Chapter 20 Flashcards
(39 cards)
1
Q
Ecosystem ecology
A
- an extension of organismal, population, and community ecology
- ecosystem comprises all the biotic components (living things) and abiotic components (non-living things) in a particular geographic area
2
Q
Ecology of Ecosystems
A
- Ecosystems range in size and habitat
- Three general environment: freshwater, marine, terrestrial
3
Q
Food chains
A
-Linked sequences of feeding relationships in a community
4
Q
Producers
A
-Autotrophs that supply energy to rest of food chain
5
Q
Consumers
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-Heterotrophs that eat producers
6
Q
Predators
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-One organism feeds on the other (Prey)
7
Q
Herbivores
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-Predation on plants, which may or may not kill the plant
8
Q
Trophic levels
A
-Feeding levels based on positions in a food chain
9
Q
Food webs
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-Complex, interconnection of feeding relationships in community
10
Q
Omnivores
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-Eat both plants and animals
11
Q
Biological magnification (Consequence of food webs)
A
-The increasing concentration of persistent, toxic substances in organisms at each successive trophic level
12
Q
Toxicants accumulation
A
- Some toxicants can be excreted or metabolized.
- Fat-soluble toxicants are stored in fatty tissues.
- Bioaccumulation: toxicants build up in animal tissues
- Biomagnification: toxicants concentrate in top predators
- Near extinction of peregrine falcons, bald eagles, and brown pelicans
13
Q
The water cycle
A
- Water is essential for biochemical reactions and is involved in nearly every environmental system.
- Hydrologic cycle: summarizes how liquid, gaseous, and solid water flows through the environment
- Oceans are the main reservoir.
- Less than 1% is available as fresh water.
- Evaporation: water moves from aquatic and land systems to air
- Transpiration: release of water vapor by plants
- Precipitation: condensation of water vapor as rain or snow returns water from the air to Earth’s surface
14
Q
Aquifers
A
-Underground reservoirs of spongelike regions of rock and soil that hold groundwater
15
Q
Groundwater
A
-Water found underground beneath layers of soil
16
Q
Water table
A
-The upper limit of groundwater held in an aquifer
17
Q
Carbon cycle
A
- Humans are changing the climate
- Carbon dioxide concentrations highest in 700,000 years
- Fossil fuels
18
Q
Fossil fuels
A
-Carbon-rich energy source (coal, petroleum, or natural gas) formed from compressed, fossilized remains of organisms
19
Q
Carbon cycle (definition)
A
-Describes the routes that carbon atoms take through the environment
20
Q
Humans affect the carbon cycle
A
- Burning fossil fuels moves carbon from the ground to the air.
- Cutting forests and burning fields moves carbon from organisms to the air.
- Today’s atmospheric carbon dioxide reservoir is the largest in the past 800,000 years.
21
Q
Nitrogen cycle
A
- Nitrogen comprises 78% of our atmosphere and is contained in proteins, DNA, and RNA.
- Nitrogen cycle: describes the routes that nitrogen atoms take through the environment
- Nitrogen gas is inert and cannot be used by organisms.
- Needs lightning, bacteria, or human intervention
- Nitrogen fixation: Nitrogen gas is combined (fixed) with hydrogen by nitrogen-fixing bacteria or lightning to become ammonium
22
Q
Nitrification
A
-Bacteria that convert ammonium ions first into nitrite ions then into nitrate ions
23
Q
Denitrifying bacteria
A
-Convert nitrates in soil or water to gaseous nitrogen, releasing it back into the atmosphere
24
Q
Phosphorus cycle
A
- Phosphorus cycle: describes the routes that phosphorus atoms take through the environment
- No significant atmospheric component
- Most phosphorus is within rocks and is released by weathering.
- With naturally low environmental concentrations, phosphorus is a limiting factor for plant growth.
- Phosphorus is a key component of cell membranes, DNA, RNA, and other biochemical compounds
25
Human affects on the phosphorus cycle
- Mining rocks for fertilizer moves phosphorus from the soil to water systems.
- Wastewater discharge also releases phosphorus, which boosts algal growth and causes eutrophication.
- May be present in detergents
- Consumers should purchase phosphate-free detergents.
26
Biomes
- Large geographic area defined by its characteristic plant life
- Determined by climatic factors like temperature and rainfall
- A major regional complex of similar communities recognized by:
- Plant type
- Vegetation structure
27
Different biomes
- Aquatic: marine
- Aquatic: freshwater
- Tropical forest
- Temperate forest
- Grassland
- Desert
- Taiga
- Tundra
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A variety of factors determine the biomes:
- The biome in an area depends on a variety of abiotic factors.
- Temperature, precipitation, ocean and air circulation, soil
- Climatograph: a climate diagram showing an area’s temperature and precipitation
29
Temperate deciduous forest
- Deciduous trees lose their leaves each fall and remain dormant during winter
- Mid-latitude forests in Europe, East China, Eastern North America
- Fertile soils
- Forests: oak, beech, maple
30
Temperate grasslands
- More extreme temperature difference between winter and summer
- Less precipitation
- Also called steppe or prairie
- Once widespread throughout parts of North and South America and much of central Asia
- Much was converted for agriculture
- Bison, prairie dogs, antelope, and ground-nesting birds
31
Temperate rainforest
- Coastal Pacific Northwest region
- Great deal of precipitation
- Coniferous trees: cedar, spruce, hemlock, fir
- Moisture-loving animals
- Banana slug
- The fertile soil is susceptible to erosion and landslides.
- Overharvesting has driven species to extinction and ruined human communities.
32
Tropical rainforest
- Central and South America, southeast Asia, west Africa
- Year-round rain and warm temperatures
- Dark and damp
- Lush vegetation
- Highly diverse species, but at low densities
- Very poor, acidic soils
- Nutrients contained in plants
33
Tropical dry rainforest
- Tropical deciduous forest
- India, Africa, South America, northern Australia
- Wet and dry seasons
- Warm, but less rainfall
- Converted to agriculture
- Erosion-prone soil
34
Savanna
- Tropical grassland interspersed with trees
- Africa, South America, Australia, India
- Precipitation only during rainy season
- Water holes
- Zebras, gazelles, giraffes, lions, hyenas
35
Desert
- Minimal precipitation
- Some deserts are bare, with sand dunes (Sahara).
- Some deserts are heavily vegetated (Sonoran).
- They are not always hot.
- Temperatures vary widely
- Saline soils (“lithosols”)
- Nocturnal or nomadic animals
- Plants have thick skins or spines
36
Tundra
- Canada, Scandinavia, Russia
- Minimal precipitation
- Nearly as dry as a desert
- Seasonal variation in temperature
- Extremely cold winters
- Permafrost: permanently frozen soil
- Few animals: polar bears, musk oxen, caribou
- Lichens and low vegetation with few trees
37
Boreal forest (taiga)
- Canada, Alaska, Russia, Scandinavia
- Variation in temperature and precipitation
- Cool and dry climate
- Long, cold winters
- Short, cool summers
- Poor, acidic soil
- Few evergreen tree species
- Moose, wolves, bears, migratory birds
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Chaparral
- Mediterranean Sea, California, Chile, and southern --Australia
- High seasonal
- Mild, wet winters
- Warm, dry summers
- Frequent fires
- Densely thicketed, evergreen shrubs
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Aquatic systems have biome-like patterns
- Various aquatic systems have distinct communities.
- Coastlines, continental shelves
- Open ocean, deep sea
- Coral reefs, kelp forests
- Coastal systems (marshes, mangrove forests, etc.)
- Freshwater systems (lakes, rivers, etc.)
- Aquatic systems are shaped by:
- Water temperature, salinity, and dissolved nutrients
- Wave action, currents, depth
- Substrate type and animal and plant life
