CHAPTER 6BIOMES

6-1 What is a biome?

1. What is a biome?

• A large region characterized by a specific type of climate and certain types of plants and animal communities.

2. What is a terrestrial biome?

• A terrestrial biome is a land biome.

• The major terrestrial biomes are:– Tropical rain forest - Chaparral– Temperate forest - Desert– Taiga - Tundra– Tropical savanna - Mountains– Temperate grassland

Terrestrial Biomes

3. What is the name of the biome often based on?

• The plant life in the area (this determines what other organisms can live there)

• The climate determines the type of plants that live there

• The plants in a particular biome have characteristics (adaptations) that allow them to survive in that biome.

4. What is climate?

• Refers to the average weather conditions in an area (temperature, precipitation, humidity, winds) over a long period of time

5. What are the 2 most important factors in a regions climate?

• Temperature• precipitation

6. How do temperature and precipitation determine what

lives in the biome?

• Biomes that do not receive enough rainfall to support large trees, support communities dominated by small trees, shrubs, and grasses.

• In biomes with very little rainfall, the vegetation is mostly cactuses and desert shrubs.

• The higher the temperature and precipitation are, the taller and denser the vegetation is.

7. How do latitude and altitude affect climate?

• Latitude – the distance north or south from the equator, expressed in degrees

• Altitude – the height of an object above sea level

• Climate varies with altitude and latitude

• The climate generally gets colder as latitude and altitude increase and it gets warmer as altitude and latitude decrease.

• As latitude and altitude increase, biomes and vegetation change.

• Trees of tropical rainforests usually grow closer to the equator, while mosses and lichens of the tundra grow closer to the poles.

• The temperate region includes biomes such as temperate forests and grasslands, which have moderate temps and fertile soil that is good for agriculture.

8. What are the different regions of latitude?

• 0° to 30° - Tropical

• 30° to 60° - Temperate

• 60° to 90° - Arctic

Latitude and Altitude

6-2 Forest Biomes

1. What are the forest biomes?

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

• The large trees of forests need a lot of water, so forests can be found where temperatures are mild to hot and where rainfall is plenty.

• There are three main forest biomes of the world: tropical, temperate, and coniferous

2. What are some characteristics of the tropical rain forest?

• Occurs in a belt around the Earth near the equator

• Sometimes called jungles• Help regulate world climate and play vital

roles in the nitrogen, oxygen, and carbon cycles

• Humid and warm• Rains a lot (80-180in/year)

(200-450cm/year)

More characteristics of the Tropical Rain Forest

• Gets strong sunlight year round

• Little seasonal variation

• More different species of plants grow here than in any other biome

• Thin/poor soil

Tropical Rain Forest

Major Rainforests of the World

3. How are plants adapted to living in a tropical rain forest?

• Most nutrients are within the plants instead of in the soil.

• Nutrients from dead organic matter are removed so efficiently that runoff from rain forests is often pure as distilled water.

• Most tropical soils that are cleared of plants for agriculture lack nutrients and cannot support crops for more than a few years.

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

4. What are the layers of vegetation in the tropical

rainforest?• Plants grow in layers:

– Emergent layer– Upper Canopy– Lower layer– Understory

Layers of the Rainforest

5. What are some characteristics of the emergent

layer?• The emergent layer is the top foliage layer

in a forest where the trees extend above surrounding trees.

• Trees in this layer grow and emerge into direct sunlight reaching heights of 60 to 70m (180-210ft) and can measure up to 5m (15ft) around.

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

6. What are some characteristics of the canopy?

• Canopy is formed by trees as tall as 30 m (100ft.) and 95% of the sunlight is absorbed by these trees

• The canopy is considered to be the primary layer of the rain forest.

• The canopy can be split into an upper and lower canopy with the lower canopy receiving less of the sunlight.

Canopy of Rainforest

• Epiphytes are plants that use another plant for support but not for nourishment and are located on high trees in the canopy.

• Growing on tall trees allows them to reach the sunlight needed for photosynthesis and to absorb the water and nutrients that run down the tree after it rains.

• Most animals that live in the rain forest live in the canopy because they depend on the abundant flowers and fruits that grow here.

Epiphytes

7. What are some characteristics of the understory?

• The understory is the foliage layer that is beneath and shaded by the main canopy of a forest.

• There is little light and there are smaller trees/shrubs adapted to shade living here

• Most plants here do not grow more than 3.5m tall.• Forest floor is mostly bare because of the lack of

sunlight• Herbs have large, flat leaves to capture any sunlight

that does reach the floor

Rainforest floor

8. How are animals adapted to living in the tropical rain forest?

• Greatest diversity of animals anywhere• Almost all rain forest animals are specialists

(organisms adapted to exploit a specific resource in a particular way) to avoid competition

• They have adapted amazing ways to capture prey and avoid predators (EX: Collared anteater, wreathed hornbill) p.159

• Insects use camouflage to avoid predators and may be shaped like leaves or twigs.

9. What are some threats to the rain forest?

• Used to cover 20% of Earth’s surface, today cover about 7%

• Destruction by logging, clearing for agriculture, timber, or oil exploration

• Exotic pet trading• This leads to extinction

of plants/animals and displacement of the native people

10. How can you help prevent the destruction of the rain forest?

• Do not buy rain forest woods such as teak and mahogany

• Do buy products that support sustainable use of rain forests such as nuts, fruits, rubber, coffee

• Support organizations that help preserve tropical forests

Collecting sap from a rubber tree

11. What are some characteristics of the temperate rain forest?

• Occur in N and S America, Australia, New Zealand

• Cool, humid forest• Never freezes because ocean waters moderate

the temperature• High rainfall, moderate temperature• Olympic National Forest in Washington State• Dominated by evergreen trees such as Douglas

Fir and Sitka Spruce

12. What are some characteristics of the temperate deciduous forest?• Trees shed leaves each fall

• Generally occur between 30° and 50° North latitude

• Can have extreme seasonal variations

• 4-6 month growing season

• Moist (30-50in rain per year) (75-125cm)

• Very rich soil

TEMPERATE DECIDUOUS FORESTS

Temperate Deciduous Forest

13. How are plants adapted to living in the temperate deciduous

forest?• Plants grow in layers• Canopy is dominated by tall trees (maple, oak, birch)• Small trees, shrubs and bushes in understory• More light reaches the floor here than in the rain

forest so this has more plants (ferns, mosses, herbs)• Adapted to survive seasonal changes (EX: trees

shed leaves in winter when H2O is locked up in ice; herb seeds, bulbs, rhizomes become dormant in winter)

14. How are animals adapted to living in the temperate deciduous

forest?• There are numerous habitats for animals

(generally organized by layers of vegetation)

• Many migratory birds

• Animals hibernate (become inactive)

• Insects enter a state of very low metabolic activity

15. What are some characteristics of the taiga (Northern Coniferous

Forest)?• The region of evergreen, coniferous forest below the

arctic and subarctic tundra regions• Also called the “boreal forest”• Located in a broad band across the N hemisphere just

below the arctic circle• Rough terrain• Long winters (6-10 mo) and little vegetation• Extremely cold• Short growing season (50 days in some areas)• Plant growth enhanced by constant daylight during the

summer• Most of the precipitation is snow

TAIGA

Taiga

16. How are plants adapted to living in the taiga?

• Conifers – a tree whose seeds grow in cones• Most trees here do not shed leaves• Leaves are narrow and have a waxy coating to retain

water• Conifers cone shape helps it shed snow whose weight

would otherwise crush it• Dominant tree species are pine, hemlock, fir, spruce• Conifer needles are acidic so when they die and fall to

the ground they make the soil acidic• Because of the acidic soil, the forest floor is mostly bare• Soil forms slowly here because the climate and acidity

slow decomposition.

http://www.mbgnet.net/sets/taiga/pict/tz1.htm

17. How are animals adapted to living in the taiga?

• Lakes and swamps are common so birds that feed on wetland organisms (insects and fish) are also common

• Migratory birds

• Underground burrowers (shrew, vole)

• Have moose and snowshoe hares

• Hares change coat color from brown to white in winter

4-3 GRASSLAND, DESERTS, AND TUNDRA

1. How does rainfall affect the characteristics of a biome?

• In climates that have less rainfall, forest biomes are replaced by savanna, grassland, and chaparral biomes

• As even less rain falls in these biomes, they change into desert and tundra biomes.

• As precipitation decreases in an area, the diversity of the species in the area also decreases. But, the number of individuals of each species present may still be very large.

2. What are some characteristics of tropical savannas?

• An EX. would be the West African Plains• Occur in parts of Africa, western India, northern

Australia, and parts of South America• Located in tropics near equator• Occur inland so get too little rain for many trees to

grow• Periods of heavy rainfall followed by periods of

drought• May have grass fires to help restore nutrients to

soil during dry season

TROPICAL SAVANNAS

Tropical Savanna

3. How are plants adapted to living in the tropical savanna?

• Dominated by grasses, shrubs, and small trees

• Trees/grasses have large underground root systems that survive fire and droughts

• Vertical leaves that conserve water

• Trees/shrubs often have thorns/razor sharp leaves that deter herbivores

4. How are animals adapted to living in the tropical savanna?

• Have large grazing herbivores that migrate (follow rain to areas of newly sprouted grass)

• EX of herbivores: antelopes, giraffe, elephants, gazelle, rhinos

• EX of predators that live here: cheetahs, lions, hyenas

• Many give birth only during rainy season• Herbivores avoid competition for food by

eating vegetation at different heights

http://www.sandiegozoo.org/

5. What are some characteristics of the temperate grasslands?

• Called prairies in US, steppes in Russia, veldt in South Africa, and pampas in S America

• Low rainfall so few to no trees are found here• Periodic droughts• High temperatures in summer• Most fertile soil of any biome• Found inland where there is too little rain for

trees to grow• Mountains are important in maintaining

grasslands• Fires common

TEMPERATE GRASSLANDS

Temperate Grassland

6. How are plants adapted to living in the temperate grasslands?

• Grasses are perennials (survive from year to year)

• Root systems survive drought and fire, hold soil in place

• Root depth and grass height vary with rainfall

• Few trees survive because of drought, fire and winds

How root depth and height vary with rainfall:

7. How are animals adapted to living in the temperate grasslands?• Adequate food (grasses) for grazers such

as buffalo and pronghorn antelope• Grazers have large, flat back teeth for

chewing the coarse prairie grass• Buffalo have thick coats to survive winters;

shed coats in spring• Badgers, prairie dogs, and owls burrow

underground. This protects them from predators

http://www.answers.com/topic/prairie-grass-jpg

8. What are some threats to the grasslands?

• Cultivation – grain crops that have replaced native grasses contribute to more soil erosion

• Overgrazing – leads to erosion

• Constant use can change the fruitful grasslands into desert-like biomes

9. What is the chaparral?• A type of temperate woodland biome with vegetation

that includes broad leafed evergreen shrubs.• Hot, dry summers and mild, wet winters (slight

variations in seasonal temps)• Located in mid-latitudes, 30°N and S of the equator• Located mostly in coastal areas that have

Mediterranean climates (moderately dry, coastal with little or no rain in summer)

• Similar to desert but chaparral has more vegetation

10. How are plants adapted to the chaparral?

• Mostly low-lying evergreen shrubs and small trees that grow in dense patches (include chamise, manzanita, scrub oak, and herbs like sage and bay)

• Plants have small, leathery leaves that resist water loss

• Leaves contain oils that promote burning. This allows natural fires to destroy competing trees

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

11. How are animals adapted to the chaparral?

• Camouflaged (quail, lizards, chipmunks, and mule deer)

• Adapted to seasonal differences in food

12. What are some threats to the chaparral?

• Development by humans

13. Where is the chaparral in the US?

• California

14. What are some characteristics of the desert?

• Less than 10 in. rain per year (25cm)• Soil is rich in minerals but poor in organic matter

DESERTS

Desert

15. How are plants adapted to living in the desert?

• Conserve water• Fleshy stems and leaves store water (succulents)• Waxy coating to prevent water loss• Cactus spines deter herbivores that would feed on

plants• Store water in underground bulbs• Roots are shallow to get any water available and often

contain toxins that prevent other plants from growing nearby

• Drought resistant plants (can survive in light or sporadic rainfall)

• Some escape drought by dying and dropping seeds that stay dormant until the next rainfall

Deserts of the US

16. How are animals adapted to living in the desert?

• Reptiles (Gila monster and rattlesnakes) have dry/scaly skin to prevent water loss

• Amphibians estivate (spadefoot toad) (bury themselves in ground and sleep through dry season)

• Most desert animals are at least partly nocturnal (active at night)

• Desert insects and spiders are covered with thick body armor that helps retain water

17. What are some threats to the desert?

• Residential development

• Off road and all terrain vehicles kill desert vegetation

18. What are some characteristics of the tundra?

• No trees• Grasses and tough shrubs that grow in the frozen soil• Located north of the Arctic Circle• Very short, cool summers (only top few inches of soil

thaws)• Permafrost – permanently frozen soil• Because permafrost is impermeable, the tundra become

dotted with bogs and swamps when top layer of soil thaws

• Swamps/bogs attract mosquitoes/blackflies in the summer

TUNDRA

Tundra

19. How are plants adapted to living in the tundra?

• Mosses and lichens grow here (do not need soil)

• Where soil exists, plants have wide, shallow roots that anchor them against arctic winds

• Flowering plants are tiny• Plants grow flat and trail along the ground to

avoid wind and to absorb heat from sunlit soil• Woody plants and perennials have evolved

dwarf forms that grow flat along the ground

20. How are animals adapted to living in the tundra?

• Migratory birds and caribou• Predators such as wolves prey on the

migratory caribou, moose, and smaller animals

• Rodents burrow underground but are still active

• Arctic fox – changes color for camouflage• Winter animals are very insulated (EX:

musk ox)

21. What are some threats to the tundra?

• One of the most fragile biomes on earth

• Food chains are simple and easily disrupted

• Land is easily damaged and slow to recover

• Oil exploration (EX: Prudhoe Bay in northern Alaska)

• Pollution caused by spills or leaks of oil and other toxic materials may poison food and water here