Test #1 Flashcards
1
Q
what are the seven characteristics of life
A
- cellular organization
- ordered complexity
- sensitivity
- growth, development, and reproduction
- energy utilization
- homeostasis
- evolutionary adaptations
2
Q
deductive reasoning
A
application of general principles to predict specific results
- tests the validity of ideas
- knowledge of big ideas to shape understanding
3
Q
inductive reasoning
A
using specific observations to create a general set of scientific principles
- leads to generalization that can then be tested
- evidence => idea
4
Q
hypothesis
A
a suggested explanation that accounts for observed phenomenon
- something that can be tested and proven wrong or right
5
Q
reductionism
A
philosophical idea: used to understand a complex system by reducing it to its working parts
limitations - for complex interconnected functions it can be hard to predict emergent properties
6
Q
setting the framework for biology
A
- life is subject to chemical and physical laws
- structure determines function
- living systems transform energy and matter
- living systems depend on information transaction
- evolution explains the unity and diversity of life
7
Q
evolutionary thought
A
recognition that species change over time - rooted in ideas of ancient greeks, romans, and chinese
8
Q
the three key observations about life
A
- organisms are adapted for life in their biotic and abiotic environments
- many shared characteristics of life (unity of life)
- extensive diversity of life
9
Q
evolution
A
the process by which species accumulate differences from their ancestors as they adapt to different environments over time
- a pattern that reveals life has evolved over time
- process that consists of the mechanisms that cause the patterns of change
10
Q
aristotle
A
believed species were fixed, created a hierarchy based on “complexity”
- earliest record of using a system of classification
11
Q
Carolus Linnaeus
A
created systems of classification used today
- nested classification that groups similar species
- binomial format for naming species
12
Q
Charles Lyell
A
rejected evolutionary ideas
but conceptualized that the earth was shaped by forces working gradually over an extended period of time (think plate tectonics)
13
Q
cuvier
A
- boundaries between strata represent sudden catastrophic events
- older strata contain fossils less similar to organisms in the current strata
14
Q
strata
A
the layers of sedimentary rock
15
Q
Lamarck’s hypothesis of evolutioon
A
two principles to explain evolutionary change
1. use and disuse: body parts used extensively become larger and stronger, unused parts deteriorate
2. inheritance of acquired characteristics: modifications aquited in one’s lifetime can be passed to offspring
- mechanisms not supported by experimental evidence
16
Q
Alfred Russel Wallace
A
came to same evolutionary conclusions as Darwin - widely forgotten
17
Q
Darwin’s “descent with modification”
A
organisms are related by descent from a common ancestor that lived in the past
- related organisms living in different habitats gradually accumulate diverse modifications to fir them to specific ways of life
18
Q
Darwin’s journey on the HMS Beagle
A
- collect specimens
- noted that fossils resembled living species from where they were found, and living species resembled other species from nearby areas
19
Q
adaptation
A
inherited characteristics that enhance an organism’s survival and reproduction in specific environments
*perceived that new species could arise from ancestral forms through gradual accumulation of adaptations
20
Q
natural selection
A
a mechanism of evolutionary change
- process in which individuals with certain inherited traits tend to survive and reproduce at higher rates because of those traits
(domestic breeding can produce variation in traits - nature can also apply selective pressures)
21
Q
obs: members of a population often vary in their inherited traits
A
individuals with inherited traits that increase survival and reproduction in an environment tend to produce more offspring than other individuals
22
Q
obs: all species produce more offspring than the environment can support and many of these offspring fail to survive and reproduce
A
the unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the populations over generations
23
Q
what are the key features of natural selection
A
- individuals with certain heritable traits survive and reproduce at a higher rate than other individuals
- natural selection increases frequency of adaptations that are favorable for a given environment
- if the environment changes, natural selection may drive adaptations to new conditions, and thus new species
24
Q
evidence to evolution
A
direct observations, homology, fossil record, biogeography
25
direct observation
in soapberry bugs - correlation between fruit size and beak size
- longer beaks evolved when bugs fed on larger fruit of introduced plants
*natural selection selects for traits already present in population (it doesn't create new ones)
26
homology
definition: similarity resulting from common ancestry
- related species can have characteristics that have an underlying similarity yet function differently
- comparative embryology reveals anatomical homologies not visible in adult organisms (all vertebrate embryos have post-anal tail but can develop into different functions in adults)
27
vestigial structures
remnants of features that served a function in the organism's ancestors
- some snakes retain vestiges of pelvis and leg bones as they arose from ancestors with legs
28
molecular homology
genetic code that is shared by all life and specific genes that are shared between vastly different organisms
29
convergent evolution
evolution of similar or analogous features in distantly related groups
(analogous traits = arise through independent adaptation to similar environments)
*sugar gliders of Australia and flying squirrel of North America
30
the fossil record
can provide evidence of the extinction of species, origin of new groups, and changes over time
31
biogeography
the study of geographic distribution of species
- affected by continental drift (pangea, land bridges)
32
what mechanisms cause the evolution of population
- evolution occurs when the allele frequencies of a population change over time
via = genetic drift, gene flow, natural selection
33
genetic variation
difference in genes or other DNA sequences among individuals
- phenotype is the product of inherited genotype and environmental influences
34
sources to genetic variation
- originates when new genes and alleles arise by mutation, gene duplication, other processes
- sexual reproduction can produce genetic variation by recombining existing alleles
35
new alleles
formed by mutation (change in nucleotide sequence of DNA)
36
mutations
caused by replication errors, exposure to certain radiations or chemicals
often harmful
can be hidden in heterozygous individuals (recessive)
37
alternation gene number or position
- deletions, disruptions, or rearrangements of many loci are usually harmful
duplication of small segments of DNA potential key source to genetic variation
- persistence of duplicated genes can allow mutations to accumulate and potential new funtions
38
how does sexual reproduction account for most variation
recombination of alleles by
- crossing over (exchange of genetic material between homologous chromosomes during meiosis)
- independent assortment (random distribution of chromosomes into gametes during meiosis)
- fertilization (random combination of gametes)
39
gene pool
consists of all copies of every allele at every locus in all members of the population
40
the hardy-weinberg equation
the equation describes the expected genetic makeup for a population that is not evolving at a particular locus
- if the observed genetic makeup of the population differs under Hardy-Weinberg then the population may be evolving
(hint: the population is almost always evolving)
41
what are conditions for Hardy-Weinberg
1. no mutations
2. random mating
3. no natural selection
4. extremely large population size
5. no gene flow
42
adaptive evolution
process in which traits that enhance survival or reproduction increase in frequency over time
43
how does natural selection result in altering of allele frequencies
selection results in alleles being passed to the next generation in proportions that differ from the present generation
- based on differential success in survival and reproduction
44
genetic drift
process in which chance events cause allele frequencies to fluctuate unpredictably from one generation to the next
*the smaller the sample, the greater the chance of random deviation from a predicted result
- genetic drift tends to reduce genetic variation through the random loss of alleles
45
founder effect
(genetic drift)
occurs when few individuals become isolated from a larger population
- allele frequencies different from parent population
46
bottleneck effect
(genetic drift)
drastic reduction in population size due to sudden change in environment
- the resulting gene pool may no longer be reflective of the original population's gene pool
47
gene flow
movement of alleles among populations
- tends to reduce variation among populations over time
- can increase population's fitness (flow of resistance alleles into new population can increase its fitness)
48
adaptive evolution
natural selection is the only mechanism that consistently causes adaptive evolution
- evolution by natural selection includes both chance and sorting
- reproductive advantage
49
relative fitness
the contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals
50
directional selection
(frequency distribution)
favors individuals at one extreme end of the phenotypic range
51
disruptive selection
(frequency distribution)
favors individuals at both extremes of the phenotypic range
52
stabilizing selection
(frequency distribution)
favors intermediate variants and acts against extreme variants
53
sexual selection
process where individuals with certain heritable traits are more likely to obtain mates than other individuals of the same sex
- can result in difference in secondary sexual characteristics between the sexes (sexual dimorphism) [difference in size, color, behavior]
54
intrasexual selection
direct competition among individuals of one sex for mates of the opposite sex
55
intersexual selection
"mate choice" - individuals of one sex are choosy in selection their males
- female choice is often dependent on male showiness
56
the good genes hypothesis
females select males with traits that are related to their genetic quality or overall health
57
balancing selection
preserves variation at some loci by maintaining stable frequencies of two or more phenotypes
58
frequency dependent selection
(balancing selection)
fitness of a phenotype depends on how common it is (selective advantage changes)
59
heterozygote advantage
(balancing selection)
heterozygotes have higher fitness than both kinds of homozygotes
60
why can't natural selection create perfect organisms?
limitations
- selection can act only on existing variations
- evolution is limited by historical constraints
- adaptations are often compromises
- chance, natural selection, and environment all interact
61
the biological species concept (defining "species")
defines a species as a group of populations whose members have the potential to interbreed in nature, produce viable fertile offspring, do not produce viable fertile offspring with members of other such groups.
- based on potential to interbreed
- gene flow between populations holds a species together genetically
62
reproductive isolation
biological barriers impede members of two species from interbreeding and producing viable, fertile offspring
- limits formation of hybrids
- can occur before of after fertilization
63
prezygotic barriers
block fertilization from occuring
- block attempts to mate
- prevent successful completion of mating
- hindering fertilization if mating is successful
64
habitat isolation
(prezygotic barrier)
two species that occupy different habitats within the same area may encounter each other, rarely
65
temporal isolation
(prezygotic barrier)
species that breed at different times of the day, different seasons, different years cannot mix their gametes
66
behavioral isolation
(prezygotic barrier)
courtship rituals and other behaviors unique to a species can prevent mating
67
mechanical isolation
(prezygotic isolation)
mating is attempted by morphological differences prevent successful completion
68
gametic isolation
(prezygotic barrier)
sperm of one species may not be able to fertilize eggs of another species
69
postzygotic barrier
prevents hybrid zygotes from developing into viable fertile adults
70
reduced hybrid viability
(post zygotic barrier)
genes of different parent species may interact in ways that impair the hybrid's development or survival in its environment
71
reduced hybrid fertility
(postzygotic barrier)
meiosis may fail to produce normal gametes, resulting in sterility if the parent species have chromosomes of different numbers of structure
- Mules
72
hybrid breakdown
(postzygotic barrier)
first generation hybrids are viable and fertile but offspring in the next generation are feeble or sterile
73
what are the limitations to the biological species concept (BSC)
- the number of species to which BSC can be usefully applied is limited (cannot be applied to fossils or asexual organisms)
- the BSC emphasizes absence of gene flow, but gene flow occurs between many morphologically and ecologically distinct species (the grolar bear)
74
the morphological species concept
distinguishes species by structural features
- can be applied to sexual and asexual orgs
- relies on subjective criteria
75
ecological species concept
defines species by its ecological niche, the sum of its interactions with the nonliving and living parts of the environment
76
allopatric speciation
populations are geographically isolated
- gene flow interrupted when population is divided into geographically isolated subpopulations
* effect of geographic barrier dependent on organisms ability to move
77
evidence of allopatric speciation
sister species diverged as lands became isolated = snapping shrimp isolated by isthmus of panama
- isolated or highly subdivided regions usually have more species than those with fewer barriers
- reproductive isolation between populations generally increases with geographic distance
78
sympatric speciation
speciation occurs in populations that live in the same geographic area
- reduced gene flow
79
sympatric speciation via polyploidy
accidents during cell division can cause polyploidy = presence of extra sets of chromosomes
- can form new species within single generation
80
autoplyploids
more than two sets of chromosomes all derived from single species (cell division error)
- mating between tetraploids and diploids produces triploids offspring with no or reduced fertility - hard to interbreed
81
alloployploids
more than two sets of chromosomes derived from different species
- chromosomes from diff species do not pair during meiosis = hybrid sterility
- formed if the number of the chromosomes doubles in subsequent generations
- allopolyploids can't interbreed with parent species
82
sympatric speciation via sexual selection
can be driven by sexual selection - reproductive isolation?
83
sympatric speciation via habitat differentiation
the exploitation of new habitats or resources can lead to evolution of new species
84
hybrid zone
region which members of different species mate and produce hybrid offspring
- typically located wherever habitats of interbreeding species meet
- outside hybrid zone, gene flow may be impeded by obstacles
85
how does environmental change affect hybrid zones
- changing environmental conditions can result in the relocation of existing hybrid zones, new zones
- alleles can be transferred from one parent species to the other through breeding of parents and hybrid, which may help parent species cope with changing environments
86
hybrid zone outcomes
if hybrids don't become reproductively isolated from parent species, reinforcement, fusion, or stability can occur
87
what is reinforcement
reproductive barriers are reinforced
- if hybrids are less fit than the parent species, then strong selection for prezygotic barriers should reduce hybrid population
- stronger in sympatric vs allopatric populations
88
what is fusion
the two parent species may fuse into a single species
- substantial gene flow between species if hybrids are as fit as their parents
- reproductive barriers are weakened
89
what is stability
continued hybridization
- extensive gene flow from outside the hybrid zone can overwhelm selection for increase reproductive isolation inside the hybrid zone
90
rate of speciation
observed via patterns in the fossil record
morphological and molecular data
91
punctuated equilibria
describes the periods of apparent stasis punctuated by sudden change
92
macroevolution
broad pattern of evolution above the species level
93
abiotic
things that aren't living or organic
94
production of simple cells
1. abiotic synthesis of small organic molecules
2. joining of these small molecules into macromolecules
3. packaging of molecules into protocells, droplets with membranes that maintain an internal chemistry different from the environment
4. origin of self-replicating molecules
95
organic molecules
consist of carbon atoms - abiotic synthesis of building blocks for organic compounds
96
abiotic synthesis of macomolecules
the miller-urey experiement
- hypothesized and demonstrated that the building blocks for organic molecules were likely in reducing atmospheric conditions and near volcanoes
97
protocells
replication and metabolism are key properties of life and may have first appeared together in protocells
- may have formed from fluid-like vesicles with a membrane-like structure
- in water, lipids and other organic molecules can spontaneously form vesicles with lipid layer
98
self-replicating RNA
first genetic material was likely RNA
- central role in protein synthesis
- RNA molecules (ribozymes) have been found to catalyze many different reactions
99
radiometric dating
used to determine the age of fossils based on the decay of radioactive isotopes
- uses half-lives
100
first organisms on life
microbe - too small to see with the naked eye
microbiome - community of microbes that inhabit a particular environment
101
stromatolite
first single-celled organisms
- layered rocks that form when prokaryotes bind thin films of sediment together
102
prokaryotes
unicellular organism that lacks a membrane bound nucleus, mitochondria, other membrane-bound organelles
103
eukaryotes
organisms whose cells have a nucleus enclosed within membranes (domain eukarya)
104
endosymbiotic theory
large eukaryotic cell engulfed (ate) a smaller prokaryote
"food became friend"
105
serial endosymbiosis
hypothesis that mitochondria evolved before plastids through a sequence of endosymbiotic events
106
origin of multicellularity
1.2 bya - red algae fossils
600 mya - larger more diverse multicellular organisms
107
cambrian explosion
phenomenon - animal phyla appear suddenly in fossils
greater diversity of animals
108
colonization of land
mutualism between plants and fungi to colonize land
- arthropods first to colonize land about 450 mya
109
plate tectonics
theorizes that the earth's crust is composed of plates floating on the underlying mantle
- movements in the mantle cause the plates to gradually shift in a process called continental drift
110
effects of pangea (250 mya)
-ocean basin became deeper
-most shallow-water habitat was destroyed
-interior of the continent became colder and drier
- changes to climate
111
the breaking up of pangea
- regions that were once connected became isolated
- organisms on new continents diverge and allopatric speciation occurs
112
mass extinctions
- 5 mass extinctions in fossil record
- triggered by disruptive global change (environmental change)
113
consequences of mass extinction
- can take 5-10 million years for diversity to recover (varies)
- can change the type of organisms found in ecological communities
- can curtail lineages with novel and advantageous features
114
adaptive radiation
rapid period of evolutionary change where many new species arise and adapt to different ecological niches
occurs in response to:
- opening of niches to fill
- evolution of novel characteristics that enable the exploitation of new habitats/resources
- colonization of new regions with few or weak competitors
115
phylogeny
evolutionary history of a species or group of related species
116
systematics
discipline focused on classifying organisms and determine their evolutionary history
117
taxonomic groups (broad too narrow) (most inclusive too least)
domain, kingdom, phylum, class, order, family, genus, species
118
what are the limitations to phylogenetic trees?
- don't show patterns of descent, not phenotypic similarity
- alone they don't indicate when species evolved or how much change occurred in a lineage
- do not assume that a taxon evolved from the taxon next to it
119
clade
a group of species that includes an ancestral species and all its descendants (monophyletic)
120
monophyletic groups
consist of the ancestor and ALL of the descendants
121
paraphyletic group
consist of the ancestor and some, not all of the descendants
122
polyphyletic group
includes distantly related species but not their most common recent ancestor
123
shared ancestral character
character that originated in an ancestor of the taxon
124
shared derived character
evolutionary novelty unique to a particular clade
- can include both new feature or the loss of features
125
using molecular comparisons to deduce relatedness
can trace relatedness to organisms that are morphologically/phenotypically different
remember: different genes can evolve at different rates in same lineage -DNA coding for ribosomal RNA changes slowly while mitochondrial DNA evolves relatively rapidly
126
increase in gene duplications
gene duplication increases the number of genes in genome, more opp for evolutionary change
repeated gene duplications result in gene families - groups of related genes within a genome
127
orthologous genes
homology is the result of speciation event and occurs between genes found in different species
- reflect history of speciation events
128
paralogous genes
homology results from gene duplication and occurs between gene copies within a species
- can diverge within a species as they are present in more than one copy
129
genome evolution
lineages that diverged long ago often share many orthologous genes
130
3 domains
bacteria: most known prokaryotes
archaea: diverse prokaryotes
eukarya: single-celled and multicellular organisms that have cells containing true nuclei
131
horizontal gene transfer
movement of genes from one genome to another
- can occur by exchange of transposable elements and plasmids, viral infection, fusion of organisms
