Environmental Science Chapter 6 Lecture Biomes. Chapter 6 Targets 1. I can describe how plants determine the name of a biome. 2. Using a world map, I.

Environmental Science

Chapter 6 Lecture

Biomes

Chapter 6 Targets

1. I can describe how plants determine the name of a biome.

2. Using a world map, I can identify general locations of the world’s biomes.

3. I can define climate and explain how temperature and precipitation determine which plants grow in an area.

4. I can explain how latitude and altitude affect which plants grow in an area.

Biomes and Vegetation (Plants)

• Biomes: largelarge regions characterized by a specific climate specific climate and plant and animal communitiesplant and animal communities

• Each biome is made of many different ecosystems• Biomes are described by their PLANTSPLANTS

– Plants determine what other organisms that can live there

– Plants have traits, special structures, or adaptations that allow them to survive in specific biome

– Adaptations include size, shape, and color– Example: tundra plants tend to be short because

they don’t get enough water to grow larger– Other examples??

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The World’s Major Terrestrial Biomes T2T2

Biomes and Climate

• Climate: average weather conditions average weather conditions in area over long period of time

– Main factor in determining which plants can grow in certain area defines the biome.

– Temperature and precipitation are most important factors determining climate (see video)

T3

Temperature and Precipitation• -Most organisms don’t survive at temperatures too far

above/below a range they have adapted to

• -Precipitation limits organisms found in a biome

– -↑↑ plant size = ↑↑ water it needs

-Biomes receiving low amounts of rainfall support communities dominated by small trees, shrubs, and grasses

-In biomes where rainfall is not frequent, plants are mostly cacti and desert shrubs

-In extreme cases, lack of rainfall results in no plants, no matter what the temperature is

• -↑↑ temperature + ↑↑precipitation = ↑↑ plants T3

T3

Latitude and Altitude• Latitude: distance north or south from equator (expressed in degrees)• Altitude: height of an object above a reference point, such as sea level

or the Earth’s surface.– Climate varies with latitude and altitude. – Climate gets colder as latitude and altitude increase.– This is why it gets colder as you move further up a mountain.

T4

T4

Comprehension Check

According to the maps, which of the following determines the main characteristics of a biome?A. Geographic bordersB. Latitude C. Longitude D. Distance from the ocean

Comprehension CheckWhich of the following describes a biome?

A. All the areas on Earth that are life-supportingB. Weather conditions in an area for a specific time periodC. A region characterized by specific climate and organism communitiesD. An area where the animal population interacts with its abiotic environment

Comprehension Check

What is the diversity of the species in an area most dependent on?A. Plant lifeB. RainfallC. SunlightD. Temperature

Comprehension CheckWhat are the main factors that determine

weather?A. Altitude, latitude, precipitation, temperatureB. Altitude, latitude, precipitation, vegetationC. Air currents, altitude, temperature, vegetationD. Air currents, precipitation, temperature, vegetation

Chapter 6 Targets

5. Based on climate, I can predict where forest biomes are located.

6. I can list three characteristics of tropical rain forests and identify their location on a world map.

7. I can name and describe the main layers of a tropical rain forest.

8. I can name the main threats to rain forests and the global effects of rain forest destruction.

9. I can list three characteristics of temperate rain forests and identify their location on a world map.

Forest Biomes

• Of all biomes in the world, forests are most widespread and diverse

• Because trees need a lot of water, forests are found where temperatures are mild to hot and rainfall is plenty

• 3 main forest biomes of the world: 1. Tropical 2. Temperate 3. Coniferous

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Tropical Rain Forests• Forests/jungles near equator

characterized by:– 1. large amounts of rain– 2. little change in temperature– 3. greatest biodiversity on Earth– 4. humid, warm, and strong

sunlight• Regulate climate and play a role

in nitrogen, oxygen, and carbon cycles.

T 6

• Most nutrients are in plants, not soil– Decomposers on forest floor break down dead

organisms return nutrients to soil plants quickly absorb the nutrients

– There are so few nutrients in the soil that runoff from rain forests is often as pure as distilled water

• Most tropical soils cleared for agriculture cannot support crops for more than a few years

• Many trees form above-ground roots called buttresses or braces that grow sideways from tree to provide extra support in the thin soil

Nutrients in Tropical Rain ForestsT 7

Layers of the Rain Forest• In tropical rain forests, different types of plants grow in

different layers• 4 main layers of the rain forest:

• 1. The Emergent Layer• 2. The Upper Canopy• 3. The Lower Layer• 4. The Understory

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Layers of the Rain Forest• Emergent layer: top leaf

layer where tallest trees extend above everything else– Trees reach direct sunlight

at heights of 60-70 m (~23 stories tall) and can measure up to 5 m around

– Animals such as eagles, bats, monkeys, and snakes live in the emergent layer

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Layers of the Rain Forest

• Canopy: layers of treetops that shade forest floor– Considered main layer

of rain forest– Trees form dense layer

that absorbs up to 95% of sunlight

– Can be split into upper and lower canopy with lower canopy receiving less sunlight

T 7

understory

Layers of the Rainforest

• Epiphytes: plants that grow on another plant but do not harm it

– Located on tall trees in canopy to reach sunlight for photosynthesis, and absorb water and nutrients

• Most animals living in the rain forest Most animals living in the rain forest live in canopylive in canopy because they depend on the many flowers and fruits that grow there.

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Layers of the Rainforest• Understory: plant layer beneath and shaded by

main canopy of a forest

– Little light reaches this layer allowing only trees and shrubs adapted to shade to grow here

– Most plants in understory are less than 3.5 m tall

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Threats to Rain Forests

• Every minute, 100 acres of tropical rainforest are cleared or damaged for:

1. Logging operations

2. Agriculture

3. Oil exploration

4. Exotic-pet trading • ~50 million native people live in tropical rain forests and

are threatened by habitat destruction– Loss of habitat forces them to move to cities– This drastic lifestyle change may force them to lose

their culture and traditions

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Temperate Rain Forests• Characterized by:

1. coolcool, humid weather

2. heavy rainfall

3. tree branches draped with mosses

4. tree trunks covered with lichens

5. forest floor covered with ferns

Found in North America, Japan Australia, and New Zealand

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Temperate Rain Forest Climate• Pacific Northwest keeps

mild temperatures year round

• Rarely freezes because Pacific Ocean blows cool ocean water over forest (regulates temp)(regulates temp)

• As ocean winds meet Olympic Mountains, a large amount of rainfall is produced, keeping temperature cool and moist

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Chapter 6 Targets

11. I can list three characteristics of temperate deciduous forests and identify their location on a world map.

12. I can describe one plant in a temperate deciduous forest and an adaptation that helps the plant survive.

13. I can list two characteristics of taigas and identify their location on a world map.

14. I can identify unique characteristics of conifers.

15. I can describe one adaptation that help animals survive in taiga.

Temperate Deciduous Forests• Characterized by:

1. Trees shed leaves in fall

2. Located between 30º and 50º northnorth latitude.

3. Range of temperatures can be extreme; summer temps soaring to 35ºC (95oF) and winter temps often falling below freezing

4. 75 to 125 cm (29-49 inches) of precipitation annually, helps decompose dead organic matter into rich soils

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Temperate Deciduous Forest Locations T 11

Plants of Deciduous Forests• Plants grow in layers grow in layers with tall trees like birch

that dominate the canopy and shrubs cover the understory (no emergent layer)

• More light reaches deciduous forest floor than rain forest floor allowing more small plants to grow

• Plants are adapted to survive seasonal changes– In fall and winter, trees shed leaves and

seeds go dormant under insulation of the soil

– With returning warmth in spring, trees grow new leaves and seeds sprout

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Taiga (Boreal Forest)

• Region of evergreen, coniferous forest below arctic and subarctic tundra regions.

– has long winters and little vegetation.

– growing season short (50 days) with most plant growth during summer months because of nearly constant daylight and larger amounts of precipitation.

T 13

Taiga Video (11")

Taiga LocationsT 13

Plants of the Taiga• Conifers: trees that have seeds that develop in cones

– Leaves’ arrow shape and waxy coating help retain water in winter

– Conifer’s shape helps tree shed snow and not get weighed down

– Conifer needles contain substances that make soil acidic when they fall, preventing plants from growing on the floor

– Soil forms slowly because climate and acidity slow decomposition

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Animals of the Taiga• Taiga has many lakes and swamps

attracting birds that feed on insects during the summer

• To avoid harsh winters, birds migrate

• Some year-round residents, such as shrews, burrow underground for better insulation.

• Other animals avoid predation by shedding brown summer fur and growing white fur to camouflage them in the snow

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Snowshoe Hare

Comprehension Check

What type of forest has the greatest biodiversity?

A. Taiga forestB. Temperate deciduous forestC. Temperate rain forestD. Tropical rain forest

Chapter 6 Targets

16. I can describe the climate and locations of savannas.17. I can describe adaptations of savanna plants and

animals.18. I can describe the climate and locations of temperate

grasslands.19. I can explain why fire is important to grassland and

savanna biomes 20. I can describe adaptations of temperate grassland

plants and animals.21. I can describe how farming and overgrazing have destroyed temperate grasslands.

Savannas• Plains full of grasses, scattered

trees and shrubs• Found in tropical and

subtropical habitats• Mainly in regions with dry

climate, such as East Africa and western India

• Have wet and dry seasons (though ↓ precipitation)– Many animals active only

during wet season– Grass fires restore nutrients

to soil during dry season

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Savannas T 16

Plants of the Savanna

• Only rains during wet season, plants must be able to survive prolonged periods without water

1. Some plants have large horizontal root systems to help them survive dry season. These roots also enable them to grow quickly after fire.

2. Grasses have coarse vertical leaves that expose less surface area to conserve water, while some trees shed their leaves.

3. Almost all have thorns for protection from herbivores.

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Animals of the Savanna

1. Grazing herbivores, like elephants, migrate, following rains to areas of new grass and fresh watering holes.

2. Many savanna animals give birth only during rainy season, when food is abundant and young are more likely to survive.

3. Some species of herbivores reduce competition for food by eating vegetation at different heights than other species do.

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Temperate Grasslands• Temperate grasslands:

– Dominated by grasses, few trees

– Hot summers and cold winters– Amount of rainfall is between

that of a forest and a desert– Most fertile soil of any biome

• Few natural temperate grasslands remain because most have been replaced by grazing areas and farms growing crops such as corn, soybeans, and wheat

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Temperate Grasslands• Located where too little rain falls

for trees to grow• Mountains often play a role in

forming grasslands because they block rain clouds from the west– Rainfall does ↑ as you move

east, allowing taller grasses to grow.

• Heavy precipitation is rare in grasslands, so hot temperatures in summer often create fires

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Temperate Grasslands

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Classifying U.S. Grassland Types• U.S. grasslands (prairies) classified by

examining 2 things:1. Annual Precipitation2. Soil Type:

• MESIC: dark black soil, rich in nutrients»drains well, yet retains some water

• LOESS: “glacier dust”»Mineral particles mixed with clay

• DOLOMITE: near fens»High pH»Formed from calcium carbonate (limestone)

that has been worn down

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Plants of Temperate Grasslands

1. Root system of prairie grasses forms dense layers that survive drought and fire, allowing plants to come back from year to year

2. Few trees survive on grasslands because of low rainfall, frequent fire, and constant winds

3. Amount of rainfall in the area determines types (varying root depth and grass height) of plants that will grow in that area

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Grassland PlantsT 20

~10 inches rain~20 inches rain

~35 inches rain

Animals of Temperate Grasslands

1. Some grazing animals, such as bison and pronghorn antelope, have large, flat teeth for chewing the coarse prairie grasses.

2. Other grasslands animals, such as prairie dogs, owls, and badgers, live protected in underground burrows that protect them from predators on the open grasslands.

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Threats to Temperate Grasslands

• Farming/overgrazing have changed grasslands

• Crops don’t hold soil in place as well as native grasses because their roots are shallow, soil erosion eventually occurs

• Constant farming can change fruitful grasslands into desert-like biomes

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Chapter 6 Targets

22. I can describe the climate and locations of the chaparral biome.

23. I can describe adaptations of chaparral plants and animals.24. I can describe the climate and locations of desert biomes25. I can name two desert animals and plants, and describe the

adaptations that help them survive.26. I can describe the climate and location of the tundra biome.27. I can name two tundra animals and plants, and describe the

adaptations that help them survive.28. I can describe one threat to the tundra

biome.

Chaparral• Chaparral

– temperate woodland biome

– plants are broad-leaved evergreen shrubs

– located in areas with hot, dry summers and mild, wet winters

• Located in middle latitudes, about 30° north and south of the equator.

» Primarily in coastal areas with Mediterranean climates.

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ChaparralT 22

Plants of the Chaparral• Most are low-lying, evergreen shrubs• Some small trees grow in dense

patches• Include chamise, manzanita, scrub

oak, and herbs like sage and bay.• Have small, leathery leaves that

contain oils to promote burning, allowing natural fires to destroy competing trees.

• Well adapted to fire and can regrow from small bits of surviving plant tissue.

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Animals of the Chaparral

• Common adaptation is camouflage, shape or coloring allowing animals to blend into environment

– Quail, lizards, chipmunks, and mule deer have a brownish gray coloring that lets them move through the brush without being noticed.

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What is a Desert Like?

• Land of extremes: extreme heat and extreme dryness; sudden flash floods and cold nights.

• Very harsh, often have names likes "Death Valley," "the empty quarter," and "the place from where there is no return."

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Dryness

• VERY dry. Even wettest deserts get less than ten inches of precipitation a year.

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Hot During the Day, Cool at Night

• During day many deserts are very hot. Temperatures in excess of 100oF are common.

• Yet at night, temperatures fall into the 40s or 50s? Why?

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-Other biomes insulated by humidity. -At night water acts like a blanket, trapping heat inside the biome

-Deserts have only 10-20% humidity to trap temperatures.

-Have few trees and other plants to retain heat

-Deserts cool down rapidly when sun sets heat up quickly after sun rises

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Where Are Deserts Located?

Many are found in bands along 30o north and 30o south of the equator* (called the desert belt)

*between red lines on the map

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Why do “desert belts” form?

• As warm air rises over equator rises, it cools and loses moisture

• As it falls (north and south of the equator), it warms and picks up moisture, drying out the land

• This downward movement of warm air masses over the earth has produced two belts of deserts

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The Rain Shadow Effect• Deserts near mountains are caused by "rain

shadow" effect• As air moves up over mountains, it gets cold and

loses moisture -- causing rain or snow• When air moves down the other side of the

mountain, it gets warmer. • Warm air can hold more moisture, so it doesn't

rain as much, and a desert is formed.

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Deserts of North America NOTE: All deserts in North America are influenced by the rain shadow

effect

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Desert Plant Adaptations

Plants adapt to dryness by reducing rates of evapotranspiration:1. reduced leaves (spines)2. waxy coating on leaves and stems3. store water in fleshy parts (succulents)4. large, shallow root systems absorb water quickly –or- deep taproots5. mature quickly and produce flowers/seeds in the few days when water is available6. seeds in some can remain dormant for over 50 years

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Desert Animal Adaptations

• Usually small (ex. Jackrabbits, snakes, and kangaroo rats)

• Adapted to conserve water:1. get water from their own respiration2. excrete concentrated urine3. camel’s hump?

Camel's Hump Video

• Adapted to survive in temperature extremes:1. Nocturnal2. Burrow3. Estivate

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Tundra

• Tundra: treeless plain located in Arctic or Antarctic, characterized by:– Very low winter temperatures– Short, cool summers– Plants are grasses, lichens, and perennial herbs.– Short summers , only the top few centimeters of

soil thaw.• Permafrost: the permanently frozen layer of soil or

subsoil found in tundra regions.

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Tundra LocationsT 25

Tundra Plants/Producers

• Mosses and lichens cover vast areas of rocks in the tundra (why would these be able to grow here?)

• Other plants have wide shallow roots to help anchor them against icy winds in the thin soil

• Most flowering plants are short, this keeps them out of the wind and helps them absorb heat from the sunlit soil

• Woody plants and perennials have evolved dwarf forms that grow flat along the ground

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Tundra Animals Adaptations

• Migratory birds fly to tundra to breed in summer when food is abundant.

• Caribou migrate throughout tundra in search of food and water. Predators such as wolves prey on migratory caribou, deer, and moose.

• Rodents stay active, but burrow under the snow to avoid the cold.

• Only tundra animal to hibernate is arctic ground squirrel

• Other year-round residents, such as arctic foxes, lose brown summer coat for white fur to camouflage them with the snow

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Threats to the Tundra

• One of the most fragile biomes on planet.

• Food chains are simple and easily disrupted.

• When oil was located in parts of tundra, oil exploration, extraction, and transport disrupted many tundra habitats

• Pollution caused by spills or leaks of oil and other toxic materials may also poison food and water sources in tundra

T 28