Transcript Document 7586467

CHAPTER 2
LIFE ON LAND
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Life on Land
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Natural history: Study of how organisms in
particular area are influenced by factors such as
climate, soils, predators, competitors, and
evolutionary history.
Daniel Janzen’s study case of Guannacaste tree
(Enterolobium cyclocarpum) in CR (1981a.1981b)
– Each tree produce average of 5000 fruit.
– Most seeds remain on the floor under the trees
– Large herbivorous animals feeding on fruits were hunted
10,000 years ago.
– European introduce cattle which feed on those seeds,
which eventually helped to disperse those trees.
– His study help to understand the role of natural history
on restoration of G tree and G National Park.
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Fig. 2.2
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Terrestrial Biomes
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Biomes: divisions of the terrestrial environment with
distinguish predominant plants and associated climate.(
e.g. tropical forest, desert).
Soil: Complex mixture of living and nonliving material
upon which most terrestrial life depends.
Soil form a medium in which organisms grow, and their
activities in turn affect soil structure.
Soil vertical profile :
– O horizon: organic, decomposed organics as result of bacteria,
fungi, and soil animals. Merger gradually with A horizon.
– A horizon: mixture of minerals material such clay, support high
level of biological activities, rich in mineral nutrients.
– B horizon: contains clay, humus and other materials
transported from A. Distinct color and banding patterns.
Occupied by the roots of plants, and gradually merge with C.
– C horizon: deepest layer, weathered parent material, small
fragments of particles (sand, silt, clay).
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Fig. 2.3
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Large-scale patterns of climatic
variation
Uneven heating of earth’s spherical
surface by the sun and tilt of earth axis
will results predictable climate variation
 The geographical distribution of terrestrial
biomes corresponds closely to variation in
climate, especially temperature and
precipitations.
 Pattern of atmospheric circulation and
Coriolis effect.
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Fig. 2.4
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Fig. 2.5
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Fig. 2.6
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Climate Diagrams
 Develop
by Heinrich Walter (1985)
 Tool used to explore the relationship
between distribution of terrestrial
vegetation and climate.
 Scale of temperature and
precipitation where scaled so 10 °C =
20 mm of precipitation.
 Climate diagram for various cities
(see fig 2.8 page 20)
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Fig. 2.7
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Biomes
 Tropical
Rain Forest
– The more alive biomes
– Illuminated by dim greenish light shining through a ceiling of
leaves.
– Availability of rain and warm and wet around the year.
– Falls within the equator in three regions :
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Southeast Asia, West Africa , and south and Central America.
– Soil is nutrient-poor, acidic, thin, and low in organic matter.
– Nutrients are tied up in living tissues than in soil.
– Beneficiary partnership such as “Mycorrhizae” in which fungi
associated with plant roots.
– Rain forest could occur on volcano fertile soil, or along rivers.
– Animal and plants diversities are immense.
– Human influences on tropical rain forest has been devastated.
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Fig. 2.10
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 Tropical
Dry Forest
– Life responds to the rhythms of annual solar cycle.
– During dry season most trees are dormant, they flourish
during the rainy season.
– Occupy a substantial portion of the earth’s surface ( 10° and
25° latitude) (Cancer and Capricorn)
– Climate is more seasonal than tropical forest (see fig 2.13).
– More seasonal variations in temperature.
– Soil is less acidic, and more richer in organic.
– Soil is more vulnerable to erosion, particularly when disturbed
by agriculture.
– Plants are strongly influenced by physical factors.
– Share many animal species with the rain forest and savanna
– Animal may migrate during dry season.
– Dry forest has been severely exploited more than tropical
forest, by agriculture and cattle grazing.
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Fig. 2.13
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Fig.
2.14
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 Tropical
Savanna
– Tropical grassland dotted with scattered trees.
– Believed ancient humans lived in it and scattered to other
biomes.
– Occur north and south of tropical dry forests within 10° to 20°
of the equator.
– Life cycles to rhythms of alternating dry and wet seasons, with
intense lightening and often fires.
– Fires help to maintains grassland as nutrients will be recycled.
– Soil layers with low permeability resulting in maintaining
plants.
– Soil low permeability prevent trees as trees occur only where
soils are well drained.
– Biological activities take place near ground level.
– Animals response to rainfall and food availability.
– Human early use as hunting and gathering of food ground.
– Human influence were seen as livestock ranching activities.
– Drought and climate change have devastated most of it.
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Fig. 2.16
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Desert
– Landscape sculptured by wind and water scarcity in general.
– Drought and treacherous floods, heat and better cold often go
hand in hand.
– Life is not luxuriant, organisms adapted to water shortage and
extreme temperatures (low & High).
– Occupy 20% of the land surface of the earth.
– Two bands of deserts ring the globe, one 30°N and 30°S
latitudes. These bands corresponds to where dry subtropical
air descends.
– Environmental conditions varies from one desert to another
(rain, temp, evaporation, plants transpiration).
– Soil is low in organic and classified as lithosols, which means
stone or minerals soil. Soil may cumulate salts, and forming
calcium carbonate –rich hardpan horizon (Caliche)
– Desert animals can effect soil properties (burrows, leaves
under shrubs).
– Plant cover is rare, and plants are adaptive to drought through
leaves or dormancy.
– Desert cultures flourished, because of human activities deserts
have expanded in expense of other biomes.
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Fig. 2.19
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 Temperate
woodland and shrubland
– Location above the tropic of Cancer and Capricorn between
about 30° and 40° latitude, most extensive in the
Mediterranean sea and North America.
– Climate is cool and moist during fall, winter and spring.
Summer in most regions is hot and dry, causing frequent fire.
– Soil is low to moderate fertility and fragile.
– Organisms show adaptations to drought and adapted
mutualistic relationship with microbes to fix atmospheric
nitrogen. Decomposition is slow during dry summer.
– Fire-resistance plants and resprout rapidly.
– Animals (vertebrate and invertebrate) are highly diverse.
– Human impacted it by clearing trees and shrubs and used it
for agriculture.
– Most of temperate and woodlands and shrubs are destroyed
and converted to various human land activities.
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Fig. 2.22
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 Temperate
Grassland
– Largest biomes in North America and Eurasia.
– Receive between 300 and 1,000 mm of rain. However, may
experience occasional drought that extend to several years.
– Grass height varies from 5 cm to 200 cm with great species
varieties. Supported once huge herds of herbivores.
– Maximum precipitations during summer, with growing height in
summer. Cold winter and hot summer.
– Soil is drive from wide varieties of parent materials. Contain
large quantities of organic matter and fertile.
– Dominated by herbaceous vegetation. Trees and shrubs are
often limited to margins of streams and rivers.
– Animals of intermediate size generally had one of two lifestyles
(borrowing and fleet).
– First human populated it were nomadic hunters. Next came
nomadic herders. Then came farmers.
– Produce the most fertile farms and fed much of the world.
– Lost its fertility through human usage 35-40%.
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Fig. 2.25
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 Temperate
Forest
– Found between 30° and 55° latitude, with majority lies between
40° and 50°.
– Forests may be coniferous or deciduous, with temperatures are
not extremes with precipitation averages of 650-3,000 mm.
– Few deciduous trees are restricted to streamside.
– Soil are usually fertile, with the most fertile develop under
deciduous forests. Soil is neutral to slightly acidic and rich of
organic and inorganic nutrients.
– Have lower diversity than tropical forest, it is vertically stratified.
– Animals uses all levels, with small to medium animals presents.
– Organic materials are stored on the floor, with microscopic and
invertebrates used to recycle those nutrients.
– Large cities where build on temperate forests, first forests were
removed and agriculture were practiced.
– Most deciduous trees were cut to support lumber and wood
industries.
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Fig. 2.28
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 Boreal
Forest or Taiga
– Covers over 11% of the earth’s land area, and confined to
Northern Hemisphere.
– Extend between 50° and 65° N latitude.
– Winter is long (>6 months), with moderate precipitation
ranging from 200 to 600 mm.
– Low rate of evaporation and brief drought if any.
– Soil of low fertility, thin and acidic, with low decomposition
rate. Nutrients are tide up in a thick layer of plant litter. In
extreme boreal forest the subsoil is permanently frozen.
– Plant roots are shallow with mycorrhizal fungi.
– Dominantly green, and home of many animals including
migratory birds and big animals like bears.
– Early caveman live in boreal forest.
– Human invasion is relatively light, however forest becomes
intense lately as lumber being cut.
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Fig. 2.31
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 Tundra
– Covering the land north of the Arctic circle.
– Climate is typically cold and dry, less temperature than boreal
forests. Winter is less severe and summer are shorter.
– Precipitation varies from less than 200 to a little over 600 mm,
as exceed evaporation.
– Soil loaded with accumulated organic matter.
– Freezing and thawing of surface soil and action of water and
gravity produce “Solifluction” where soil moves slowly down
slopes and bringing stones to the surface forming a net of
polygonal pattern (see fig. 2.35).
– Dominated by perennial herbaceous plants (grass, sedges,
mosses and lichens).
– Support substantial numbers of large native mammals.
– Human is limited, however recently increased
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Fig. 2.34
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 Mountains
– May consist of several biomes due to altitude variations.
– Mountains built by geological process such as volcanoes or
earth’s crust movement . North to South in America, and East
to West in Asia and Europe, and isolated in Africa and
Australia.
– Climate is different according to latitude
– Soil changes with elevation, soil is well drained, effected by
wind and erosion.
– Vegetation is influenced by altitude.
– Human influenced mountains by exploitations and grazing.
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Fig. 2.35
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Fig. 2.37
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Fig. 2.38
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