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80 Cards in this Set

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Explain stable unstable, equilibrium, and metastable climate systems. What is the earth’s climate.
Earth climate is metastable.
unstable= positive feedback
stable= no feedback
Metastable= life has been allowed to persist with both fluctuations and stability.
How does the Younger Dryas provide evidence for a past disruption of the thermohaline circulation?
Thermohaline circulation is the heat conveyor of the oceans. By the ice caps melting there is a sea water freshening, and then there is a floating bunch of water that shuts off. This has happened at the Younger Dryas where there was a 7 degree cooling in 50 years or less.
Why is the chaos in the climatic environment important?
It means that there is a certain limit of predictability in the climate, but there is also an inherent level of unpredictability.
Climate models will never be able to predict climate variabilities no matter how great our supercomputers become.
Organisms and species have to face an inherently unpredictable future.
What is negative and positive feedback?
positive feedback=Unstable, where tiny differences amplify
Negative feedback= equilibrium, no feedback
How, and over what time scales, do abiotic environmental factors vary?
Organisms affect abiotic environment.
Stability (enough to keep water on earth) versus instability (huge climate variability in earth’s history)
Key abiotic variables:
heat (temperature),
nutrients/ food/ chemicals,
air (oxygen, CO2, CO),
information/ communication media.
On time scales of tens of thousands of years plants migrate in responses to climate changes.
Water and temperature are the most dominant abiotic factors characterizing plant environments.
What is mean residence time?
How long a gas stays in the atmosphere. CO2 is two years.
How does MRT account for seasonal fluctuations in CO2, the patchy distribution of water over the globe, the regional effects of acid rain, and the constancy of the atmospheric oxygen levels?
The lower the MRT the more spatially variable the biogeochemical is in the atmosphere.
H2O atmospheric MRT is 9 days. Compared to ~1 year atmospheric mixing time.
àwhy 02 is evenly distributed and why CO2 (~2 years) isn’t
àair from Midwest carrying nitric, sulfurous acid ~3-5 days why northeast has acid rain
àalso why aerosol pollutants are a localized and worldwide problem ~3-5 days
How do organisms alter and constrict their own abiotic environments?
By isolating themselves from external conditions and literally creating their own environments
By buffering themselves against changes in external conditions and variability in resources
By “niche” construction
What is the Gaia hypothesis?
Regulation of earth’s climate by living organism.
Not by conscious design.
Earth’s biota exert a strong control on the planetary environment.
What are the three main lines of evidence for earth homeostasis?
Historical global temperature stability in spite of variable solar output.
Atmospheric oxygen level maintained at extreme disequilibrium.
Earth’s atmosphere is much different from ‘dead’ mars or Venus.
How might ocean plankton and sulfate aerosols act as a global thermostat?
Plankton: dimethylsulfide production by ocean plankton may act as a global thermostat; higher temperatures more DMS production by plankton; more DMS leads to more cloud condensation nuclei; more clouds less light penetration cooler ocean waters less production of DMS.
Aerosols scatter/ reflect incoming solar radiation so less reaches earth’s surface; modify cloud properties there are more clouds and more reflective clouds increase cloud albedo.
What is global dimming?
Anthropogenic alteration of the global climatic environment. Earth gets less light
Two wrongs made a precarious right
Greenhouse gases warm earth.
Aerosol pollutants cool earth.
What is the relationship between aerosols, cloud amount, albedo and global dimming?
Aerosols scatter/ reflect incoming solar radiation so less reaches earth’s surface; modify cloud properties there are more clouds and more reflective clouds increase cloud albedo.
Explain the three types of climate reengineering: biosequestration, geosequestration, and alternation of planetary albedo.
Biosequestration= both terrestrial and oceanic; capture emissions by planting trees
Geosequestration= of the earth; capture emissions by putting it under the earth
Alteration= of planetary albedo through ground level and atmosphere
put out aerosols
What is phenotypic plasticity? Why is it common?
Phenotypic plasticity occurs during development and involved gene regulation and internal processes. It is common because the environment has heterogeneity in both biotic (light) and abiotic (predators) factors.
What is reaction norm?
Reaction norm is the set of phenotypes produced by a genotype across a range of environments.
What is the difference between direct effects of the environment on development and adaptive plasticity?
Direct effects (does not change phenotype) are because the environment is variable while adaptive plasticity (does change phenotype) makes the right phenotype depending on the environment and increases fitness.
What are the conditions for the evolution of adaptive plasticity?
Environment varies
Trade offs: no one best phenotype
Information: cue predicts conditions
Why don’t red eyed tree frogs all hatch at the same age?
Because they have predators that induce an early hatching that allows them better survival in the waster.
How do genotype by environment interactions affect the validity of measures of heritability?
Information is only valid for the environment it was measured in.
How might environmental change affect organisms with environmentally-dependent development?
Consistent environment creates environmentally dependent development. Development varies with environment. Same genotype produces different phenotypes in different environments. New environment= new phenotype, affect community structure (predation), evolution of diversity (phenotypic variation upon which natural selection acts upon)
Inevitable direct effects
Adaptive responses to ecological conditions
What is ecological interaction between barnacles and mussels?
Mussels settle in little crevices of barnacles, when barnacles feel safe they are open and more mussels can fit in, when the barnacles are not in safe places they close us and there is less room for mussels
What are the two sources of phenotypic novelty?
New mutation or
New environment
What are the two ways that environment affect phenotypes?
Competition, predation, mutualism, depend on phenotypes
Speciation and generation of novelty
Who were the following: Homo sapiens, H. erectus, H. habilis, H. floresiensis, H. neanderthalensis.
Homo sapiens: our direct ancestors out of Africa theory 100,000 years ago
H. Erectus: first one to leave Africa 1.8 and 300,000 years ago lived in Africa Asia Europe
H. Habilis: first to use tools 2.4 and 1.5 million years ago lived in Africa
H. Florensiensis: small human 95 to 13,000 years ago lived in Indonesia
H. Neanderthalensis: our ancestor 100, 000 years ago to today lived in Europe and Western Asia
Where did they live and what is their relationship to modern humans?
Homosapiens: first out of africa then to americas asia and europe
H. Erectus: first one to leave Africa 1.8 and 300,000 years ago lived in Africa Asia Europe
H. Habilis: first to use tools 2.4 and 1.5 million years ago lived in Africa
H. Florensiensis: small human 95 to 13,000 years ago lived in Indonesia
H. Neanderthalensis: our ancestor 100, 000 years ago to today lived in Europe and Western Asia
What factors were important in the expansion of the neocortex in early hominids?
Clever foraging
Machiavellian intelligence
More resources for brain
Veins that release “bad blood”
What is the genetic basis for lactose intolerance?
The gene for lactase, the enzyme that breaks lactose down into the more digestible forms of glucose and galactose is normally switched off as children are weaned.
What are the advantages to bipedalism?
Picking fruit
Hands free to carry objects
Thermoregulation in exposed grasslands
More efficient long distance locomotion
Allowed evolution of increased manual dexterity/ tool use
Why do we have a natural predilection for spices and salt in our diet?
Spices prohibit bacterial inhibition.
Salts were previously less eaten because of other more important nutrients we needed now have more because we have less nutrient intake.
Why do some early hominids have a pronounced saggital crest?
Allowed for their hunched over postures
Gave them bigger canines
Gave them bigger face
Brow ridge and sloping foreheads
What do we mean when we say that there is no biological basis for race?
All come from same ancestors; it is y chromosome that is passed down and has no mutational diversity.
Where would you expect to find the greatest amount of genetic diversity?
100,000 years ago, also in races
What are examples of human universals?
Family structure (kinship), rites of passage, mating practices, belief in the supernatural, body ornamentation, incest taboo, property laws, complex verbal and non-verbal communication, etc.
What do UV light, melanin, folate, and vitamin D have to do with the evolution of skin color in humans?
UV light- perfect correlation between the average skin color in a native population of humans and the level of UV light to which they are exposed.
Folate levels correspond with male fertility (low-low) and birth defects when women have babies (low Folate high risk) dark skin helps protect against Folate loss=UV light sucks up Folate
Vitamin D-requires UV light for vitamin D synthesis in the skin which is crucial for bone development. If the pelvic bone is too fragile women can’t give birth. In areas of low UV radiation, fair skin allows enough UV light to be absorbed in the skin to prevent vitamin D deficiency
Melanin-human skin color is determined by the amount of melanin produced in the skin. It is polygenic (encoded by multiple genes) so a large range of phenotypes are possible.
What are the anatomical evidence of bipedalism?
There is torque (on unweighted leg) produced by body weight and then torque (on weighted leg) produced by abductor muscles to balance it out.
fossil records.
Humans, ancestors, and chimps have same legs.
Sexual size difference.
What is Diamond’s explanation for the large scale patterns of human history?
The large-scale patterns of human history were caused not by differences among people but by differences among their environments-- “history’s have and have-nots”
What is the essence of agriculture and how did it first originate?
Agriculture- the science, art, or occupation of cultivating the soil, producing crops, and raising livestock”
Local domestication
Adoption of domesticates from elsewhere
Replacement of local hunter-gatherers by foreign agriculturalists
How and why does agriculture affect population density, specialization and social stratification, and the evolution of diseases?
Population density- with people living together there is pooled resources to create more food, more food=more people
Specialization- certain people created the food so others were left to manufacture other goods, also people who planted food got good at it
Social stratification- certain people created food and became the lower class used by the upper class who specialized in other acts
Evolution of diseases- animals were domesticated and it is animals that carry diseases, more interaction between humans and animals
Of the independent origins of agriculture, which were first, middle and last?
Local domestication
Adoption of domesticates from elsewhere
Replacement of local hunter-gatherers by foreign
1. fertile crescent
2. new guinea
3. eastern us
What are the different ways in which agriculture spread?
Locals adopting foreign foods and animals
What are five reasons to farm rather than hunt and gather?
Depletion of wild foods
Increased availability of domestic able plants
Development of food-production technologies
Supports higher population densities
Displace or kill hunter gatherers
What is domestication?
Human (artificial) selection for useful traits; natural selection under altered conditions
What makes a plant more suitable for domestication, or why have some useful wild plants not been domesticated? (Know wheat, corn, sump weed, almonds, and oaks examples.)
Large edible parts
Less poisonous
Easier to harvest
Loss of germination inhibition
Reproductive self-compatibility
Wheat- already edible and high wild yield; annuals; store well, need little genetic change
Corn- several thousand years of selective breeding--Mesoamerica
Sump weed- eastern US small & nasty
Almonds-3-4 years to fruit and 1 dominant bitterness gene
Oaks- acorns--numerous bitterness genes and over 10 years to fruit
What were the advantages of the fertile crescent for the origin of agriculture?
Advantages of Fertile Crescent plants:
Mediterranean climate- wet winters, dry summers
Large-seeded annual plants- wheat and barley
Good wild harvest- 1 ton/ha 50:1 food: work ratio
Easily stored- sedentary, technology, then agriculture
Hermaphrodite self-fertilizers- easily improved
Few changes needed- dispersal, germination inhibition
Fertile crescent vs. other Mediterranean areas
Larger area, more biodiversity
Greatest seasonal variation > most annuals-- of 56 largest-seeded grasses 32 in fertile crescent
Greater altitude range> staggered harvests
Four big mammals: goat, sheep, pigs, cows + 8 founder crops (3 cereals, 4 pulses, 1 oil/ fiber)
What makes an animal more suitable for domestication, or what are reasons animal domestication fails?
Easy to feed, efficient
Grows fast
Breeds in captivity
Nice disposition
Relaxed, not panicky
Social groups with dominance hierarchy and overlapping home ranges
What were the 14 large domestic mammals domesticated?
Major 5:
Minor 9:
Arabian camels
Bactrian camels
Llama/ alpaca
Water buffalo
What is the evidence that agriculture spread more easily in Eurasia than in the Americas?
More domestic able animals
More domestic able food
Archaeological dates of arrival
Never arrived in some suitable regions (CA)
Multiple domestications of same species in Americas
Less of a climate barrier east to west not north to south
Earlier and better farming
Dense populations, stratified society, specialists, and technology
Where is Cajamarca?
A village in the Peruvian highlands
Who are Pizarro and Antahuallpa?
Antahuallpa is the leader of the Incas
francisco pizarro is the leader of spanish conquistadors
they clashed on november 16, 1532
What is the significance of the collision at Cajamarca?
Of specific interest because the capture of the Incan monarch Antahuallpa marks “the decisive moment in the greatest collision of modern history”
Of general interest because: “the factors that resulted in Pizarro‘s seizing Antahuallpa were essentially the same ones that determined the outcome of many similar collisions between colonizers and native peoples elsewhere in the modern world”
What advantages did the Spanish enjoy over the Incans?
Weapons: guns, steel swords and armor, war horses
Transport: horse, ocean going ships
Communication: writing
Germs: smallpox
Why did the Spanish, and not the Incas have guns, germs, and steel?
Guns came from their stratified specialized societies.
Germs came from their domesticated animals.
Steel also came from their stratified societies.
What are the proximate and ultimate factors involved in the inequities between the world’s have and have-nots?
Guns and steel swords
Ocean going ships
Political organization and writing
East west continental axis
Abundance of domestic able species
Ease of species spreading
What role did smallpox play in the collision between civilizations in Europe and the Americas?
Between 1520 and 1618 the Aztec population plummeted from about to 20 million to 1.6 million.
A smallpox outbreak 5 years before the arrival of Pizarro killed much of the Inca population and precipitated a civil war (won by Antahuallpa over his half brother)
Smallpox, was a horrible, frightening disease and because it killed Americans and spared Spaniards it contributed to a sense of Spanish invincibility
What infectious disease existed in the Americas versus Eurasia---why?
Eurasia- smallpox, influenza, measles, plague, tuberculosis, typhus, cholera, etc.
America- nonsyphillitic Treponema
Population density: agriculture sustains a population density 10-100 times greater than hunting and gathering.
Sedentary populations: a) farmers live in the vicinity of their own sewage. This provides easy route of infection from feces to drinking water b) sedentary populations surrounded by abundant stored food provide attractive habitats for disease carrying rodents and insects.
Food surpluses: a) allow the formation of dense cities where not everyone is involved in food production b) promotes trade. Trade routes spread disease in Europe, North Africa, and Asia.
Livestock are the sources of many infectious diseases in humans: a) DNA sequences reveal that the closest relatives of many human pathogens are pathogens affecting domesticated animals b) crowd infectious diseases are sustained in animal species that live in groups, herd species such as cattle and horses c) a tendency to form social groups or herds is one of the prerequisites for successful domestication of larger animals.
Why was there a disparity between the infectiousness of diseases between Eurasia and the Americas?
High transmission rate: spread quickly from person to person. All of a small population becomes simultaneously infected.
Acute illness. Death or recovery occurs quickly.
Survivors develop lifelong immunity.
Pathogen is unable to survive in the soil or in other animal hosts.
Why can’t a highly virulent infectious disease be sustained in small populations?
Faeroes Island Study
In 1781, a severe measles outbreak occurred in the Faeroes Islands
The epidemic killed many but quickly died out. There were no new cases for 65 years.
In 1846, a carpenter from Denmark reintroduced the measles virus to the Faeroes
Almost every inhabitant of the islands (7782 people) contracted measles
Each sufferer quickly died or quickly recovered and measles disappeared again
In larger populations spread over a wider area, the disease will progress from one region to another. By the time it returns to the original site of infection, sufficient time will have passed that naïve hosts (previously unexposed young people) will be available to sustain the disease
How do populations respond to a new epidemic disease? How does this differ between hunter-gatherer and agrarian societies?
Resistance vs. susceptibility. Prior to the first infection, the population consists of susceptible individuals and individuals possessing genetically based resistance.
More susceptible persons are quickly infected. They respond with symptoms of the disease.
Acquired immunity. The immune system allows some individuals to acquire lifelong immunity to the specific pathogen. Others succumb to the disease.
The next generation. Immunity is a trait acquired as an adult (in the soma), and it is not passed on to the offspring. However, resistance is a genetic trait, and it may be passed onto the offspring.
Hunter gatherer “tribelets” are too small to sustain an epidemic introduced from the outside and too small to evolve their own unique epidemics that they could then give back to outsiders. For this reason “tribelets” do not harbor many resistant individuals.
What is habitat fragmentation?
The breaking up of a habitat into unconnected patches interspersed with other habitat which may not be inhabitable by species occupying the habitat that was broken up. The breaking up is usually by human action, as, for example, the clearing of forest or grassland for agriculture, residential development, or overland electrical lines.
What is habitat fragmentation?
The breaking up of a habitat into unconnected patches interspersed with other habitat which may not be inhabitable by species occupying the habitat that was broken up. The breaking up is usually by human action, as, for example, the clearing of forest or grassland for agriculture, residential development, or overland electrical lines.
What are five principle drivers leading to deforestation in Amazonia?
Clearing for cattle pasture
Subsistence crop farming (squatters rights)
Road infrastructure
Commercial agriculture
Timber extraction
How does climate change lead to habitat fragmentation?
Affects biodiversity
Climate change can create by creating island fragments.
What are the ranges of estimated annual tropical deforestation- how accurate are these estimates?
.38-5.9% they are considered lower than what they actually are.
What is Lovejoy’s “Biological Dynamics of Forest Fragments Project”? What are the major observations of this project?
Mission: determine ecological consequences of habitat destruction and fragmentation in the Amazon, and to disseminate this information widely in such a way as to foster conservation and rational use of forest resources
Smaller ‘islands’ lost far more species
Due to both range size requirements and edge effects (dry winds drying out interior)
Lots of idiosyncratic ‘secondary effects’- “trophic cascades”
What is biodiversity- is it quantifiable? What is alpha, beta, and gamma diversity?
Biodiversity is the number and variety of organisms found within a specified geographic region or the variability among living organisms on the earth, including the variability within and between species and within and between ecosystems.
Alpha diversity: is the number of different kinds of creatures within an area (= species richness)
Beta diversity: is the number or border length among adjacent unlike communities (= habitat patchiness)
Gamma diversity: is the sum of species richness over regional/ continental scales
How much biodiversity is there in earth? Are these numbers known or unknown?
Biodiversity usually gets boiled down to species richness in global level assessments
Total number of species on earth: 4-100 million
Number formally described so far: 1.75 million
Number grows by ~300/ day
How did Terry Erwin attempt to quantify biodiversity?
Fogged 19 trees of 1 species
Collected 955 beetle species
163 of those beetle species were monophagous
Multiply by total number of tree species
Found that beetles represent ~40% of all species of insects, spiders, arthropods
What kind of relationship exists between species and habitat area- what is the equation that relates these variables?
As area increases so do species amount logarithmically
# of species = C (Area^z)
Log (# of species)= C + z (Log of Area)
What does the species area curve depend on?
The species-area curve depends on whether we are considering area “samples” within a large, uniform area, versus true “isolates,” like islands or landscape fragments.
What are the effects of habitat isolation and the species area curve?
While species richness increases with area of habitat, it declines with degree of habitat isolation
What is the “Equilibrium Theory of Island Biogeography”? How has it been studied in the Florida Keys and the Krakatau islands?
Hypothesis: for any island (or isolate) there is a dynamic equilibrium between the influx and extinction of species.
Krakatau flora and fauna: volcano eruption
After eruption, species quickly colonized, and approached an equilibrium species richness.
Species ‘turned over’- some new ones came, some went extinct, equilibrium roughly maintained
Florida keys insects fumigation
Insects quickly decolonized after fumigation
Farthest, smallest islands had fewest species at equilibrium
What are three important limitations to the “Equilibrium Theory of Island Biogeography”?
All species are treated the same, disregards requirements for range size by different species.
Doesn’t account for speciation
Doesn’t account for habitat heterogeneity
What are 5 major human factors leading to global biodiversity loss?
Land use (habitat destruction/ fragmentation)
Climate change
Nitrogen deposition
Species introduction
Elevated CO2
What is the nitrogen cycle? What is the Haber Process?
The Nitrogen cycle is the biogeochemical cycle that describes the transformations of nitrogen and nitrogen-containing compounds in nature. Nitrogen is released into the atmosphere sometimes it gets trapped in water and gets circled around also comes back to us through lightning. Haber process is the industrial process used to make NH 3 from N 2 and H 2 .
What percent of nitrogen is contributed by human activity?
170/270 units of terrestrial N comes from humans~ 63%
What are the effects of nitrogen on biodiversity? Know the example of the study on grass species diversity in Cedar Creek, Minnesota.
The goldilocks hypothesis: too little nitrogen (or other resources) is bad for biodiversity but so is too much. Biodiversity is maximized at intermediate levels of N availability.
Cedar Creek, Minnesota
Plot that received no nitrogen retained its original plant diversity.
Plot that received nitrogen lost almost all of its original plants and was dominated by the weed quack grass.
What are three things that can be done to preserve biodiversity?
Reduce habitat destruction and environmental damage
Hotspot conservation
Re-connecting and re-wilding
What are hotspots?
it is a biogeographic region which is a significant reservoir of biodiversity which is threatened with destruction..
What is being done to reconnect wildlife in Banff National Park?
Wild overpasses created along with roads underneath highways so animals can pass through and putting up gates so that little animals won’t cross the highway.