chapter 14 – ecosystems & biomes 14.1 ecosystems support life 14.2 matter cycles through...
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Chapter 14 – Ecosystems
& Biomes
14.1 Ecosystems support life14.2 Matter cycles through ecosystems14.3 Energy flows through ecosystems14.4 Biomes contain many ecosystems
14.1 Ecosystems Support Life
• Living things depend on the environment
• Ecology is the scientific study of how organisms interact with their environment and all the other organisms that live in that environment.
• Ecosystem is a particular environment and all the living things that are supported by it.
14.1 Biotic Factors
• Biotic Factor = all the living parts of an ecosystem• Biotic factors interact with an ecosystem and
influence it. • Living things depend on the ecosystem for food,
air, water, etc. for survival needs and they intern impact the ecosysstem. – Ex: Plants (biotic) impact abiotic factors such as:
• Soil enrichment, depletion, retention, temperature, animals, etc.• Animals (biotic) impact biotic and biotic (beaver building a dam,
cattle overgrazing a grassland cause soil erosion - abiotic
14.1 Abiotic Factors
• Abiotic factors = non-living parts (physical as well as chemical) of the environment (oxygen, CO2, soil, water, sunlight, temperature, minerals & compounds, etc)– Temperature affects plants (type & varieties), animals,
available shelter, etc.– Light impacts amount/variety of plants, how much
photosynthesis– Soil affects plant growth, water percolation, supply– Water impacts carrying capacity (# of plants/animals
an area can support) of all plant & animal life, variety of species, etc.
14.2 Matter Cycles
• All ecosystems need certain materials (matter)
• Cycle: movement of matter (living/nonliving) is a continuous process or cycle.
• Cycle = a series of events that happen repeatedly
• 3 Main Cycles are: Water, Carbon, Nitrogen
14.2 Water Cycle
• Water is constantly moving through the environment through the water cycle
• Water has two elements oxygen & hydrogen• Water changes form as it cycles: solid (ice,
snow), liquid, gas (water vapor), etc.• Evaporation = change of state from liquid to gas
form• Plants release water as they breathe or respire
& release more vapor through transpiration of vapor through their leaves.
14.2 – Carbon Cycle
• Carbon cycles through ecosystems in the carbon cycle.
• CO2 in our air has carbon in it.• Plants use CO2 to produce sugars during
photosynthesis. • Carbon is re-released as plants/animals use
energy or decompose.• Earth’s oceans contain more carbon than the air.• Algae & bacteria also use/release carbon
14.2 Nitrogen Cycle
• Four fifths of our air has nitrogen (a clear colorless gas), but we cannot use it in gas form.
• Nitrogen has to be “fixed” into a useable state by plants before they/we can use it.
• Plants take in nitrogen compounds through their roots. We get it when we eat the plants.
• Lightning breaks apart or fixes pure nitrogen as well
• Nitrogen fixing bacteria live in the oceans as well as in plants roots. Soybeans & alfalfa are good sources of nitrogen
14.3 Energy Flows Through Ecosystems• We use chemical energy (from food; ultimately
from the sun) and need to replace it with energy in our ecosystem.
• Producers – capture energy and store it in food as chemical energy.– Plants are most common producers on land– Photosynthetic bacteria and algae produce energy in
the oceans (exception: deep ocean trench bacteria use heated chemicals released from vents in process called chemosynthesis)
– They make the energy available for themselves and the rest of the ecosystem.
14.3 Energy Flows – cont’d• Consumers - organisms that get energy from
eating/consuming other organisms.• Classified by their position in a feeding
relationship: Example– 1st level consumers = primary consumers – feed on
grasses & plants– 2nd level consumers = secondary consumers feed on
primary consumers– 3rd level = tertiary consumers feed on secondary
consumers• Decomposers – break down dead plant/animal
material into simpler compounds– They release the last bit of energy from once living
organisms.
14.2 Feeding Models
• Food Chain = Model of a feeding relationship between a producer and a single chain of consumers in an ecosystem.
• Food Web = model of the feeding relationships between many different consumers and producers in an ecosystem.
• Energy Pyramid = model that shows the amount of energy available at teach feeding level of an ecosystem.
• All show how organisms receive energy
14.4 Biomes contain many ecosystems
• Regions of Earth are classified into 6 biomes:
• Tundra & Taiga– Dessert & Grassland– Temperate Forrest & Tropical Forrest– Mountain Zones & Polar Ic
• Biome = geographic area similar in climate (temp.-soil-water), plants, and animals
14.4 Biotic & Abiotic
• Biotic = living factors in an ecosystem.
• Abiotic (Non-living) factors in a particular biome are similar and impact the biotic.
14.4 Tundra
• Both are northernmost regions w/long cold winters and short cool summers
• Tundra = -50 – 18 degrees centigrade– less than 25 cm. rain per year, yet wet – Permafrost (deep layer of permanently frozen
soil just below the surface; trees can’t root)– Plants = mosses, lichens, grasses, shrubs– Animals = rodents, caribou, musk oxen, grizzly
bear, white fox, snowy owl, migrating birds
14.4 Taiga
• 30-60 cm rain per year• -40 degrees to 20 degrees centigrade• Cold winters and short cool summers;
more snow• No permafrost; soil low in nutrients• Plants = coniferous (evergreen) trees
w/needles that produce food all year long• Animals = insects, deer, elk, snowshoe
hare, beaver, lynx, owl, bear, wolf
14.4 Desert
• Found in middle latitudes
• Less than 25 cm of rainfall
• Dry, sandy soil; some are hot some cold
• Plants = cactus
• Animals = lizards, kangaroo rat, ground squirrel, snake, owl, fox
14.4 Grassland
• 50-90 cm rainfall • Supports grasses, but
– No trees
• Found in middle latitudes often near desert; warm summers (30 degrees centigrade)
but cold wintersPlants = sun loving grassesAnimals = bison, horse, gazelle, zebra, tiger, wolf,
lion• Wildfires/drought keep out invading trees/shrubs
Temperate Forest
• 75-150 cm water; enough to support trees• Short winters• Deciduous trees (drop their leaves) in fall &
grow new leaves in spring (exception: Pacific Northwest has coniferous redwoods, spruce, fir)
• Most common plants: oak, birch, beech, maple, seed plants, fruiting plants
• Diverse animal variety: mice chpmunks, squirrels, raccoons, deer, wolf, bobcat, fox cougar
14.4 Tropical Forest
• Wet 200-450 cm rain
• 25 degrees year-round
• Soil is nutrient poor, but
tree litter breaks down quickly to supply nutrients
• Diverse plants/animals; more than anywhere else on earth. More tree dwelling species (snakes, monkeys, etc)
14.4 Water Biomes
• Water covers ¾’s of Earth’s surface
• Two Broad Types = Fresh Water &Salt Water– Freshwater Biomes: affected by land topography
• Runoff, lakes, rivers, streams, farms, etc.• Plants may live in or near water; may root below &
grow above water, etc. • Phytoplanktons won’t grow in rivers due to moving h20
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