died out
european
cared for sick and used tools
maybe a separate species (homo neanderthalensis)
short, sturdy builds, heavy supraorbital ridges and jaws, large front teeth, nasal cavities with triangle boney projectile rituals
183
homo sapiens
modern humans
| in africa about 195,000 years ago
184
what led to bigger brains?
cooking food, which predigests it, making more calories
