ES LECTURE 8:
World Biomes
Prepared by: DIVINE GRACE S. BATENGA, MSc.
WESLEYAN UNIVERSITY-PHILIPPINES
College of Arts and Sciences
Department of Science and Mathematics
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BIOMES AND CLIMATE
Desert in Africa
Rainforest in Australia
What is the most obvious difference between the two
places? What causes these two places to be so different?
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What is Climate?
• Climate is the average weather in an area over a long period of time, whereas
weather is a day to day explanation.
• Weather and climate are described in terms of factors such as temperature
and precipitation.
• The climate of a particular location depends, in turn, on its latitude
(distance from the equator) and altitude (distance above sea level).
• Other factors that affect an area’s climate include its location relative to
the ocean or mountain ranges.
• Temperature and moisture are the two climatic factors that most affect
terrestrial biomes.
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What effect do mountains have on surrounding
land?
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BIOMES
➢A biome is an area of the planet that can be classified according
to the plants and animals that live in it.
▪ Temperature, soil, and the amount of light and water help
determine what life exists in a biome.
➢ A biome is different from an ecosystem.
▪ An ecosystem is the interaction of living and nonliving things in
an environment.
▪ A biome is a specific geographic area notable for the species living
there.
▪ A biome can be made up of many ecosystems.
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Fundamental Classification of Biomes
❑ TERRESTRIAL (land) BIOMES
▪ Desert
▪ Forest
▪ Grassland
▪ Tundra
❑ AQUATIC BIOMES
▪ Freshwater biomes
▪ Saltwater biomes (marine)
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BIOMES OF THE WORLD
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TERRESTRIAL BIOMES
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TERRESTRIAL
BIOMES
• Latitudinal patterns of climate over the
Earth’s surface--- latitudinal patterns of
biome distribution
• Most terrestrial biomes are named for major
physical or climatic features (predominant
vegetation)
• The species composition of any biome differs
from location to location.
• Human activity has radically altered the
natural patterns of periodic physical
disturbance.
• Humans have altered much of the Earth’s
surface, replacing original biomes with urban
or agricultural ones.
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Tropical Forests
• Found close to the equator.
• Tropical rain forests receive constant
high amounts of rainfall (200-400 cm
annually).
• In tropical dry forests, precipitation is
highly seasonal.
Tropical rain forest
• In both, air temperatures range between
25°C and 29°C year round.
• Tropical forests are stratified, and
competition for light is intense.
• Animal diversity is higher in tropical
forests than in any other terrestrial
biome.
Tropical dry forest
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Tropical Forests
Tropical Rain Forests
• The forest biome which is
characterized by high temperature
and moist habitat.
• Seasonality: wet and dry season
(winter is absent)
• The length of daylight is 12 hours
• Precipitation is evenly distributed
throughout the year with annual
rainfall exceeding to 2000 mm
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Tropical Forests
Tropical Rain Forests
• Highest animal diversity
• Highest plant diversity
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Tropical Forests
Tropical Rain Forests
• Soil is nutrient-poor and
acidic
• Decomposition of products
are immediately taken up by
plant extensive root system
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Tropical Forests
Tropical Rain Forests
• Sunlight is a limiting factor
• Canopy in tropical forests is
multilayered and continuous,
allowing little light
penetration
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Tropical Forests
Tropical Dry Forests
• Short dry period in a very wet
tropical region
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DESERTS
• An ecosystem that forms due to low level of rainfall it receives
each year.
• Deserts have low and highly variable rainfall, generally less
than 30 cm per year.
• Temperature varies greatly seasonally and daily.
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DESERTS
FACTS ABOUT DESERT BIOME
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DESERTS
HOW ARE DESERTS
CLASSIFIED?
• Deserts are classified on how
much rain-fall the area receives
per year
• If it receives under 254 mm per
year it is classified as a desert
• 2 types of desert: hot and cold
Cold Desert
Hot Desert
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DESERTS
COLD DESERT
• Average annual rainfall: <250 mm
• Temperature
summer: 21°C to 26°C
winter: -2°C to 4°C
• Very salty
• Precipitation is mainly snow
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DESERTS
HOT DESERT
• During the day: temperature usually
averages at 38°C and 7°C at night
• Average annual rainfall: <250 mm
• Soils: salty (as the minerals never
wash away)
• They are extremely hot during the
day
• They are extremely cold at night
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DESERTS
Desert Plants
• Desert vegetation is usually sparse
and includes succulents such as
cacti and deeply rooted shrubs.
• The vegetation does not grow tall
• Have thick stem
• Their roots extend up to 2 meters to
collect water
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DESERTS
Desert Animals
• Many desert animals are
nocturnal, so they can avoid
the heat.
• Desert organisms display
adaptations to allow them to
resist or survive desiccation.
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DESERTS
Desert Animals
(adaptation)
• Have thick skin to preserve
water
• Some animals can bury
themselves to protect them
from strong heat
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DESERTS
Desert Animals
(adaptation)
• Animals are nocturnal and hide
under the bushes during the
day
• DESERT HEDGEHOG
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DESERTS
Desert Animals
(adaptation)
• CAMELS are one of the animals
who can easily withstand
deserts (well-adapted for many
years)
• They need very little water and
food and store fat in their hump
to avoid starvation
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GRASSLAND
• A region where the average
annual precipitation is great
enough to support grasses.
• Trees in few areas
• 2 Divisions:
➢ Tropical grasslands or
Savannas
➢ Temperate grasslands
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GRASSLAND
Savanna
• Is found in equatorial and
subequatorial regions.
• Rainfall is seasonal, averaging 30–50
cm per year.
• The savanna is warm year-round,
averaging 24–29°C with some
seasonal variation.
• Savanna vegetation is grassland
with scattered trees.
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GRASSLAND
Savanna
• Covers almost half the surface of Africa
• CLIMATE- the most important factor in
creating savanna
• Savannas are always found in warm or hot
climates where the annual rainfall is from
about 50.8 to 127 cm (20-50 inches) per
year.
• Always found in warm or hot climates
• Fire is important in maintaining
savanna biomes.
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GRASSLAND
Savanna
• CLIMATIC SAVANNA – savannas
which result from climatic conditions
• EDAPHIC SAVANNAS –
savannas that are caused by soil
conditions and that are not entirely
maintained by fire
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GRASSLAND
Temperate Grassland
• Temperate grasslands are areas of
open grassy plains that are sparsely
populated with trees.
• Various names of temperate
grasslands include pampas, downs,
and veldts.
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GRASSLAND
Temperate Grassland
• Temperatures vary with seasons
with tornadoes, blizzards, and
fires occurring in many temperate
grassland regions.
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GRASSLAND
WHY FIRE IS IMPORTANT IN
GRASSLAND BIOME?
• Fire is a natural part of the grassland
ecosystem and helps maintain its health
and vigor.
• It warms up the soil and reduces the leaf
litter that accumulates each year,
allowing sunlight to penetrate.
• Warming the soil increases microbial
activity, which releases nutrients from
decaying plant material that new grasses
and flowers need to grow.
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GRASSLAND
Temperate Grassland
• Temperate grasslands are home to
many large and small herbivores.
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CONIFEROUS
FOREST OR
TAIGA/BOREAL
• The largest terrestrial biome on
Earth.
• Coniferous forests have long cold
winters, and short wet
summers.
• The conifers that inhabit these
forests are adapted for snow and
periodic drought.
• They are found majorly in Northern
hemisphere
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CONIFEROUS
FOREST OR
TAIGA/BOREAL
• Coniferous forests are
home to many birds and
mammals.
• These forests are
being logged at a very
high rate and oldgrowth stands of
conifers may soon
disappear.
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TEMPERATE
BROADLEAF
FOREST
• Have very cold winters, hot summers,
and considerable precipitation.
• A mature temperate broadleaf forest has
distinct vertical layers, including a closed
canopy, one or two strata of understory
trees, a shrub layer, and an herbaceous
layer.
• The dominant deciduous trees in
Northern Hemisphere broadleaf
forests drop their leaves and become
dormant in winter.
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TEMPERATE
BROADLEAF
FOREST
• In the Northern Hemisphere, many
mammals in this biome
hibernate in the winter, while
many bird species migrate to
warmer climates.
• Humans have logged many
temperate broadleaf forests
around the world.
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TERRESTRIAL
BIOMES
Tundra
• Covers large areas of the Arctic, up to
20% of the Earth’s land surface.
• Tundra vegetation is mostly
herbaceous, consisting of a mixture
of lichens, mosses, grasses, forbs,
and dwarf shrubs and trees.
• Coldest biome.
• Permafrost – a permanently frozen
layer that prevents water infiltration
and restricts root growth.
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TERRESTRIAL
BIOMES
Alpine Tundra
• Found on high mountaintops at
all latitudes, including the
tropics.
• The plant communities in
Alpine and Arctic tundra
are very similar
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TERRESTRIAL
BIOMES
Arctic Tundra
• The Arctic tundra winter is long and
cold, while the summer is short and
mild.
• The growing season is very short.
• Large grazing musk oxen are resident
in Arctic tundra, while carbon and
reindeer are migratory.
• Migratory birds use Arctic tundra as
extensively during the summer as
nesting grounds.
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TERRESTRIAL
BIOMES
Arctic Tundra
• Arctic tundra is sparsely
settled by humans but has
recently become the focus
of significant mineral and
oil extraction.
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Tundra Plants
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AQUATIC BIOMES
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AQUATIC BIOMES
• Aquatic biomes occupy the largest part of the biosphere.
• Ecologists distinguish between freshwater and marine biomes
on the basis of physical and chemical differences.
• Marine biomes generally have salt concentrations that average
3%, while freshwater biomes have salt concentrations of less
than 1%.
• Marine biomes cover approximately 75% of the earth’s surface
and have an enormous effect on the biosphere.
• Freshwater biomes are closely linked to the soils and biotic
components of the terrestrial biomes through which they pass.
• Most aquatic biomes are physically and chemically stratified.
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AQUATIC BIOMES
Aquatic Zones
• Light is absorbed by the water and by
photosynthetic organisms, so light
intensity decreases rapidly with depth.
• There is sufficient light for
photosynthesis in the upper
photic zone.
• Very little light penetrates to
the lower aphotic zone.
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AQUATIC BIOMES
Aquatic Zones
• The substrate at the bottom of an
aquatic biome is the benthic zone.
• This zone is made up of sand and
sediments and is occupied by
communities of organisms called
benthos.
• A major food source for benthos is
dead organic material or
detritus, which rains down from
the productive surface waters of
the photic zone.
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AQUATIC BIOMES
Aquatic Organisms
• In aquatic biomes, community
distribution is determined by
depth of the water, distance from
shore, and open water versus
bottom.
• In marine communities,
phytoplankton, zooplankton, and
many fish species live in the
relatively shallow photic zone.
• The aphotic zone contains little life,
except for microorganisms and relatively
sparse populations of luminescent fishes
and invertebrates.
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Anglerfish
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AQUATIC BIOMES
Water temperature
• Sunlight warms surface waters, while
deeper waters remain cold.
• As a result, water temperature in
lakes is stratified, especially in
summer and winter.
• In the ocean and most lakes, a
narrow stratum of rapid
temperature change called a
thermocline separates the more
uniformly warm upper layer from
more uniformly cold deeper water.
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Types of Aquatic Biomes
There are broadly two categories of aquatic biomes:
❑Freshwater biome
❑Saltwater/Marine biome
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FRESHWATER
BIOME
• Freshwater is defined as having
a low salt concentrationusually less than 1%
• Plants and animals in
freshwater regions are adjusted
to the low salt content and
would not be able to survive in
areas of high salt concentration
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FRESHWATER
BIOME
❑ Ponds and lakes
❑ Streams and rivers
❑ Wetlands
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FRESHWATER
BIOMES
Ponds
• Many ponds are
seasonal, lasting just a
couple of months
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FRESHWATER
BIOMES
Lakes
• May exist for hundreds of
years or more
• Vary greatly in oxygen and
nutrient content.
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FRESHWATER
BIOMES
Lakes
• Zones of lakes
• Littoral zone – the
shallow, well-lit water close
to shore
• Limnetic zone – the open
surface water.
• Profundal zone – deepest
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FRESHWATER
BIOMES
Lakes
➢ OLIGOTROPHIC LAKE – are deep,
nutrient poor, oxygen rich, and contain
little life.
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FRESHWATER
BIOMES
Lakes
➢ EUTROPHIC LAKE – are shallow,
nutrient rich, and oxygen poor.
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FRESHWATER
BIOMES
Wetlands
Are areas covered with sufficient water to support aquatic plants.
They can be saturated or periodically flooded.
Wetlands include marshes, bogs, and swamps.
They are among the most productive biomes on Earth and are home
to a diverse community of invertebrates and birds.
• Wetlands have a high capacity to filter dissolved nutrients and
chemical pollutants.
• Humans have destroyed many wetlands, but some are now
protected.
•
•
•
•
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Wetlands
Marshes
➢ A marsh is a wetland that is dominated by herbaceous rather than
woody plant species.
➢ Marshes can often be found at the edges of lakes and streams, where
they form a transition between the aquatic and terrestrial ecosystems.
➢ They are often dominated by grasses, rushes or reeds.
➢ Both saltwater and freshwater tidal marshes serve many important
functions: They buffer stormy seas, slow shoreline erosion, offer
shelter and nesting sites for migratory water birds, and absorb excess
nutrients that would lower oxygen levels in the sea and harm wildlife.
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Wetlands
Coastal/Salt Marshes
• Flooded coastal wetland that are drained
by tides
• Ecological guardians of the coast (buffer
stormy seas)
• Serve as nursing grounds for young
marine life
• Support different species of animals,
such as shrimp, shellfish, and various
grasses
• Offering shelter and nesting sites for
several species of migratory waterfowl.
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Wetlands
Freshwater Marshes
• Act as natural water filter
• Filter out nutrients (N and P) that threatens
the rivers and lakes
• Wetland plants take up excess nutrients and
convert it to less harmful forms, and over
time, the nutrients are recycled within the
wetlands
• Unfortunately, freshwater marshes have
suffered major acreage losses to human
development.
• Some have been degraded by excessive
deposits of nutrients and sediment from
construction and farming.
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Wetlands
Swamps
• A swamp is a wetland that is forested.
• Swamps are considered to be transition
zones because both land and water play
a role in creating this environment.
• Other swamps occur on the shores of
large lakes.
• Swamps also protect coastal areas from
storm surges that can wash away fragile
coastline.
• The swamp ecosystem also acts as a
water treatment plant, filtering wastes
and purifying water naturally.
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Wetlands
Bog Land
➢ Bog or bog land is a type of freshwater
wetland that accumulates peat, a
deposit of dead plant material—often
mosses, and in a majority of cases,
sphagnum moss.
➢ It is oxygen-poor and nutrient-poor,
making biodiversity much lower than in
other wetland ecosystems.
➢ Few plants can survive in such an
acidic, waterlogged soil
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FRESHWATER
BIOMES
Streams and Rivers
• Are bodies of water moving
continuously in one direction.
• Headwaters are cold, clear, turbulent,
and swift.
• They carry little sediment and
relatively few mineral nutrients.
• As water travels downstream, it picks up
O2 and nutrients on the way.
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FRESHWATER
BIOMES
Streams
• A stream is a body of
water with surface water
flowing
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FRESHWATER
BIOMES
Rivers
• A wide, natural stream of
fresh water that flows
into an ocean or other
large body of water
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FRESHWATER
BIOMES
Streams and Rivers
• Nutrient content is largely determined
by the terrain and vegetation of the
area.
• Many streams and rivers have
been polluted by humans,
degrading water quality and
killing aquatic organisms.
• Damming and flood control
impairs the natural functioning of
streams and rivers and threatens
migratory species such as salmon.
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MARINE BIOMES
❑ Oceans
❑ Coral reefs
❑ Estuaries
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MARINE BIOMES
• Marine regions cover about ¾ of
the Earth’s surface
• Marine algae supply much of the
world’s oxygen supply and take in
a huge amount of atmospheric
carbon dioxide
• The evaporation of the seawater
provides rainwater for the land
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MARINE BIOMES
Estuaries
• Are areas of transition between river and
sea.
• The salinity of these areas can vary
greatly.
• Estuaries have complex flow patterns,
with networks of tidal channels, islands,
levees, and mudflats.
• They support an abundance of fish and
invertebrate species and are crucial
feeding areas for many species of
waterfowl.
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MARINE BIOMES
Oceans
• The largest of all ecosystem
• Large bodies of water that
dominate the Earth’s surface
➢ Intertidal zone
➢ Pelagic zone
➢ Benthic zone
➢ Abyssal zone
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MARINE BIOMES
Intertidal zone
• Marine biome that is periodically
submerged and exposed by the tides.
• The upper intertidal zone
experiences longer exposure to air
and greater variation in salinity and
temperature than do the lower
intertidal areas.
• Many organisms live only at a
particular stratum in the intertidal.
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MARINE BIOMES
Oceanic pelagic biome
• The open blue water, mixed by winddriven oceanic currents.
• The surface waters of temperate
oceans turn over during fall through
spring.
• The open ocean has high oxygen
levels and low nutrient levels.
• This biome covers 70% of the Earth’s
surface and has an average depth of
4,000 meters.
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MARINE BIOMES
Marine benthic zone
• Consists of the seafloor below the surface
waters of the coastal or neritic zone and the
offshore pelagic zone.
• Most of the ocean’s benthic zone receives no
sunlight.
• Organisms in the very deep abyssal zone are
adapted to continuous cold (about 3°C) and
extremely high pressure.
• Unique assemblages of organisms are
associated with deep-sea hydrothermal vents
of volcanic origin on mid-ocean ridges.
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MARINE BIOMES
Coral reefs
• Widely distributed in warm shallow waters
• Barriers along continents, fringing islands,
and atolls
• Corals as dominant organisms
• HERMATYPIC- coral species that build
reefs; also called “hard” corals because they
extract calcium carbonate from seawater
• POLYP- individual coral
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MARINE BIOMES
Coral reefs
• Limited to the photic zone of stable
tropic marine environments with
high water clarity. They are found at
temperatures between 18°C and
30°C.
• They are formed by the calcium
carbonate skeletons of coral animals.
• Coral reefs are home to a very diverse
assortment of vertebrates and
invertebrates.
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MARINE BIOMES
HOW DO CORAL REEFS
OBTAIN NUTRIENTS?
• Reef waters tend to be
nutritionally poor
• Corals obtain nutrients
through the algae via
photosynthesis and
extending tentacles to obtain
plankton from the water
• Corals are animals, they are
the invertebrates
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MARINE BIOMES
Coral reefs
• Collecting of coral skeletons
and overfishing for food and the
aquarium trade have reduced
populations of corals and reef
fishes.
• Global warming and pollution
contribute to large-scale coral
mortality.
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WE SHARE THE WORLD WITH MANY
OTHER SPECIES OF PLANTS AND
ANIMALS. LET US PROTECT AND
CONSERVE OUR BIOMES!
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End of Lecture…
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