Unit 1 Flashcards
How old is life?
3.7 billion years
study of fossils
paleontology
relative position of layers and their place in geological time scale
stratigraphy
what are the layers of rock called?
strata
extant
living today
geologic time is divided into
eons, era, period, epoch
We are in what eon?
Phanerozoic
We are in what era?
Cenozoic
We are in what period?
Quaternary
We are in what epoch?
anthropocene
What is the age of homo sapiens?
200,000 years ago
What is the age of animals?
500-600 million years ago
What is the age of life/prokaryotes?
3.7 billion years ago
What is the age of Earth?
4.5 billion years ago
Fault
crack in Earth’s crust
Where have fault lines been found?
1975 earthquake in Morris
Rocks in (blank) MN are 3 bya
Montevideo
What eon are we living in?
Phanerozoic
What era are we living in?
Cenozoic
What period are we living in?
Quaternary
What epoch are we living in?
Anthropocene
How old are homo sapiens?
200,000 years old
How old is life on land?
300 million years
How old are animals?
500 to 600 million years
How old is life/prokaryotes?
3.7 billion years
How old is Earth?
4.5 billion years
What is the first step of oxygen throughout time?
1) CO2 + H2O—- Sugar + O2
Early atmosphere had little or no free O2 until photosynthesis released O2 as a waste product
List steps 2-5 of the role of oxygen throughout time
2) O2 in water + iron = BIF
3) GOE killed anaerobes; aerobes thrived (high O2 concentration supports large cells)
4) O2 increased, allowed eukaryotes and multicellular life
5) invasion of land by plants, increased O2
formation of BIF
- oxygen captured by iron in water which fell to the sea floor creating a BIF
- sedimentary in mesabe range NE MN
great oxygenation event
- water saturated with O2 was the tipping point that led to the goe
- opened resources for aerobic bacteria
development of complex life
-rise of aerobic lifestyle; efficient, led to eukaryotes and multicellularity due to the surface area to volume ratio of oxygen in larger cells (vs previous small cells) due to diffusion
invasion of land
invasion by plants led to an increased amount of O2 due to increase in photosynthetic processes
great dying
- cause unknown
- low O2
describe general carbon trends over past 400,000 years
- Plesitocene
- Petit graph (temp and CO2 data could be placed on top of each other because they are so similar, up and down until present day)
- Lake Vostok in Antarctica CO2 and temp both from ice
describe general carbon trends over past 300 years
- Keeling curve measures CO2 levels
- Hawaii steady increase, senses seasons
- fluctuating between 175 and 275 ppm until present
- present day CO2 increase past 400 ppm
- “the world passes 400 ppm carbon dioxide threshold. permanently” - Sept 2016
- –should have been at lowest point after season
How do we know these general carbon trends?
glacial formations
How are glacial formations evidence of past climate change?
new ecosystems developed after glaciers
- geologic formations
- vegetation records
What are some examples of glacial formations? When did they disappear?
end moraine, kame, esker, coteau, 10000 years ago
terminal dump of glacial debris
end moraine
hill of sand debris laid by glacial meltwater
kames
ridge of sand/debris, laid by meltwater
eskers
big piles of snirt with uneven melting over 3000 years
coteaus
Explain the significance of Tiktaalik’s discovery
-transition from water to land
-“missing link”
2006 disvoery of tiktaalik roseae
Describe differences between fish and Tiktaalik; Tiktaalik and tetrapods
fish (gills, scales, fins)
tiktaalik (lung like organ, wrists, neck, flat face)
tetrapod (4 limbs, no scales, lungs)
movement from finn to limb
Define homology
traits shared from common ancestor
Define analogous
traits that don’t share a common origin (wings, independent evolution of interlocking shells)
three principles of fossil discovery
age of rock, type of rock, exposed rock
phylogenic tree
more related = more recent common ancestor
phenotype
physical expression of an organisms genes
genotype
genetic makeup of an organism
allele
different forms of a gene
evolution
change of allele frequencies within a population
gene pool
set of all alleles
allele frequency
proportion of times a certain allele occurs in a population
population
group of individuals of a single species living together (evolve)
Can you form a sentence including these words (allele, population, evolution, mechanism)
the way populations evolve is through changing their allele frequencies and there are five mechanisms in which they can do so.
what is evolution?
evolution is the change of allele frequencies, also known as genetic composition, of a population over time due to 5 mechanisms
mutation
change in nucleotide sequence of DNA
characteristics of mutations
- most are harmful or neutral
- increase genetic variation
- random (not goal directed)
Can you make a sentence with these words? (evolution, mutation, population)
mutation in a population leads to evolution
gene flow
migration of individuals between populations
characteristics of gene flow
- increase similarity between pop
- example = homo sapiens expand range into neanderthals, interbreeding
genetic drift
random changes in allele frequencies
characteristics of genetic drift
- affects small populations most
- reduces genetic variation
- population bottleneck and founder effect
population bottleneck
population drastically reduced by a natural catastrophe or overhunting
founder effect
drastically reduced population, moved to another place (huterite population)
lack of genetic variation leaves populations with (blank)
little flexibility to evolve if their environmental circumstances change
How might genetic drift cause evolution?
only allows certain alleles through populations
nonrandom mating
occurs when individuals choose mates with particular phenotypes
draw a concept map with allele, population, evolution, and mechanism
population—mechanism—change—-allele frequency—evolve
Debunk 2 common misconceptions of evolution
1) theory > hypothesis (theory has unifying explanation developed through extensive observations)
2) individuals do not evolve, populations do
what are the 3 types of selection?
-natural, artificial, sexual
natural selection
- populations evolve via natural selection
- favors individuals best adapted to environment
- acts on individual, but pop changes with evolve
- not progressive
adaptation
feature that improves fitness
-fly/cricket example in hawaii- variations in flies produced change mutation which was passed on because silent males didn’t attract parasitic flies, therefore increasing fitness
artificial selection
purposeful selection of specific phenotypes by humans
sexual selection
- increase female choice
- outcompete other males
- widowbird with long tail feathers
What are the three ways selection can act on a population?
stabilizing, directional, disruptive
Stabilizing
preserves average phenotype (human birth weights)
Directional
favors individuals that vary in one direction (texas longhorn)
Disruptive
favors individuals that vary in both directions from the mean (birds beak size)
Ingredients for natural selection
Variation, heritability, differential fitness
variation ingredient
individual differ from one another
heritability ingredient
characteristics passed from parent to offspring
differential fitness ingredient
traits increase/decrease fitness
fitness
reproductive success relative to others (progeny born and survive long enough to reproduce)
Darwins role in defining evolution
- recognized artificial over short time periods (geology important)
- proposed evolution via natural selection mechanism
- Darwin and the voyage of the HMS beagle (origin of species)
miss-step of evolution
Lamark- offspring can inherit characteristics that were modified in their parents through use or disuse
3 bodies of knowledge = proposed mechanism of natural selection
age of earth, artificial selection, study of plants/animals
constraints of evolution
- follow laws of universe
- allele must exist
- cost < benefits
what does it mean by the “allele must exist”
if the allele for a given trait doesn’t exist, it can’t evolve even if favored by natural selection. All evolutionary innovations are modifications of previously existing structures. Engineering vs tinkering
Why do the benefits of evolution have to outweigh cost?
benefit of adaptation must outweigh cost if adaptation is to evolve, trade off must be worthwhile
Disadvantages to sexual reproduction
- can break up adaptive gene combinations
- dividing offspring into genders reduces overall reproductive rate
Advantages to sexual reproduction
- genetic variation ingredient for selection (new combos of genes)
- some individuals with harmful mutations, some with few (few more likely to survive)
- defense against pathogens
red queen hypothesis
“it takes all the running you can do just to stay in the same place”
-correlation between host and pathogens, selects for sexual reproduction
principles of radiometric dating
determine absolute age of rocks and rock layers to determine geologic and evolutionary events
-decay in half lives
hardy-weinberg
frequency of alleles in populations remains constant throughout generations, none of the five mechanisms can occur
frequency of AA =
p^2
frequency of A
p
allele
variant of gene
igneous
form when molten rock cools and forms a solid (radiometric dating)
metamorphic
formed when existing rock formations are altered due to extreme heat and or pressure (chemical and physical change)
–deep in earth’s surface or tectonic plates (gneiss)
sedimentary
fossils
material that has weathered from other rock formations or formed by living organisms deposited or precipitated out of solution
What are some ways fossils form?
petrification, carbonization, and mold/cast
What are the 3 domains?
archaea, bacteria, eukaryea
