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36 Cards in this Set
- Front
- Back
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Extinction-level events (2 major) |
Permain-Triassic (PTr) Crestaceous-Tertiary (KT) |
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Permian-Triassic extinction event |
250MYA Siberian volcanism - releases methane hydrate runaway greenhouse effect up to 95% species extinction |
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Cretaceous-Tertiary extinction |
65MYA atmospheric particles - decreased sunlight and photosynthesis up to 75% species extinction |
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6 major threats to biodiversity |
human population growth overexploitation habitat destruction pollution species invasions climate change |
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human population has experience ______ growth |
hyperexponential |
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Late Pleistocene extinctions |
Large herbivores disappeared from America, Europe and Australia All >1000kg 75% 100-1000kg 41% 5-100kg <2% <5kg |
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Late pleistocene extinctions coincided with... |
arrival of human hunters |
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Positive side for human population growth |
it is slowing and will likely end this century population size is dropping in many industrialized countries education is a major driver of declining birth rates |
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Exploiations examples |
bluefin tuna Billfish: swordfish and marlin |
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extinction risk is related to... |
generation length and value |
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destructive exploitation - methods |
deep-sea trawling cyanide and dynamite fishing bushmeat trate clearcut logging |
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Positive side of exploitation |
tropical countries have largely restricted overhunting on land some pops recovering due to conservation and management measures destructive forms of exploitation are being increasingly limited or banned consumer awareness is increasing |
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Habitat destruction: caused by |
logging intensive agriculture urban sprawl |
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extent of forest loss by continent |
Russia and Europe has most forest cover Asia has next with the most cleared North and Central America has 3rd |
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___% of population within 100km of coast |
38 |
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Coastal habitat destruction - by |
settlements dikes aquaculture harbors, jetties mass tourism pollution |
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Seafloor habitat loss |
TRAWLING |
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Case study: palm oil plantations |
15 million hectares worldwide demand expected to double by 2020 used in food and industry high-yielding biofuel |
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consequences of habitat loss |
fewer habitats - fewer species reproduction impaired if spawning or juvenile habitat is destroyed changes in local climate increased erosion |
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on the positive side for habitat loss |
foest cover is increasing again in Europe and US wetlands are now being restored protection of critical habitat is becoming a cornerstone of conservation |
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Pollution: types |
toxic nutrient debris noise and light |
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Toxic pollution: examples |
hydrocarbons, tar heavy metals acid rain organochlorines (DDT, PCB, dioxin etc.) toxic algal blooms |
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Nutrient pollution: examples |
increase in nitrate, ammonium and phosphate from (sewage, agri- and aquaculture, erosion) cause algal blooms, hypoxia, species- and habitat loss |
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Plastic pollution: examples |
plastic debris in ocean - up to 100 000 items per km2 on ocean surface microplastic particles are a new and emerging threat |
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plastic pollution: dangers |
ingestion entanglement vector for other pollutants and invasive species |
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Noise and light pollution: examples |
ship noise impairs whale communication light pollution misleads turtle hatchlings |
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Postive side to pollution |
major persistent pollutants such as DDT, PCB, leaded gasoline are banned and decreasing in environment sulphur emissions and lake acidification have decreased through cap and trade nutrient pollution is being reduced through sewage treatment |
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Species invasion: biological invasion definition |
the occur when a novel species enters a community for the first time |
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species invasions can be due to... |
natural and human introductions |
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what kind of invasions have been particularly destructive and where? |
predator and pathogen invasions especially on islands |
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Example |
New Zealand endangered birds surviving on a predator-free island |
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Example in the black sea |
Jellyfish invade - fisheries crashed |
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positive side of invasive species |
being removed from many islands some invasive species can also be beneficial to ecosystems stricter regulations on ballast water are implemented - research at dal |
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As human populations grow ... |
overexploitation, habitat destruction, pollution and species invasions became severe threats to biodiversity |
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Extinction rates today are .... |
100 - 1000X higher than pre-human (uncertain) |
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dominant threat in this century? |
might by climate change |
