STEM Ecosystems

8/11/2019 STEM Ecosystems

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Earths Ecosystems


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Ecology

Ecology:

Scientific study of the interactions between organisms and the environment

Rediscovery of the nearly extinct harlequin toad in Costa Rica raises many ecological questions

What environmental factors limit their geographic distribution?

What factors (food, pathogens) affect population size?


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Ecological Research Areas of Ecological Research:

Global Ecology:examines the influence of energy and materials on organisms across the

biosphere

Landscape Ecology:focuses on the exchanges of energy, materials, and organisms across

multiple ecosystems

Ecosystem Ecology:emphasizes energy flow and chemical cycling among the various biotic

and abiotic components

Community Ecology:deals with the whole array of interacting species in a community

Population Ecology:focuses on factors affecting population size over time

Organismal Ecology:studies how an organisms structure, physiology, and (for animals)

behavior meet environmental challenges


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Figure 52.2

Global ecology

Landscape ecology

Ecosystem ecology

Community ecology

Population ecology

Organismal ecology


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Weather vs. Climate

Weather:

Local areas short term temperature, precipitation, humidity, wind, cloud cover andother physical conditions of the atmosphere measured over hours or days

Climate:

Long-term prevailing weather conditions in an area

Major components of climate are temperature, precipitation, sunlight, and wind

Macroclimate:

Consists of patterns on the global, regional, and landscape (multiple ecosystems) level

Microclimate: Consists of very fine patterns, such as those encountered by the community of organisms

underneath a fallen log

Determined by fine-scale differences in the environment that affect light and wind patterns


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Water Currents Affect Climate


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Air Circulations Affect Climate


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Rain Shadow Effect

The Earths surface affects climate.


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Biomes

Biomes:

Major life zones characterized by vegetation type (terrestrial biomes) or physical environment

(aquatic biomes)

Climate is very important in determining why terrestrial biomes are found in certain areas

Climate affects the latitudinal patterns of terrestrial biomes

Biomes are affected not just by average temperature and precipitation, but also by the patternof temperature and precipitation through the year

Leads to formation of tropical (hot), temperate (moderate) and polar (cold) regionsdeserts,

grasslands and forests

Terrestrial Biomes:

Often named for major physical or climatic factors and for vegetation Characterized by distribution, precipitation, temperature, plants, and animals

Usually grade into each other, without sharp boundaries which may be wide or narrow

Climb a tall mountain from its base to the summit, youll see changes as you might as you

travel from the equator to the poles


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Tropic ofCancer

30

N

30

S

Tropic of Capricorn

Equator

Tropical forest

Savanna

Desert

Chaparral

Temperate grassland

Temperate broadleaf forest

Northern coniferous forest

Tundra

High mountains

Polar ice

Figure 52.9


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Biomes Based on Elevation


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Biomes

Similar characteristics can arise in distant biomes through Convergent Evolution

For example, cacti in North America and euphorbs in African deserts appear similar butare from different evolutionary lineages


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Tropical Rain Forest

Tropical Rain Forests:

Hot temperature, moisture laden air rises resulting in constant rainfall (200 inches per year)

Temperature is high year-round (2529C) with little seasonal variation

High Biodiversity: home to millions of animal species, including an estimated 530 million stillunknown species of insects, spiders, and other arthropods

2% of the land but of worlds species; single tree can have several thousand insect species

Dominated by broadleaf evergreen plants; their dense tops block out most of the sun notreaching the forest floor

Ground has little vegetation (those that do have large leaves); vines (lianas) grow on trees toreach the sun

Little wind because of the dense vegetation; plants depend on bats, birds, bees and otherspecies for pollination

Rapid human population growth is now destroying many tropical forests


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Tropical Rain Forests


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Olinguito

New mammal species in the cloud forests lining the Andes Mountains of South

America - Olinguito and classified it in the Procyonidae family, the same as raccoons.


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Temperate Rain Forest

Coastal Coniferous Forest or TemperateRain Forests:

Found in scattered coastal temperate

areas that have ample rainfall ormoisture from dense ocean fogs

Douglass firs and redwoods


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Deserts

Desert:

Annual precipitation is low; often scattered unevenly throughout the year

Heat of day bakes the earth causing evaporation of water from leaves and soil

Soils have little vegetation and moisture to store the heat so you can roast during the day andfreeze at night

Tropical Deserts:

Hot and dry most of the year; few plants and a hard wind blown surface of rocks and somesand

Temperate Deserts:

Daytime temperatures are high in the summer and low in winter; more precipitation than in thetopical deserts; drought resistance vegetation - cacti

Cold Deserts:

Vegetation is sparse; winters are cold; summers warm or hot and precipitation is low; plantsand animals have adapted to stay cool and get enough water

Fragi le Ecosys tem: slow plant grow th; low sp ecies diversi ty; slow nutr ient recycl ing and lack

of w ater


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Deserts


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Deserts


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Savannah

Savannah

Equatorial and subequatorial regions

Warm temperatures year round with wet and dry seasons

Precipitation is seasonal

Temperature averages (2429C) but is more seasonally variable than in the tropics

Contains widely scattered clumps of trees (aracia with thorns to prevent being eaten)

Grasses and make up most of the ground cover; fire-adapted and tolerant of seasonal drought

Plants have adapted to survive drought and extreme heat

Grazing animals (grass and herb eating; wildebeest) and browsing animals (twig and leaf

eating; giraffe) along with predators (lion)


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Savannah


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Chaparral

Chaparral:

Occurs in mid-latitude coastal regions on several continents

Summer is hot (30C+); fall, winter, and spring are cool (1012C)

Close to sea provides a slightly longer winter rainy season than nearby temperate deserts

Precipitation is highly seasonal with rainy winters and dry summers

Fogs in the spring and fall reducing evaporation Consist of dense growth of low growing evergreen shrubs and occasional small trees with

leathery leaves to reduce evaporation

Dominated by shrubs, small trees, grasses, and herbs; adapted to fire and drought

Prone to fires in the dry season

Many plants produce seeds that only germinated after a wildfire

Animals include amphibians, birds, reptiles, insects, small mammals, and browsing mammals

People like to live here because of its moderate, sunny climate with mild wet winters and warm drysummers; risk losing their homes to frequent fires and mud slides


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Chaparral


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Chaparral


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Temperate Grasslands

Temperate Grassland

Found on many continents

Precipitation is highly seasonal

Winters are cold (often below10C) and dry; summers are hot (often near 30C) and dry

Dominant plants are grasses and adapted to droughts and fire

Little tree growth

Large grazers such as bison and wild horses and small burrowers such as prairie dogs

Most grasslands have been converted to farmland (Midwest)


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Temperate Grassland


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Mountains Mountains:

Some of the worlds most spectacular environments are high on Mountains, steep or high

lands that cover of the Earths surface; dramatic changes in altitude, slope, climate, soil and

vegetation occur in a very short distance

1.2 bil people (18% of the worlds population) live on them or their edges; 4 bil (59%) dependon mountain systems for all or some of their water

Majority of the worlds forests; habitats for biodiversity and contain endemic species found no

where on Earth

Help regulate the earths climate: mountains covered in ice and snow help to reflect solar

radiation back into space helping to cool the plant and offset global warming

Can affect sea levels: storing or releasing water in glaciers; as the earth warms, water can be

released in oceans causing them to rise Major storehouses of water

Despite their signif icance, mou ntain ecosystems are not a high p rior i ty for go vernments

and/or environm ental groups


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Mount Rainier National Park


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Forests


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Northern Coniferous Forest

Northern Coniferous Forest or Taiga:

Spans northern North America and Eurasia and is the largest terrestrial biome on Earth

Cold forests are often found just south of Artic tundra and above certain altitudes in the HighSierras or Rockies

Precipitation varies; some have periodic droughts and others, especially near coasts, are wet

Winters are cold; summers may be hot (Siberia ranges from50C to 20C) Subarctic climate: winters are long, dry and extremely cold; sunlight may only be available 6-8

hrs; summers are short, with cool to warm temperatures; sun shines 19 hrs

Plant diversity is low as few species can survive the winters when soil moisture is frozen

Conifers such as pine, spruce, fir, and hemlock dominate; conical shape of conifers preventstoo much snow from accumulating and breaking their branches

Migratory and resident birds; large mammals such as moose, brown bears, and Siberian tigers


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Northern Coniferous Forest


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Temperate Broadleaf Forest

Temperate Broadleaf Forest:

Found at midlatitudes in the Northern Hemisphere, with smaller areas in Chile, South Africa,Australia, and New Zealand

Significant amounts of precipitation fall during all seasons as rain or snow

Winters average 0C; summers are hot and humid (near 35C)

Long warm summers, cold but not severe winters and abundant moisture, often fairly spreadthroughout the year

Dominated by deciduous trees in the Northern Hemisphere; evergreen eucalyptus in Australia

Broad-leaf trees: oak, hickory, maple and beech; survive cold winters by dropping their leavesin the fall and becoming dormant; each spring, new leaves form and turn colors in the fall

Mammals, birds, and insects make use of all vertical layers in the forest

Eastern US were home to bears, foxes and pumas (many have been killed) and the dominant

mammal often is deer In the Northern Hemisphere, many mammals hibernate in the winter

Impact of human activities: disturbed more than any other for growing of crops, wood or cities;within 100-200 years after its left undistributed, it can return to forest


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Temperate Broadleaf Forest


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Tundra

Tundra:

Covers expansive areas of the Arctic; alpine tundra exists on high mountaintops at all latitudes

Precipitation is low in arctic tundra and higher in alpine tundra

Winters are cold (below30C); summers are relatively cool (less than 10C)

Treeless and bitterly cold

Swept by cold winds and covered by ice and snow

Winters are long and dark

Little precipitation

Permafrost, a permanently frozen layer of soil, prevents water infiltration

Vegetation is herbaceous (mosses, grasses, forbs, dwarf shrubs and trees, and lichen) andsupports birds, grazers, and their predators; alpine can be flowers

Most of the growth occurs in the 7-8 week summer when the sun shines almost 24 hrs

Mammals include musk oxen, caribou, reindeer, bears, wolves, and foxes; many migratorybird species nest in the summer


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Tundra


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Water

Earth is covered with water - known as the Water Planet

Saltwater covers 71% of the Earth

Freshwater 2.3%

Aquatic Life Zones:determined by the amount of salinityamount of salt (NaCl) in the water

Saltwater:

Marine:brackish which is a combination of salt and freshwater and are considered to besaltwater and include

Global ocean is a single and continuous body of water

4 oceans: Atlantic, Arctic, Indian and Pacific; Antarctic

Oceans and estuaries, coastlands and shorelines, coral reefs and mangrove forests

Freshwater

Lakes, rivers and streams and inland wetlands


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Water Planet


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Aquatic Biomes

Aquatic Biomes:

Account for the largest part of the biosphere in terms of area

Marine biomes have salt concentrations of about 3%

Largest marine biome is made of oceans, which cover about 75% of Earths surface andhave an enormous impact on the biosphere

Freshwater biomes have salt concentrations of less than 0.1%

Freshwater biomes are closely linked to soils and the biotic components of the surroundingterrestrial biome

Stratified into Zonesor layers defined by light penetration, temperature, and depth:

Pelagic Zone:

Photic Zone has sufficient light for photosynthesis; most animals live here

Aphotic Zonereceives little light; extensive with little life

Deep in the Aphotic Zone lies the Abyssal Zonewith a depth of 2,000 to 6,000 m Benthic Zone:

Organic and inorganic sediment at the bottom of all aquatic zones

Communities of organisms are collectively called the Benthos

Detritus:

Dead organic matter, falls from the productive surface water; important source of food


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Aquatic Biomes

Figure 52.15


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Tropic ofCancer

Tropic ofCapricorn

30

N

30

S

Equator

Oceanic pelagic and benthic zones

Intertidal zones

Estuaries

Coral reefs

Rivers

Lakes


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Lakes

Lakes:

Natural bodies of freshwater formed from precipitation, runoff or groundwater that fill indepressions in the surface caused by glaciers (Bear Mountain), volcanoes (Crater Lake) orother ways such as supplied with water from rain (precipitation) or streams

Size varies from small ponds to very large lakes

Oligotrophic Lakes:

Nutrient-poor and generally oxygen-rich

Small supply of plant nutrients

Generally deep with steep banks; fed by glaciers and mountain streams with little sediment;crystal clear

Eutrophic Lakes:

Nutrient-rich and often depleted of oxygen if ice covered in winter

Rooted and floating aquatic plants live in shallow and well-lighted area close to shore

Water is too deep to support rooted aquatic plants; small drifting animals called zooplanktongraze on the phytoplankton

Invertebrates live in the benthic zone; Fishes live in all zones with sufficient oxygen


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Lakes


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Lakes


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Wetlands Surface Water: precipitation that does not sink into the ground or evaporate

Runoff: precipitation that runs into a stream

Watershed, Drainage Basin: land that delivers runoff, sediment and dissolved substances into astream; small streams form rivers and rivers flow downhill to the ocean

Aquatic Life Zones: Source Zone:

Headwaters or mountain highland streams; usually shallow, cold, clear and swift flowing;waterfalls and rapids

Not productive because of lack of nutrients and producers; food is from decomposition;algae; fishes

Transition Zone:

Middle; become wider, deeper and warmer; slower; more turbid (cloudier) Producers; both cold and warm water fish (black bass)

Floodplain Zone:

Over time, they shape the land including leveling or cutting through mountains formingcanyons; streams can join others, forming wider and deeper rivers

Large amount of producers and fish; rivers end in a mouth or delta; absorb the floodwatersand add nutrient rich land


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Human Activity

Human activities are disrupting and degrading many of the ecological and economic services providedby fresh water rivers, lakes and wetlands:

Dams and Canalson rivers fragment about 40% of the worlds 237 large rivers

Alter or destroy aquatic wildlife habitats by reducing water flow and increasing damage fromcoastal storms

Flood Control Levees and Dikes:

Built along rivers and disconnect the rivers from their floodplains

Destroy aquatic habitats and alter or reduce the function of nearby wetlands

Hinders the spawning cycle of fishes and birds and can disrupt food chains; species are lostand the biodiversity is threatened

Interrupts sediment flow and distribution

Pollutantsfrom cities and farms add excess nutrients causing algal explosions (blooms) anddepleting the oxygen

Wetlandshave been drained or filled to grow crops or covered to build buildings or roads


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Wetlands


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Wetlands

Wetlands

Habitat that is inundated by water at least some of the time and that supports plants adaptedto water-saturated soil

High organic production and decomposition and have low dissolved oxygen content

Can develop in shallow basins, along flooded river banks, or on coasts of large lakes and seas

Wetlands are among the most productive biomes on Earth

Plants include lilies, cattails, sedges, tamarack, and black spruce

Wetlands are home to diverse invertebrates and birds, as well as otters, frogs, and alligators

Humans have destroyed up to 90% of wetlands; wetlands purify water and reduce flooding


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Wetlands


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Restoration of Wetlands


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Streams and Rivers

Streams and Rivers:

Most prominent physical characteristic of streams and rivers is current

Headwaters are generally cold, clear, turbulent, swift, and oxygenrich; they are often narrow

and rocky

Downstream waters form rivers and are generally warmer, more turbid, and more oxygenated;they are often wide and meandering and have silty bottoms

May contain phytoplankton or rooted aquatic plants

Diversity of fishes and invertebrates inhabit unpolluted rivers and streams

Damming and flood control impair natural functioning of stream and river ecosystems


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Streams and Rivers


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Coastal Wetlands

Estuaries:

Where rivers meet the sea; partially enclosed bodies of water where sea water mixes withfresh water as well as nutrients from streams, rivers and runoff from the land

Coastal Wetlands:

Coastal land areas covered with water all or part of the year

Combined with Estuaries, they are some of the Earths most productive ecosystems becauseof nutrients, rapid flow of water and ample sunlight:

Estuaries and Coastal Wetlands: include river mouths, inlets, bays, sounds, salt marshes andmangrove forests

Seagrass Beds:

Species of plants that grow underwater in shallow marine and estuaries along the coastline

Highly productive and support a variety of marine species

Stabilize shorelines and reduce wave impact

Life is harsh; adapt to daily and seasonal changes in tidal and river flow; water temperatures andsalinity; and runoff from the land including soil sediment and pollutants; because of this, they mayhave low plant diversity but high productivity


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Coastal Wetlands

Mangrove Forests:

Found along 70% of gently sloping sandy and silt coastlines in the tropics and sub-tropics

Grow in salt water and have extensive root systems that can support during changes in waterlevels

Coastal Aquatic Systemsprovide important ecological and economic services:

Maintain water quality by filtering toxic pollutants, excess plant nutrients, sediments andabsorb other pollutants

Provide food, habitats and nursery sites

Reduce storm damage and coast erosion by absorbing waves and storing excess waterproduced by storms and tsunamis

Provide timber and wood for fuel

UN estimates that between 1980 and 2005 at least 1/5 of the mangrove forests were lost duemainly to human coastal development

Loss of mangroves can lead to polluted drinking water caused by inland intrusion of saltwater intofresh water aquifers used to supply drinking water


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River Delta


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Estuaries


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Mangrove Trees


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Life in Coastal Wetlands


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Coastal Shoreline

Intertidal Zone:

Area between high and low tides (gravitational pull of the moon and sun)

Organisms must adapt to movement of water; high tides to drying out at low tides

Oxygen and nutrient levels are high

Deal with daily salinity and moisture changes

Organisms need to hold on:

Rocky Shores:

Pounded daily by waves

Numerous pools and other habitats with a great variety of species; marine algae

Animals have adapted to attach themselves to the hard surface

Sandy Shores:

Barrier beaches

Many organisms are hidden from view by burrowing, digging or tunneling in the sand;home to shore birds that feed on crustaceanssea grass and algae

Barrier Islands:

Narrow islands that form offshore parallel to the coast


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Intertidal Zones


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Life Along the Coast


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Importance of Sand Dunes

Importance of Sand Dunes:

Sand is held in place by plant roots

1stline of defense against the sea

Often removed by developers; and when large storms hit and cause damage, they areincorrectly called Natural Disasters


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Oceanic Pelagic Zone

Oceanic Pelagic Zone:

Constantly mixed by wind-driven oceanic currents

Oxygen levels are high

Turnover in temperate oceans renews nutrients in the photic zones; year-round stratificationin tropical oceans leads to lower nutrient concentrations

Biome covers approximately 70% of Earths surface

Phytoplankton and zooplankton are the dominant organisms in this biome; also found arefree-swimming animals

Zooplankton includes protists, worms, copepods, krill, jellies, and invertebrate larvae

Other animals include squids, fishes, sea turtles, and marine mammals


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Oceanic Pelagic Zone


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Coral Reefs

Coral Reefs:

Worlds oldest, most diverse and most productive ecosystem

Known as Natural Wonders

Biodiversitymarine equivalent of Tropical Rain Forests

Formed by tiny animals known as polypsjellyfish; calcium carbonate

Occupy only 0.2% of the oceans floor

15% have been destroyed and another 20% damaged

They provide important ecological and economic services;

Moderate atmospheric temperatures

Act as natural barriers protecting coasts from erosion

Provide habitats

Support fishing and tourism businesses Provide jobs and building materials


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Coral Reefs


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Life on a Coral Reef


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Death of a Coral Reef


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Marine Benthic Zone

Marine Benthic Zone:

Consists of the seafloor below the surface waters of the coastal zone

Organisms in the very deep benthic zone are adapted to continuous cold and extremely highwater pressure

Mainly soft sediments; some areas are rocky Shallow areas contain seaweeds and filamentous algae

Deep-sea hydrothermal vents of volcanic origin on mid-oceanic ridges are surrounded byunique chemoautotrophic prokaryotes, as well as echinoderms and arthropods

Benthic communities include invertebrates and fishes


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Marine Benthic Zone


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