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78 Cards in this Set
- Front
- Back
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Theory of Plate Tectonics
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earth's outermost layer is the lithosphere with tectonic plates that slide on the athenosphere. the magnetic field of earth affects the movement of these plates
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Meganesia
Australaisa |
Australia + New Guinea
shares flora and fauna: marsupials, beech trees (deciduous), gymnosperms, monkey puzzle |
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Antipodean
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coming from or relating to Australia or New Zealand
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Gondwana Sequence
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of rocks, India, S. America, S. Africa, Australia, Antarctica
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Continental Drift
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1915 idea of Wegener that continents used to be connected
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Mesozoic Era when and composed of
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245-65mya
1. Triassic 2. Jurassic 3. Cretaceous |
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Triassic: when, dominant fauna
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245-205mya, giant amphibians that persisted only in australia probably b/c absense of crocs
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Theropod (world's oldest large one"
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Triassic, three toad, carnivore, proof of Aussie dino in Triassic (no fossil, only trackways)
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Cretaceous: when, dominant fauna, major events
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144-65mya, dinos, flowering plants evolve 127mya due to rapid climate change accompanying Gondwana break up
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Jurassic period: when, dominant fauna, important event
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205-144 mya, dinos, Gondwana breaks up only Aust +Antarctica, hot and rainy
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When was the Tertiary: name the five epochs that make it up and major events
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65-1.6mya, Paleocene, Eocene, Oligocene, Miocene, Pliocene, demise of non avian dinos, aus and ant separate, rodents enter via collision with SE asia, Aust starts to dry out and rainforest becomes more grassy and eucalypt
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Great Artesian Basin
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QLD becomes big inland sea, many islands, during Early Cretaceous
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much of the evolution of mammals consisted of
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specialization of jaws and dentition
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3 main regions with distinctive fauna during EARLY tertiary
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1. Laurasia (N. AM, Europe, Asia, AFrica) Placentals
2.. S. America-mix of placentals and marsupials 3. Australasia- same as S. Am |
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Australia's early tertiary: window into 55mya Murgon
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1. modern bandicoots
+gondwananan grp- microbiotherians +archaic marsupials 2. Placentals- archaic bats NO diprotodontians! |
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Placentals in Australia, when?
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no non-flying ones before it split from Antarctica, tingamarra evidence before rodents
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Antipodean Ark set free
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bw 45-38 mya (also when s. am separates from Antarctica)
currents don't reach ant and polar ice caps form- aust-drier |
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Miocene: when? terrain? animals?
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23-5.3mya, rainforest, 1st diprotodonti(koala, kanga, wombat, possum and huge mars. cows), freshwater crocs, first modern platypus,ans no echidna, emus/cassowary, rat kangaroos (common), MELON MUNCHER
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Riversleigh
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window into miocene- diverse possums, think it was once covered in lush rainforest
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Pliocene: when? terrain? animals?
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5mya, rainforest begins to contract, drier, spread grasslands and eucalypt, grazers overtake browsers, collides with SE ASia and rodents appear
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Quaternary: when, epochs, major events
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1.6mya-now: Pleistocene and Holocene, human evolve, terrestrial vertebrates get huge and many go extinct, ice ages occured
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Australian geography and climate during Quaternary
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very arid during ice ages, connected to New Guinea and Tazmania (sea levels drop), interglacial periods are warmer and wetter, more like now (Holocene close to present day habitats)
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Pleistocene Gigantism: who? how big?
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especially mammals, marsupials, greater than 40kg aka megafauna
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Why giants in the Pleistocene
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1. better food access
2. bigger endotherm allows retention of body heat in ice ages 3. stronger |
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Diprotodontoids in Pleistocene
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begin to crash, browsers overtaken by grazers (spread of grasslands)
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Marsupial Lions
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Thylacoleo carnifex, related to koala? "flick blade like" thumb claws, meat shearing cheek teeth, 101-130 kgs
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Thylocines
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tasman tigers, carnivore, al over Aust and Tasman in Pleistocene, convergence, dissappeared about 3000yrs after dingo entered, exterminated in 1800's, last one died in 1936
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Mekosuchine
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freshwater crocs continue to diversify in Pleistocene, terrestrially inclined, now 2 croc species in aust
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arrival of humans
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40k-120kya, older than 50,000 based on charcoal/rock paintings
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Megafauna exctinctions: when? why?
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36kya, 88%lost, most bw 80-28kya, earlier than in N.Hemi, corresponds to human arrival but not climate change, maybe expansion of arid zone eventually killed them. confusion
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Australia as an old continent
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stable geography, no growing mountains or active volcano, oldest west to east (action in New Guinea), landscape and soils no longer rejuvenated by fresh rocks, chemical weathering
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Weathering has shifted from physical to chemical. What does this mean for Australia?
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chem. weathering leaches out rarer minerals that are essential for life, N and P are limited in Oz soils, low nutrient, sands, and clay are very common
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Rhyolite
Basalt Granite schist Nutrients? |
rhyolite low, granite low, basalt, hi, schist depends on parent
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Main Divide "The Great Dividing Range"
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high ground along eastern margin dividing major river catchments, lower topography than GE but is higher, catch northwesterly moving rain clouds
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Great Escarpment
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GE usually East of Main Divide, resulted from rifting bw Oz and NZ, catch northwesterly moving rain clouds
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Archipelago of Volcanoes
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5 main volc in Brisbane over this hot spot, major source of hi nutrient soils, chain centred on Main Divide
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Great Artesian Basin
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.2 of Oz, permeable sandstone aquifers that allow water during high rainfall along Main Divide. Major water source in arid areas to allow agriculture
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Hadley Cell
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@equator air rises creating low pressures and rain,hot air rises and then descends forming high pressure belt, air moves back to equator
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Essence of Oz weather
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low and erratic rainfall, strongly affected by el nino la nina, continent under the high pressure belt
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Australian plants: how many species? how to classify
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20,000vascular, 700 euc, 1000 acacia, 85%endemic
hgt to tallest statum +life form+foliage projective cover |
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Australian plants are adapted to
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high evaporation, frequent droughts and fire, unpredictable rain, low nutrient soils, leaf shape convergence
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schlerophyll leaf
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woody fibrous to prevent herbivory, tough, grey/green,narrow and points downward, EUCALYPTUS (promotes fire)
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Acacia
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wattles, shrubs/short trees, yellow flowers in spikes or pompoms, phyllodes are photosynthetic stems, true leaves lost early
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Symbiosis
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Mutualism, commensalism, parasitism
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Banksia
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schlerophyll, seed cones or vertebrate pollinated, old Godwanan family
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wet schlerophyll
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unique to Oz, schlerophyll canopy and rainforest understory maintained by periodic fire
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Thynnid Wasps +
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Dragon Orchid, pollinated by male wasp attracted to female smell, moving part bangs male against the pollen
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Tree Fall Gap Dynamics in Rainforest
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Gap > Early & Late Building Stages > Secondary forest > Primary Forest
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Pioneer Species
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small trees and shrubs, grow fast, die young, many seeds widely dispersed, viable for a long time, germinated after disturbance, shade intolerant
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Climax Species
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big trees, seeds disperse 3-5 years, seed viability not long grow slowly, live up to 1000 yrs, shade tolerant
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Types of rainforest and gradient of characteristics
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Tropical>Sub>Warm Temperate>Cool T (soil quality, leaf size, # of canopy species, rainfall, temperature, layers)
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Dry Rainforests: species, number of canopy tree species, soils?, temp?, leaf size
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Emergent Araucaria, Bottle Trees (hold water in trunk), no buttress but vines, good soils, warm, small leaves
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Shade loving and Fire Fearing
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pyrophobic (Euc is pyrophillic), rainforest can regenerate in low light and has a closed canopy, epiphytes
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Cauliflory
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presenting flowers/fruit directly on trunk where they are better advertised to foraging animals
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What 3 factors contribute to fire intensity?
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fuel load, wind, temperature
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Jackson's Ecological Drift Model
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fire frequency determines vegetation, 300 yrs no fire > rainforest, more frequent > mixed, more frequent> Eucalypt then shrubland then grassland
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Why wet schlerophyll burns well naturally?
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dry woody tissue, low litter decomposition, open canopy for more wind
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Resprouting
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specially protected buds replace lost foliage after fire. IE Lignotuber grows in ground for a few weeks
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Reseeding
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fire stimulates sead release and germination
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Serotiny
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seeds protected in woody capsule and are protected, open in response to heat ie BANKSIA
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flash frying
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very intense temp promoted briefly, chars trunk but doesn't ignite
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Why reseed?
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competition reduced, fewer herbivores, more space, nurietns available
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Fire stick farming benefits?
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sync's crop, low intensity frequent fires with low litter, clears competing veg
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Characteristics of Aussie Outback
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arid/semi arid <250mm annual rain, patchy mosaic controlled by water run on and run off distributing nutrients and topsoil, affected by fire
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Vegetated Deserts
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vegetative cover in all Aussie deserts, unpredictable but deeply wetting rain allow deep rooted plants and dormant ephemerals to survive droughts
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Lake Eyre
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dry saltpan, but 2-3 times every century it'll rain and fill up, 1 million sq. km of central OZ
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Acacia and Example
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dominant tree genus in central Oz, Mulga has vase shaped branch structure to funnel water into trunk and roots (specialist K)
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Ethnobotony of desert Acacia
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mulga apples edible, gum edible, hard wood for tools, harbors edible insects, seeds =carbs
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Cacti in Oz outback?
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prickly pear introduced as host for bug that makes red dye, invasive weed that is now under control by moth cactoblast. rainfall not predictable for storage
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Spinifex
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grass with schlerophyll characteristics, lack nutrients to support large herbivores, pass straight to decomposers like termites
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Resurrection
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strategy to survive in deserts, foliage dies of and plants lay dormant, grow and reproduce after being awoken by rain (burrowing frog ie)
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Extinctions in the outback
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australia has world's worst record of mammal extinctions, all fall in critical rang 35g-5kg maybe because of cessation of traditional burning>loss of mosaic and introduction of predators like fox and cats
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Insects: structure + function
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head, thorax (movement), abdomen (visceral functions), 6 legs, covered in hair detecting the environment 5-15million species
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Why are insects so successful?
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winged, small, rapid life cycles, lay eggs
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Insects help and harm us by
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1. pollinators
2. predators/parasites 3. sting us 4. herbivores 5. decomposers |
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How are insects threatened?
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geological fragmentation and clearing, insecticide, and introduction of invasive species like the cane toad. flower introduced that is toxic to birdwing butterfly larvae
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When must we conserve? for mammals/
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threatening process is identified, decline in abundance, or decline in area. for mammals: when 30% of population is reduced in 10yrs or 3 generations, whichever is longer
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Why would monarchs go extinct?
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insecticide clears out the single milkweed trees rather than patches. Females lay eggs on single trees for a higher survival rate. Bt corn pollen is toxic to milkweed and drops onto it, climate also affects the growth of monarchs and milkweed
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