Transcript Document

TERRESTRIAL
BIOMES
Introduction
 Biomes are the major regional
groupings of plants and animals,
discernible at a global scale.
 distribution patterns are correlated with regional
climate patterns and identified according to the
climax vegetation type.
 a biome is composed not only of the climax
vegetation, but also of immature communities
To understand the nature of
biomes one needs to learn:
1) Global distribution pattern
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Where each biome is found and how each
varies geographically.
A given biome may be composed of different
taxa on different continents.
To understand the nature of
biomes one needs to learn
2) The dominant, characteristic, and unique
growth forms
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
vertical stratification
leaf shape, size, and habitat
special adaptations of the vegetation
To understand the nature of
biomes one needs to learn
3) The types of animals (especially
vertebrates) characteristic of the biome.

Their typical morphological, physiological,
and/or behavioral adaptations to the
environment
Major Biomes
 Deserts (Tropical, Temperate, Polar)
 Forests (Tropical and Temperate)
 Grasslands (Tropical, Temperate, Polar)
 Aquatic (Ch. 7)
Deserts
 Deserts cover about one-fifth of the Earth’s
surface and occur where rainfall is less than
50 cm/year.
 Most deserts occur at low latitudes.
 Cold deserts occur in the basin and
mountain ranges (leeward side of the mountain)
 Most deserts have a considerable amount
of specialized vegetation, as well as
specialized vertebrate and invertebrate
animals.
Deserts
 Soils often have abundant nutrients because they need only
water to become very productive and have little or no organic
matter.
 Soils are course-textured, shallow, rocky or gravely with good
drainage and have no subsurface water
 They are coarse because there is less chemical weathering
 Disturbances are common in the form of occasional fires or
cold weather, and sudden, infrequent, but intense rains that
cause flooding.
Types of Deserts
 Hot and Dry (Tropical)
 Semiarid (temperate)
 Cold (polar)
Hot and Dry Desert
Temperature
 Desert surfaces receive a little more than twice
the solar radiation received by humid regions and
lose almost twice as much heat at night.
 Many mean annual temperatures range from 2025° C
 The extreme maximum ranges from 43.5-49° C.
Minimum temperatures sometimes drop to -18° C
Hot and Dry Desert
Precipitation
 Rainfall is usually very low and/or concentrated in short
bursts between long rainless periods
 Evaporation rates regularly exceed rainfall rates
 Sometimes rain starts falling and evaporates before
reaching the ground
 Rainfall is lowest on the Atacama Desert of Chile, where
it averages less than 1.5 cm
 Inland Sahara also receives less than 1.5 cm a year
 Rainfall in American deserts is higher—almost 28 cm a
year
Hot and Dry Desert
Plants
Canopy in most deserts is very rare
Plants are mainly ground-hugging shrubs and short
woody trees
Leaves are “replete” (fully supported with nutrients) with
water-conserving characteristics- succulents
They tend to be small, thick and covered with a thick cuticle
(outer layer)
In the cacti, the leaves are much-reduced (to spines) and
photosynthetic activity is restricted to the stems
Some plants open their stomata (microscopic openings in the
epidermis of leaves that allow for gas exchange) only at night
when evaporation rates are lowest
Hot and Dry Desert- Vegetation
Yuccas
Ocotillo
Turpentine bush
Prickly Pears
False mesquite
Sotol
Ephedras
Agaves
Brittlebush
Hot and Dry Desert
Animals
The animals include small nocturnal (active at
night) carnivores
The dominant animals are burrowers and
kangaroo rats
There are also insects, arachnids, reptiles and
birds
The animals stay inactive in protected hideaways
during the hot day and come out to forage at dusk,
dawn or at night, when the desert is cooler
Snakes
Lizards
Tortoise
Bighorn Sheep
Coyote
Tarantula
Ants
Tarantula Wasp
Semiarid Desert- Temperate
Temperature
 The summers are moderately long and dry,
and like hot deserts, the winters normally bring
low concentrations of rainfall
 Summer temperatures usually average
between 21-27° C
 It normally does not go above 38° C and
evening temperatures are cool, at around 10°
C.
Semiarid Desert
Precipitation
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Cool nights help both plants and animals by
reducing moisture loss from transpiration, sweating
and breathing
Condensation of dew caused by night cooling may
equal or exceed the rainfall received by some
deserts
As in the hot desert, rainfall is often very low and/or
concentrated
The average rainfall ranges from 2-4 cm annually.
Semiarid Desert
Plants
The spiny nature of many plants in semiarid deserts
provides protection in a hazardous environment
 The large numbers of spines shade the surface
enough to significantly reduce transpiration
 Many plants have silvery or glossy leaves, allowing
them to reflect more radiant energy
 These plants often have an unfavorable odor or
taste.

Semiarid Desert
Creosote bush
Bur sage
White thorn
Cat claw
Mesquite
Brittle bushes
Lyciums
Jujube
Semiarid Desert
Animals
 During the day, insects move around twigs to
stay on the shady side; jack rabbits follow the
moving shadow of a cactus or shrub
 Naturally, many animals find protection in
underground burrows where they are
insulated from both heat and aridity
Semiarid Desert
Kangaroo rats
Rabbits
Skunks
Side-blotched Lizard
Mountain Lion
Rattlesnake
Burrowing owls
Western Bluebird
Cold Desert
Temperature
 Cold winters with snowfall and high overall
rainfall throughout the winter and occasionally
over the summer
 Antarctic, Greenland and the Arctic
 short, moist, and moderately warm summers
with fairly long, cold winters
 mean winter temperature is between -2 to 4° C
and the mean summer temperature is between
21-26° C
Cold Desert
Precipitation
 winters receive quite a bit of snow
 mean annual precipitation ranges from 15-
26 cm
 annual precipitation has reached a
maximum of 46 cm and a minimum of 9 cm
 heaviest rainfall of the spring is usually in
April or May
 rainfall can be heavy in autumn in some
areas
Cold Desert
Soil
 heavy, silty, and salty
 relatively porous and drainage is good
so that most of the salt has been
leached out
Cold Desert
Plants/ Vegetation
 widely scattered, short ground cover
 about 10 % of the ground is covered
 some areas of sagebush it approaches 85 %
 Lichens (algae/fungi)
 Mosses and algae
Cold Desert
Lichens
Bryophytes
Antarctic Algae
Snow Algae
Kelp
Cold Desert
Animals
 Terrestrial animal rely on phytoplankton
from marine environments as the base of
the food chain.
Cold Desert
Temperate
Desert food
web
Grasslands
 characterized as lands dominated by
grasses rather than large shrubs or trees
 largest land animals due to huge
vegetation
 There are two main divisions of grasslands
 tropical grasslands called savannas (Africa) pampas (S.
America) or veldts (Australia)
 temperate grasslands – prairies
** TEMPERATE SHRUBLAND – chaparral ; found in between
coastal deserts and temperate grasslands
Tropical Grasslands: Savanna
 Savanna is grassland with scattered
individual trees
 Climate is the most important factor in
creating a savanna – dry and rainy seasons
 Fires are important to maintain a savanna
Tropical Grasslands: Savanna
Tropical Grasslands: Savanna
Precipitation
 always found in warm or hot climates where
the annual rainfall is from about 50.8 to 127
cm (20-50 inches) per year
 crucial that the rainfall is concentrated in six
or eight months of the year, followed by a
long period of drought when fires can occur
Tropical Grasslands: Savanna
Soils
 porous, with rapid drainage of water
 only a thin layer of humus (the organic
portion of the soil created by partial
decomposition of plant or animal
matter), which provides vegetation
with nutrients
Tropical Grasslands: Savanna
Plants
 characterized by a continuous cover of
perennial grasses, often 3 to 6 feet tall
at maturity
 may or may not also have an open
canopy of drought-resistant, fireresistant, or browse-resistant trees, or
they may have an open shrub layer
Tropical Grasslands: Savanna
Animals
 When the rains come, savanna bunch
grasses grow vigorously
 larger grasses may grow an inch or more in
24 hours
 a surge of new life at this time
 For example, many antelope calves are born and with so much grass to
feed on, mothers have plenty of milk; calves die if the rains fail to
come.
Tropical Grasslands: Savanna
Animals
 do not all occur in the same savanna
 giraffes, zebras, buffaloes, kangaroos,
mice, moles, gophers, ground squirrels,
snakes, worms, termites, beetles, lions,
leopards, hyenas, and elephants
Giraffes
Zebras
Water buffaloes
Cheetah
Crocodile
Meerkats
Hyenas
Baboon
Wild Dog
Lions
Elephants
Ants
Termites
Leopards
Rhinoceros
Temperate Grassland
 Grasses as the dominant vegetation with
trees and large shrubs absent
 seasonal drought and occasional fires are
very important to biodiversity.
 effects aren’t as dramatic in temperate grasslands as
they are in savannas
Temperate Grassland
Precipitation
 usually occurs in the late spring and
early summer
 annual average is about 50.8 to 88.9
cm (20-35 inches).
Temperate Grassland
Temperate Grassland
Temperate Grassland
Temperature
 range is very large over the course of
the year
 summer temperatures can be well over
38° C (100 degrees F)
 winter temperatures can be as low as
40° C (-40 degrees F)
Temperate Grassland
Soil
 deep and dark, with fertile upper
layers
 nutrient-rich from the growth and
decay of deep, many-branched grass
roots
 rotted roots hold the soil together
and provide a food source for living
plants
Temperate Grassland
Plants
 different species of grass grows best in a
particular grassland environment
 seasonal drought, occasional fires, and
grazing by large mammals all prevent
woody shrubs and trees from invading and
becoming established
 a few trees, such as cottonwoods, oaks,
and willows grow in river valleys, and
some nonwoody plants, specifically a few
hundred species of flowers, grow among
the grasses
Temperate Grassland
Purple needlegrass
Blue Grama
Buffalo grass
Asters
Coneflowers
Sunflowers
Goldenrods
Clovers
Temperate Grassland
Animals
 Mostly grazers
 wild horses, wolves, prairie dogs,
rabbits, deer, mice, coyotes, foxes,
skunks, badgers, blackbirds,
meadowlarks, quails, sparrows,
hawks, owls, snakes, grasshoppers,
leafhoppers, and spiders
Tundra: Polar Grassland
 comes from the Finnish word tunturia,
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meaning treeless plain
frost-molded landscapes
extremely low temperatures
little precipitation
poor nutrients
short growing seasons
Tundra: Polar Grassland
Tundra: Polar Grassland
Tundra: Polar Grassland
Temperature
 growing season ranges from 50 to 60
days
 average winter temperature is -34° C
(-30° F)
 average summer temperature is 3-12° C
(37-54° F) which enables this biome to
sustain life
Tundra: Polar Grassland
Precipitation
 may vary in different regions of the arctic
 yearly precipitation, including melting snow, is 15
to 25 cm (6 to 10 inches)
Tundra: Polar Grassland
Soil
 formed slowly
 layer of permanently frozen subsoil called
permafrost exists, consisting mostly of gravel and
finer material
 when water saturates the upper surface, bogs and
ponds may form, providing moisture for plants
 no deep root systems in the vegetation of the arctic
tundra, however, there are still a wide variety of
plants that are able to resist the cold climate
Tundra: Polar Grassland
Plants
 There are about 1,700 kinds of plants in the arctic and
subarctic
 adapted to sweeping winds and disturbances of the
soil
 short and group together to resist the cold
temperatures and are protected by the snow during
the winter
 carry out photosynthesis at low temperatures and
low light intensities
 growing seasons are short and most plants reproduce
by budding and division rather than sexually by
flowering
 low shrubs, sedges, reindeer mosses, liverworts, and
grasses, lichens
Tundra
Animals
 Strategies evolved to withstand the harsh
conditions of the tundra (example: fur changes color to
camouflage during seasons)
 Can be divided into resident and migratory
animal groups.
Tundra: Polar Grassland
Resident Animals
 small number of birds and mammals (e.g., musk ox, arctic hare,
arctic fox)
 Morphological adaptations
 large, compact bodies
 a thick insulating cover of feathers or fur
 pelage and plumage that turns white in winter, brown in summer
 Physiological adaptations
 ability to accumulate thick deposits of fat during the short growing season
 insulation and as a store of energy for use during the winter, when animal
species remain active
 Population adaptations
 cyclical fluctuations in population size, best seen perhaps in the lemming, a
small rodent which is the major herbivore in the tundra's simple food chain
 predator populations and plant populations respond in kind to the peaks
and crashes of the herbivore populations
Tundra: Polar Grassland
Migratory
 species such as waterfowl, shorebirds and
caribou adapt to the tundra by avoiding the
most severe conditions of winter
 each year at the end of the short growing
season they move southward into the boreal
forest or beyond, but return to the tundra to
breed due to the long growing season
Tundra animals
Siberian Lynx
Musk ox
Ermine
(summer and winter)
Reindeer
Temperate Shrubland- Chaparral
Temperate conditions with characteristics in between a
coastal desert and temperate grassland.
Slightly longer rainy season
Dense growth of low-growing evergreen shrubs and small
trees
Long, hot dry summers are susceptible to forest fires.
Fires help reduce overgrowth of vegetation and periodic fires
are maintained by parks services regularly.
Adaptations include fire resistant roots and seeds that
sprout only under extreme heat.
Location: southern California and Mediterranean
Animals: similar to desert rodents, small herbivores and
insects.
FORESTS
 occupy approximately one-third of Earth’s land area
 account for over two-thirds of the leaf area of land
plants
 contain about 70% of carbon present in living
things
 are major casualties of deforestation, pollution, and
industrial usage
 forest biomes are classified according to
numerous characteristics, with seasonality
being the most widely used.
Types of Forests
 Tropical
 Temperate
 Boreal forests (taiga)
Tropical Forests
 are characterized by the greatest diversity of
species.
 occur near the equator, within the area bounded
by latitudes 23.5 degrees N and 23.5 degrees S
 distinct seasonality:
 winter is absent
 only two seasons are present (rainy and dry)
 The length of daylight is 12 hours and varies
little.
Tropical Forests
Tropical Forests
Tropical Forests
Temperature
 average 20-25° C and varies little
throughout the year
 the average temperatures of the three
warmest and three coldest months do not
differ by more than 5 degrees
Tropical Forests
Precipitation
 evenly distributed throughout the year
 annual rainfall exceeds 2 meters
Tropical Forests
Soil
 nutrient-poor and acidic
 decomposition is rapid
 subject to heavy leaching
Tropical Forests
Plants
 Stratification of tree layers
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Emergent layer
Canopy
Understory
Shrub layer
Ground layer
 Flora is highly diverse
 one square kilometer may contain as many as
100 different tree species
 Trees are 25-35 m tall
 buttressed trunks and shallow roots
 mostly evergreen, with large dark green leaves.
Tropical Forests
Plant Adaptations
 ability to tolerate constant shade
 adapt strategies to reach sunlight;
intense competition!
 Epiphytes
Tropical Forests
Epiphytes
(grow on another plant)
Ferns
Moss
Curare
Palms
Tropical Forests
White-faced Monkey
Tree frog
Toucan
Vine Snake
Gecko
Vested Anteater
Transparent butterfly
Jaguar
Unicorn grasshopper
Red-eyed tree frog
Silver-throated Tanager
Tropical king snake
Scorpion
Temperate Forest
Temperature
 Well-defined seasons, with a distinct
winter, characterize this forest biome
 Moderate climate and a growing season
of 140-200 days during 4-6 frost-free
months distinguish temperate forests
 Temperature varies from -30° C to 30° C.
Temperate
Forest
Temperate Forest
Temperate Forest
Precipitation
 (75-150 cm) is distributed evenly
throughout the year
Soils
 fertile, enriched with decaying litter
Temperate Forest
Plants
 Canopy
 moderately dense
 allows light to penetrate
 resulting in well-developed and richly diversified
understory vegetation and stratification of
animals
 Flora is characterized by 3-4 tree species per
square kilometer
 Trees are distinguished by broad leaves that
are lost annually (deciduous trees)
Temperate Forest
Oak
Hickory
Beech
Hemlock
Maple
Basswood
Elm
Willow
Spring-flowering herbs
Black Bear
Gray Squirrel
Raccoon
White-tailed Deer
Cardinal
Turkey
Yellow-bellied Sapsucker
Rat Snake
Temperate
Forest
Temperate Forest
 Further subdivisions of this group are determined by
seasonal distribution of rainfall:
 moist conifer and evergreen broad-leaved forests: wet winters and
dry summers (rainfall is concentrated in the winter months and
winters are relatively mild)
 dry conifer forests: dominate higher elevation zones; low
precipitation.
Mediterranean forests: precipitation is concentrated in winter,
less than 1000 mm per year
 temperate coniferous: mild winters, high annual precipitation
(greater than 2000 mm)
 temperate broad-leaved rainforests: mild, frost-free winters, high
precipitation (more than 1500 mm) evenly distributed
throughout the year
 Only scattered remnants of original temperate forests
remain
Temperate Rain Forest
Boreal forests, or taiga
 represent the largest terrestrial biome
 Occurs between 50 and 60 degrees north
latitudes
 seasons are divided into short, moist, and
moderately warm summers and long, cold, and
dry winters
 length of the growing season in boreal forests is
130 days
Boreal forests, or taiga
Boreal forests, or taiga
 Temperatures are very low
 Precipitation is primarily in the form of
snow, 40-100 cm annually
 Soil is thin, nutrient-poor, and acidic
 Canopy permits low light penetration,
and as a result, understory is limited
Boreal forests, or taiga
 The conical shaped needle leaf trees common to the taiga are
adapted to the cold and the physiological drought of winter
and to the short-growing season:
 Conical shape - promotes shedding of snow and prevents loss of branches.
 Needleleaf – narrow shape reduces surface area (transpired), especially
during winter when the frozen ground prevents plants from replenishing
their water supply. The needles of boreal conifers also have thick waxy
coatings--a waterproof cuticle--in which stomata are sunken and
protected from drying winds.
 Cones protect seeds and adapted to burst open in warm temperatures.
 Evergreen habit - retention of foliage allows plants to photosynthesize as
soon as temperatures permit in spring, rather than having to waste time in
the short growing season merely growing leaves.
 Dark color - the dark green of spruce and fir needles helps the foliage
absorb maximum heat from the sun and begin photosynthesis as early as
possible
Taiga Plants
Balsam Fir
Black Spruce
Paper Birch
Douglas-fir
Eastern Red Cedar
Jack Pine
White Fir
White Poplar
Siberian Spruce
White Spruce
Taiga Animals
American Black Bear
Bald Eagle
Canadian Lynx
Gray Wolf
Long-Eared Owl
Red Fox
Snowshoe Rabbit
Bobcat
Grizzly Bear
River Otter
Wolverine
Boreal
forests,
or taiga