Grade 8 Integrated Science Chapter 19 Lesson 1 on land biomes. This lesson covers basic characteristics of the 7 major land biomes: deserts, grasslands, temperate deciduous forest, temperate rainforest, tropical rainforest, taiga, and tundra. The objective is that students should be able to recall defining characteristics of each biome and identify a biome by temperature and precipitation.
2. Vocabulary
Biome – a geographic area on Earth that contains
ecosystems with similar biotic and abiotic features
Desert – biomes that receive very little rain
Grassland – biomes are areas where grasses are the
dominate plants
Temperate – Regions of Earth between the tropics
and the polar circles
Taiga – forest biomes consisting mostly of cone-
bearing evergreen trees
Tundra – biome that is cold, dry, and treeless
3. Land Ecosystems and Biomes
The living or once-living parts of an environment
are the biotic parts
The nonliving parts that the living pasts need to
survive are the abiotic parts
An ecosystem includes an environments:
Biotic factors
Abiotic factors
*Cultural factors
4. Land Ecosystems
Earth’s continents have many different
ecosystems, from deserts to rainforests.
Scientists have classified similar ecosystems in
large geographic areas called biomes
Biomes are geographic areas on Earth that
contain ecosystems with similar biotic and abiotic
factors.
Earth has 7 major land biomes with similar climates
and organisms
6. Deserts are biomes that receive
very little rain. They are on nearly
every continent and are Earth’s
driest ecosystems.
• Deserts are hot during the day and
cold at night
• However in Antarctica the deserts
remain cold all year.
• Rain drains away quickly because
of thin, porous soil. Large patches
of ground are bare.
The Seven Major Land
Biomes
Deserts
8. The Seven MajorLand
Biomes
Biodiversity
Animals include lizards, vats,
woodpeckers, and snakes. Most animals
avoid activity during the hottest parts of
the day
Deserts
9. The Seven Major Land
Biomes
Biodiversity
Plants include spiny cactus and
thorny shrubs. Shallow roots
absorb water quickly.
Deserts
10. The Seven Major Land
Biomes
Biodiversity
Some plants have accordion-like stems that expand and
store water
Small leaves or spines reduce the loss of water
Deserts
11. The Seven MajorLand
Biomes
Human Impact
Overuse of water resources
Because plant grow slowly,
impact to desert plants can take
a long time to recover
Deserts
12. The Seven MajorLand
Biomes
Human Impact
Overuse of water resources
Because plant grow slowly,
impact to desert plants can take
a long time to recover
Deserts
13.
14. The Seven MajorLand
Biomes
• Grassland biomes are areas where
grasses are the dominant plants.
• Also called prairies, savannas, and
meadows.
• Grassland are the world’s
“breadbaskets.”
• Wheat, corn, oats, rye, barley, plus other
cereal crops are grown here
• Grasslands have wet and dry seasons
• Deep, fertile soil supports plant growth
• Grass roots form a thick mass, called
sod, which helps soil absorb and hold
water during periods of drought
Grasslands
15. The Seven Major Land
Biomes
• Biodiversity
• Trees grow along streams and
rivers
• Large herbivores graze here
• African savannas and Australian
grasslands are home to many
different animals.
Grasslands
18. The Seven Major Land
Biomes
• The forests that grow near the equator
are called tropical rain forests. These
forests receive large amounts of rain
and have dense growths of tall, leafy
trees.
• Weather is warm and wet year-round
• Soil is shallow and easily washed away
• <1% of sunlight reaches the forest floor
• Half of Earth’s species live in tropical rain
forests. Mostly in the upper canopy.
Tropical Rainforest
19. The Seven Major Land
Biomes
• Biodiversity
• Few plants live on the dark forest floor
• Vines climb tall trees
• Mosses, ferns, and orchids live on
branches.
• Insects make up the largest group of
tropical animals
• Many larger animals such as snakes,
monkeys, and jaguars
Tropical Rainforest
20. The Seven Major Land
Biomes
• Human Impact
• People have cleared more than 50%
of Earth’s tropical rain forests for
lumber, farms, and ranches
• Poor soil does not support rapid
growth of new trees in cleared areas
• Some organizations are working to
encourage people to use less wood
harvested from rain forests
Tropical Rainforest
21.
22. The Seven Major Land
Biomes
• Regions of Earth between the
tropics and the polar circles are
temperate regions.
• Distinct seasons
• Mild climates
• Temperate rain forests are moist
ecosystems mostly in coastal areas
• Winters are mild and rainy
• Summers are cool and foggy
• Soil is rich and moist
Temperate Rainforest
23. The Seven MajorLand
Biomes
• Biodiversity
• Mainly very tall trees such as spruce,
hemlock, cedar, fir, and redwoods
• Fungi, ferns, mosses, vines, and small
flowering plants grow on the floor
• Many animals including butterflies,
mosquitoes, frogs, owls, eagles, deer,
elk, and bears
Temperate Rainforest
24. The Seven MajorLand
Biomes
• Human Impact
• Over logging
• Rich soil allows cut forests to
grow back quickly
• Tree farms help provide lumber
without destroying habitats
Temperate Rainforest
25.
26. The Seven Major Land
Biomes
• Temperate deciduous forests
grow in temperate regions where
winter and summer climates have
more variation than those in
temperate rain forests
• These are the most common in the
US
• Most of the trees are deciduous,
meaning they lose their leaves
during fall
• Winter temperatures are below
freezing and snowy
• Summers are hot and humid
• Soil is rich in nutrients and supports a
large amount of diverse plant growth
Temperate Deciduous
Forest
27. The Seven MajorLand
Biomes
• Biodiversity
• Most plants stop growing during
winter and begin again in spring
• Animals include snakes, ants,
raccoons, foxes
• Some animals hibernate, like
chipmunks and bats
• Many animals migrate, like
butterflies and birds
Temperate Deciduous
Forest
28. The Seven Major Land
Biomes
• Human impact
• Over the past several hundred
years, humans have cleared
thousands of acres of Earth’s
deciduous forests for farms and
cities
• Today, much of the clearing has
stopped and some forests have
regrown
Temperate Deciduous
Forest
29. The Seven Major Land
Biomes
• A taiga is a forest biome consisting mostly of cone-bearing
evergreen trees
• They exist only in the Northern Hemisphere
• It occupies more space on Earth’s continents than any other
biome.
• Winters are long, cold, and snowy
• Summers are short, warm, and moist
• Soil is thin and acidic
Taiga
30. The Seven Major Land
Biomes
• Biodiversity
• Evergreen trees, such as spruce,
pine, and fir, are thin and shed
snow easily
• Animals include cold-adapted
species like mice, owls, moose,
and bears
• Abundant insects attract migrating
birds in the summer
Taiga
31. The Seven Major Land
Biomes
• Human Impact
• Over logging also known as
tree harvesting
Taiga
32. The Seven Major Land
Biomes
• A tundra biome is cold, dry, and
treeless
• Most tundra is south of the North
Pole, but also exists in
mountainous areas at high altitudes
• Winters are long and freezing
• Summer are short and cool
• Growing seasons is on 50-60 days
• Permafrost – a layer of permanently
frozen soil – prevents deep root
growth
Tundra
33. The Seven Major Land
Biomes
• Biodiversity
• Plants include shallow-rooted
mosses, lichen, and grasses
• Many animals hibernate or migrate
south for the winter
• A few animals, like lemmings, live
there year round
Tundra
34. The Seven Major Land
Biomes
• Human Impact
• Drilling for oil and gas can interrupt migration patterns
Tundra