Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
41 Cards in this Set
- Front
- Back
|
Biogeopgraphic realms
|
Six vast expanses where expect to find communities of specific types of plants and animals.
|
|
|
Biomes
|
Finer subdivisions of great realms, still identifiable on a global scale. They owe their distribution to topography, climate, and interactions among species.
|
|
|
Hot spots
|
portions of biomes and ecoregions that are the richest in biodiversity and most vulnerable to species losses.
|
|
|
Deserts
|
Between latitudes 30 degrees North and South. Rainfall is less than 10 cm. Evaporation is high due to infrequent pulses of rainfall eroding the topsoil. Humidity is low, the ground heats fast and cools fast at night.
|
|
|
Desertification
|
Long term shifts in climate and human activities convert grasslands into deserts. Overgrazing by livestock contributes and periodical droughts worsen the matter. Dust from the North Africa contribute to the decline of coral reefs far away in the Caribbean Sea. Dust carries fungal, bacterial, and viral pathogens.
|
|
|
Dry Shrublands
|
Less than 25 to 60 cm of rain annually. California=6 million acres chaparral. Lightening sparked fires due to shrubs having highly flammable leaves, fire causes their seeds to germinate.
|
|
|
Dry Woodlands
|
Dominant trees can be tall, no continuous canopy. Eucalyptus woodlands of Australia and oak woodlands of California.
|
|
|
Grasslands
|
Zones between deserts and temperate forests. Warm in the summer and winters are extremely cold. Annual rainfall 25 to 100cm to prevent deserts from forming. Grazing and burrowing species are dominant animals. Their activities combined with periodic fires keep shrublands and forests from encroaching.
North America main grasslands are Shortgrass and Tallgrass that form on flat or rolling land. |
|
|
Dust bowl
|
Great plains were overgrazed and plowed under to grow wheat which requires more water than sometimes received in Oklahoma, Nebraska, etc. Winds, drought, and unsuitable farming turned the prairie into the dust bowl.
|
|
|
Tallgrass prairie
|
Once extended west from deciduous forests. Tall grasses, legumes, and composites. Had richer topsoil and more frequent rainfall so farmers originally converted tallgrass prairie to agriculture.
|
|
|
Savannas
|
Africa and Australia are broad belts of grasslands with smattering of shrubs and trees. Extended, seasonal droughts occur where rainfall is sparse and fast-growing grasses dominate. Shrubs grow in regions that get a bit more moisture.
|
|
|
Broadleaf Forests
|
Tall trees grow closely together form a continuous canopy. Evergreen broadleafs, deciduous broadleafs, and evergreen conifers.
|
|
|
Evergreen broadleaf
|
Africa, Southeast Asia, South America. Annual rainfall can exceed 200cm. Tropical rain forests, here grow new leaves and shed old ones all year round. Decomposition and mineral cycling are rapid, given the hot, humid climate, litter does not accumulate. Soils are weathered, humus-deficient and poor nutrient reservoirs.
|
|
|
Deciduous Broadleaf
|
Trees drop some or all of their leaves during dry season. A moisture-preserving adaptation. Moon soon forest for example. Temperate zones. Many nutrients are conserved in accumulated litter on the forrest floor.
|
|
|
Coniferous Forest
|
Cone-bearing trees which have thickly cutticled, needle-shaped leaves to help them conserve water during droughts and winter. Boreal forests stretch across Northern Europe, Asia, N. America. Rains mostly in summer with cold and dry winters in the Eastern parts. In west, the ocean winds moderate the climate. Spruce and balsam fir dominate the Boreal Forrest which are less dense to the north grading into the tundra. Firs and pines in the south, lower regions. Sitka spruce in far north and redwood to far south. Pine species are adapted to dry, sandy, nutrient-poor soil and frequent fires. Fires burn up shrubs but dont hurt them.
Cold winters but not as bad as tundra. Avg 70" rainfall, freezing winter. Moose, lynx, birds. Fir trees, pine trees. |
|
|
Tundra
|
"treeless plain"=coldest biome. Arctic tundra lies b/t polar ice caps and boreal forests. Bitter-cold winters, little precipitation, warmer summer days and permafrost. Vegetation and trees cannot survive. Soils are wet and shrubs are present with the Musk Ox, reindeer, birds.
Alpine Tundra at high altitudes where temperatures fall below freezing, trees cannot grow, soil is thin and nutrient-poor, unlike Arctic, here is fast draining and no permafrost. |
|
|
Permafrost
|
Layer beneath the thawed surface soil that is always frozen. Sometimes more than 500 meters thick. It prevents drainage so surface soil that thaws is perpetually waterlogged and slows nutrient cycling. It is a storehouse of carbon. With global warming heating the permafrost, releasing the carbon as methane increasing global warming.
|
|
|
Eastern Deciduous Forest (EDF)
|
Giant forest right through the east coast of U.S. 50" avg. rainfall uniformly, every month. Winter-time freezing cold and summer is hot & humid. Soil is a good reservoir. Trees lose all leaves once a year in winter. Maple, Oak=big leaves.
|
|
|
Tropics
|
Hot year-round, precipitation up to 100". Vegetation stratification. Animals associate with specific strata. Greatest diversity of species.
|
|
|
Vegetation Stratification
|
species growing to a specific height, vertical distribution.
|
|
|
4 Characteristics of Chaparral
|
1. Temperature: many of the seeds lay (thermal dormancy) in the soil until they receive a temperature shot.
2. Nutrients: Leaves fall to the ground, fire converts everything to ash, mixes with rain, and you get very rich soil. 3. Cover: presence of shrubs so animals can seek cover from predators. 4. Allelopathy: some materials that leak into the soil can negatively affect the growth of species. |
|
|
Primary Succession
|
Where no living plant or animal before has lived. Glacier moving or volcanic island. Receive pioneer species.
|
|
|
Secondary Succession
|
Where you get succession by fire or insect disruption, some major disturbance.
|
|
|
Pioneer Species
|
birds collecting seeds, coconut seeds traveling across the ocean, ferns seeds traveling by air. Microorganisms modifying the environment to allow other species to spawn. Spiders can fly 100's of miles.
|
|
|
Food Chains
|
A chain of organisms for which both matter and energy flow.
|
|
|
Succession
|
Change is species composition over time.
|
|
|
Biomagnification
|
Concentration of elements increases over trophic levels. EX: DDT in algae gets eaten by eel which in turn gets eaten by bird. The amount the bird eats is 100x more powerful than original of algae.
|
|
|
humus
|
Decomposition organic particle. Forms from dead organisms and organic litter: fallen leaves and feces. A lot of this means the nutrient holding capacity is large.
|
|
|
Decomposition
|
Enzymes carry out this function.
|
|
|
Tropics vs. EDF
|
Tropics: nutrients recycled very quickly, rapid decomposition. Greater amount of nutrients in the biomass because biomass is overall much bigger. Very little nutrients in the soil. Clear cut here they may never be regenerated.
EDF: small biomass with larger soil distribution. Nutrients are greater in the soil. If you clear out trees there is no problem for growback. |
|
|
Moisture
|
Dry: no enzyme activity
Wet: much more enzyme activity |
|
|
Temperature
|
Cold: less enzyme activity
Warm: More enzyme activity |
|
|
niche
|
an number of factors in the environment of dimensional volume of physiological tolerance to which a species is restricted.
|
|
|
Gene flow
|
A physical flow of alleles between populations. As long as it continues there will always remain some species. If it is blocked, isolation between populations will create 2 new species over time.
|
|
|
Isolation Mechanisms: Geographic
|
geography prevents interbreeding by isolation. Grand Canyon or a river separates a species.
|
|
|
Isolation Mechanisms: Behavior
|
2 species closely related, yet reproduction dances of courtship slightly vary. Women know which one to choose to procreate.
|
|
|
Isolation Mechanisms: Genetic
|
Chromosomes are so different between the two species that it won't allow reproduction. Mules: half donkey half horse, can rarely bare children. Strong genetic differences.
|
|
|
Ecological succession
|
Transformation of a meadow to a forest over time. One array of species is replaced by another, which is then in turn replaced by another.
|
|
|
Climax Stability
|
Succession ends with the formation of a stable climax community that does not change over time. In any particular habitat succession always produces the same climax community.
|
|
|
Nitrogen Cycle (Nutrient Cycle)
|
Gaseous nitrogen travels in an atmospheric cycle. Nitrogen fixation: certain bacteria in the soil split all three bonds in gaseous nitrogen and then use the nitrogen atoms to synthesize ammonium(NH4+) and nitrate (NO3-). These forms of nitrogen most plants rape.
|
|
|
Nitrogen Cycle (Nutrient Cycle)
|
Gaseous nitrogen travels in an atmospheric cycle. Nitrogen fixation: certain bacteria in the soil split all three bonds in gaseous nitrogen and then use the nitrogen atoms to synthesize ammonium(NH4+) and nitrate (NO3-). These forms of nitrogen most plants rape.
|
