THE WORLD’S MAJOR BIOMES
Objectives: I CAN … Analyze the environments and the interdependence among organisms found in the
world’s major biomes.
I CAN … Identify the biotic and abiotic elements of the major biomes.
Think about it…
1) What’s the difference between a biome and an ecosystem?
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2) How would you define an animal adaptation?
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Biomes & Adaptations
An ecosystem is the interaction of living (biotic) and non-living (abiotic) things in an environment. An
ecosystem can be large or small. (Remember the Five Levels of Environmental Organization?)
A biome is a large geographic area defined by characteristic climate features, plant and animal life.
Biomes are generally found in bands of latitude around the planet. The have similar biotic and abiotic
factors.
The organisms living in a particular biome have adapted to the terrain and weather of that region. An
adaptation is a way an organism’s physical features or behavior.
World’s Major Biomes: Tropical Rainforest, Savannas, Temperate Grasslands, Temperate Deciduous
Forest, Desert, Alpine & Polar Tundras, Coniferous Forest
TROPICAL RAINFOREST
Located near equator
Covers less than 2% of Earth’s total surface area, but home to 50% of Earth’s plants and animals.
Greatest biodiversity: Home to 15 million species of plants and animals
Endangered Biome – threatened by mining and logging practices
Abiotic Factors
Warm temps and high rainfall allow a lot of plant growth
Less than 1 cm of topsoil
Average temperatures: Day 34* C/93 F
Night 20* C/68 F
Average yearly rainfall up to 400 cm (157.5 in)
Sunlight is a limiting factor
Little light reaches ground
Plant Adaptations
Plants grow in 4 layers: forest floor, understory, canopy, and emergent layer
Trees form a continuous green roof or canopy
Canopy prevents sunlight reaching floor
Soil so thin plants have shallow, wide roots.
Some plants have roots above ground for support
Most of nutrients are found in the plants not the soil
Animal Adaptations
1) Behavior
2) Structural (physical)
3) Camouflage
Many symbiotic relationships
Animals adapt to living on their forest level
Tree sloth’s fur covered in algae
Toucan’s long beak can snag hard to reach fruit
TEMPERATE DECIDUOUS FORESTS
Location: Found in temperate zone (about 48* north latitude)
Much of the human population lives in this biome
Abiotic Factors
Characterized by an abundance of deciduous (leaf bearing) trees
4 seasons - Leaves change color and fall off
Soils: Deep soil layers, rich in nutrients
Average yearly rainfall:
75 cm to 125 cm (29.5 in. to 49 in.)
Average Temps:
Summer 28* C (82 F)
Winter 6* C (43 F)
Plant Adaptations
More diversity in the deciduous forest vs. the coniferous forest due to increased sunlight.
Trees adapt to varied climate by becoming dormant in winter
Deciduous forests grow in layers
More sunlight reaches the ground compared to a rainforest so you will find more ground dwelling
plants.
Animal Adaptations
Lose Winter Coat
Adapt to many seasons
Eat from different layers of the forest
Physical features
CONIFEROUS FOREST a.k.a. Taiga
Location: Found only in Northern Hemisphere
Abiotic factors
Average Yearly Rainfall
35 cm to 75 cm (14 in to 29.5 in)
Soil poor in nutrients and very acidic
Trees prevent sunlight from reaching ground
Average temperatures:
Summer 14* C / 57* F
Winter -10* C / 14* F
Plant adaptations
Coniferous (needle-bearing) trees are abundant – produces seeds in cones
Roots long to anchor trees
Needles long, thin with waxy coating
Low sunlight and poor soil keeps plants from growing on forest floor
Animal Adaptations
Adapt for cold winters
Burrow, hibernate, warm coat, insulation, etc.
Some birds migrate south
Snowshoe Hares change fur color each season
Bears hibernate underground
Moose fur traps air to act as an insulator
GRASSLANDS
Made up of mainly grasses, small flowering plants, and few trees
Two kinds: Temperate Grasslands and Savannas
SAVANNAS
Contains the greatest number of grazing animals on Earth
Location: Found in the tropics…near equator
Amount of precipitation supports tall grasses but only occasional trees
Abiotic Factors
Two seasons: Wet and dry season (Fires occur often in dry season)
Average yearly rainfall: 150 cm (59 in.)
Average Temperatures: Dry season 34* C (93* F)
Wet season 16* C (61* F)
Plant Adaptations
Grows in Tufts
Resistance to Drought
Many plants have thorns and sharp leaves to protect against predators.
Animal Adaptations
Adapt for short rainy season—migrate as necessary
Limited food leads to vertical feeding (trees)
Live in herds (Zebras striped pattern makes hard for lion to pick single zebra from group)
Camouflage
TEMPERATE GRASSLANDS
Abiotic Factors
Average yearly rainfall: 25 cm to 75 cm (10 in to 29.5 in)
Characteristic high Winds
Average temperatures: Summer 30* C (86* F)
Winter 0* C (32* F)
Plant Adaptations
Sod-forming grasses that won’t dry out or blow away in wind.
Animal Adaptations
Many adaptations to survive extremes
Bison - Broad, flat topped teeth to chew grasses
Prairie dog - front paws can dig easily to hide underground
Prairie Rattlesnake --What is its adaptation? _________________________________________________
DESERT BIOME
Very hot -- Very dry -- Organisms have special adaptations
Abiotic factors
Less than 10 in/year of rain
Little to no topsoil due to high winds
Minerals not deep in soil - Too dry for decay
Average Temperatures: Summer 38* C (100* F) Winter 7* C (45* F)
Plant Adaptations
Spines --- Cactuses store water
Thick, waxy cuticle
Shallow, broad roots near surface to take up water quickly after rain
Animal Adaptations
Get water from food
Thick outer coat
Burrow underground during day
Large ears
Nocturnal – active at night
Some animals have salt glands to secrete salt without a loss of water
TUNDRA- Very cold temperatures and very little rainfall.
TWO TYPES: Polar Tundra (a.k.a. Arctic) or Alpine Tundra
Polar Tundra is found near North and South Poles.
Alpine Tundra is found at the tops of tall mountains.
Abiotic Factors
Average Yearly Rainfall 30 cm to 50 cm (12 in to 20 in)
Average Temps: Summer 12* C (54* F)
Winter -26*C (-15* F)
Permafrost – layer of soil below surface stays frozen
Summer melting - soil becomes very muddy
Plant Adaptations
Growing close to the ground helps resist wind and cold
Shallow roots to absorb the limited water resources
Above elevation called “tree line” (trees cannot grow on a mountain)
Animal Adaptations
Migration & hibernation --- Few predators --- Little Competition
Arctic fox: Small ears reduces heat loss -- Insulation, thick coat
Mountain goat has rough pads on each toe provides grip
Polar Bears can close their nostrils to swim underwater
PUTTING IT TOGETHER
BIOME PROJECT – Total of SIX Biomes
Create poster presentations to illustrate differences
among the world’s major biomes.
Coniferous Forest
Temperate Deciduous Forest
Alpine or Polar Tundra (choose one)
Tropical Rain Forest
Desert
Grasslands: Temperate Grasslands or Savannas (choose one)
FOR EACH BIOME:
Colored Illustration includes:
2 abiotic & 2 biotic factors
Write 2 interesting facts
Describe 2 organisms’ adaptations