Exam 1 Flashcards
Who came up with the idea of evolution?
Charles Darwin
What is Gregor Mendel known for?
genes and discovering basic principles of heredity
what are genes?
-sections of DNA that code for a particular trait
-a specific sequence of nucleotides making up a DNA molecule
what is the molecular order in which genes are formed?
nucleotides -> codon -> gene -> chromosome -> genome
what is a gene made up of?
a bunch of codons
how many pairs of chromosomes do humans have?
23
in a diploid cell how many chromosomes do humans have
46
how much of our genes make up who we are and what us individual?
2%
what genes make us who we are?
protein-coding genes
transcriptone
what is a character?
a heritable feature (ex: flower color)
what is a trait?
a variant of character (ex: purple flower)
what is a locus (loci)?
a specific location on a chromosome where a gene is located
what are alleles?
different versions of the same gene
-code for the trait in
-found in the same location
-1 from mom 1 from dad
what is a genotype?
the genetic makeup of an organism (PP, Pp, pp)
What are confounding features of inheritance? (CFI)
complete dominance, codominance, incomplete dominance
What type of dominance is mendel known for?
Dominance inheritance/ complete dominance
What are the 2 laws of inheritance Mendel was known for?
Independent Assortment
Segregation
explain complete dominance
-phenotypes of heterozygote and dominant homozygote are identical
-presence of a single dominant allele produces full dominant phenotype
-ex: purple pea flowers
explain codominance
-2 dominant alleles affect the phenotype in separate ways
-ex: human blood type (AB)
-ex: Pp= red AND white flower
explain incomplete dominance
-phenotypes of F1 hybrids are somewhere between the 2 phenotypes of the parental variates
-3 phenotypes are seen visually
- red + white = pink
what is ecology?
the study of interactions between organisms and their environment
what constitutes an environment?
biotic and abiotic (minerals, pH, humidity, etc)
what is life’s fundamental characteristic?
having a high degree of order or organization
-based on a hierarchy of structural levels
what are novel properties?
properties that emerge at each step increase in the bio hierarchy
-results from interactions between components
-ex: a neuron is not much but a bunch together builds our conscious
organismal ecology
interactions between INDIVIDUALS and their environment
population ecology
same species 1 group of organisms
community ecology
interactions between different species (groups of populations)
-can have same species but different populations
ecosystem ecology
interactions between communities and abiotic factors (ex: pH, humidity)
ecosphere/biosphere ecology
sum of all Earth’s ecosystems
what is a key idea in ecology
INTERACTION
what kind of science is ecology?
quantitative
hypothesis
-not accepted. only failed to be rejected
-must be testable and falsifiable
theory
-a hypothesis that has been repeatedly tested and not yet falsified but still can
what is evolution?
change in allele frequencies in a population over time
what is natural selection?
differential reproductive success
-some individual in a population can make more
healthy fertile babies than others
first mechanism for evolution
What were Darwin’s hypothesess of origin of species
1) life is related through “descent w modification” aka evolution
2) natural selection is an extremely important mechanism for evolution
observation: heritable variation exists within a species
observation: all species produce more offspring than
the environment can support which creates competition
Inference #1 of the origin of species
different reproductive success among individuals (w “best” traits) help them survive and reproduce leaving more offsprings
ex: bird eating dark beetles on white tree
What is the difference between natural selection and evolution?
selection works on individuals
evolution works on populations
genetic drift
-large drop in diversity because something happened
-random
bottleneck effect
-a type of genetic drift
-catastrophic arbitrary event
ex:founder effect: only a few individuals from a large population move/ colonize a new area
mutations and the 4 types of them
-change in DNA sequences
-RANDOM
-can lead to new alleles
1) substitution 2)insertion 3) deletion 4)inversion
what is the #1 driver of diversity?
mutations
gene flow
-sharing of genes between populations (in and out)
-introducing alleles or restricting the flow of them
-can be the movement of individual organisms or their gametes
random vs non-random mating
random: alleles have the same probability of entering the next generation (allele frequencies stay the same)
what are the 2 types of non-random mating?
asortive: preference for mates with SIMILAR geno/phenotypes
disasortive: preference for mates with DIFFERENT geno/phenotypes
what is the modern synthesis?
evolution + genes
what is a phylogenetic tree?
a graphical representation of these relationships
what is the most recent common ancestor?
what all lineage be traced back to
what is needed for life?
-information storage
-compartmentalization
-energy acquisition utilization
-reproduction
informational storage
presence of a genome that carries the info specifying a phenoype
compartmentalization
the ability to keep ocmponents together and distingyis itself from the env
what are examples of energy acquisition utilization?
metabolism, growth, behavior
differnce between DNA, RNA, and proteins
DNA: store and transmit info
proteins: perform biology functions
RNA: store info AND do bio work
what are ribozymes
-RNA molecule that catalyze rxns like splicing and gene expression
what is the driving force from RNA to protein?
RNA
difference between DNA and RNA
RNA is extremely unstable and breaks down easily
what organisms have ribosomes?
all iving things
what did the Miller-Urey Experiment show?
-many of components necessary for life could be produced i a “pre-biotic” atmosphere
-debris collected contained amino acids which later formed more complex compounds after a week
what is the hypothesis of Panspermia?
-origin of life may not have started in Earth
-life on Earth originated from microorganisms or chemical precursors of life present in outer space and able to initiate life once reaching a suitable environment
Murchison Meteorite in Murchison, Australia
-contained high levels of polyols (precursor of glucose)
-came from a parent body that had liquid water
-estimated to be 7BYA (older than earth)
-implies that early life may have been “seeded” by organic compounds falling from skies rather than starting from scratch here
-purine and pyrimide= could have been precursors to nucleic acid
evidence of life on mars
-evidence of liquid water in the past
-present and active methane (CH4) in Mar’s atmosphere
how can we trace back to find common ancestor?
life descended from a primordial form that used DNA to store heritable info and proteins to express that info
all life uses DNA and proteins in the same way
what does all life share?
-same genetic material (DNA, mRNA, tRNA)
-same genetic code (A,C,G,T)
-same basic process of gene expression (transcription and translation)
-same molecular building blocks (proteins made of 20 a.a.)
-presence of ribosomes
How is unity possible with such diversity?
evolution -> stem from a common ancestor that had these same characteristics
how are genes different?
each gene (locus) has an different history due to recombination, lateral gene transfer, and sometimes different grouping
what does the whole genome approach support?
archaea and eukarya are sister taxa
igneous rock
created from molten material after it cools and solidifies
sedimentary rock
deposition and solidification of sediments, accumulate in layers (created after heat, pressure and time)
metamorphic rock
results from the transformation of igneous or sedimentary rock under high pressure and temp
what types of rock are you likely to find fossils in and why?
sedimentary because lay on top and traps life/biological material
How do we know dates of rocks?
1.) relative dating
2.) absolute dating
3.) plate tectonics
relative dating
-arranges geological events in a sequence
-DOESNT provide numerical dates for rocks/specific ages
-sedimentary rocks do NOT yield absolute ages
stratiography
study of layered sedimentary rocks. comes from idea of superposition
superposition
younger sedimentary rocks laid down on older rocks
how are lava and sedimentary rocks laid down?
horizontally
original horizontality
bending or tripping occurred after deposition
cross-cutting relationship
intruding rocks are younger than host rocks
faunal succession
Groups of fossil plants and animals follow (succeed) each other in time in a predictable manner, even when found in different places
what does radiometric dating use?
unstable isotopes
what are radioisotopes?
radioctive isotopes that randomly emit neutrons, protons, end electrons
what can absolute dating infer?
actual dates using halftime measurement (time required for quantity to get to half ->daughter isotope)
dendochronology
biological dating w tree rings
-age determination of trees to the exact calendar year
-types of wood
plate tectonics
-continental drift
-alfred wagner
-fossils of several species present in Brazil AND Africa
-outer layer of earth is made up of plates that move across face of the planet
what are the 3 types of plate boundaries?
divergent: moving apart (ex: ocean floor)
convergent: moving towards each other (ex: can produce mountains)
transform fault: grinding against each other (ex: earthquakes)
what is a fossil?
any trace left by an organism that lived in the past
compression fossils
preserved in sedimentary rocks and have undergone physical compression
PLANTS!!! NOT ANIMALS!!
cast and mold
physical characteristics of organisms are impressed onto rocks
-especially coarse, porous rocks like sandstone
usually the harder parts of an organism (shells, skeletons, bones and teeth, chitinous exoskeleton, trunks of trees)
(think jello)
permineralization
-deposits of minerals within cells of organisms
-most common method of fossilization
-calcite, iron, and silica
-organism must become completely covered by sediment after death
-skeletal remains, teeth, traces of skin, soft tissues
unaltered remains
preserved with little or no change
-ancient organisms are sometimes frozen in ice or permafrost (frozen soil) at high latitudes and altitudes (or amber)
Ichnofossils
-aka trace fossils
-dont record body, but something else
-left by the behavior/ ongoings of animals
-footprints: mud or sand
-coprolites: fossilized feces
-burrows
Index fossils
-aka guide, indicator, or Zone fossils
-fossils that are characteristic to a particular span of geological time
-good index fossils found in many locations 1 layer
what are rapidly evolving species good for?
index fossils
why is the fossil record incomplete and biased?
some things fossilize better than others
-geography bias
-taxonomic bias
-temporal bias
what are 2 difficulties in the interpretation of fossils?
1.) age can only imprecisely be estimated by their strata
-many fossils are crushed or fragmented
species
temporally distinct parts of a single evolutionary lineage, which contains successive phenotypically different form groups (chronospecies)
-basic unit of classification and a taxonomic rank of an organism and unit of biodiversity
anagenesis
-evolutionary change of a single lineage in which taxon replaces another
-evolution of a new species that replaces old
-NO BRANCHING
-doesn’t promote biological diversity`
cladogenesis
-evolutionary change of a species where new one branches off
-branching of lineage
-promotes biological diversity
pseudo extinciton
lineage changes so much that its original name (species) disappears
“real” extinction
lineage that fails to leave descendants
“Big Five” extinction events
1.) ordovician
2.) devonian
3.) permian
4.) triassic
5.) K-T (creaceous-tertiary)
population
group of organisms of the same species living in the same area and the same time
biome
a major and distinct biogeographical community that has developed in response to a shared regional climate/ environment
environmental classification
to understand how organisms with different ancestor evolve out of necessity due to environment
what determines species distribution
1.) physical environment (tolerance limits to abiotic factors)
2.) biotic interactions (food, predators, competitors, parasites, diseases)
abiotic factors determining geographic range
1.) angel of incidence
2.) earth’s axial tilt (obliquity)
angle of incidence
at higher latitudes, light strikes earth’s surface at lower angle and is spread out over a large area (global
incident solar radiation
earth’s axial tilt
aka obliquity
-axis isn’t perpendicular
-tilt of 23.5 degrees
-because of this, sun shines at different latitudes
-causes seasons
subpolar points
location where the sun is directly overhead (perpendicular) surface
what is equation for intensity?
photons/ area
where will light intensity be highest?
at equator
what are 2 reasons of large-scale patterns of climate variation?
1.)uneven heating of earth’s surface
2.) drives air circulation patterns and consequently precipitation patterns
3.) results in defined regions for biomes
hadley cells
circulation of air rising near equator flowing towards the poles, descending in the subtropics, and returning toward equator
(circulation pattern of air)
what does the hadley cells pathway create?
trade wings, rain-belts, hurricanes, deserts, and jet streams
coriolis effect
causes deflection of surface winds clockwise in the N hemisphere and counter clockwise in S hem
(polar easterlies come from east but travel west)
adibatic cooling
drives temperature change depending on altitude
-drop in air pressure = drop in temps
laps rate
rate of temp drop with altitude
-depends on humidity
-10C/km or 5.5F/1000 ft
oceanographic lift
when wind hits a mountain and is forced up over time
rain shadows
can serve as marked boundaries between different biomes
windward
side of mountain that wind hits first
-heaviest precipitation lush vegetation, and cloud coverage
leeward
side of mountain that air is descending on
-very little precipitation/ warm air
soil
the foundation. of terrestrial biomes
-a complex moisture of living and non-living material
-soil diversity can change evolutionary trajectors
soil horizons
classification based on vertical layering
-physical, chemical, and biological characteristics differ from layers above and beneath
O
A
B
C
O horizon
-newest layer
-organic, freshly fallen material
A horizon
mixture of minerals, clay, silt, and sand
B horizon
clay, humus, and other materials leached from A horizon
-often have plant roots
O Horizon
oldest layer
-weathered plant material
gross primary production
total energy assimilated by photosynthesis
net primary production
total energy available to consumers
climate diagrams
-summarize climatic info using a standardized structure
10 C = 20 mm precipitation
-adequate moisture for plant growth happens when precipitation is higher than temp
what is energy lost to?
entropy and energy change
what are the 3 components that explain how evolutionary history affects distribution?
1.) geological history (continental drift, glaciation)
2.)historical shifts in climate
3.) phylogenetic history (phylogenetic conservatism of the species’ range limits. )
terrestrial biomes
-land based
-9 distinguished by temp and precipitation rates
-same biome can occur in geographically distinct areas with similar climate
What does the existence of a 2 billion year-old cyanobacteria fossil indicate?
That the most recent common ancestor of DNA based life existed at least 2 billion years ago.
