GEOG 1265 FINAL 2019
people involved with insular biogeography
Darwin and Wallace, Robert MacArthur (mathematician) and E.O. Wilson (biologist)
Darwin and Wallace observations: o extinct forms tend to be found in the same geographical area as their living relatives---why?
Fossil evidence in same area as living species in same area Phyletic evolution, change through time
Ecological desserts and lodgepole pines
Just lodgepole pines and nothing else Doghair stands :lodgdgepole pine is intolerant to shade and thrives in the aftermath of fire; many lodgepole produce serotinous cones, which open in response to extreme heat and release an abundance of seeds. These long-lived cones may remain viable for decades, waiting for a fire to release their seeds. The prolific regeneration that naturally occurs in the open, sunny areas left in the fire's wake often results in dense stands of 20,000 or more trees per acre. These forests often are referred to as dog-hair stands. Cones with only sap (very quiet no seeds for birds)
The "Ice Ages"
Long periods of cooler conditions during which glaciers advanced over large areas of the continents Interrupted by shorter periods of warmer conditions, like today, during which glaciers retreated to higher elevations and more northerly locations Linked to earth-sun geometry
Darwin and Wallace observations: closely related species are found in close proximity to one another---why?
Monkeys (two different species, closely related, other side of river) Allopatric Speciation is reason (below)
Consequences of Plate tectonics and biogeography
Movement of humans and glacial ice Dispersal and diffusion • Great American Interchange
island dwarfism--Advantage of smaller size:
Need fewer resources, especially if competition is intense Size not needed to defend against predators Need smaller territories Short gestation periods (Fetal development period from the time of conception until birth)
South Mesa Lake organic content---revisited
Organic matter and minerals accumulating Higher bulk density with rocks in water Springs, snow melt bring all that shit in Never overflows? Hydrologically isolated (no streams in or out)
Fire adapted trees
Ponderosa pine= thick bark, self-pruning branches (remove branches and needles so fire doesn't climb into crown) Adapted to fire in the understories o Sequoias THICK bark and tree grows around burn scars Don't burn well o Lodgepole pines have serotinous cones (open when heated by fire)
Dendroclimatology + dendrochronology + dendroecology
Reconstruct time Most trees in the mid-latitudes add an annual increment of growth that forms a tree ring ("grain" in wood) Old wood and new wood cells (annual couplets) Thickness determined by environmental conditions in the specific year of growth
Evidence of human impact after arrivals: large drop off of animals
Wooly Mammoths persisted and then died 33 of 45 genera of large mammals became extinct in N.A with arrival of humans Clovis tool complex found with mammal remains Folsom tool complex associated with extinct bison remains
island Gigantism may result from:
a lack of large carnivores that can colonize island (niche filled by birds, reptiles, small carnivores) removal of constraints on size related to predation or competition better able to defend territory among territorial animals
Insular Biogeography (Island Biogeography)
islands as "natural experiments" isolated and small o so can study processes too complex on mainland o evolution works at different rates no dilution of effects of selection and mutation o but also more vulnerable to habitat change and extinction introduction of predators or herbivors
Darwin and Wallace revisited...
the idea of evolution resulting from natural selection survived and succeeded because it fits the observable facts better than any alternative idea, doing exactly what a scientific theory must do: explain material effects by way of material causes using empirical evidence
Darwin's idea of hyperfecundity
"As many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected. From the strong principle of inheritance, any selected variety will tend to propagate its new and modified form", C. Darwin, 1859.
Dendroclimatology
Use of tree ring information to reconstruct earlier climates
sediment cores: accessing the archive (lowest layer=oldest)
Used to determine sea level, ocean, and climate conditions
commercialization of flowers
Valentine's Day sells the most flowers, 224 million grown, 220 million sold, red is passion so red roses are primarily grown, also Mother's Day has good sales too, flowers are used in teas (over 36 types in china) and saffron is a cherished spiced that is expensive and rare because saffron corcus only has few pistils and must be collected carefully
Effect of ice ages on vegetation
Changes in the distributions of vegetation changing of climate=changing of vegetation o General southward migration in northern hemisphere (northerly places covered with ice cuz of ice age, so everything shifted south) o Fragmentation of some biomes (Tropical Rain Forests)
Milankovitch Cycles
Changes in the shape earth's orbit and tilt (23.5 degrees) largely responsible as a cause of glacial periods and interglacial periods. (NATURAL RADIO FORCES)
Lamarck
French naturalist who proposed that evolution resulted from the inheritance of acquired characteristics (1744-1829), Proposed theory that organisms pass on traits they acquire in their lifetime. (Incorrect) i.e. Scars
pyrogeography
- the study of the past, present, and projected distribution of wildfire. - Pyrogeography uses a framework of ecological niche concepts to evaluate the environmental controls on fire. By examining how environmental factors interact to facilitate fire activity, pyrogeographers can predict expected fire behavior under new conditions.
proxy methods
- using pieces of information found in the natural environment to reconstruct historic climates - example: width of tree rings indicate climatic conditions that occurred thousands of years before temperature record-keeping began.
carbon dioxide/methane
-biggest greenhouse gases in terms of climate change -primary source of CO2 are fossil-fuel combustion, biomass burning, the removal of forests, industrial agriculture, and cement production. lasts 50-200 years in the atmosphere -methane is the second most prevelent greenhouse gas. comes from livestock, the mining of coal, oil and natural gas, the burning of vegetation in fires. lasts about 12 years in the atmosphere
Medieval Climate Anomaly
From 800 to 1200 C.E., a number of climate proxies (tree rings, corals, and ice cores) show a wild climatic episode known as the Medieval Climate Anomaly. During this time, warmer temps occurred in some regions, whereas cooling occurred in other regions. The warmth in over the North Atlantic region allowed a variety of crops to grow at higher latitudes in Europe, shifting settlement patterns northward. Vikings settled Iceland and coastal southwestern Greenland remaining there for several centuries before abandoning the settlements around 1400 for unknown reasons, among which was possibly climate change.
Little Ice Age
From approximately 1250 through about 1850 C.E., temperatures cooled globally during a period known as the Little Ice Age.
Hanging valleys
Glacial feature associated with waterfalls
continental glaciers (ice sheets)
Glaciers which cover continent size masses, for example, Greenland and Antarctica. In the Pleistocene, vast portions of the Americas and Eurasia were covered by continental glaciers. Canada had ice coast-coast July 21 thousand years ago
During the resulting faunal exchange, the biodiversity of North America was not changed much despite the invasion of porcupines opossums armadillos, and giant sloths
However the diversity of south American fauna increased with the arrival from N.A of rabbits, weasels, squirrels , dogs, bears, raccoons, cats, deer, peccaries, tapirs, camels, and now extinct mastodons and horses
The extent of glacial ice in northern hemisphere at the last glacial maximum (LGM) of the Pleistocene
Iceland ice caps today etc. o Effects on sea level? Water gets on continents or melting back into ocean, so sea level was lower (400ft lower than today) o Consequences of lower sea level: (last 6000 years it at the level of now)
oxygen isotope analysis
In ice cores, a lower 18^O/16^O ratio (less "heavy" oxygen in ice) suggests colder climates, with more 18^O tied up in the oceans and more light oxygen locked into glaciers and ice sheets. Conversely, a higher 18^O/16^O (more "heavy" oxygen in ice) indicates a warmer climate during which more 18^O evaporates and precipitates onto ice-sheets surfaces.
Native American burning?
Influence the forest prairie ecotone ( region of transition between two biological communities.) Ecotone pushed to east (ecotone is A boundary zone between different, but adjoining, ecosystems at any scale)
relative dating
Method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock Relative dating is the science of determining the relative order of past events (i.e., the age of an object in comparison to another), without necessarily determining their absolute age (i.e. estimated age)
DARWIN'S BIGGEST IDEA
NATURAL SELECTION=PRIMARY PHYSICAL MECHANISM FOR EVOLUTION
possible climate futures
99-100% Probability: - cold days and nights will be warmer and less frequent over most land areas - hot days and nights will be warmer and more frequents over most land areas - the extent of permafrost will decline - ocean acidification will increase as the atmosphere accumulates CO2 - global average sea level will rise and continue to do so for many centuries 90-100% Probability: - arctic sea ice cover will continue to shrink and thin; northern hemisphere spring snow cover will decrease - the frequency of warm spells and heat waves will increase - the frequency of heavy precipitation events will increase - the ocean's conveyer-belt circulation will weaken - extreme high sea-level events will increase, as will ocean wave heights pf midlatitude storms.
disturbance ecology-human impacts
=habitat loss, habitat fragmentation, and invasive species
commercialization of flowers
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Modern synthesis
A comprehensive theory of evolution that incorporates genetics and includes most of Darwin's ideas, focusing on populations as the fundamental units of evolution. , o Putting genetics and natural section is the holistic definition of evolutions (synthesized theory of evolution) o Not just phyletic evolutions, but also speciation, gene theory, distribution of species, systematic taxonomy, etc.......!!!
Arête
A jagged, narrow ridge that separates two adjacent glacier valleys or cirques. An arête is a thin, crest of rock left after two adjacent glaciers have worn a steep ridge into the rock.
mastodon
A large, extinct, elephant-like mammal
Moraines
A mound, ridge, or mass of material that were left on the ground by a receding glacier. • landforms formed are morraines
Moulin (Glacier Mill)
A narrow, tubular chute or crevasse through which water enters a glacier from the surface. Occasionally, the lower end of a moulin may be exposed in the face of a glacier or at the edge of a stagnant block of ice.
supraglacial streams
A stream that flows over the surface of a glacier. Most supraglacial streams descend via moulins into the depths or base of a glacier.
absolute dating
A technique used to determine the actual age of a fossil, uses "natural clocks" determines the actual age or date of event
ice caps and glaciers
A thick mass of glacial ice and snow that permanently covers an area of land, such as either of the polar regions or the peak of a mountain. o Iceland o Alpine glaciers
loess deposits
A wind-formed deposit made of fine particles of clay and silt
Alpine (or valley) glaciers (in CO)
Alpine glaciers form in former river valleys, 5000-6000 feet, anything above treelike would have been glaciated in the ice age
threatened species
Amphibians have a higher risk of extinction than mammals, fish, and birds because they are vulnerable to changes such as habitat destruction, pollution, invasive species, and changing climate. The bottom line is that these species are not evolving fast enough to keep up with the rate of environmental change. Some species are also captured and sold illegally, known as wildlife trafficking. For example, traders and poachers kill elephants for their tusks, rhinos for their horns, and tigers for their bones and skins.
Fens
An area of waterlogged soil that tends to be peaty; fed mainly by upwelling water; low productivity. A type of peat-forming wetland where the water table is kept high by a combination of precipitation and groundwater
primary succession
An ecological succession that begins in an area where no biotic community previously existed o On surface that has never had vegetation on it before o Never been vegetated before, undergoes succession (volcano ash on land example) o Pioneer species: low stature, low diversity o "climax community" are higher stature and generally higher diversity
Disturbance ecology (not just in rainforests!)
An event that changes a community by removing organisms or changing resource availability. Disturbances may be natural anthropogenic, take time, and be a combo o Can be fires, weather, biological or geological processes Ex. storm, fire, flood, drought, and human activity
sea ice
As evidence of accelerating losses of Arctic sea ice, scientists have noticed a decline in multilayer ice, the oldest and thickest, having survived through two or more summers. Younger, thinner, seasonal ice forms over one winter and typically melts rapidly the following summer.
climate models and radiative forcing
Radio forcing: earths energy budget under normal conditions the amount of social radiation coming in is balanced by amount going out If more energy in wasn't equal earth temp would change Now we know it's change, what's forcing the change? What's creating the temp change? The forcing mechanisms are largely increase in greenhouse gases CH.10
carbon isotope analysis
Scientists use carbon-12 and carbon-13 to decipher past environmental conditions by analyzing the 13C/12C ratio in a manner similar to oxygen isotope analysis. Different types of plants use different types of photosynthesis, each of which produces a different carbon isotope ratio in the plant products. Thus, scientists can use the carbon isotope ratio of dead plant material to determine past vegetation assemblages and their associated rainfall and temperature conditions.
glacial striations
Scratches and grooves on bedrock caused by glacial abrasion • sandpaper in ice polishes=shiny surface, scratches can show direction of ice flow
Glaciation and sea level
Sea level goes down during times of glaciation Glacial melting increases sea level
Martin's Pleistocene Overkill Hypothesis
States that humans were primarily responsible for the demise of the megafauna at the close of the Pleistocene, approximately 10,000 years ago, from overhunting as human populations expanded at that time. o When and how did humans arrive in North America? Same time!!!! NOT COINCIDENCE SAYS SULLY o Martin suggests that humans arriving in the Americas near the beginning of the Holocene encountered a number of species of large naïve megafauna that were easily hunted, eventually to extinction
bulk density
The mass of dry soil per unit volume, including the air space, • Bulk density provides info on glacial dynamics (mass of a cubic cm of sediment; provided info on glacial activity in Grand Mesa cores.
till
The sediments deposited directly by a glacier, • sediment that is transported and deposited by glacial ice is called till
alpine glacier
a glacier in mountainous regions that flows down preexisting valleys.
pollen analysis
a method of determining the past climate of a location by examining the percentages of pollen varieties in a soil sample. Or... you collect pollen in a soil sample and have it tested for how old the sample is. then you count the individual pieces of pollen and then figure out what plants existed in that location sediments accumulate information about the basin pollen grains of gymnosperms can preserve things for a long time if VERY WET or VERY DRY in lakes or desert caves • otherwise they oxidize and disappear • studied by palynologists • can be identified to family and genus, some to subgenus, few to species
carbon sinks
a natural or artificial reservoir that accumulates and stores some carbon-containing chemical compound for an indefinite period
ria coast
a primary coast formed when rising sea level, caused by the melting of glaciers and ice sheets following the last ice age, flooded coastal river valleys
glacial polish
a smooth, glistening rock surface formed by the movement of sediment-laden ice over bedrock, • sandpaper in ice polishes=shiny surface, scratches can show direction of ice flow
Catotelm
always below the water table, waterlogged section of peat
virgin forest
an area of old-growth trees that never has been harvested by humans old growth forest, primary forest, "climax vegetation" o No succession/change anymore
glacial plucking
an erosional process by which rocks are pulled out of the ground by a glacier, the process by which a glacier breaks off and carries away fragments of bedrock
Great American Interchange
an important paleozoogeographic event in which land and freshwater fauna migrated from North America via Central America to South America and vice versa, as the volcanic Isthmus of Panama rose up from the sea floor and bridged the formerly separated continents. Mostly a savannah grassland, during glacial periods, savanna spread over much of Central and Northern and South America, during interglacials, tropical forest covered land bridge
Flightlessness develops ....
because no advantage to fly or travel anywhere examples: -Moas (MAORI KILLED EM) -Dodos
Cirques
bowl-shaped depressions that may be left on mountains after glaciers have melted (amphitheater head of glacier)
biogeochemical data (SOUTH MESA?)
bulk density and organic matter in lake sediments and peat cores.
invasive species
can migrate but mostly humans non-native species likely to cause harm, economic, environmental, or harm to human health introduced intentionally or unintentionally by humans • animal, plant, microbe, etc
erosional features of glaciers
cirque, horn, arête, U-shaped valley, hanging valley, truncated spur, fjord
glacial outwash
coarse sediment deposited on a glacial outwash plain by meltwater streams
speleothems
commonly known as cave formations, are secondary mineral deposits formed in a cave. Speleothems typically form in limestone or dolostone solutional caves.
Proxy evidence
data or records relating to an environmental variable that were derived indirectly or reconstructed from natural archives as opposed to data that is directly observed or measured, infer past climate conditions from observations of glacier length and ice core provide proxy evidence for temperature, natural record-keeping phenomena that preserve a record of past environmental conditions
Frequency of Fires?
depends on vegetation community
lateral moraines
lines of till along the sides of a glacial valley
ice cores
method for studying climate change by drilling cores in ice caps and glaciers that have build up over thousands of years, • glaciers: layers, slice ice and investigate sections of years • atmospheric gases within glacial ice that tell of what was in air back then
Holocene Epoch
most recent epoch, which began 10,000 years ago, the "post-glacial" (11.6 kya-present)
Kudzu—introduced from Asia for forage and erosion control in late 1800s
o "the vine that ate the south" o aggressively covers vegetation, structures, etc.
High intensity burns
o Bake the soil o Kill seed bank o Create hydrophobic soils o Increase erosion, mudslides, etc. o Stream pollution
frequency of fires in midlatitude grasslands
o Burn frequently in midlatitude grasslands so no human invasion wouldn't impact it too much o Grasslands adapted with biomasses undergrown and basil marrow stems that allow them to survive frequent burning
C:N (looking at the carbon, nitrogen ratio)
o C:N < 10=aquatic sources (little carbon, unlike trees) o C:N > 10 (40 usually)=terrestrial sources
what makes an aggressive alien invasive species?
o Competition o lack of predation o dispersal ability o fast growth o eurytopic, euryphagous o association with humans o multiple opportunities for establishment
Pleistocene megafauna (fossils)
o Ice camels (evolved into llamas) o Giant Ground sloth o Mastodon o Mammoth o Bison o Sabertooth cat
Island Gigantism, dwarfism, flightlessness
o Island gigantism is one aspect of the more general "island effect" or "Foster's rule", which posits that when mainland animals colonize islands, small species tend to evolve larger bodies, and large species tend to evolve smaller bodies (insular dwarfism). o Dwarf mammoths and Santa Rosa Elephants o Komodo dragons o Dodo
Snowmastodon Project (DMN&S)
o More than 5000 bones from 41 species of Pleistocene animals have been recovered o Aspen
application of insular biogeography theory to conservation biology (morphed into some conservation of species diversity)
o National Parks o Mountain Tops o Wildlife Refugees o SLOSS—single large or several small Jared Diamond-single large Habitat fragmentation (corridors helps minimize) o Corridors Paths that connect between national parks so wildlife can migrate (across highway and stuff etc).
Glacial landscapes—agents of erosion and deposition
o Note the more angular landscape, different erosional features, straightened stream courses Thawing etc. causes jagged edges o glaciers as agents of erosion (glacial ice has rock impregnated within it, bc ice itself is too soft to cut through ground)
The Scientific Method (with plate tectonics as an example)
o Observation Complimentary fit of the continents o Problem or research question If Africa and South America were joined together, should the rocks on their coasts match? Etc. Or fossils should be the same? o Developing hypotheses o Collect data/experimentation o Eventually, theory building A scientific theory is an explanation for phenomena, evidence driven, if contradicted must be revised or thrown out, or check evidence Always undergo modification (theories evolve) • Plate tectonics includes distribution of mountains and volcanos, or how they differ, etc.
Proxies from peatlands
o Peatlands of various types cover less than 5% of the Earth's surface, but store more that twice. As much carbon as all the world's forests o Peat: partially decomposed plant material Decomposition is reduced by high water table (anoxic conditions)
Fire suppression (forest as commodity for lumber)
o Smoky the bear policy o Minimize fire to maximize ability to harvest timber o Increase in fuel build up for fires causes stand replacing fires/crown fires
secondary growth
o What comes after disturbance o Trees blown by volcano but still growing on vegetation
Salt Cedar (Tamarisk)—introduced from Eurasia as an ornamental in early 1800s
o aggressively displaces native riparian species lowers water table; salinifies soil
Cheatgrass—accidentally introduced from Eurasia/Africa in 1800s
o aggressively invades rangeland, pastures, and prairies o changes fire regimes—increases frequency and intensity degrades native communities and forage Asian carp
Biological Proxies
o diatoms: aquatic and marine single-celled algae that secrete silica frustules (shells) that preserve in sediments o diatom species are marine and aquatic, sensitive to water temp, turbidity (how clear is water how much sediment), salinity need lake and tell u what's in lake not around lake limited in time and geography as well
European starling—intentionally introduced in 1890
o large flocks displaces native species, damages crops Shakespeare dude
Robert MacArthur (mathematician) and E.O. Wilson (biologist)
o relation between island area and species diversity oceanic vs continental (on continental shelf or not) islands how do species reach islands • dispersal vs. remoteness o dispersal abilities-how far from source, Galapagos: 60% by bird, 30% by wind, 9% drifted Species-Area Relationship • Some evidence that as island area increases by a factor of 10, species number doubles immigration vs extinction • The number of species on islands is determined by immigration vs. extinction habitat diversity as or more important than size topography etc.
early European impacts on islands
o resources and introduced species o resulting extinctions
The Sediment Archive
o sediment accumulation in lakes and wetlands applies to a variety of locations at bases that form terminal moraine and little ponds-highest flat-top mountain
recessional moraines
successive end moraines left behind by a retreating glacier, Recessional moraines are small ridges left as a glacier pauses during its retreat.
glacial stairway (Cyclopean steps)
term refers to the longitudinal profile of a glaciated valley that has several consecutive hanging valleys. • glacial plucking causes this and jointing, increases efficiency of erosion
zone of accumulation
the area where a glacier forms The part of a glacial system where snow and ice are accumulating faster than they are melting away. • accumulating snow • accumulation>ablation
Geochronology-dating the past, rocks and geological events
the branch of geology concerned with the dating of rock formations and geological events
Mass Budget of a glacier
the difference between accumulation and ablation (sublimation and melting).
Pleistocene Epoch
the first epoch of the Quaternary period, the Ice Ages (2.6 mya-11.6 kya)
Speciation
the formation of new and distinct species in the course of evolution. o One species involves into two species, an increase in total number of species
glacial melting
the global loss of glacial ice as a result of climate change, causing a rise in global sea level
radiometric dating (based off knowing half-life of elements)
the process of measuring the absolute age of geologic material by measuring the concentrations of radioactive isotopes and their decay products using the decay rates of radioactive elements as geologic clock • potassium-argon, allows us to date VERY OLD Stuff • carbon-14, radiocarbon (recent)
U-shaped valleys
the shape of a valleys carved by glaciers
paleoclimatology
the study of past climates
phyletic evolution
transformation of one species into another CHANGE OVER TIME, RESULTS FROM THE ACCUMULATION OF TRAITS THAT RESULT FROM POSITIVE MUTATIONS OR BEHAVIORAL CHANGES o Given enough time, these accumulated traits will produce clear morphological and/or behavioral changes o Takes place in a temporal(time) dimension Involves one species evolving into another, does not increase "biodiversity"
radiocarbon dating (carbon-14 dating) (used in conjugation with other dating)
type of radiometric dating that can be used to date organic material Willard Libby formation of radiocarbon (14C) theory behind radiocarbon dating RCYBP (Radiocarbon Years Before Present)—1950 calibrating radiocarbon dates
Acrotelm
upper section of peat, water table fluctuates Due to occasional drying, organic matter decomposes 100 times faster in the acrotelm than the catotelm
• Human characteristics that show humans are still evolving
vestigial organs/body parts, appendix, wisdom teeth,
Zone of ablation (glacier)
wasting away (melting zone) ablation>accumulation
Sediment sampling
we could take samples out of the core and process them to determine chemical or physical properties of sediment or fossils to look at past watershed, etc., biological and geological and chemical
Grand Mesa:
• 1. Fens may be even more sensitive recording paleotemperature fluctuations than lakes • 2. There is strong correlation between fen peat cores from different fens • 3. Humification analysis indicates that earlier in the Holocene, when it was warmer than today, it was drier • 4. These results suggest that even if monsoonal rainfall intensified during warmer periods, increased evaporation made it effectively drier • 5. The data seem to validate Global Climate Models that indicate drier conditions under doubled CO2 conditions
Under what circumstances might species evolve more quickly?
• Non-mammals: insects have day(s) to live and evolution happens faster (rapid turnover), bacteria, • When an isolated population starts with a small gene pool, little genetic variation in a small geographic area they start evolving more quickly
when the environment changes, whether short-term disturbances or long-term, organisms respond in a few ways
• adapt (eurytypic (better at adapting) vs stenotypic often depends on genetic diversity of the population • migrate or go extinct lol (not everything can adapt) o plants: seeds are dispersed to new location (SLOW) o animals just migrate lol duh
organic content (where did organic matter come from?)
• allochthonous. + • autochthonous
Brown tree snake—unintentionally introduced to Guam from Australia in 1950s
• venomous, preys on native lizards, birds; power outages
coast-to-coast ice
just ice from Atlantic to pacific in N.A
sea level rise
Roughly two-thirds of the rise comes from the melting of land ice in the form of glaciers and ice sheets. The other third comes from the thermal expansion of seawater that occurs as the oceans absorb heat from the atmosphere and expand in volume.
Younger Dryas
- a period of rapid cooling in the late Pleistocene 12,800 to 11,500 calendar years ago. - It followed closely on the heels of a dramatically abrupt warming that brought the last Ice Age to a close (17,500 calendar years ago), lasted for about 1,300 years, then ended as abruptly as it started.
ground fire/crown fire
- ground fires burn surface level fuels but do not reach tree crowns - crown fires occur when fuels accumulate on the forest floor, either through fire suppression or natural processes. (fire in the tops of the trees)
Examples of invasive species
kudzu vine, purple loosestrife, African honeybee "killer bee", water hyacinth, fire ant, zebra mussel, gypsy moth, Asian Long Horned Beetle
Keeling Curve
- a graph of monthly average CO2 concentrations from 1958 to 2016 as recorded at the Mauna Loa Observatory on the Big Island. - The graph shows a steadily increasing trend for atmospheric CO2.
How shall we study the prehistoric past?
"proxy" (substitute) evidence o Proxy data, tree rings, ice etc
Darwin and Wallace observations: sexual reproduction allows creatures to vary—parents from their offspring, and siblings from each other---why?
(Gregor Mendel wasn't father of genetics yet) MENDEL's WORK, produced modern synthesis (below) Creates Variation within species (population of differing individuals) o Mendel and genetics Darwin didn't know it was genetics cuz it wasn't invented yet Found that heredity is based on paired factors that are segregated when gametes formed and rejoined at fertility Most of his work was done from 1856-1865; published in 1866, but largely unnoticed
quaternary biogeography
(last 2.6 million years) organisms and environmental change o when the environment changes, whether short-term disturbances or long-term, organisms respond in a few ways
island biogeography
- A key conceptual model for understanding species distributions and the effects of fragmented habitat Theory summarized: 1.) the number of species increases with island area 2.) the number of species decreases with island isolation (distance from mainland) 3.) the number of species on an island represents an equilibrium between the rates of immigration and extinction. Larger islands have a wider variety of habitat and niches and thus lower extinction rates.
global carbon budget
- The overall exchange of carbon between the different systems on earth - should naturally remain balanced as carbon moves between sources and sinks.
Greenland Ice Cores
Data found in the ice cores here can be used to see methane concentrations o Mesa lake contains record just like it o Good paleotemperature records o Productivity in lake based on temp (higher temps, higher productivity) • oxygen isotopes: O16, O18 • paleotemperature records More 018 when warmer More 016 when cooler cuz in ice not ocean Carbon nitrogen levels to determine organic content and changes, higher organic content in lake sediments = higher temperatures warmer water means more organically productive lake is
The Theory of Evolution doesn't just include the idea of phyletic evolution, that species arise from an ancestral form.
It also includes allopatric speciation; gene theory (genes, DNA, sexual reproduction, crop and animal breeding, genetic engineering), and natural selection; and explains variation within species; varieties and subspecies within species; accounts for the distribution of species today (with plate tectonic theory); explains why related species are found in close proximity to each other, and the reason that fossil organisms are found near their descendents; and provides the underlying structure and explanation for all systematic taxonomy of plants, animals, protists, monera, fungi, etc.
glacials/interglacials
Large, continental ice sheets in the Northern Hemisphere have grown and retreated many times in the past. We call times with large ice sheets "glacial periods" (or ice ages) and times without large ice sheets "interglacial periods." The most recent glacial period occurred between about 120,000 and 11,500 years ago. Since then, Earth has been in an interglacial period called the Holocene. Glacial periods are colder, dustier, and generally drier than interglacial periods. These glacial-interglacial cycles are apparent in many marine and terrestrial paleoclimate records from around the world.
hyperfecundity
Malthus is economist and saw organisms produce far more offspring than can possibly survive • Population is greater than resources (creates point of crisis=famine, wars, sickness, pop drops, cycle) • Creates Competition
Mammals evolve slowly Why?
Mammals have long lifespans so evolution takes slowly
Tool complexes associated with kill sites after extinction of the megafauna are more adapted to hunting smaller prey like deer and rabbits and modern bison
Martin would argue that tools changed cuz bigger animals were being driven to extinction
Animals distributed in Africa and S.A
Pangaea separated=separated animals adapted in different locations
carbon in permafrost
Permafrost is soil and sediment that remain frozen for two or more consecutive years. It lies under a thin "active layer" of seasonally frozen ground that thaws every summer to provide a growing medium for seasonal grasses and other plants that absorb CO2 from the atmosphere. In winter, the active layer freezes, trapping plant and animal material before it can decompose completely. Over hundreds thousands of years, the carbon-rich material has become incorporated into permafrost and now roughly makes us half of all organic matter stored in Earth's soils. Permafrost covers 24% of land in subarctic and tundra climate regions of the Northern Hemisphere.
allopatric speciation
The formation of a new species as a result of an ancestral population's becoming isolated by a geographic barrier. Requires geographic isolation • Population is separated geographically • Over time, each go through phyletic evolution that are slightly different (whether diff environment or chance genetics) • Enough changes occur so they can't reproduce and become two different species Occurs in a spatial (not temporal) dimension\ EVOLUTION and SPECIATION ARE NOT SYNONYMOUS
oceans absorbing CO2
The oceans absorb about one-quarter of the CO2 emitted into the atmosphere. As atmospheric CO2 increases, the oceans naturally offset the increase by taking up more CO2. This triggers the process of ocean acidification, in which dissolved CO2 mixes with seawater to form carbonic acid (H2CO3).
contributions of greenhouse gases
The primary greenhouse gases in Earth's atmosphere are water vapor (H2O), carbon dioxide (C2O), methane (CH4), nitrous oxide (N2O), and halogenated gases. Of these, water vapor is the most abundant. However, water vapor has a short resistance time in the atmosphere (about 9 days) and is subject to phase changes at certain temperatures. Carbon dioxide, in contrast, has a long resistance time in the atmosphere-50 to 200 years- and remains in a gaseous state at a wider range of temperatures.
accumulation of glaciers
The process of adding snow/ice to a glacier
Dendrochronology
The process of counting tree rings to determine the age of a tree
Ablation of glaciers
The process of losing snow/ice through melting, subliming, or calving
Age of Exploration
Time period during the 15th and 16th centuries when Europeans searched for new sources of wealth and for easier trade routes to China and India. Resulted in the discovery of North and South America by the Europeans. *WHOLE ASS STORY I DIDN'T PAY ATTENTION TO*
Meltwater Stream
When valley glaciers stop advancing, melting ice forms streams that flow out from the glacier, carries away sand and gravel
About one half of the current south American species are derived from North American ancestors, while only about 10%of the north American species are of south American origin
Why?? • Northern forms were better migrators • Also better survivors and speciators (kinkajous, coatimundus, guanacos, vicuñas) • And better competitors, having greater genetic and species diversity so filter stopped or allowed some to cross
human-wildfire interface
Wildfires are increasing in many regions of the world with rising temperatures and more frequent lasting droughts. In the US West, earlier spring snowmelt has extended the length of the fire season. In addition, especially North America, tree die-off from insect infestations (such as spruce beetle and pine beetle) has helped produce more fuel and feed larger fires. In the United States, the devastation of wildfires is increasing as urban development encroaches on forests, putting homes at risk and threatening public safety.
terminal moraines
form when sediment is dropped at the front of the glacier, terminal moraines mark the maximum advance of the glacier
ground moraines
gently rolling plains that were deposited as a glacier begins to retreat
How do glaciers form?
glacers form only in areas where more snow falls than melts. Snow build up, and its weight compacts the snow, forming ice that then begins to move downhill Ice=plastic solid (deforms under its own weight) • If glacial ice is big enough it deforms (once it starts to move=glacier) • Key=cooler summer allows ice ages to start
glacial grooves
grooves in solid rock formations made by rocks that are carried by glaciers • sandpaper in ice polishes=shiny surface, scratches can show direction of ice flow
Bog Bodies!!!
human cadaver that has been naturally mummified in a peat bog o Well-preserved human remains (fingerprints, hair)
Plate tectonics and biogeography
if continents moved around, it must've had an impact on biogeography
Succession generally results
in an increase in stature and complexity of the vegetation over time
autochthonous
inputs of organic matter that are produced by algae and aquatic plants inside an ecosystem o auto-same o formed within lake (algae, shrimp, fish)
Allochthonous
inputs of organic matter, such as leaves, that come from outside of an ecosystem o allo-other, cthnon-earth o material coming from outside of lake (washed in from the surrounding slopes)
peat humification process
peat is partly decomposed plant material (plant humification) if water table is high in peatland, then very little peat is exposed to oxygen so peat doesn't decompose as much, if water table lowers throughout the year then the peat will be more composed So more decomposition if acrotelm exposed longer so take samples of peat and samples are treated with sodium hydroxide to extract humic acids, filtered, and analyzed for color using light transmissivity (a lot of decomposed peat=dark water) liquid, the darker=more decomposed peat, tells us and relates to what happened with water tables, and during ice age temps were cooler so water tables were higher, so we can see if we had cooler (more like little ice age) conditions we'd see that we would have more water, so it tells us that future will have drier rockies because they will be warmer (tells us of future) cooler ice age, summers=less evaporation so things get wetter and peat is preserved more, summer is warmer even if more rain, still dryer!!! pollen evidence supports the organic matter/humification data, organic content is low, and transmissivity high, indicating cooler, wetter periods, spruce and sedge pollen percentage's increase , and a sarcobatus and amaranthus-type pollen decrease (expansion of forests and wetlands, decrease of warm desserts, when low organic content), also an increase in Aboral Pollen:Non-treeP, suggesting an expansion of forest taxa at the expense of desert shrubs
horns (glaciers)
pointy boi- A horn results when glaciers erode three or more arêtes, usually forming a sharp-edged peak.
Dendroecology
recording ecological processes
Equilibrium Line Altitude (ELA)
reflects the boundary between the area of net ablation and net accumulation on the glacier surface and is controlled by climate, can be approximated in the field by measuring the elevation of the firn line on a glacier at the end of the melt season in early fall point where accumulation and ablation are equal • if conditions get cooler, equilibrium moves down slow • if conditions get warmer, the line moves up • moving up when glacier recedes moving lower when glacier advances • balance determines whether a glacier advances or retreats or remains
glacial flour
rock material that has been ground to the texture of very fine talcum powder by glacial action, o the water is cloudy (fine-grain sediment) in stream•
