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CHAPTER 8
BIOGEOGRAPHIC PROCESSES
VISUALIZING PHYSICAL GEOGRAPHY
BY ALAN STRAHLER AND ARTHUR STRAHLER
Jarmila Bílková
Faculty of Science
Department of Geography
Jan Evangelista Purkyně University in ÚSTÍ NAD
LABEM CZECH REPUBLIC
Contents
BIOGEOGRAPHIC PROCESSES
• Biogeography is a branch of geography the
distribution of plants and animals—the biota
—over the Earth
• Ecological biogeography: the distributions of
organisms in time and space
• Historical biogeography: evolution, dispersal,
and extinction of species through time
ENERGY AND MATTER FLOW IN ECOSYSTEMS
• Ecology is the study of the interactions
between life-forms and their environment
• Ecosystem = group of organisms and the
environment with which they interact
Salt marsh
Tundra
Savana
ENERGY AND MATTER FLOW IN ECOSYSTEMS
The Food Web (food chain): describes how food energy flows from organism
to organism within an ecosystem.
3.Primary producers (the snails, insects, and fishes): are plants and animals that are able to
synthesize carbohydrates from carbon dioxide, water and light energy through a process known as
photosynthesis
2. Consumers (the mammals, birds, and
larger fishes): feed on the primary
producers or on other consumers
3. Decomposers (microorganisms and
bacteria): feed on dead plant and animal
matter from all levels of the food web
•
Energy is lost at each level in food web
by respiration
•
Only 10 to 50% of the energy stored at
one level passes up to the next level
ENERGY AND MATTER FLOW IN ECOSYSTEMS
Photosynthesis and Respiration
Photosynthesis: is a biochemical reaction which results in the production
of carbohydrates and oxygen using water, carbon dioxide, and light energy
H20 + CO2 +light energy
 Rates of
photosynthesis
depend on light
intensity, duration of
daylight, and
temperature.
 Photosynthesis only
occurs when light is
available
CHOH
+ O2
ENERGY AND MATTER FLOW IN ECOSYSTEMS
Photosynthesis and Respiration
Respiration: is the opposite of photosynthesis
•
In this process, carbohydrate is broken down and combines with oxygen
to yield carbon dioxide and water.
CHOH
+ O2
CO2 + H2O + chemical energy
•
Gross photosynthesis is the total amount of carbohydrate produced by
photosynthesis
•
Net photosythesis is the amount of carbohydrate remaining after
respiration has broken down a sufficient amount of carbohydrate to
feed the plant
•
Net photosynthesis increases with temperature until approximately
18°C, after which it declines as the rate of respiration increases faster
than the rate of photosynthesis
 NET PHOTOSYNTHESIS = GROSS PHOTOSYNTHESIS − RESPIRATION
ENERGY AND MATTER FLOW IN ECOSYSTEMS
Net Primary Production
Net primary production: annual yield of useful energy produced by the
ecosystem, in grams (square meter) year
Biomass: the dry weight of organic matter per unit of surface area within an
ecosystem grams/square meter or tons/hectare
•Equatorial rainforests and freshwater swamps and marshes are among the
most productive ecosystems, while deserts are least productive
 Forests have the greatest
biomass
 Day length, air and soil
temperature, and water
availability are the most
important CLIMATIC
FACTORS that control net
primary productivity
ENERGY AND MATTER FLOW IN ECOSYSTEMS
Biomass as an Energy Source
•
Biomass is an important source
of renewable energy
•
Energy can be obtained by
burning firewood, or through
intermediate products such as
charcoal, methane gas, and
alcohol
•
the conversion of agricultural
wastes to alcohol yeast
microorganisms are used to
convert the carbohydrate to
alcohol through fermentation
ENERGY AND MATTER FLOW IN ECOSYSTEMS
The Carbon Cycle
•The carbon cycle is a biogeochemical cycle in which carbon flows among
storage pools in the atmosphere, ocean, and on the land
•Biogeochemical cycles define the pathways of particular nutrients or
materials through the Earth's ecosystem
•All life is composed
of carbon compounds
ENERGY AND MATTER FLOW IN ECOSYSTEMS
The Nitrogen Cycle
•The nitrogen cycle is another important biogeochemical cycle
•Nitrogen makes up 78 percent of the atmosphere volume
•nitrogen can only be utilized through nitrogen fixation and is lost to the
biosphere through denitrification
ECOLOGICAL BIOGEOGRAPHY
Ecological biogeography examines the distribution patterns of plants and
animals from the viewpoint of their physiological needs
Bacis terms:
• Habitat: subdivision of the environment according to the needs and
preferences of organisms or groups of organisms
• Ecological niche: describes how a species obtains energy and how it
influences other species within its own environment
• Community: a group of interacting organisms that occupy a particular
habitat
Factors controlling distribution of plants and animals:
 Water, Temperature and Other Climatic Factors
 Bioclimatic Frontiers
 Geomorphic and Edaphic (Soil) Factors
 Interaction among Species
ECOLOGICAL BIOGEOGRAPHY
Water Need
• Species have a variety of adaptations to help them cope with the
abundance or scarcity of water
• Characterized by waxy coating on leaves or reduced leaf area,
needlelike leaves or spines, light colored to reflect light
• Xerophyte:
plant adapted
to dry
conditions
• Phreatophyte:
plants that
obtain water
from ground
water
Succulents
plants with
thickened
leaves and
stems (Prickly
pear cactus Opuntia)
ECOLOGICAL BIOGEOGRAPHY
Live oak – sclerophyll
Water Need
• Tropophyte: plant adapted to changing conditions/dry season alternating
with wet season
• Deciduous: plants that drop their leaves seasonally
• Evergreens: plants that keep most of their leaves more than 1 year
• Sclerophylls: mediterranean climat´s plants often
xerophytic, evergreen, with hard, leathery
leaves
Xeric animals:
•active only at night, stay in burrows in the day
•do not sweat through skin glands
ECOLOGICAL BIOGEOGRAPHY
Temperature
Temperature affects:
•physiological processes in plants and animal
tissues
•colder climate generally fewer species
•cold-blooded animals lack the ability to internally
control temperature (e.g. reptiles) some
vertebrates are in hibernation (Bats)
•warm-blooded animals create their own heat,
but need more food (e.g mammals)
 characteristics such
as fur, hair, and
feathers, thick layer
of fat provide
excellent insulation
ECOLOGICAL BIOGEOGRAPHY
Other Climatic Factors
Light affects:
• plant distribution
• plant growth rate
• timing of budding, flowering, fruiting,
leaf shedding
• animal behavior
• wind affects vegetation structure
• Bioclimatic frontier - critical level of
climatic stress beyond which a species
cannot survive
ECOLOGICAL BIOGEOGRAPHY
Geomorphic and Edaphic Factors
• Geomorphic (landform) factors: include slope angle, slope aspect, and relief
(which way the slope is facing)
• Edaphic (soil) factors: include soil particle size and the amount and nature of
organic matter in the soil
ECOLOGICAL BIOGEOGRAPHY
Disturbance
Disturbance includes: fire, flood, volcanic
eruption, storm waves, high winds
ECOLOGICAL BIOGEOGRAPHY
Interactions Among Species
Negative interactions:
• Predation: on species feeding on another
• Parasitism: one species gaining nutrition from another
• Herbivory: animal grazing reduces the plant population viability
• Allelopathy: chemical toxins emitted by one plant species inhibits the
growth of another
Positive interactions:
b)Commensalisms: one species benefits
while the other is unaffected
c)Protocooperation: both species benefit
from the relationship
d)Mutualism: one or both species cannot
survive without the other
ECOLOGICAL SUCCESSION, CHANGE AND EQUILIBRIUM
Ecological Succession: sequence of distinctive plant and animal communities
occurring within a given area of newly formed land or land cleared of plant cover
by burning, clear cutting, or other agents
•The stable community, which is the end point of succession, is the climax
•Primary succession: succession on a new deposit of rock or mineral fragments
•Secondary succession: succession on a previously vegetated area that has been
disturbed
•Old-field succession: on abandoned farmland
• Disturbances may interrupt succession, alter ecosystems and change
successional pathways: wind, fire, floods, introduction of new species
Secondary succession on old fields
HISTORICAL BIOGEOGRAPHY
Evolution
•Evolution: the creation of diversity of life-forms
through the process of natural selection
•Natural selection: individuals with qualities best
suited to the environment are more likely to
propagate: “survival of the fittest”
•Sources of variation:
1. Mutation: changes in genetic material
2. Recombination: offspring receives 2
slightly different copies (alleles) of each
gene from parents
Genus: collection of closely
related species that share a
similar genetic evolutionary
history
HISTORICAL BIOGEOGRAPHY
Speciation
• Speciation: the process by which species are differentiated and maintained
• Speciation arises from several processes acting over time
• Genetic drift: chance mutations that don’t have any particular benefit,
change the genetic composition of a population
• Gene flow: opposite to genetic drift--populations exchange genes as
individuals move among populations; keeps gene pool uniform
HISTORICAL BIOGEOGRAPHY
Extinction
Over geologic time, all species are doomed
to extinction
Conditions change, and species unable to
adapt become extinct
Catastrophic natural events may
cause extinctions
Human activities may cause
extinctions
HISTORICAL BIOGEOGRAPHY
Dispersal
•nearly all types of organisms can move
from a location of origin to new sites
•movement of individuals from source
location
•slow extension of species over long periods
= dispersal
HISTORICAL BIOGEOGRAPHY
Distribution Patterns
•Endemic species: species found in one location or region, and nowhere else
•Cosmopolitan species: distributed very widely – homo sapiens
•Disjunction: one or more closely related species found in widely separated
regions
• Two Cosmopolitan species:
peregrine falcon (Falco
peregrinus) and the human
(Homo sapiens)
HISTORICAL BIOGEOGRAPHY
Biogeographic Regions
Closely related species often found near each other
BIODIVERSITY
• Biodiversity: the variety of biological
life on Earth or within a region
• Human activity on Earth is rapidly
decreasing biodiversity by
contributing to extinctions through
dispersing competing organisms,
hunting, fire, habitat alteration, and
fragmentation
• Tropical and equatorial regions have
more species
Degree of endangerment of plant and animal
groups in the United States (Data from Nature
Conservancy)
BIODIVERSITY
Geographic areas in which biodiversity is especially high and also threatened
are referred to as hotspots
(National Geographic Image Collection)
The sources used
• STRAHLER, Alan H a Arthur Newell STRAHLER. Introducing physical
geography. 4th ed. Hoboken, N.J.: J. Wiley, c2006, xxv, 728 p. fourth
edition. ISBN 04-716-7950-X
• Wiley. HELSEL, Dennis R. Statistics for censored environmental data
using Minitab and R [online]. 5nd ed. Hoboken: John Wiley, c2012
[cit. 2013-10-24]. Dostupné z: http://bcs.wiley.com/hebcs/Books?action=chapter&bcsId=2190&itemId=047167950X&chap
terId=17819
• http://bcs.wiley.com/hebcs/Books?action=chapter&bcsId=2190&itemId=047167950X&chap
terId=17819
• https://www.google.cz/imghp?hl=cs&tab=wi&authuser=0&ei=skOSUtqhI8
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