Unit 1 JTT, Unit 2 JTT, Unit 3 JTT
Atomic number:
the number of protons in the nucleus of an atom
Radiometric Dating
the process of measuring the absolute age of geologic material by measuring the concentrations of radioactive isotopes and their decay products. Has nothing to do with DNA
Habitable zone
the region around a star in which planets could potentially have surface temperatures at which liquid water could exist
Basic argument
those with larger brains were more socially competent, which allowed them to have more offspring
What is the name method used by the scientists to discover the exoplanets
transit method
According to Dr. Dave, human history is dominated by two major patterns, both of which have a common root. Which one of the following does NOT demonstrate both patterns?
Development of carpet industries that reuse old carpets (carpets improve human living standards, but by reusing materials these industries actually reduce our environmental impact rather than increasing it)
Big Bang
13.8 bya
How to find a date: molecular clock
A 200 nucleotide segment of DNA found in two species of turtles differs between the two species at seven nucleotides, and the mutation rate for this segment of DNA is one nucleotide every 20,000 years. Approximately how long ago did the most recent common ancestor of these turtle species live? 7 X 20,000 years = 140,000 years ago
What type of fossil fuel formed from the horsetail and club moss forests of the Carboniferous Period?
Coal
Evidence for ______ comes primarily from archeological artifacts rather than from fossils?
Cognitive revolution (archeological artifacts from 70,000 years ago, such as needles made out of bone, artwork, ornaments, and technologies such as a floating boat), all show that our brains took on a dramatic reorganization)
Endosymbiosis
A theorized process in which early eukaryotic cells were formed from simpler prokaryotes.
What represents evidence that the Earth formed through massive collisions?
Craters found on all solid objects within solar system 1) The story to explain the Earth's formation is the nebular hypothesis, which posits that lots of matter collapsed together because of gravity and that this led to a series of collisions that ultimately formed the Earth. The data to support this model include our measurements of nebulae collapsing all over the galaxy in ways that are consistent with our model of gravity, and also the measurements of craters on solid objects of the solar system such as Mercury, the Moon, and Mars. Venus and Earth also have craters, but it's harder to see them because of a thick cloud cover (Venus) or because of erosion (Earth)
What accurately describes these "creationists" according to public opinion surveys?
Creationists are nearly always motivated, at least partially, by their religious/spiritual beliefs. yes, this was one of the biggest findings of our public opinion surveys; when asked why they reject human evolution, they will always cite their religious/spiritual beliefs as one of biggest reasons, if not the only reason
Although Homo sapiens was historically an African species, it now lives in Africa, Australia, Eurasia, North America, and South America. Which of the following represents the order in which these continents were colonized by H sapiens?
Africa, Eurasia, Australia, North America, South America
Great Oxygenation event spikes
At end of snowball earth Carboniferous and Permian periods (Giant amphibians)Jurassic & Cretaceous Periods (giant reptiles)
Soon after it was invented, penicillin was called the "miracle drug," because it would cure just about any infectious disease. Now, however, the drug is rarely used. Why?
Bacteria have evolved resistance to penicillin through natural selection
Multicellularity
Cells divide but remain stuck together (occurred in several lineages)
Reinforcing effect
Change leads to even more drastic change if it's getting cold, it will get colder
How did the different beak types first arise in the Galapagos finches?
Changes in the finches' beaks occurred by chance, and when there was a good match between beak structure and available food, those birds had more offspring.
Atomic emission spectra
Characteristic patterns of bright lines produced when atoms are vaporized in high-temperature flames or electrical discharges
Why are the rib bones of the turkey are fused?
Bone fusion provides increased body support for flying vertebrates such as birds.
What represents scientific evidence that supports the social competency hypothesis more so than a competing hypothesis?
Brain scans made during social interactions show that lots of brain space is used during interactions (yes, this is 'evidence' because it represents something that is actually measured, and it supports the idea that individuals with larger brains would have been more socially competent)
What provided strong evidence for the Cambrian explosion?
Burgess Shale this was a large collection of fossils in Alberta, Canada that dates to 542mya. It shows an enormous diversity of animals at this layer of the fossil record, which contrasts dramatically with the lack of animal fossils immediately prior to this time period. The cause of the Cambrian explosion is still under debate, although it may have had something to do with the rising oxygen levels at the end of Snowball Earth, which facilitated the origin of collagen - a key component of the body plans of most animals)
Wobble method
Detecting an extrasolar planet by noticing its gravitational tug of the planet on the star, around the center of mass
Who invented the theory that the universe has not existed forever but had a distinct and explosive beginning?
Lemaitre, early 1900s
Approximately what percentage of participants rejects all forms of evolution—even gradual genetic change in a single species?
Less than 10%The
Which of the physical feature likely describes the humans that first crossed Beringia?
Lighter skin than the average human (because Beringia is at high northern latitudes less sunlight -> natural selection favors lighter skin color to maximize Vitamin D production)
How oceans formed
Meteor shower earth (inside tiny crystals of salt and droplets of water) bombarded earth for 20 million years, pools of water begin to grow- Mega storm hits earth for many years and rains- Meteor shower, Rock under the crust is hot, movement is generated between the rocks, plates pushed and pulled for 400 million years and Rhodina is formed.Heat breaks apart crust & Rodina super crust splits, the intense geological activity forms massive volcanoes and pumps c02 into the atmosphere, which creates acid rain (CO2 mixes with oxygen), and then the acid is absorbed into rocks.- C02 absorbed out of the atmosphere means not enough c02 to trap the sun's heat, so in a few thousand years, temp drops to -60 and freezes.SNOWBALL EARTH- Entire earth covered in ice sheet- Volcanoes erupt and pump out billions of tons of co2 back into the atmosphere, warms the earth. This traps the sun's warmth around the planet causing temperature to rise.
Drake equation
Method to estimate the number (N) of communicating/technological civilizations in our Galaxy
Each gene codes for one _______
Protein
Nebular hypothesis is..
Solar system evolved from an enormous rotating cloud called the solar nebula
Dr dave 2 patterns in application
The agricultural revolution contributed to both rising living standards for humans and to our rising environmental footprint
Which best describes the connection between the agricultural revolution, which began ~10,000ya, and Dr. Dave's two patterns of human history?
The agricultural revolution contributed to both rising living standards for humans and to our rising environmental footprint
What specifically is altered by a genetic mutation?
The sequence of DNA
How do we know the size of the meteor 65mya, and how do we know it had a global impact? (Hint: this question is about data, not mechanisms)
The size of Yucatan crater global iridium layer
Daughter product
The substance produced when radioactive isotopes decay.
Mass number:
The sum of the number of protons and the number of neutrons in an atom.
The 3 components of natural selection
Variation -difference Differential fitness- some type of predator that is killing off a certain or preventing reproduction Heritability-correlation between parents and offspring
Snow Ball Earth II
We do not know what caused the temperature to drop again. However, we do know there was an albedo effect.
Two adaptations that distinguished humans from apes were... These two adaptations occurred in different Geological Periods
bipedalism and a dramatic increase in brain size. TRUE (Bipedalism originated in the Ardipithecus genus during the late Neogene Period, and brain size expansion occurred in the Homo genus during the Quaternary Period)
Body support
bones
How Oxygenation Event caused the earth to be more habitable for humans
breathable air, UV protection, blue sky and energy reserves
Biotechnology - De-extinction
bring back extinct species like the mammoth or the Neanderthal
Adaptations
evolution never starts from scratch; instead it "tinkers" with existing body parts
The highlanders of New Guinea have a history of farming nearly as long as Eurasians, yet New Guinea highlanders never developed "cargo" like the Europeans.
farming is important, but the types of species that get domesticated are also very important; crops w/ high protein content that can be stored easily provide more food surplus, and megafauna livestock also make a big difference for protein, fertilizer, muscle power,etc
Food surpluses emerge only in...
farming societies
Modern humans (Homo sapiens)
migrated out of Africa ~50,000 years ago and almost certainly encountered (and perhaps wiped out!) the other human species Humans ~70,000ya (right as a population of Homo sapiens was starting to leave Africa)
Climate change affected human...
migrations 1. b/c some climates are unsuitable for humans to live, e.g., Sahara likely dried out just prior to earliest (coastal) human migrations out of Africa 2. b/c of changes in sea level, e.g., Borneo wasn't an island when Homo sapiens first encountered it, Bering Straits were the isthmus of 'Beringia' 3. b/c the ice itself blocked human movement, e.g., at Beringia AND origin of civilization 1. b/c climate change affects where humans can live, e.g., desert vs. grassland, Neanderthals living in cold Northern Europe probably wore clothes 2. b/c climate change affects success of farming due to changes in temperature, precipitation, wind, and presence of domestic livestock
Formation of erratic rocks in polar regions...
occurred again because glaciers were still present after Snowball Earth—just not to the same extent. For example, during the Quaternary Period the Earth has gone through a series of >20 ice ages
Fossils of new species of multicellular organisms...
occurred again e.g., fossil dinos, birds, humans and other mammals
Formation of a new mountain range...
occurred again, because 400mya is pre-Pangaea, and we know that many mountain ranges formed after Pangaea, such as the Andes, Alps, Himalayas, Rockies, etc.
NS adaptations to climate
resulted in the biological difs we usually associate with race, e.g., skin color, body shape, hair type
How did the east-west axis of Eurasia play a role in the spread of farming? What if there had been a north-south mountain range similar to the Andes just west of the Fertile Crescent?
similar latitudes have similar climates, so crops and livestock that survived well in the Fertile Crescent also thrived in places like N India, W Europe, and US Midwest; if a huge N-S mtn range was just west of Fertile Crescent then farming would have spread a lot to the east but not to the west; perhaps India would dominate and not Europe
Gas exchange
stomata
Bones
support the bodies of vertebrates
Cuticle
is the wax-like surface found on the tops of the leaves of all plants, which makes leaves waterproof.
Phloem
is the way that plants transport sugary fluids around the body, but it is more about overcoming the challenge of distributing nutrients, not overcoming the three challenges listed in the table
Element is defined by
# of protons, # protons are the same as atomic #
_____ is defined as the accumulation of DNA mutations over time
'natural selection' and 'genetic mutation'
Cretaceous-Paleogene extinctions
(65.5mya, meteor) 10X normal iridium concentration in a global rock layer dated at 65mya Yucatan crater dated at 65.5mya Global dust cloud Blocks sunlight Food chain disrupted Debris returns to Earth
Triassic/Jurassic extinction
(~200mya, supervolcano) A LOT of ancient lava at 7 sites in eastern North America and one site in Morocco, all date 201.5mya Lots of fossil pollen immediately below ancient lava
The order of paleogeographic events in Phanerozoic Eon
- Australia isolated from rest of the continents - Cambrian explosion - Formation of Appalachians - Formation of Pangaea - India collides with Asia - Laurasia and Gondwana form when Pangaea breaks up - Snowball Earth
Origin of life
- Happened just once ~4-3.5 bya (Archean Eon)- Aquatic- Simple (fossil prokaryotes ~3.5 bya)Still a mystery- Origin of anything subcellular- Mechanisms
Some misconceptions about natural selection
- NS involves organisms trying to adapt. - NS is about the survival of the very fittest in a population - The fittest organisms in a population are those that are strongest, healthiest, fastest, and/or largest - NS gives organisms what they need. - NS produces organisms perfectly suited to their environments.
Consequences of bipedalism
-Pelvis tilt: difficulty with childbirth -Stress on knee, joints, and back -Non-grasping feet -Freeing of hands
0.2 million years vs. 5000 years
0.2 million years is 40X bigger than 5000 years; 0.2 million = 200,000, and 200,000/5,000 = 40.
Dr Dave 2 patterns
1) Humans have dramatically improved their living standards relative to the living standards of other species 2) Humans have dramatically increased their environmental footprint relative to the footprints of other species
Explain how reinforcing feedback plays a role in the social competency hypothesis.
1) Reinforcing feedback means change promotes more change, which promotes even more change. According to the social competency hypothesis, individuals with slightly larger brains were more socially competent, which was favored by natural selection and therefore led to evolution for brain size. However, as brain size increased and societies became populated by more socially competent individuals, the societies would become even more complicated, which would increase the strength of natural selection, which would result in further evolutionary change with regard to brain size
A nebula begins with 4% of the mass of our Sun, and because of gravity it begins to collapse on itself. explain whether or not the nebula will ever become a star AND why
1) The nebula will not become a star, because it is below the critical threshold of 0.1M, i.e., 4% is less than 10% of the mass of our Sun, so gravity will never be strong enough to result in atoms combining through nuclear fusion. Any nebula that starts with at least 0.1M will eventually become a star. Any nebula that starts with at least 8M will become a star and then blow up as a supernova. Any nebular that starts with at least 24M will become a star, eventually blow up as a supernova, and then become a black hole. Stars with 8-24M become a neutron star (or pulsar) after they blow up as a supernova. Stars with 0.1-8M never blow up and become a white dwarf after consuming all of their nuclear fuel.
Rank the following species based on how closely related they are to the gorilla:
1) human 2) orangutan 3) monkey 4) dog
Additional benefits of domesticating animals and plants
1. Additional food, e.g., milk products 2. Fertilizer, e.g., cow manure 3. Muscle power, e.g., horses pull plow and carry people long distances 4. Raw materials for clothes (e.g., wool, cotton), buildings (e.g., lumber), personal items (e.g, soap, music), etc. Companionship, e.g., dogs, budgies
Humans are altering the planet in unprecedented ways
1. Biodiversity: another mass extinction? 2. Land use: it's not just about plate tectonics and climate change anymore 3. Biogeochemistry, e.g., climate change, acid rain, N deposition
Shape of hair
1. Curly hair adds SA ->maximize heat transfer; good if you need to lose lots of heat (adaptive in hot climates) Straight hair minimizes SA; good if1. if you want to conserve heat (adaptive in cold climates)
Denisovans
1. Discovered in 2010 in a Central Asian cave 2. Not much is known about them because the only fossils are molars and finger bone fragments 3. Two things we do know from these fragments a. Date: 30-50,000ya b. Genome: we interbred with them, and Neanderthals interbred with them; because of all the interbreeding and the lack of fossil evidence scientists are unsure yet whether to call them a unique species (Homo denisova)
Atahuallpa
1. Inca = most advanced civilization in the New World prior to colonial period 2. Absolute monarch over the largest ever empire in the New World 3. Considered a god by his people Surrounded by tens of thousands of Incas at the time he encountered Pizarro
How global temperature is determined
1. Incoming solar radiation 2. Albedo (light radiation reflected by a surface) 3. Greenhouse effect(CO2 and other gasses in the atmosphere trap heat, keeping the earth warm)
Three types - all change in some way the amount of heat that reaches the Earth's surface, which affects whether snowpack melts vs. persists during the summer months
1. Orbit path (eccentricity) varies between more circular and more elliptical - cycles every ~100,000years 2. Tilt (obliquity) varies btwn 22o and 24.5o every ~41,000years (affects contrast btwn seasons) 3. Wobble (precession) varies every ~20,000years (affects whether summer comes in July vs. January)
Amount of melanin is shaped by natural selection due to sun exposure
1. Pro: Sun provides Vitamin D (therefore when sun is the limiting factor natural selection favors white skin, blonde hair, and blue eyes) 2. Con: UV rays from Sun can mutate your DNA (therefore when sun is abundant NS favors dark skin, dark hair, and dark eyes)
Population structure
1. Small bands of a few dozen to ~150 individuals, all human (no livestock/pets, 1st domesticated animal = dog ~15,000ya - originally used for hunting, fighting, and alarm system against invasion by predators/outside humans) 2. Band members would know each other very well, and many members of the band would be genetically-related->loneliness and privacy were both rare 3. Limited social interactions outside the band: "The average person might live many months without seeing or hearing a human from outside of her own band, and she encountered throughout her life no more than a few thousand humans"
Eurasians domesticated early b/c of geographic advantages, not b/c of the people themselves. Eurasia happens to be...
1. large continent 2. oriented east-to-west 3. lacks major geographic barriers 4. long history with multiple human species (and therefore never had a mass extinction of megafauna)
Earliest multicellular fossil
1.2 bya
About what percentage of our genome is composed of genes?
2%
Pangaea breaks up
200 my
Earliest Homo sapiens
200,000 years
If the earth is ~11,000 years old, which of the following comes closest to the minimum amt of C-14 in any fossil sample
25%
Earliest cells
3.5 bya
200,000 years vs. 4.5 billion years: _______ is _______ times bigger than _______
4.5 billion years is 22,500X bigger than 200,000 years; 200,000 years = 0.2 million = 0.0002 billion
Origin of the Earth
4.5 bya
Two stick insects possess 30 differences in the nucleotides of a 15,000 nucleotide segment of DNA. The mutation rate for this segment of DNA in stick insects is one mutation every 800,000 years. Approximately how long ago did these stick insects share a common ancestor?
800,000yrs = 0.8 million years (my). Each of the 30 differences represents a mutation, and 30 mutations X 0.8my/mutation = 24 mya
Big advantage = agriculture is MUCH more productive than hunting/gathering
90% of the plants in a farmer's field produce edible food (i.e., not weeds), which contrasts with ~0.1% of the plants in a wild grassland 1. Agricultural societies therefore feed more people, fueling population growth
Approximately what percentage of species in fossil record are now extinct?
99%
Doppler effect
A change in sound frequency caused by motion of the sound source, motion of the listener, or both.
Genetic Drift
A change in the allele frequency of a population as a result of chance events rather than natural selection. (for example a wildfire, earthquake, etc)
A pterosaur's DNA sequence would best align with which species?
A monkey reptiles and mammals are more closely related to each other than either species is amphibians
Natural Selection
A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.
Suppose for your birthday you get a 2.8g lump of radioactive polonium (half life = 122 days). On your next birthday, how many milligrams of the radioactivity will remain?
After 365 days, three half lives will have passed. Therefore there will be 100->50->25-> 12.5% remaining; 12.5% of 2.8g is 0.35g or 350mg; you could also do three half lives manually: half of 2.8 = 1.4, half of 1.4 = 0.7, half of 0.7 = 0.35g = 350mg
From the perspective of someone living 10,000ya, which of the following was the biggest advantage of the earliest forms of agriculture compared to hunting and gathering?
Agricultural land contained a higher proportion of edible plants yes, this is a major point. Agricultural land produces far more edible calories for humans than any non-agricultural land. Therefore, farming results in food surpluses, which facilitates the division of labor among agricultural societies, which in turn facilitates the development of technology and other cultural innovations, sophisticated political and military organization, etc.
Homologous
Are structures in different species that are similar because of common ancestry.
Based on Jared Diamond's argument, label each of the following as a proximate factor or an ultimate factor.
Andes mountain orientation: ultimate Books: proximate Diseases: proximate Megafaunal extinction: ultimate
When Pizarro met Atahuallpa in battle, the horses of the Spaniards provided an enormous advantage. Which of the following BEST explains why Incas lacked large domesticated mammals for combat?
Any candidate mammals that might have been domesticated had already gone extinct (because of the megafaunal extinctions that followed soon after the colonization of South America by Homo sapiens ~10,000ya)
Origin of photosynthesis
Archean
Origin of proteins
Archean
One of the few traits that defines life on Earth is the presence of DNA. DNA first originated during which eon?
Archean Eon contained both the origin of life (nucleotides/amino acids) and the origin of the first cells (prokaryotes)
Evidence for the cognitive revolution that occurred ~70,000 years ago comes mostly from...
Archeological artifacts cognitive revolution means a rewiring of the human brain in a way that made it more innovative. Exactly how it happened is unclear, although most scholars agree that genetic mutations and/or changes to human language probably played a role. Human fossils show the size of the cranium (and therefore the size of the brain within that cranium), but provide almost no clues about how the brain was wired. It is plausible that data from DNA sequences or linguistics might provide future insights about the cognitive revolution, but for now the evidence a cognitive revolution occurred comes from the diversity of archeological artifacts that started to appear around 70,000ya, such as boats, needles, artwork, and new kinds of tools.
Earliest bipedal human fossil
Ardi (~4.4mya)
Rita drinks a half gallon of water in 10min. Her blood quickly becomes really watery, which triggers specialized cells within her kidneys immediately to start producing enormous amounts of urine. An hour later, and after several trips to the toilet, Rita's blood becomes less watery. This story illustrates which of the two types of feedbacks?
Balancing feedback because the initial change was counteracted. Although we use the term 'balancing feedback,' it is also called negative feedback or stabilizing feedback
What represents the evidence for the Great Oxygenation Event?
Banded iron deposits is basically rusted rock, and it can form only in the presence of oxygen. Banded iron deposits were formed in rock layers dated to 2.7bya. Therefore we infer that photosynthesis began 2.7bya, thus causing the GOE, and resulting in various effects, such as the generation of ozone
Based exclusively on our class discussions and the fact that Neanderthals had the largest brain size of any human, predict whether or not Neanderthals were monogamous, AND explain why.
Based on our class discussions Neanderthals should have been monogamous, because they had big brains like us. Therefore they should have had an extended period of child development, so natural selection would have favored monogamous males over polygynous males; if you research this question on the internet you will learn that conflicting data exist and that the topic is not yet resolved among scientists/archeologists
Which of the following BEST explains why the megafauna of Southern Europe did not go extinct immediately after the arrival of Homo sapiens?
Because Homo neandertalensis had lived in Southern Europe for ~500,000 years (because the megafauna of Southern Europe coevolved with a human predator species for 500,000years, the megafauna had evolved several sophisticated antipredatory mechanisms that served them well with the arrival of a new human predator species, Homo sapiens)
Blue shift
Blue shifted = higher frequency The displacement of the spectrum to shorter wavelengths in the light coming from distant celestial objects moving toward the observer.
Given that races do not differ much genetically, why do they appear so different to us?
Because each race evolved to adapt to its physical climate; these differences arise because of some of the key genetic differences that distinguish races
Ultimate factors behind Eurasia's dominance
Biogeography i. Larger areas get more species ii. Species spread well east-west, but not north-south (because climate changes with latitude) iii. Geographic barriers such as mountains, coastlines, and large lakes, also impede the spread of species Availability of species for domestication i. Geography ii. For megafauna, it matters greatly how long the species have lived alongside humans (megafaunal mass extinctions everywhere except Eurasia and Africa) iii. Chance 1. Eurasian wheat and barley vs. American corn (number of genetic changes between wild and domestic species) 2. African zebra vs. Eurasian horse (behavioral disposition)
Taxonomic Groups
Birds Reptiles Mammals Amphibians Fish Invertebrates Fungi Protists Archaea Bacteria
Mechanisms for thaw
Blue increases, Albedo decreases, gets warmer H2o increases, GH effect increases, gets warmer
photosynthesis
CO2 + H2O + light--> food + O2Led to Great Oxygenation Event and eventually aerobic respiration in proteobacteria Evidence for photosynthesis: iron deposits Cyanobacteria evolved the ability to make food and O2 (waste product) using sunlight energy and inorganic molecules (CO2, H2O)
Greenhouse Gas
CO2,H2O, CH4 (methane)
Compare and contrast with genetic drift
COMPARE Both natural selection and genetic drift are mechanisms for evolution (they both change allele frequencies over time) CONTRAST Genetic drift causes evolution by random chance due to sampling error, whereas natural selection causes evolution on the basis of fitness.
Some rocks such as limestone contain carbonate, and limestone dating to 600 mya had exceptionally high levels of carbonate. Why were carbonate levels so high in these rocks?
Carbon dioxide levels built up gradually throughout the most recent Snowball Earth
What is shared by BOTH eukaryotes and prokaryotes?
DNA
The DNA inside the chloroplast organelle of a eukaryote cell lines up the best with DNA from...
DNA inside a prokaryote cell
the DNA inside chloroplast organelle of a eukaryote cell lines up with the best DNA from
DNA inside a prokaryote cell
What is evidence used to build trees of life?
DNA sequences shared anatomical sequences behavioral traits
Who proposed natural selection as a mechanism for how species change over time?
Darwin, 1859, He convinced scientists that species change over time due to natural selection, and that all species belong to a single tree of life
What mechanism played a major role in ending Snowball Earth?
Decreased albedo effect (yes, as ice melted the surface of the Earth changed from the white of ice to the dark blue of ocean; this shift in color would result in the reflection of less heat from the Earth's surface (i.e., decreased albedo), which would heat the planet even further (i.e., reinforcing feedback)
Polymorphism
Defined as a position in the genome that varies between individuals; humans 99.9% similar
DNA structure
Double = two strands; helix = strands are twisted The molecular structure of DNA is the same in all organisms
Formation of Earth
Earth formed when gravity pulled swirling gas and dust in to become the third planet from the Sun. Like its fellow terrestrial planets, Earth has a central core, a rocky mantle and a solid crust.
Abundance of elements
Energy and mass are interchangeable Einstein's Prediction: the universe's atoms mostly H, then He 75% of the universe is hydrogen then 25% is helium
Formation of earth by collisions
Earth's mass increased.Earths heat storage increased (plate tectonics)
Scientists used to think the universe was static, but observations of "red shifted" galaxies led scientists to infer that the universe is actually expanding. Which of the scientists below observed red shifts?
Edwin Hubble was not the first scientist to observe red shifts, but he was the first to both observe them AND be recognized for this grand discovery
Equations of his theory of relativity predicted an expanding universe
Einstein
Complex cells (eukaryotes)
Endosymbiosis: large prokaryote cells swallowed small prok cells (proteobacteria that could do aerobic respiration, cyanobacteria that could do photosynthesis)
Latitude patterns of climate
Equator: more heat, more direct/intense sun Poles: much less sunlight/heat
What would constitute the strongest evidence that a Snowball Earth occurred?
Erratic with magnetite oriented in a way that indicates 10o latitude this shows glaciers were at 10o latitude; given that the poles are always colder than the Equator, this evidence shows conclusively that all or nearly all of the Earth's surface would have been frozen
Miller-Urey experiment
Experiment that found that organic molecules can form in a strongly reducing atmosphere.
Humans evolve from modern chimps
FALSE
Caucasians are 99.9% similar genetically to other Caucasians, but only 99.6% similar to Australian Aborigin
FALSE All humans, regardless of race, are ~99.9% similar genetically to each other
Your weight would still be the same as it is now if we had experienced one fewer collision
FALSE Your weight depends on the mass of the planet on which you are standing, and each massive collision increased the mass of the Earth a little more. With one fewer collision, the Earth would have had a little less mass, and we would all weigh less
Most animal species are tetrapods
FALSE Animals consists of more than 1 million invertebrate species, but just ~50,000 vertebrate species, of which approximately half are fish, and half are tetrapods (amphibians, reptiles, mammals, and birds). So there are >40 invertebrate species for every one tetrapod species
Year length would still be 365 days if we had experienced one fewer collision
FALSE Because each massive collision would have changed the speed and/or direction of the Earth's revolution, one fewer collision would mean we would probably have had a different year length
Daylength would still be 24 hours if we had experienced one fewer collision
FALSE Because each massive collision would have changed the speed and/or direction of the Earth's rotation, one fewer collision would mean we would probably have had a different daylength
It was common for young male hunter-gatherers to leave their group every few months to join another group of hunter-gatherers
FALSE, hunter-gatherers stayed within the same group for many years, and often for their entire lifetime
One 'half life' is equal to half of the time needed for a radioactive sample to fully decay
FALSE, In theory a radioactive sample never fully decays, and it does not make sense to take half of an infinite amount of time. Rather, one 'half life' is the amount of time needed for 50% of a radioactive sample to decay. After a 2nd 'half life' half of the remaining radioactivity will decay,
Our sun will one day blow up as a supernova
FALSE, Supernovae occur only for stars that begin with >8M. Because our sun is 1M it does not have enough mass for a supernova to occur. Instead after our sun runs out of nuclear fuel it will become a white dwarf, which is a dense ball of residual matter
Storytelling and shared knowledge
For most species the only relevant information is what they can physically sense at the moment. Language allowed humans to imagine abstract concepts, ideas, and characters that may or may not actually exist.
History of Appalachian Mountains
Formation of Appalachians (3rd, pre-Pangaea) The Appalachian mountains and the mountains in Scandinavia used to be part of a single volcanic mountain range (very well supported; data = identical rock structures, "fossil lava")
What represents an effect of the Great Oxygenation Event?
Formation of ozone layer Ozone (O3) formed soon after O2 was introduced into the atmosphere, thus giving organisms protection from harmful UV rays
why scientists do not know very much about mass extinctions that occurred in earlier eons?
Fossil record is biased; we know more about Phanerozoic extinctions because they are recent and involved organisms with hard body parts
Foraging
Gathering >> hunting (i.e., not much meat, most meat eaten was from small game like rodents and rabbits, not large animals like giraffes and water buffalo) Foods varied greatly btwn populations based on what food was available Sweet food, greasy food and other high-calorie foods were extremely limited
A scientist living in an alternate universe examines lithium on her planet and collects the data on the top panel. Then she points her telescope to several distant galaxies, and representative data are shown in the bottom panel. What inference can she make about her Universe?
Given that the two panels show similar atomic spectral patterns, the distant galaxy must contain a lot of lithium. More importantly, the data from the distant galaxy are all blue-shifted, meaning that her universe is collapsing. Several students said something like "red-shift->universe is expanding." That's what Hubble found for our universe, but a red shift would mean the colors of the lower panel would have shifted to the right, rather than shifting to the left.
What event started an eon?
Great Oxygenation Event (started the Proterozoic Eon)
Formation of the moon
Hadean
In which eon was the Earth's motion set at one revolution around Sun every 365days?
Hadean (Earth's current motion resulted from the collisions)
If you combined the atomic nuclei of two hydrogen atoms, the product would be which element?
Helium; because a hydrogen is defined as an element with one proton (i.e., an atomic number of 1), combining two hydrogens would result in an element with two protons, (i.e., an atomic number of 2), which is what defines helium
What trait does NOT make much of a difference in dissipating excess heat?
Higher melanin in skin
the degree of intelligence in humans is impressive, especially when applied to the entire population
Highlight examples, e.g., facial/voice recognition, empathy, precision and broad applicability of language, internet/google
Why did the mass extinction of megafauna take place in Australia prior to the Americas?
Homo sapiens arrived in Australia before it arrived in the Americas
A snake skeleton have ribs similar in both structure and function to the ribs of humans. Therefore, ribs in snakes and humans are which one of the following
Homologous (because the underlying rib structure is similar in both species; homologous implies that the common ancestor of snakes and humans also had ribs, which is supported by the fact that all reptiles and mammals have ribs. Furthermore, ribs are never found in an invertebrate animal.)
How did human language become complex, and when did it happen?
How? Most likely a genetic mutation that changed either the voice box or the brain When? No idea b/c language cannot fossilize, but likely around the time of the Cognitive Revolution
His measurements of red shifts showed an expanding universe
Hubble
Which is the broadest pattern of human history according to Jared Diamond?
Humans from Eurasia tend to dominate humans from all other continents
Evidence collected by anthropologists and animal behavior scientists demonstrates which one of the following?
Hunter-gatherers have a higher material standard of living than wild animals
Paleogene Period:
Mammals diversify to fill vacant ecological niches
Role of reinforcing feedback
In a reinforcing feedback loop (aka "positive" feedback loop), the influence coming back from the loop tends to push the system even farther in the direction of the initial impetus
What event was NOT affected by a rise in the level of atmospheric oxygen
Increase in amount of atmospheric water vapor.
Explain how each factor listed below gave Spaniards an advantage over the Inca
Infectious diseases:Europeans had several infectious diseases because of their long history with domesticated livestock, and they had evolved resistance to these diseases over several centuries. Because the Inca had never encountered these deadly diseases, a large percentage of them were wiped out even before the Spaniards arrived. Megafaunal extinctions:Most of the megafauna in the Americas went extinct with the arrival of the first Homo sapiens ~10,000ya, because these large mammals had no long history with a human species and therefore lacked effective antipredatory mechanisms to counter the intelligent hunting strategies and tools of Homo sapiens. The megafaunal extinctions meant that other than the llama, the Inca had no large domesticated mammals that would allow them to counter the Spaniard horses.
Electromagnetic spectrum
Is the complete range of electromagnetic waves placed in order of increasing frequency
Why would it be incorrect to say that half life is half the time it takes for a radioactive sample to decay?
It takes much much much longer than two half lives for a radioactive sample to decay fully
Gossip
Language facilitated a much more thorough management of social relationships
Invented the concept of a 'primeval fireball', which exploded long ago
Lemaitre
Simple cells (prokaryotes)
Lipid membrane surrounds DNA and other organic molecules
What was NOT associated with the evolution of bipedal locomotion in human ancestors?
Loss of the tail (Apes already lack a tail, so this did not change in the evolutionary transition leading from ape to human. Furthermore, the existence of bipedal organisms such as birds and some dinosaurs like T rex show it is possible to have a tail and still be bipedal)
Although tropical regions always feature lots of sunlight with the sun high in the sky, tropical mountainous regions can be chilly, as exemplified by the Andean highlands of Ecuador and the Himalayan highlands of Nepal. Which of the following traits would you expect to find for the Sherpa living in the high Himalayas?
Lots of melanin (yes, high melanin in skin, hair, and eyes is adaptive in high-sun environments because it helps Sherpas avoid skin cancer) Shorter body (yes, because it is so cold in the high Himalayas, Sherpas were more likely to survive if they minimized surface area. Therefore over the generations Sherpas evolved to have shorter bodies, which helped them to preserve their heat)
Tropical areas are normally both sunny and hot, but high-altitude tropical areas, such as the Andes Mountains of South America or the Himalayas of Nepal, are sunny and cold. For each line below, circle which trait is best adapted for humans living in those sunny but cold environments.
Lots of melanin Short and stocky Straight hair
Climate change in quartenary period
Many ice ages This period included dramatic changes in climate, which affected food resources and brought about the extinction of many species. But this period brought about a new species of predator: Man.Milankovitch cycles - where regular changes in the Earth's tilt and orbit combine to affect which areas on Earth get more or less solar radiation CAUSE IT!!!!
Be skeptical of the concept of a "noble savage" who cares tenderly for the environment
Many moderns maintain the misguided belief that if we just adopted the values of our hunter-gatherer ancestors then all environmental problems would be solved
Force of gravity depends on...
Mass- amount of matter, the heavier the stronger the attraction Distance- the closer, the stronger the gravity
Nebular hypothesis
Matter exists from Big Bang -> Starts to form a sphere -> Nuclear fusion starts, pushing sphere larger ->Heavy elements begin to form -> results in Super nova
What differs between eukaryotes and prokaryotes?
Membrane-bound organelles
Which of the following best describes Milankovitch cycles?
Milankovitch cycles regulated whether or not the Earth was experiencing an Ice Age
Molecular Clock
Model that uses DNA comparisons to estimate the length of time that two species have been evolving independently Molecular clock is LOOKING at mutation
Suppose that it was biologically possible for modern human infants to develop into a normal human adult within two years rather than two decades. If this development pattern were present during the last several million years, which of the following would NOT have evolved?
Monogamy faster human development would mean parents would have an easier job, which means natural selection would no longer favor a father who commits exclusively to the mother of his children, which means polygyny would persist in the human lineage. Bipedalism and multiple human species both evolved prior to the origin of large brains/intelligence. Because intelligence is still present, animals would still be domesticated.
In the US, how common are creationists?
More than a 3rd of the population average has between 30-40%, 38% more recently in 2017
What played a role in explaining the evolution of social monogamy?
Most of the development in brain biomass takes place after birth in humans
Evolution of color vision
Most vertebrates and inverts(4 photoreceptors, includes UV)apes and humans (3rd photoreceptor)Most mammals 2 receptors
2nd wave: ~45,000ya
Much larger migration Led first into Eurasia, where Homo sapiens encountered H. neandertalensis, Denisovans, and probably H. floresiensis Last two continents colonized via Bering Strait ~12,000ya: NAm and then SAm These early migrations determined where each human race lived historically
Which of the following distinguishes Homo sapiens from all other species?
NONE OF THESE Dramatic differences in its DNA sequences ii. Different kinds of cells and tissues iii. Unique anatomical organs not found in other species iv. Bipedalism - walking on two legs instead of four
What is an isotope of Na-23?
Na-22 (11P and 11N) Isotopes have the same number of protons, but different number of neutrons. Na-23 has 11P and 12N
What applies to all primates AND distinguishes them from other mammal groups?
Nails instead of claws
The Greenhouse Effect
Natural situation in which heat is retained in Earth's atmosphere by carbon dioxide, methane, water vapor, and other gases
Based on our understanding of human evolution, which of the following should be true for Neanderthal DNA?
Neanderthal DNA should align equally well with both bonobo and chimp DNA (the same is true for Homo sapiens, i.e., our DNA aligns equally well with both bonobo and chimp DNA)
The Bushmen of subtropical Africa continue to live as hunter-gatherers. Recently some Bushmen provided DNA samples, but unlike my DNA, they did not have any Neanderthal genes. What is the best explanation for the lack of Neanderthal DNA in the Bushmen genome?
Neanderthals lived only in Europe and never encountered Bushmen ancestors
Body-machine interface
Neuroscience advances: e.g., Avatar-like creatures
Some of the effects of DNA mutations can be...
Neutral, Negative, or Positive When the effects of a mutation are positive, ns usually increases the frequency of the mutation in the population
Why did Ice Ages begin ~2.7mya?
No one knows! Most favored hypotheses involve plate tectonics 1. Air currents altered by new mountain ranges; what major mountain range has been forming a lot in the last few million years (Himalayas) 2. Ocean currents altered a lot by new coastline; what major coastline has changed remarkably in the last few million years (Panama)
Foragers
Nomadic in search of food - ecological patterns such as seasons, migrations, and growth cycles played a big role in determining their movements. "Foragers moved house every month, every week, and sometimes even every day, toting whatever they had on their backs" "foragers had very few artefacts to begin with, and these played a comparatively modest role in their lives...We hardly notice how ubiquitous our stuff is until we have to move it to a new house." As a result of all the movement, hunter-gatherers would have received regular exercise: "Varied and constant use of their bodies made them as fit as marathon runners. They had physical dexterity that people today are unable to achieve even after years of practicing yoga or t'ai chi"
In humans, DNA's information consists of 20,000 to 30,000 genes. Each one of these genes consists of a sequence of hundreds of _________
Nucleotides
Suppose a band of hunter-gatherers migrated ~70,000ya along the southern coast of Asia from the Middle East to Australia. If you were a modern archeologist looking for metal artifacts left behind by this band, where would you need to look?
On the seafloor just off the southern coast ~120m below the ocean surface
Information transfer
Open-ended language facilitated an unprecedented variety and precision of information transfer between individuals ("the need to warn other humans about the presence of danger would be the most important to humans of this time (rather than gossiping or speaking about nonexistent things). Before forming large communities and cultures, early Homo sapiens would have been most concerned with staying alive in the wild and defeating predators"
Based on the fossil record, what represents a similarity between the marine organisms of the Cambrian Period and the marine organisms of the late Proterozoic Eon?
Organisms were multicellular multicellularity evolved hundreds of millions of years before the end of the Proterozoic. Therefore there were a variety of multicellular organism both before and after the Cambrian Explosion
What event did NOT occur during the Quaternary Period
Origin of bipedalism (happened ~6 to 5 mya, so during the late Neogene Period)
major evolutionary event occurred 1.2bya
Origin of multicellularity
Evolution tinkers
Original -> Adaptation Gill Arches --> Jaws swim bladder --> Lungs pec / pelvis fins --> fore/hind limbs reptile scales --> feathers reptile forelimbs --> bird wings sweat glands --> mammary glands "hands" of forelimbs --> bat wings mammal forelimbs --> whale front fins
What events was NOT affected by a rise in the level of atmospheric oxygen?
Oxygenation Event would have triggered massive global cooling, which scientists think would have led to the first Snowball Earth. As global glaciation occurred, whatever water vapor was in the atmosphere would have reduced greatly to become part of the ice; in other words, the amount of atmospheric water vapor would have decreased, not increased)
Similarities and differences between taxonomic groups
PROKARYOTES - Archea - Bacteria EUKARYOTES - Plants - Fungi - Invertebrates (fish, amphibians, mammals, reptiles, birds)
Suppose a new infectious disease is discovered 10 years from now, and molecular clock studies show the disease had existed for 200 years. What is the most likely origin for a disease like this?
Pathogen causing disease used to infect domesticated livestock then mutated to invade humans (most human infectious diseases originated from livestock, e.g., the virus that causes smallpox mutated from a virus that infected cows, the virus that causes the flu mutated from a virus that infected pigs)
Discovered background cosmic radiation throughout the universe
Penzias and Wilson, and it did not occur until the 1960s
Of the five mass extinctions of the Phanerozoic Eon, which one caused the most extinctions?
Permian mass extinction
Origin of dinosaurs
Phanerozoic
Plants colonize land
Phanerozoic
Pterosaurs went extinct in which eon?
Phanerozoic (All of the dominant reptiles of the Mesozoic, including pterosaurs, dinosaurs, plesiosaurs, and ichthyosaurs, went extinct 65mya with the meteor that hit near the Yucatan Peninsula)
During which eon, era, and period did millipedes and scorpions first walk up on land?
Phanerozoic Eon, Paleozoic Era, and Silurian Period
What represents the cause of the Great Oxygenation Event?
Photosynthesis in cyanobacteria O2 is a byproduct of photosynthesis. Prior to photosynthesis there was no such thing as O2 in the atmosphere
Other than animals, what is one example of a multicellular organism.
Plants, fungi, some protists such as seaweed and slime molds; prokaryotes are never multicellular
Role of plate tectonics
Plate motions cause mountains to rise where plates push together, or converge, and continents to fracture and oceans to form where plates pull apart, or diverge. The continents are embedded in the plates and drift passively with them, which over millions of years results in significant changes in Earth's geography.
Why don't other species cause so much destruction?
Populations rarely get high because of environmental constraints and resource limitation; all human populations were subject to similar fluctuations prior to the cognitive revolution Individuals of other species lack the technology to consume very much
Key factors that facilitated life
Position, size, and motion of planet earth.
Why are proteins important in your cells, what do they have to do with DNA, and what do they have to do with phenotypes in genetics?
Proteins are the machines of the cells. They are constructed using the information in DNA, i.e., the sequence of nucleotides codes for a sequence of amino acids. The phenotypes of genetics are based on protein function. For example, a plant gene that code for tall phenotype actually codes for a protein that stimulates lots of mitosis in the plant stem, which results in a tall plant
Origin of multicellularity
Proterozoic
In which eon was the beginning of the most recent Snowball Earth?
Proterozoic (All Snowball Earth episodes occurred during the Proterozoic)
The cells in your body depend on organelles called mitochondria to generate their ATP. During which eon did mitochondria originate?
Proterozoic Eon is when eukaryote cells first originated when a larger prokaryote swallowed proteobacteria through endosymbiosis. The larger prokaryote became the first eukaryote, and the proteobacteria became mitochondria
A new species is discovered that is single-celled, eukaryotic, photosynthetic, and moves through water using three flagella. This organism would be classified as which one of the following?
Protist plants and animals are always multicellular. Bacteria are always prokaryotes.
How the great Oxygenation Event caused aerobic respiration and ATP
Protobactera can get 18x as much ATP and grow faster and larger. Eukaryotes evolved by swallowing protobacteria and making mitochondria.
During which period of the Cenozoic era did erratics from in polar regions?
Quarternary period
Cosmic Radiation
Radiation that comes to Earth from distant stars. It comes from an explosion sometime in the past, which effected all parts of space.
What represents an advantage of radiometric dating over the molecular clock method?
Radiometric dating usually leads to more precise estimates for when an evolutionary event occurred (this is true because of the enormous sample sizes; radiometric dating measures billions upon billions of atoms, whereas the molecular clock measures merely a few thousand nucleotides. Thus the dates obtained through the molecular clock generally have more uncertainty associated with them than the dates obtained through radiometric dating
Big Bang theory: three lines of evidence
Red shifts Cosmic Rays Abundance of small elements
Analogous
Refers to body parts that have a similar function but differ in structure, such as the wings of a bat and the on wings an airplane
Assuming human brains evolved to such a large size because of natural selection for social competency, what kind of feedback would have played a significant role in the evolution of brain size?
Reinforcing feedback (reinforcing feedback loops lead to exponential change, which would have continued until the size of the female pelvis (and the resulting birth canal) set a hard limit to how large human brains could become. In other words, selection for social competency would have led to reinforcing feedback that dramatically increased brain size, but the fixed size of the female pelvis would have provided a balancing feedback that counteracted brain size expansion)
Vestigal
Relating to visible traces left by something that no longer exists
1st wave of migrations out of Africa: ~70,000ya
Relatively smaller migration Coastal migration to Australia The coastline leading from Africa to Australia was much farther south, because sea level was ~100m lower Glaciation had locked up much of the ocean's water Therefore any archeological and fossil evidence is underwater (no hard evidence...yet) Evidence that early humans ate lots of seafood
Cognitive revolution ~70,000ya
Rewiring of the brain without changing its overall size or the anatomical structures within the brain (therefore no change in the fossil record) Evidence = archeological artifacts Why it happened? (no one knows for sure, but likely brought on by one or more genetic mutations that resulted in improvements to human language ability)
Isotope
Same # of protons, but different # of neutrons unstable isotopes, such as carbon-14 atoms, undergo a process known as radioactive decay. This involves changes in the nucleus of the atom with the release of particles and energy and the conversion of the original atom into an atom of another chemical element.
For those who do accept evolution, what is their primary reason for doing so?
Scientific Evidence
Which BEST represents the position of scientists regarding human evolution? (the key here is to understand what BEST motivates scientists: data. If it weren't for the existence of compelling data that lead to the conclusion of human evolution, then scientists would not accept the concept, no matter who says what.)
Scientists accept human evolution because this explanation is consistent with diverse types of data from a variety of scientific disciplines
What species is not a tetrapod?
Shark tetrapods = everything that descended from the "fish" that first walked up on land during the Devonian Period, i.e., all amphibians, reptiles, mammals, and birds
Prior to colonial history, which began in 1492AD, which of the following was found in BOTH agricultural and hunter-gatherer societies?
Skin color evolves through natural selection (historically this has occurred in all human populations)
What was part of Laurasia?
South Carolina
Pizarro
Spanish explorer who conquered the Incas 1. Grown up pig farmer, restless and greedy 2. After the Spanish conquest of the Aztecs in Mexico, Pizarro heard about written accounts of an empire even greater than the Aztecs loaded with gold 3. Gathered up ~200 like-minded mercenaries, and sailed off to Peru with the express purpose of conquering the Inca 4. When he first encountered Atahuallpa, the nearest Spanish reinforcements were in Panama, ~1000 miles away
Modern scientists currently take seriously two hypotheses for the origin of life on Earth. Suppose that scientists were to discover that early in the history of the Earth volcanoes actually belched propane gas into the Earth's atmosphere rather than methane gas, as was originally supposed. This discovery would most affect which ONE of the two hypotheses for the origin of life on Earth?
Spontaneous generation of simple organic molecules from the early Earth's atmosphere; other names for spontaneous origin are the primordial soup theory, or the Miller-Urey experiment
How did mammals survive extinction?
Surviving tetrapods were all small (<55lbs) and many were burrowers/hibernators 3" dirt insulates from the heat and acid rain
Lungs, which evolved through natural selection from the swim bladder of fish, solved one of the major challenges of living on land. What structure in plants solved that same challenge?
Stomata, the tiny holes on the undersides of all leaves, which function in gas exchange
How would the global distribution of energy resources be different today if the land of Sub Saharan Africa had been at the equator during the Carboniferous Period rather than eastern North America being at the equator at that time?
Sub Saharan Africa would have lots of coal, whereas N America would not have much coal. 'Carboniferous' should make you think 'coal', and the equatorial regions would have had the most productive forests. Because what is now Appalachia was at the equator ~350mya, Appalachia now has a lot of coal deposits. If the scenario in this question had been true, however, Sub Sahara might be mining lots of coal and exporting it to the US
paleogeographic events in order with the letter of the earliest event on the left and the letter of the most recent event on the right
Supercontinent Rodinia begins to break up (~600mya) Formation of Appalachian mountain range (~400mya) Supercontinent Pangaea begins to break up (~200mya) Gondwana begins to break up (~140mya) Alps mountain range begins to form in Europe) (~40mya)
Which has the highest albedo? a. Surface of a glacier OR b. Surface of the ocean
Surface of a glacier
Mammals originated on Earth before birds
TRUE
Scientists have discovered thousands of exoplanets in recent years, but we still know of only one planet that contains life
TRUE
Most of the known exoplanets were discovered during your lifetime
TRUE 1st exoplanet discovered ~1995, and discoveries really started to take off around 2008
We would still have liquid oceans if we had experienced one fewer collision
TRUE All of the water present today was also present then—just in water vapor form. The oceans formed because the surface temperature cooled down, which was inevitable after the collisions ceased
Tropical forests such as the Amazon tend to get more precipitation than any other region of the Earth
TRUE The wettest places on Earth are in the tropics, which is why we get so much rainforest biomass in the tropics. In the distant past fossil fuel built up in locations that were tropical during that time period
Division of labor played an essential role in the improvement of human living standards over the last several centuries.
TRUE This builds off the Jared Diamond reading. According to Adam Smith, the founder of modern economics, division of labor, along with markets that allow humans to exchange the fruits of their labor, are the key ingredients that improve standards of living for humans. In the context of Journey Through Time, the story goes that farming dramatically improved the productivity of land, which led to food surpluses, which allowed individuals to specialize in something other than producing food. This division of labor led to specialists who found innovative ways to improve various aspects of society. Medical specialists found ways to improve public health. Construction specialists found ways to improve homes and buildings. Manufacturing specialists found ways to increase the variety and quantity of goods designed for human consumption
Pterosaurs, bats, and birds all have a keeled sternum bone
TRUE the keel provides lots of surface area for the attachment of the massive flight muscles that are required to keep heavy vertebrates up in the air
The genetic differences separating Norwegian and Cherokee populations are less than the genetic differences separating two populations from East vs. West Africa
TRUE there is more human genetic variation inside of Africa than in all non-Africans put together
We would still have liquid oceans if we had experienced one more collision
TRUE All of the water present today was also present then—just in water vapor form. The oceans formed because the surface temperature cooled down, which was inevitable after the collisions ceased.
Plate tectonics and continental movements would have still occurred if we had experienced one more collision
TRUE Although we do not know the exact mechanisms that drive plate tectonics, we know it occurs ultimately because of the heat deep within the Earth, and this heat originated from the many collisions >4bya early in the Hadean Eon. With one more collision there would be even more heat, and therefore continental movements
Earth would still have volcanoes and geysers if we had experienced one fewer collision
TRUE Volcanoes and geysers come because of the heat deep within the Earth, and this heat originated from the many collisions >4bya early in the Hadean Eon. With just one fewer collision there would still be lots of heat escaping through volcanoes and geysers—just a little less heat
Husbands are more likely than wives to cheat on their spouses, and this fact is consistent with evolutionary theory
TRUE because humans evolved from a polygynous system of mating in which males never would have been faithful to one wife. And yet again, I would like to emphasize that this evolutionary background DOES NOT justify male infidelity in an ethical sense. Men who cheat are behaving more like the way our ape ancestors would have behaved.
Flight evolved independently during the Paleozoic, Mesozoic, and Cenozoic Eras
TRUE winged insects originated in the Carboniferous Period of the Paleozoic Era, flying pterosaurs originated in the Triassic Period of the Mesozoic Era, flying birds originated in the Jurassic Period of the Mesozoic Era, and flying bats originated in the Paleogene Period of the Cenozoic Era
Plate tectonics and continental movements would have still occurred
TRUE Although we do not know the exact mechanisms that drive plate tectonics, we know it occurs ultimately because of the heat deep within the Earth, and this heat originated from the many collisions >4bya early in the Hadean Eon. With just one fewer collision there would still be continental movements
As a nebula becomes smaller, the force of gravity increases for the matter within the nebula
TRUE, as a nebula collapses the matter is closer together, and therefore the force of gravity increases in magnitude. This reinforcing feedback makes the collapsing object prone to even more collapsing
Genetic drift and natural selection both result in evolution
TRUE, both of these evolutionary mechanisms result in some mutations accumulating within a population
Scientists at NASA recently announced the discovery of seven Earth-sized planets in a star system about 40 light years away. Planets range in size from 0.4 to 1.4 times the mass of the Earth, and it takes between 1.5 and 12 days for each planet to revolve around its star. Scientists are now examining light that passes through planetary atmospheres to look for chemical traces of life. Using this technique, what can these scientists measure that would help them determine the elements present on the seven planets? Each element has a unique atomic emission spectrum, which is a series of specific colors. Hubble and other astronomers examine atomic emission spectra from distant objects in space to determine which elements are present in those objects. Depending on which elements they find, scientists might be able to say something about whether life is found on these distant planets
The atomic emission spectra
Natural history
The average forager had wider, deeper, and more varied knowledge of her immediate surroundings than most of her modern descendants...(in contrast) you need to know a lot about your own tiny field of expertise, but for the vast majority of life's necessities you rely blindly on the help of other experts, whose own knowledge is also limited to a tiny field of expertise. The human collective knows far more today than did the ancient bands. But at the individual level, ancient foragers were the most knowledgeable and skillful people in history
Atomic mass:
The average mass of an atom, taking into account all its naturally occurring isotopes.
Nucleotides
The building blocks of nucleic acids
Permian mass extinction
The greatest extinction ever in Earth's history caused by widespread volcanic activity that ended the Paleozoic era.90% of life killed off
The fossil record suggests that the Cambrian Period included a wide variety of animals with hard parts such as shells, but the late Proterozoic Eon shows a much lower diversity of soft-bodied, animal-like creatures. From a purely scientific perspective, what is the problem with concluding that biodiversity was much lower during the late Proterozoic Eon?
The fossil record is taxonomically biased because organisms with shells and other hard parts are more likely to fossilize. Therefore the increased biodiversity of the Cambrian Period might be due, in part, to the fact that animal shells and other hard parts had just evolved, which allowed these organisms to fossilize more easily. The late Proterozoic might have had higher biodiversity, but it's impossible to say for certain, given that soft-bodied organisms are less likely to fossilize
Mechanisms to explain the freeze
White increases > albedo increases > gets colder
Suppose that 80 degrees south of the equator you found an erratic dated at 2 million years ago. List one reason why this does NOT provide evidence for Snowball Earth.
The most Snowball Earth was ~800-600mya, so the erratic is much too recent. Also, the erratic is already fairly close to one of the poles (~80 degrees south means Antarctica, which is already ice-covered), so it does not provide evidence that the entire planet was a big "snowball."
In what ways is evolution controversial among the general public?
The only scientific claim that is truly controversial among the general public is that humans evolved from earlier animal species. Although the claim is well-supported by scientific evidence and nearly universally accepted by scientists, many in the general public resist thinking of themselves as an evolved species.
Astronomers often detect stars outside our solar system that move or "wobble" slightly from side to side. What do these slight movements indicate?
The presence of an exoplanet, which generates a small amount of gravity pulling the star towards the planet. Most exoplanets discovered using this method are "Hot Jupiters" because large exoplanets close to the star generate the most "wobble" out of the star
What is the value of having two methods for dating prehistoric events? When conflicting dates arise from the two different methods, which method is more likely to be trusted?
The value of having two methods is that dates from one method can be verified independently using the other method. If the two methods give conflicting dates,radiometric dating is more likely to be trusted, given that the enormous sample sizes of atoms tend to increase precision...although radiometric dating works only if your sample is uncontaminated
Natural selection occurs only when its three components are present. In a population of wasps most individuals collect nectar from the front of a flower (the 'workers'), but some individuals collect nectar from the back by cutting a hole in the back of the flower (the 'cheaters'). Wasps in this population often die from hunger, and cheaters get more nectar than workers on average. For both workers and cheaters, approximately 10% of their offspring turn out to the cheaters. Why WON'T this wasp population evolve towards more and more cheating?
Three components = variation, differential fitness, heritability. Heritability is missing—cheater offspring are just as likely to come from workers as from cheaters, so the strange behavior must not be coded within the genes
The males with lots of colorful spots have approximately the same number of offspring as males with few spots, and male offspring usually have the same number of spots as their fathers. Why WON'T guppies evolve to gain more colorful spots? To answer this question, write the three components of natural selection below, AND then circle which of the three components is missing.
Three components = variation, differential fitness, heritability. differential fitness is missing—males with more colorful spots do not have higher reproductive success than males with few spots
How to determine if plant is in Goldilocks zone
To determine the location of a star's habitable zone, one must first learn how much total radiation it emits. Stars more massive than our sun are hotter, and blaze with radiation, so their habitable zones are farther out. Similarly, stars that are smaller and cooler sport tighter belts of habitability than our sun. Determined by temperature and pressure (size)
A few years ago scientists discovered in northern Canada the fossil species Tiktaalik, which possesses front and rear fins like a fish, but a head that moves up and down like an amphibian. Based on our class discussions Tiktaalik would be considered a....
Transitional fossil
Artificial Intelligence
Type of software that can process information on its own without human intervention. If we ever achieve the singularity then humans (and all other forms of life) might become inferior and perhaps even redundant
Ultimate and proximate factors
Ultimate: environmental; deep historical factors that influenced the course of evolution Proximate: External; immediate factors that play a role in current events
Radioactive atoms have:
Unstable nucleus
The presence of large amounts of carbonate in rocks dated at ~600mya provides clear evidence for...
Volcanoes played a key role in ending Snowball Earth (yes: high carbonate indicates the buildup of very high CO2 over time, which indicates volcanic activity)
Under normal conditions, gravity is..
Weak
Who was originally trained in meteorology, invented a theory that was ridiculed in his time and for several decades thereafter?
Wegener, 1912 His theory of continental drift eventually became modified to become the theory of plate tectonics, which was finally accepted in the late 1960s
evidence used to reconstruct paleogeography
What was connected: rock formation composition When: measure radioactivity Where: look at fossils and magnetic angle to see its location in reference to latitude.
Vertebrates water > land
When? Devonian Body Support? Bones / vertebral column Gas Exchange? lungs Retain Moisture? waterproof skin (except for amphibians)
Bird Land -> air
When? Jurassic Reduce Weight? Hollow bones, fewer bones, Wings? forelimb wings Increased Support? fuse bones Increased Power? large breast muscles, keel
Plants water > land
When? Ordovician Body Support? Cellulose Wood Gas Exchange? Stomata Retain Moisture? Waxy Cuticle
Bats Land -> air
When? Paleogene Reduce Weight? Hollow bones, fewer bones. Wings? "hand" wings Increased Support? Fuse bones Increased Power? Large breast muscles, keel
Invertebrates. water > land
When? Silurian Body Support? n/a Gas Exchange? spiracles Retain Moisture? exoskeleton
Pterosaurs Land -> air
When? Triassic Reduce Weight? Hollow bones, fewer bones Wings? 4th digit wings Increased Support? fuse bones Increased Power? large breast muscles, keel
Methods for detecting of exoplanets
Wobble method and transit method can infer distance to from exoplanet to it's star and mass of exoplanet.
Conifer is..
a dominant plant during Jurassic Period
Ichthyosaur is...
a large marine reptile
a planet that orbits a star outside the solar system
a planet like body that orbits a star other than the sun
Exoplanet
a planetlike body that orbits a star other than the sun
Primordial soup
a solution rich in organic compounds in the primitive oceans of the earth, from which life is hypothesized to have originated.CO2, H2O, NH3 (ammonia), CH4 (methane) (Spontaneous generation of simple organic molecules)
Panspermia
a theory that life did not originate on Earth but arrived in the form of bacterial spores or viruses from an extraterrestrial source
Cranial capacity is larger for Homo fossils from 100,000ya than for Homo fossils from 2.5mya. Which of the following BEST represents the inference you should draw from these data?
a. Brain size increased in size within the genus Homo over the course of the Quaternary Period
Lots of brain space is required for many activities we associate with intelligence
a. E.g., Instant recognition of others by sight, sound, etc. b. E.g., Theory of mind: Ability to perceive what others are thinking, even when they do not reveal their feelings explicitly c. E.g., Language fossil record shows that brain size expanded greatly among Homo specie
Lack of facial/body hair
a. Good if you need to lose lots of heat (adaptive in hot climates) b. This reasoning likely explains why humans have so little hair relative to ape species
Over the ~10,000years since animals were domesticated, Europeans were exposed to many more pathogens than any other society
a. Many European deaths centuries ago, e.g., Black Plague in the Middle Ages b. Because of this selective pressure, resistant Europeans outbred nonresistant Europeans, i.e., Europeans evolved resistance in a way that no other population could have done.
Basic facts about the spread of disease in the New World
a. Up to 95% of the ~20 million indigenous Americans were wiped out by disease, because they were suddenly exposed to pathogens that were completely foreign to their evolutionary history i. Pathogens originated in domestic animals that had never been found in the New World ii. Never had an opportunity to evolve resistance to the pathogens b. Atahuallpa was in power only because European germs had killed his relatives, which led to a civil war between Atahuallpa and his brother c. Indigenous humans in the American South were decimated so much that when the British arrived about a century after Pizarro, they never encountered serious resistance comparable to what the Spanish faced from the Aztecs and the Inca
NS and reinforcing feedback loop (explain using p.46 of coursepack):
a. Variation: individuals within a population varied in social competency b. Diff fitness: those individuals with the greatest social competency (b/c of larger brain size) achieved higher reproductive success c. Heritability: their children inherit larger brains and the greater social competency that goes with it d. As brain size and social competency increased, the complexity of societies also increased, and this feedback only intensified NS, thus resulting in runaway selection for brain size (i.e., reinforcing feedback)
Biotechnology - Designer Babies
ability to create a baby with desired characteristics like eye color, height, diseases, intelligence, and whatnot. A designer baby is a gene-modified human embryo with appropriate qualities that have been shaped as per the instructions given by the parent
Cause and effect
aerobic respiration - large bodies loss of methane - first snowball earth Ozone - protection against UV Photosynthesis - Great oxygenation event Tropical Appalachia - Coal Forming
Eight adaptations
antennae, bones, cuticle, gonads, keel, phloem, stomata, wings
Gonads
are insect organs of reproduction but they did not originate to overcome any of those three challenges.
Antennae
are sensory organs on insects but antennae do not solve any of those three specific challenges
Stomata
are the microscopic holes found underneath the leaves of all plants, which allows plants to take in CO2 from the air and to give off O2
Of the 148 species of large mammals >100lbs, only 14 have been successfully domesticated, and 13 of these 14 were Eurasian species. Why were so many from Eurasia rather than other continents?
b/c of the ultimate factors we discussed earlier, e.g., larger geographic area, E-W axis, lack of geographic barriers, luck, and history of humans for ~1my so no megafaunal mass extinction when H sapiens arrived
What type of feedback leads to homeostasis in your body?
balancing/stabilizing/negative feedback
Scientists think that Australian Aborigines descended from an early wave of coastal migrations from Africa by Homo sapiens about 70,000 years ago. Nevertheless, there is no archeological evidence (e.g., cultural artifacts, human dwellings) in South Asia for such a coastal migration. Why not?
because the sea level was much lower 70,000ya during the most recent ice age. Therefore any archeological evidence is ~100m underwater at what used to be the coastline - not an easy location for doing field research
Retain moisture
cuticle
Very high melanin =
dark skin/hair/eyes
Milankovitch cycles
describe the collective effects of changes in the Earth's movements on its climate over thousands of years.
transit method
detecting exoplanets by observing the change in brightness as the planet eclipses the star.
Magnetite within an erratic oriented at 8 degrees latitude...
did not occur again because this observation would indicate another Snowball Earth, which we have not experienced again
Homo neandertalensis
discovered in 1856 (just before Darwin's Origin of Species, although Darwin did not know they were a dif spp), brain size = 1400cc (slightly larger than 1350cc in H sapiens), extinct ~30,000ya
what major event happened 3.5 bya?
earliest evidence of life, earliest fossil (prokaryotes)
Homo floresiensis
floresiensis in a small island in east Indonesia: discovered in 2003, brain size = 380cc (brain/body size ratio similar to the other human spp), extinct <18,000ya (major volcanic eruption 12,000ya wiped out several other spp on Flores Island)
Why was technology more likely to develop in large, dense, agriculture-based societies?
food surpluses frees up time for specialists, who then invent new technologies
Monogamy is rare among animals
generally occurs only when the costs of parental care are very high, e.g., birds
Lots of facial/body hair
good if you need to preserve heat (adaptive in cold climates)
Taller and skinny maximizes..
heat transfer; good if you need to lose lots of heat (adaptive in hot climates)
Shorter and plump minimizes..
heat transfer; good if you want to conserve heat (adaptive in cold climates)
Wings
help vertebrates and insects to fly, but they did not solve any of the challenges of first getting on land
Liver
helps vertebrates to process toxins but that problem is not unique to land organisms.
Several military advantages the Spaniards had over the Inca
horses->domesticated in Eurasia thousands of years before the Incan ancestors developed farming swords: farming->food surplus->large, dense, sedentary society with division of labor->technological specialists->swords, guns, armor, writing, ships, political organization, etc.
I. Spaniards vs. Inca: a microcosm of the "broadest pattern of history"
i. At the time of Columbus (1492AD), the greatest nations of the Old World and New World were respectively Spain, and the Inca empire 1. Both had highly advanced cultures, e.g., show extent of the Inca empire on map 2. Columbus's voyage set in motion a dramatic series of human migrations from Europe a. We became a global species both geographically and culturally The outcomes of these migrations dramatically altered historical trajectories of people everywhere and has shaped modern inequalities
Three things had to happen for humans to distinguish themselves from the other species
i. Brain size increases ii. Cognitive revolution iii. Key cultural innovations
Consequences of the cognitive revolution
i. Detailed intelligence...precise and detailed information, capacity to do art, science, technology, analysis, etc ii. Gossip - ~2/3 of all conversations among humans center on gossip. Much of the news centers on gossip, esp in popular tabloids and social media iii. Storytelling...shared myths for unifying humans not already in the same social group...religion, free markets, nation-states, cultural bonds
Why did early humans cause so much destruction?
i. Facilitated by intelligence, which allowed ancestors to reduce mortality ii. Genetic and anthropological data suggest pop explosion began abt the time of the cognitive revolution (~70,000ya) b. Technology for activities such as hunting, converting habitat, etc. i. Also facilitated by increased intelligence, as well as the emergence of a market economy ii. Anthropological data show noticeable increase in diversity of tools and art with the cognitive revolution (~70,000ya)
Major evolutionary changes needed for stability in bipedals
i. Heel ii. Angle between Pelvis and femur (femur must come down at an angle to put each knee directly under the center of gravity)
Space exploration
i. If the naturally-reinforcing feedback loop of environmental impact comes back to bite us, then space exploration gives us a chance to escape our own destruction ii. Space exploration also opens up tremendous opportunities 1. Economic opportunities: export pollution (e.g., nuclear waste) and/or mine new resources 2. Scientific and cultural opportunities, e.g., SETI, astrobiology
Eurasia had an advantage in nearly all respects
i. Larger, so more species ii. Long history with H. erectus and H. neandertalensis, so megafauna never went extinct iii. East-west axis, so domesticated species can spread well between regions iv. Few geographic barriers, most of which run E-W, which further facilitates the spread of agriculture Luck: many of the most productive foods and livestock happened to be found in Eurasia 1. wheat, barley, rice, oats, sheep, goat, cow, pig, horse
Brain size increased
i. Mammals have ~10X brain size of reptiles ii. Among mammals, primates and cetaceans have largest brains iii. Among primates, apes have largest brains iv. Among apes, humans have largest brains by far 1. ~3X as large as chimps and gorillas 2. evidence from fossil skulls suggests that cranial capacity increased remarkably for several human-like species (genus Homo) in the past three million years v. Large brains require a huge amount of ATP (at rest the brain requires 25% of all ATP for humans, but just 8% for apes)
evidence for social competency hypothesis (leading hypothesis for brain size expansion)
i. Mating success (fitness) in primate societies is correlated with social competency; primates spend a lot of time managing their social relationships (e.g., grooming) ii. Size of neocortex in various primate species is correlated w/ group size iii. Organization of the brain (portions of the brain that are exceptionally large in humans are often used for social tasks, e.g., facial/voice recognition, language, theory of mind) iv. Usage of spoken language in humans (mostly gossip, ~2/3 of conversations)
James Croll
i. Originally hypothesized to affect global climate by a janitor (James Croll) posing as a professor in Scotland in the late 1800s (Croll convinced his brother to do the nighttime janitorial work while he did research in the library) ii. Observed timing of recent ice ages matches the times predicted by Milankovitch cycle hypothesis iii. According to all three types of Milankovitch cycles, the Northern hemisphere should be cooling right now, but the last two centuries shows warming instead (b/c of the dawn of the Industrial Revolution, i.e., age of fossil fuels
differences in appearance between races
i. Skin color ii. Hair color and curliness iii. Amt of facial and body hair iv. Body shape, i.e., amt of surface area, relative to volume v. Notice nearly all differences are superficial 1. Anatomically and physiologically there are almost no differences btwn races
A few causes of climate change
i. Variation in solar output, e.g., only ~70% during Hadean Eon (offset by methane atmosphere and asteroid collisions); recent changes in solar output have been very minor in comparison ii. Volcanism, e.g., Triassic-Jurassic mass extinction iii. Changes in GHGs, e.g., modern climate change, end of Snowball Earth with 13% CO2, iv. Motion of tectonic plates, which affects air currents (via mountain ranges) and ocean currents (via coastlines) v. Milankovitch Cycles
Human perspective
i. we selfishly focus on just other conspecifics and mostly ignore other species unless they represent a direct threat or opportunity to us The "broadest pattern of history" according to Diamond is the inequality between races; Europeans have the most "cargo"
Nuclear bombs
i. when launched into space these bombs give us a chance of preventing a meteor impact like the one that killed the dinosaurs ii. Nuclear bombs also have waste fallout that remains more or less permanently in the fossil record iii. List of nuclear countries grows with each decade and includes US, UK, France, Russia, China, India, Pakistan, Israel, North Korea
Geographic distribution of key natural resources
land - coal oil, natural gas -ocean amount of fossil fuels depends on rainfall (latitude) high oxygen levels = more coal
Other things the great oxygenation event caused
large-bodied organisms such as dinosaurs (more potential to grow) and the formation of fossil fuels (Carboniferous period) break down of gigantic animals and plants.
how to dissipate heat
less hair, curly hair, body shape
Germs come from...
livestock, and societies with a long history of domesticated animals evolve resistance to these germs
Doppler effect
makes things "invisible"
One way to think of the history of Homo sapiens is to divide our 200,000-year history into two sequential time periods, with the earlier time period dominated by biological evolution (e.g., increasing brain size, changing skin color) and the later time period dominated by cultural evolution (e.g., new types of tools and technology, development of cultural differences between tribes). If this distinction were made, what year would you propose as the transition year, AND why?
multiple answers possible; one answer = 70,000ya because that was what Harari called the "Cognitive Revolution" when human culture began to proliferate. Another answer = ~10,000ya because that was when human farming began, which allowed technological specialists to make dramatic improvements in human culture. Another answer = ~200ya because that was when the Industrial Revolution began, which dramatically increased both human living standards and our collective environmental footprint
You notice the rocky exoplanets in this solar system have almost no craters on their surfaces. What must have been different about the formation of these planets compared to the four rocky planets in our solar system?
no craters->no major collisions during their formation
The Miller-Urey experiment was designed to simulate what major prehistoric event?
origin of life
Megafaunal extinctions
played a key role in setting the stage for which populations dominate other populations
What does "wobble" of starts indicate
presence of exoplanet wobble generated by small amount of gravity pulling star towards the planet
Red Shift
red-shift of light (is evidence that the universe is expanding) Red shifted light = lower(away from us) decrease frequency the change in the wavelength of light due to an object moving away from the observer. Wavelengths get further
Growing human populations tend to produce more medical specialists, which leads to better health care, which leads to further growth in human populations. What kind of feedback does this pattern represent?
reinforcing feedback
Bipedalism
the ability to walk upright on two legs
Evidence for glaciation at equator
the angle of magnetite within rocks orients differently based on latitude. Because a glacial erratic rock was found with magnetite that oriented at an angle consistent with 11 degrees latitude, there must have been a glacier in the tropics)
Scientists think that of the three lice species on humans, the two that are most closely related are head lice and clothes lice. In one sentence or less explain what evidence scientists use to back up this assertion.
their DNA sequences line up the best, which means there has not been very much time for mutations to accumulate between their lineages. Correct and partially correct answers focus on the DNA sequences, because that is what was measured. Answers that focus on phylogenetic lineages, similar habitat, anatomical similarities, etc., are incorrect because they do not focus on what was actually measured in the study we read
Panspermia hypothesis
theory that life was seeded on earth and other planets from outer space - Extraterrestrial origin of life (Mars?) - Amino acids and nucleotides hijack aboard meteorite to earth
Early in the Hadean Eon the Earth experienced many massive collisions by objects similar in size to the proto-Earth
these collisions played a key role in determining the conditions for life today.
What is NOT proof for why dinosaurs went extinct?
volcanos
Very low melanin =
white skin, blonde hair, blue eyes
