Unit 7 - Our BiosphereUnit 7 - Our Biosphere

Climatic Influences

Terrestrial Biomes

Aquatic Ecosystems

Vocabulary Unit 7 (22)Vocabulary Unit 7 (22)Aphotic zoneAphotic zone HibernationHibernationBenthic zoneBenthic zone Littoral zoneLittoral zoneBiomeBiome Limnetic zoneLimnetic zoneClimateClimate PermafrostPermafrostConiferousConiferous Photic zonePhotic zoneDeciduousDeciduous Thermohaline circulationThermohaline circulationEl NinoEl Nino TopographyTopographyEstivationEstivation UpwellingUpwellingEstuary Estuary WeatherWeatherFlood plainFlood plain WetlandWetlandGreenhouse effectGreenhouse effectGreenhouse gasGreenhouse gas

Unit 7AUnit 7AClimatic InfluencesClimatic InfluencesChps. 16.1 & 16.2Chps. 16.1 & 16.2

WeatherWeather

• “Weather”……………what is it?• What is happening in the atmosphere at

a particular place at a particular moment

• “The temperature is 82º with winds coming out of the southwest.”

ClimateClimate• “Climate” is the average weather in an area

over a long period of time

• “Summer temperatures usually reach into the low 90’s with scattered afternoon thunderstorms.”

• Factors: temperature, humidity, winds, precipitations

• These factors determine what types of organisms live in a region

What factors determine What factors determine climate?climate?

1. Latitude2. Atmospheric circulation patterns3. Ocean circulation patterns4. Local geography5. Seasonal changes in climate

1. Latitude1. Latitude

• The distance from the equator measured in degrees north and south of the equator

• Determines the amount of solar energy an area receives

• Vertical concentrated rays v.s. oblique dispersed rays

2. Atmospheric 2. Atmospheric circulation patternscirculation patterns

• Cold air sinks, warm air rises• Warm air can hold more water vapor

than cold air• Cooler air causes water vapor to

condense into liquid• Solar energy warms the air closest to

the Earth’s surface, causing it to rise• There’s more………………

• Rising air is replaced by cooler air flowing in from further north and south

• Resulting in a circulation cell• Cool air over the equator cannot sink

and is forced away, sinking at about 30º latitude

• This causes warmer dry air, and is why most of the Earth’s deserts are at this latitude

3. Ocean circulation 3. Ocean circulation patternspatterns

• Water holds heat• Currents redistribute warm and cool

masses of water• Coastal areas have a more moderate

climate with more moisture• U.S. temperate rain forest

4. Local geography4. Local geography• Temperatures fall with increase in

elevation (air cools as it rises)

• Mountains influence distribution of precipitation

• Warming air draws up moisture from the surface of the Earth

• Cooling air releases its moisture

• Rain on the west side, deserts in the “rain shadow” of the mountains

5. Seasonal changes5. Seasonal changes• Seasons result from the Earth’s orbit

around the sun and the tilt of the Earth relative to its path

• Four seasons occur, except in the Tropics where it remains constant

Greenhouse EffectGreenhouse Effect

• What is it?

• Light energy goes through the atmosphere and heats the Earth

• As heat rises, some of it escapes back into space

• The rest of the heat is trapped by gases in the troposphere, which then warm the air

Greenhouse GasesGreenhouse Gases

• The gases that trap and radiate heat back to the Earth

• The major greenhouse gases:

• Water vapor, carbon dioxide, chlorofluorocarbons (CFCs), methane, and nitrous oxide

Atmospheric Carbon Atmospheric Carbon Dioxide Fluctuation:Dioxide Fluctuation:

• Seasonal – lower in the summer as plants use it up; higher in the winter as dying plants release carbon

• Why?

• Burning fossil fuels releases stored carbon

• Burning living plants releases carbon

• Oceans absorb 50 times more CO2 than air

Global warmingGlobal warming• Increasing levels of greenhouse gases

increases the average temperature of the Earth

• This produces a warmer climate• Oceans absorb more heat, increasing

hurricanes and typhoons• Disrupted weather patterns could alter

agriculture• Sea levels will rise due to melting glaciers

How to slow down global How to slow down global warming:warming:

• Use less fossil fuels, reducing the amount of carbon dioxide released into the atmosphere

• Preserve existing forests

• Plant more trees

How oceans affect climateHow oceans affect climate• By transporting heat and absorbing

CO2

• Thermohaline circulation: warmer, less salty water moves along the surface; colder, saltier, denser water moves deep

• Colder, saltier water at the poles sinks while warmer, less salty from the equator moves to take the place of the cooler water

El Niño & La NiñaEl Niño & La Niña• Interactions between the oceans & the

atmosphere that affect climate

• Change in air pressure, wind patterns, ocean temperature & ocean circulation in the Pacific Ocean

• Normally, winds and currents move warm water west along the equator

• El Niño: winds weaken & warm water flows back towards S. America, rains in S. Cali.

• La Niña: opposite, cooler water in the eastern Pacific Ocean

El Niño & El Niño & La NiñaLa Niña

Unit 7 BUnit 7 BTerrestrial BiomesTerrestrial Biomes

Chapter 6Chapter 6

BiomesBiomes

•“Biomes” - areas that have distinctive climates and organisms•Biomes are named according to their plant life•Climate is the main determinant

1. Tropical Rain Forests 1. Tropical Rain Forests

• Occur in a belt around the Earth near the equator

• Always humid and warm• Get about 100” of rain a year &

strong sunlight year-round• Ideal climate for growing plants• Soil is thin and poor

Plant adaptationsPlant adaptations Tropical Rain ForestsTropical Rain Forests

•Plants grow in layers•Dense canopy at top absorbs

most of the sunlight•Little light reaches the

understory•Epiphytes: plants that grow on

other plants instead of soil

Animal adaptationsAnimal adaptations Tropical Rain ForestsTropical Rain Forests

•Great diversity of animals, each adapted to exploit a specific resource

•Camouflage is common

Threats to Rain ForestsThreats to Rain Forests

Decreased from covering 20% to 7% of the Earth

Destroyed by logging or clearing for ranches

Animals and native people are becoming extinct

• The canopy receives over 95% of available sunlight, leaving very little for vegetation below. How would this affect photosynthesis at the lower levels?

• Where would you find the greatest amount of biomass in the rain forest?

• At what level of the rain forest would you most likely find herbivores? Decomposers?

• How is a rain forest like the ocean?

• Because of the dense shade on the forest floor, a rain forest is NOT a jungle. Why?

Countries that have Countries that have Tropical Rain ForestsTropical Rain Forests• Brazil• Ecuador• Thailand• Cambodia• Venezuela• Columbia• Guatemala• Costa Rica

2. Tropical Dry Forest2. Tropical Dry Forest• Rainfall is highly seasonal; wet & dry seasons

span about ½ year each

• India, southern N. American, Central America, S. America, SE Asia

• Wet season rains are very heavy

• Organisms must adapt to fluctuations in precipitation and temperature

• Most trees are deciduous; roots deeper than tropical rain forest; some store water

• Animals migrate, estivate

3. Temperate Rain Forests3. Temperate Rain Forests •Occur in North & South America,

Australia, & New Zealand•Pacific northwest is only one in U.S.•Cool, humid forests pervaded by

moisture and abundant moss•High rainfall & moderate

temperatures provide ideal climate for lots of plant growth

•Coniferous (cone-bearing) trees like cedars, spruces, hemlocks, firs

4. Temperate Deciduous 4. Temperate Deciduous ForestsForests

• Trees drop their broad, flat leaves each fall

• Generally occur between 30 and 50 north latitude

• Seasonal variations can be extreme• Only 4 - 6 months of growing season• Moist (30-100” rainfall per year)• Soil is rich and deep

Animal AdaptationsAnimal AdaptationsTemperate Deciduous ForestsTemperate Deciduous Forests

•Numerous habitats, generally organized by layers

•Birds migrate, animals become inactive, insects enter a state of very low metabolic activity

5. Boreal Forests/Taiga5. Boreal Forests/Taiga •The northern coniferous forest•Terrain is rough and forest floor is

sparsely vegetated•Winters are long and extremely

cold•Frost-free growing season is short,

but enhanced by constant daylight•Most of precipitation falls as snow

Plant adaptations Plant adaptations - Boreal- Boreal• Conifers do not shed their needles,

whose narrow shape & waxy coat helps the conifer to retain water

• Conifer’s cone shape helps it shed snow, thick bark protects it from frost, & shallow root system uses water immediately

• Needles are acidic, deterring competitive plant growth

• Soil forms slowly because climate & acidity hinder decomposition

Animal adaptationsAnimal adaptationsBoreal ForestsBoreal Forests

• Lakes and swamps attract birds in summer….lots of insects!

• Fur color changes

• Underground burrows for insulation

Countries that have Countries that have Boreal ForestsBoreal Forests

• Norway

• Sweden

• Finland

• Russia

• Canada

• Alaska (U.S.)

• Germany

• Northern China

Grassland, Deserts, & Grassland, Deserts, & TundraTundra

Characterized by less rainfall and less diversity of species

1. Tropical Savannas1. Tropical Savannas

•Found in the tropics, inland, near the equator

•Contain the greatest # of grazing animals on Earth

•Too little rain for many trees to grow

•Grass fires are common

Plant adaptationsPlant adaptations Tropical SavannasTropical Savannas

•Large underground root systems that survive fire & drought

•Vertical leaves of grasses help conserve water

•Thorns deter hungry herbivores

Animal adaptationsAnimal adaptationsTropical SavannasTropical Savannas

•Herbivores migrate to follow rains

•Competition avoided by eating different height vegetation.

2. Temperate Grasslands2. Temperate GrasslandsPrairies, Steppes & PampasPrairies, Steppes & Pampas • Low rainfall, periodic droughts, and

high temperatures• The most fertile soil of any biome• Found in the interiors of continents

where there is too little rainfall for trees to grow

• Fire is common due to low rainfall, high temperatures

Location of Grasslands:Location of Grasslands:

•Prairies: N. America•Steppes: Russia & Ukraine

•Pampas: S. America

Plant adaptationsPlant adaptationsTemperate GrasslandsTemperate Grasslands

•Grasses are perennials with dense matted root systems that help them survive drought and fire and hold soil

•Amount of rainfall determines type of grasses

Animal adaptationsAnimal adaptationsTemperate GrasslandsTemperate Grasslands

•Burrowing animals protected from fires & the elements

Threats to Temperate Threats to Temperate GrasslandsGrasslands

•Overgrazing decreases regeneration & increases soil erosion

•Grain crops cannot hold the soil in place, increasing soil erosion

3. Deserts3. Deserts•Driest places on Earth•Defined as areas that receive

less than 10” annual rainfall•Dryness hinders decay, so soil

is very poor in organic matter•Few nutrients are washed out,

so soil is high in minerals

Plant adaptationsPlant adaptations - Deserts - Deserts

• Getting and conserving water• Thick fleshy stems, waxy

leaves, spines for protection• Shallow wide root systems• “Drought-resistance” – a

survival strategy to live through the worst desert conditions

• New plants germinate, grow and bloom very rapidly

Animal adaptationsAnimal adaptations - Desert - Desert

•Dry, scaly skin that prevents water loss

• “Estivating” – burying themselves in the ground and sleeping through the dry season

•Most animals are partially nocturnal

Threats to DesertsThreats to Deserts

•Residential development spurs water rights battles

•Off-road vehicles destroy vegetation/habitat

4. Tundra4. Tundra •Definition: a biome without

trees, where grasses and tough shrubs grow in the frozen soil

• “Permafrost” – permanently frozen soil, impermeable

•Top few inches of soil thaws in the summer, causing bogs and swamps to form as water cannot penetrate the permafrost

Tundra Plant AdaptationsTundra Plant Adaptations•Mosses and lichens grow

without soil•Most plants are tiny and short

to keep them out of the wind and help in absorbing heat from the soil

•Dwarf forms have adapted•Brief summers cause rapid

growth and flowering

Tundra Animal AdaptationsTundra Animal Adaptations

•Migratory birds feed on swamp/bog insects

•Winter camouflage and underground burrows

•Well insulated fur and feathers

Threats to the TundraThreats to the Tundra •One of the most fragile biomes on Earth as food chains are simple and easily disrupted

•Extreme conditions cause land to be easily damaged and slow to recover

• How many major land biomes are on Earth?

• 7

• Describe the distribution of tropical rainforests.

• Tropical rainforests are found mostly between the Tropic of Capricorn and the Tropic of Cancer

• In what country is ice found as a land biome?

• Greenland

• Describe the distribution of tundra.

• Tundra is found near the Arctic Circle.

• Which three terrestrial biomes can be found in large areas of the U.S.?

• Temperate grasslands, temperate forests, and deserts

• Which continent was once practically covered in temperate forest?

• Europe

Unit 7 CUnit 7 CAquatic EcosystemsAquatic Ecosystems

Chapter 6Chapter 6

Freshwater EcosystemsFreshwater Ecosystems“Freshwater” – water that

contains relatively little dissolved salt

Life depends on depth of the water, how fast the water moves and the amount of mineral nutrients, sunlight and oxygen

1. Lakes and Ponds1. Lakes and Ponds• “littoral zone” – the nutrient

rich area along the shore where sunlight reaches the bottom

• Phytoplankton, zooplankton and the organisms that feed on them live in open water where there is enough sunlight for photosynthesis

• “benthic zone” – the bottom of a body of water which is inhabited by decomposers, insect larvae and clams

• “eutrophic lake” – a lake with a large amount of plant nutrients

• As plants and algae numbers increase, so do the number of bacteria growing. The bacteria use up the oxygen dissolved in the lake’s waters

What does the benthic What does the benthic zone have lots of?zone have lots of?

C.R.A.P.• Carbon• Rich• Anaerobic• Product

Plant and Animal Plant and Animal AdaptationsAdaptations

• Floating plants in deeper waters

• Trapped air in the hairs of some insects

• Whiskers on catfish help sense food in the dark

QuestionsQuestions• What process allows an abundance of life

near the surface of a lake?• Photosynthesis• If light never penetrates into the deepest of

lakes, how can life exist?• Bacteria and decomposers feed on debris

from above• In the picture, the benthic zone is larger than

the littoral zone. Is this always the case?• Usually it is.

• Explain how the benthic zone can be located in areas where light does and does not reach.

• It is primarily located at the bottom, but some lakes are shallow enough that light penetrates to the bottom

• Which of the following bodies of water would contain a benthic zone where light does not reach: Lake Erie, Lake Michigan, Mississippi River, Walden Pond, Great Salt Lake, Lake Okeechobee?

• They all do

2. Wetlands2. Wetlands• Areas of land that are covered with

water for at least part of the year• “marshes” – contain non-woody

plants• “swamps” – contain woody plants

and shrubs• Many fish use freshwater wetlands

for breeding and feeding

• Wetlands are home for migrating and native wildlife

• Wetland vegetation traps carbon, decreasing atmospheric carbon dioxide and global warming

• Wetlands remove pollutants from the water and control flooding

MarshesMarshes• Shallow water, rich bottom

sediment

• Nesting birds attracted to marshes

• “brackish marshes” – slightly saline water

• “tidal marshes” – contain saltier water

• Everglades is the largest freshwater marsh in the U.S.

SwampsSwamps• Occur on flat,

poorly drained land

• Often located near streams

• Dominated by shrubs or water-tolerant trees

Cypress SwampCypress Swamp

Values of WetlandsValues of Wetlands• Purifiers of wastewater and

absorbers of hazardous flood waters

• Important habitats for wildlife

• Wetlands are threatened by development today

3. Rivers3. Rivers• Usually originate from snowmelt in

mountains• Headwaters are cold and highly

oxygenated• Varies with changes in land and

climate through which it flows• Slows down with deeper, less

oxygenated water as it gets further from its origin

River Plant and Animal River Plant and Animal AdaptationsAdaptations

• Churning headwaters support mosses which can anchor to rocks

• Fish’s streamlined bodies present less resistance to strong currents

• Long, thin-leafed plants near the faster moving headwaters

Threats to RiversThreats to Rivers• Industries and people use rivers

as waste dumps

• Run-offs from land put in pesticides and other poisons

• Dam-building alters flow and destroys fish habitats

Marine EcosystemsMarine Ecosystems

• Ocean environment

• Lack of water is not a problem

• Temperature and amount of sunlight and nutrients are the determining factors

1. Estuaries1. Estuaries• An ecosystem in which fresh

water from rivers mixes with salt water from the ocean

• The waters trap nutrients, which fall to the bottom

• Very nutrient-rich ecosystem

Plant & Animal AdaptationsPlant & Animal Adaptations

• Light and rich nutrients support large populations of plants, phytoplankton and zooplankton

• All organisms are adapted to tolerate variations in salinity ***

• Find lots of filter feeders in this biome

Threats to EstuariesThreats to Estuaries

• Large ports often result in dumped wastes and small oil leaks/spillage

• Fill-ins from building sites

• Sediments and run-offs

2. Coral Reefs2. Coral Reefs• Limestone islands in the sea built by

coral animals

• One of the most diverse ecosystems

• Only in salt water with enough sunlight for photosynthesis

• Found in shallow tropical seas

• Cover less than .2% of the ocean floor, yet it contains 25% of its species

Animal Animal AdaptationsAdaptations• Parrotfish have

beaklike teeth to scrape algae and corals off

• Anemonefish have slime resistant to sea anemone poison

Threats to Coral ReefsThreats to Coral Reefs• Temperature, salinity changes and

pollutants decrease limestone production• Overfishing upsets the balance of a reef’s

ecosystem• Oil spills, sewage, and pesticide & silt

runoff • Muddy or polluted water prohibits sun from

reaching the algae• Coral grow very slowly• Dropped anchors, tourism

3. The Ocean3. The Ocean• Covers nearly 75% of the Earth’s surface

• Plants grow only where there are nutrients and enough light for photosynthesis

• Much of the life is concentrated in shallow water around the edges of the continents

• Open ocean is one of the least productive of all ecosystems

Plant AdaptationsPlant Adaptations

• Flowering plants are absent from oceans except around the edges (no pollinators)

• Phytoplankton provides food for herbivores

• Buoyancy devices prevent sinkage into deep water

Animal adaptationsAnimal adaptations• Zooplankton are the smallest herbivores

• Many creatures evolved sleek, taper shapes for moving through dense water

• Sharks have oily livers to float, fish have gas-filled swim bladders

• Sound carries very well over long distances, so creatures use it for communication

Threat to the OceansThreat to the Oceans• Pollution increasing, including

radioactive wastes, industrial pollution and plant nutrient run-off

• Overfishing and nets reduce reproduction

4. Polar Ecosystems4. Polar Ecosystems

• Ice-covered polar caps at both Poles

• Considered marine ecosystems as nearly all the food is provided by phytoplankton in the ocean

The ArcticThe Arctic

• The Arctic Ocean is relatively shallow, so rich in nutrients from the surrounding land masses

• Rich diversity of fish

The AntarcticThe Antarctic

• Only continent never colonized by humans

• Fish feed on plankton

Threat to Polar EcosystemsThreat to Polar Ecosystems

• Reserves of minerals (like oil) would cause disruption of untouched ecosystems is extracted

• Increase in tourism threatens wildlife with garbage

Test ReviewTest Review

• Know the vocabulary terms

• Know the distinctive characteristics of all the major ecosystems around the world, including savannas, grassland, tropical rain forests, open ocean, deserts, tundra, taiga, rivers, estuaries, and temperate deciduous forests

• Know how animals and plants adapt for survival in some of the harshest biomes

• Know how human activities threaten some of the more fragile biomes

• Be prepared to give examples of countries that contain biomes often found between 24º N latitude and 24º S latitude, as well as between 55º and 70º N latitude

• Be prepared to write about one particular biome in detail

ReferencesReferences

• Pearson Environmental Science

• Environmental Science – Holt

• Environmental Science – Enger & Smith

• Florida Wildlife magazine

• National Geographic magazine

• Google images