Biome

a major regional terrestrial community with its own type of climate, vegetation, and

animal life

Tropical rain forestTemperate deciduous ForestTemperate rain forestBoreal Forest or TaigaGrassland

TropicalTemperate

DesertChaparral

Biomes we will discuss

Q. What determines biomes? A. Mainly climate

Q. What determines climate?A. Many things, including tilt of

earth’s axis, proximity to oceans, presence of mountains, wind currents

Tilt of earth’s axis affects climate in different parts of the world

Q. Which two aspects of climate determine biomes most?

A. Temperature and precipitation

See p. 144 in textbook.

Zones

Arctic

Temperate

Tropic of cancer

Tropical

Tropic of Capricorn

Temperate

Antarctic

Tropical Rain Forest

Tropical Rain Forest

-found near the equator (between Tropic of Cancer and Tropic of Capricorn)

-temperature varies little from approximately 23°C

-the length of daylight varies from 12 hours by less than one hour

-rainfall > 2000mm

Tropical Rain Forest

Tropical Rain Forest

- highest biodiversity of all biomes- canopy trees up to 55 m tall- largest biome, on an area basis

-soils are generally unfertile -nutrients and carbon stored in plant biomass, not soils-rapid decomposition

Layers of rainforest

emergent layer- top, most light

canopy – 90% of species live in this layer

understory – filtered light, epiphytes grow on trees (type of commensalism)

forest floor – little light

Adaptations of plants and animals

Buttresses provide support for trees in thin soil

Large leaves provide advantage in competition for light

Epiphytes grow on tall trees to reach light

Many animals have evolved as specialists to occupy a certain niche (reduces competition)

Temperate Deciduous Forest

Temperate Deciduous Forest

-distinct winter season, frost a defining feature

-summer season usually moist with ppt > evapotranspiration

Temperate Deciduous Forest

Temperate Deciduous Forest

-relatively large tree biomass

-also called the deciduous forest, but contains evergreen trees as well

Adaptations of plants and animalsTrees are deciduousMany animals hibernate or migrate to avoid

winter temps

Temperate Deciduous Forest

Sweet Home Alabama – this is our biome!

Temperate Deciduous Forest

Temperate Rain Forest

Located in temperate zones in North America (Pacific northwest), Australia and New Zealand near oceans

High precipitation (>1400mm) , high humidity and moderate temperatures (mean 4-12°C)

Lush growth of conifers, ferns, epiphytesLow instance of fires due to high moisture

Temperate Rain Forest

Boreal Forest or Taiga

Boreal Forest or Taiga-severe winters,Mean average temp can be < 0 deg C

-ppt is low, but evapo-transpiration low

-short growing season

Boreal Forest or Taiga

-10-20 m treesevergreen needle and deciduous

-second largest biome, on an area basis

-fire dominated, but on longertimescale than grassland-more nutrients and carbon stored in soils than plants-slow decomposition

Adaptations of plants needle shaped leaves with thick cuticle retain

water, can survive coldcone-shaped trees can shed snow without

losing branches

Boreal Forest or Taiga

Adaptations of animalsThick fur to withstand coldMigration, hibernation Camouflage changes with the seasons

Boreal Forest or Taiga

Caribou migration

Names vary with parts of the world:tropical savanna temperate grassland

prairies – N. Americasteppes – Asia

Characterized by vast seas of grass with some small trees and shrubs, extremely fertile soil, grazers, little precipitation, may have wet and dry seasons

Grasslands

Tropical Savanna

-found in the tropics (but > 10° latitude)

-pronounced dry seasonwith <5 cm rainfall in some months

Tropical Savanna

Tropical Savanna

-scattered trees and grass-fire an important natural part of the biome that keepstrees from moving in

- grazing by animals also contributes to predominance of grassesas they crop plants close to the ground

Temperate Grassland

Temperate Grassland-similar to tropical savanna, but with cold winter

-relatively hot summer

-potential evapotranspiration > ppt

Temperate Grassland

-scattered trees and shrubs

-trees are short statured

-fire & grazing by animals also contribute to predominance of grasses

Prairies of North America

Temperate grasslands

Texas, where more than 98% of the prairie is now gone

Steppes of Mongolia

Temperate grasslands

Steppes of Russia

Temperate grasslands

Grasslands (Tropical and Temperate)Adaptations of plantsGrasses have

extensive root system for efficient water absorption and to allow quick regrowth after fire or grazing

Grasslands (Tropical and Temperate)Adaptations of animalsGrazing adaptations

(teeth, digestive system)

Migrate to avoid dry periods

Wildebeest migration

Desert

Desert-hot or cold deserts exist

-characterized by low precipitation <25cm, sporadic

-potential evapotranspiration > ppt

Desert

DesertAdaptations of plants Succulents – term for

plants such as cactuses with thick fleshy stems and leaves that store water

Thick cuticle, roots spread out near surface help conserve water

Thorns prevent animals from eating plants

DesertAdaptations of animalsMany are nocturnal

to avoid heat of dayEstivation – similar

to hibernating, but during dry season

Spadefoot toad burrows in mud

Chaparral

Chapparal-mild winters

-seasonal rainfall:winter rain, summer drought

-located along coasts,effect of ocean is to moderate climate

Chaparral

ChaparralAdaptations of plants

and animals Plants contain oils

that encourage fires, maintains shrubby community

Plants can regrow quickly from small remains after fire

Many animals camouflaged

rosemary

Tundra

-severe winters

-short growing season,cool summer

-arctic or alpine

Tundra

Tundra

TundraPermafrost – layer of

permanently frozen soil under the topsoil, limits plant growth

TundraAdaptations of plants

and animals Small size of plants

allows absorption of limited heat from soil, reduces exposure to wind

Migration and hibernation of animals common

Camouflage changes with the seasons

Caribou eating willow

Increasing altitude has the same effect as increasing latitude (see p. 145)

Alpine – refers to community above the treeline (comes from Alps)

Effect of Altitude

Tropical Rainforest – deforestation, urbanization, pollution, collection of species to sell, slash and burn agriculture

Some estimates have the rate at 13 million hectares annually……..a hectare is roughly 2.5 acres.

Do the math!

Threats to biomes

Temperate Deciduous Forest – deforestation, acid rain, logging, urbanization, mountain top mining

Threats to biomes

Temperate Rainforest – logging, loss of old growth forests

Threats to biomes

Boreal Forest – acid rain

Threats to biomes

Grasslands (tropical and temperate) – encroachment of agriculture, fire suppression

Threats to biomes

Desert – urbanization, recreation damages fragile ecosystems

Threats to biomes

Chaparral – fire suppression, urbanization, recreation

Threats to biomes

Tundra – oil exploration threatens fragile ecosystems, oil spills

Threats to biomes

Choose a biome and a threat to research(You can Google “threats to ______” and fill in the biome of your choice to get ideas)

Summarize your findings in your own words in a report (about 2 typed pages)

Give an overview, but focus on specific information from specific locations

Due date: _________________________

Assignment