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