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bio exam one Flashcards

1
Q

what is biology

A

scientific study of living organisms and fossils

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2
Q

common features of organisms

A

-common set of chemical compounds
-contain genetic info
-universal molecular code
-made up of cells
-use molecules from environment to synthesize new molecules
-regulate internal environment

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3
Q

Miller-Vrey Experiment

A

chamber with primitive ocean water + atmosphere and jolts of electricity combined molecules into RNA

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4
Q

Gregor Mendel

A

monk who discovered genes

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5
Q

genes

A

unit of genetic code that allows traits to be inherited

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6
Q

genome

A

total genetic code

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7
Q

when was DNA discovered?

A

mid-1900s

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8
Q

internal environment

A

-made up of extracellular fluid
-requires sensory mechanisms
-monitoring and regulation of intracellular environment

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9
Q

homeostasis

A

physical and chemical composition must be kept in a narrow range

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10
Q

2 types of cellular life

A

prokaryotic and eukyarotic cells

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11
Q

photosynthesis

A

transformation of sunlight into chemical energy to build molecules

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12
Q

consequences of photosynthesis

A

-oxygen built up in atmosphere
-aerobic processes are more efficient: evolution
-ozone layer developed
-blocked UV radiation on land and made life possible

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13
Q

population

A

groups of individual of same type of organism that interbreed

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14
Q

evolution

A

process resulting in changes in genetic makeup of populations over time

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15
Q

Charles Darwin

A

understood selective breeding and bred pigeons, produced idea of natural selection

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16
Q

speciation

A

traits can be more or less popular in populations, populations may split and preferences are embedded in each & ability to interbreed dissolves

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17
Q

classifications

A

genus + specific epithet

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18
Q

at organismal level, individuals must…

A

acquire nutrients from environment and break them down into building blocks

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19
Q

scientific method - observations

A

science is based on observations, experimentation, data analysis, and logic

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20
Q

steps of scientific method

A
  1. make observations
  2. ask questions
  3. form testable ideas
  4. make predictions
  5. test predictions
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21
Q

2 types of experiments

A

-controlled experiments manipulate 1 factor while holding other variables constant
-comparative experiments compare date from populations that differ in several ways

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22
Q

model species

A

we can use closely related organisms to model others
–common ancestry
–common genetic code
–similar building blocks

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23
Q

weather

A

short-term changes in atmospheric condition

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24
Q

climate

A

long-term patterns of changes of weather in a given area

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25
evolution is...
-directly observable -a universal principle of life -a scientific theory - a change in genetic composition of a population over time
26
natural selection (Darwin)
he observed that more offspring are born than can survive, natural selection=artificial selection
27
theory of evolution (species, divergent, differential)
-species change over time -divergent species share a common ancestor -differential survival and reproduction based on trait variation
28
what are mutations?
-any change in nucleotide sequences of DNA -origin of genetic mutation -most are harmful or neutral ## Footnote random with respect to needs of organism and can restore variations other processes remove
29
gene pool
sum of all copies of all alleles at all locations in a population ## Footnote mutations can cause different forms of genes to appear
30
mutation rates | eukaryotes + viruses?
rates differ in certain organisms, low mutation rates can still create a lot of variation | viruses acquire mutations rapidly, eukaryotes acquire mutations slowly
31
selection
differential survival/reproduction in a population; acts on genetic variation to produce new phenotypes ## Footnote -can be artificial/natural/sexual
32
gene flow
the transfer of genetic material from one population to another, results in migration of individuals
33
genetic drift
the change in frequency of an existing gene variant, result of random changes in allele frequencies ## Footnote harmful alleles may increase in frequency
34
founder effect
a few individuals colonize an area, colonizing population likely will not represent all alleles
35
nonrandom mating: sexual selection
individuals in a population chase mates with particular phenotypes
36
genotype frequencies are... | and genetic structure is...
not always the same as allele frequencies | the allele frequencies at each locus
37
Hardy-Weinberg: definition
model situation where allele frequencies do not change, provides baseline for testing evolutionary change
38
Hardy-Weinberg: conditions
1. no mutations 2. no selection among genotypes 3. no gene flow 4. population size is infinite 5. mating is random
39
natural selection can...
-alter distribution of quantitative trait over time -only act on phenotype
40
fitness
how well a phenotype allows an individual to produce and contribute genetic material to the next generation
41
qualitative
influenced by alleles at only 1 locus
42
quantitative
shows continuous variation influenced by alleles at more than 1 locus
43
stabilizing selection
preserves average phenotype, reduces variation but does not change mean, also purifying selection because there is selection against deleterious mutations
44
disruptive selection
favors individuals that vary in both directions from the mean, individuals at either end are more successful
44
directional selection
favors individuals that vary in one direction, happens when individuals at one end of a continuum are more successful, increases freq of alleles at favored phenotype, positive selection
44
ways to maintain genetic variation
1. neutral alleles 2. sexual reproduction 3. frequency dependent selection 4. heterozygote advantage 5. geographically distinct populations
44
neutral alleles
alleles that do not affect fitness, added to populations by mutations, not directly acted on by natural selection
45
sexual reproduction results in…
results in new combinations of genes through combination of gametes, crossing over, and independent assortment
46
sexual reproduction disadvantages
-can break up adaptive gene combinations -rate females pass on genes to offspring is reduces -dividing offspring into sexes reduces overall reproduction rate
47
sexual reproduction advantages
-facilitates repair of damaged DNA -creates new combinations of alleles that natural selection can act on -eliminates deleterious mutations
48
Muller's Ratchet
deleterious mutations can build up in asexual species and only death of lineage can eliminate them
49
frequency dependent selection
fitness depends on frequency of a phenotype or genotype in a population
50
heterozygote advantage
different alleles are advantageous under different environmental conditions, when conditions are changing heterozygous individuals outperform homozygous
51
geographically distinct populations
populations in different areas are subjected to different environmental conditions and selective pressures, each population has its own variations on traits
52
evolutionary outcomes are limited by...
1. pre-existing traits 2. constraints of natural world 3. cost-benefit trade-offs
53
pre-existing traits
-natural selection acts on phenotypic variation -all evolutionary innovations are modifications of previously existing structures -if allele for a trait doesn't exist it cannot evolve
54
constraints of natural world
-physics and chemistry limit potential variation -cell size is constrained by surface area to volume ratios -protein folding limited by types of molecular bonds - energy transfer constrained by thermodynamic laws
55
cost-benefit trade-offs
-adaptations pose costs and benefits -benefits must outweigh costs for success -can result in traits adaptive in one context but not another
56
short-term evolutionary outcomes
changes in allele frequencies can be observed directly, manipulated experimentally, and demonstrate the actual processes by which evolution occurs
57
long-term evolutionary outcomes
patterns of evolutionary change that can be influenced by extremely rare events, which cannot usually be observed during short-term studies
58
phylogeny
evolutionary history of relationships among organisms
59
phylogenetic tree
diagram reconstructing evolutionary history
60
phylo trees can be constructed using...
physical structures, behaviors, biochemistry
61
phylo trees can be about...
species, population, gene level
62
root of phylo tree represents...
common ancestor
63
(phylo) relative position of nodes shows...
timing of splitting events
64
(phylo) ____ can be rotated around nodes
lineages
65
(phylo) taxon
any species or group of species that we designate a name
66
(phylo) clade
consists of an ancestor and all descendents of that ancestor
67
(phylo) sister species
2 species that are each other's closest relatives
68
(phylo) sister clades
2 clades that are each other's closest relatives
69
ancestral trait
something present in ancestor of group
70
derived trait
trait found in descendant that differs from ancestral trait
71
homoplasy
traits shared by 2 or more species that were independently evolved
71
(phylo) homologous traits
traits shared by 2 or more species inherited from common ancestor
72
convergent evolution
independently evolved similar traits because of similar selective pressures
73
evolutionary reversals
character reverts from derived state to ancestral state
74
ingroup
group of primary interest
75
outgroup
taxon outside ingroup to which ingroup is compared
76
principle of parsimony
tree with fewest changes is preferred

biology (6 decks)

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