Jacques W. (Jacques Wardlaw) Redway.

Elementary physical geography : an outline of physiography online

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Tuberous plants are among the important food-pro-
ducers. The potato, probably a native of Chile, has been
carried to every part of the civilized world. It thrives
best in temperate latitudes.

The yam ^ and its relative, the SAveet potato, are indige-
nous to tropical America. The beet and the turnip are
native to Europe. The former is now the principal source
of sugar. The cultivated onion seems to have come from
China, but a wdld variety occurs iu America. The manioc
(or manihot) is native to tropical America, but has been
transplanted to Asia and Africa.


The fruits are imijortant, not only as delicacies,'' but as
foods. Among the foremost are the fig, the date, and tlie
Corinth grape. They are native to the basin of the Medi-
terranean Sea, and the dried fruit is a necessary article of
food in that region. The banana, native to tropical Asia,
has become a recognized article of food in America.

The cultivated varieties of the apple, pear, peach, and
plum are native to western Eurasia ; the cherry, apricot,
and almond to the eastern part of that continent. The
melons and their near relatives, the gouixls (including the
pumpkin and squash), are also from Asia. The orange,
lemon, and lime probablv came from the southern slope of
the Himalaya Moimtains. So far as written history is con-
cerned, the grape ** has a greater antiquity than any other
fruit, manna possibly excepted. It is found in a wild
state in both hemispheres. The cranberry probably orig-
inated in the temperate zone of North America, migi'atiug
thence to Europe. The tomato is also native to America.

Most of the succulent and leguminous plants, such as
the cabbage, lettuce, spinach, and peas, have followed the
migi'ations of Europeans. The bean seems to have come
from Egypt. Celery is undoubtedly of Eurasian origin ; it
is found in a wild state over a large part of the continent,
but is extensively cultivated.

The beverage-yielding plants in one or more species are
cultivated throughout the whole civilized world. Tea is
sent from eastern and southeastern Asia to ahnost every
other country. The best quality is grown on tlie chain of
islands east of the mainland ; it is also grown in the
United States. Coffee is probably a native of Abyssinia,
but is now cultivated mainly in the New ^^'()rld. It grows
wild in the former region, and a siniihir species is native?
to the warm parts of California.

The cacao-tree yields cocoa-beans. The latter, dried


and browned, are used as an infusion ; ground with its
own fat or with hxrd it is the chocolate of commerce.
It is native to tropical America. Mate {rnd-ta), or Para-
guay tea, is the leaf of a species of holly native to South
America. Its infusion is used all over that grand divi-

The spices come nearly all from Southern Asia and the
Malaysian archipelago. Of these none except pepper has
been transplanted to any great distance from the place of
their nativity. Capsicum, or red pepper {chile Colorado),
is native to tropical America. Nutmeg is a fruit, the cov-
ering of which is the mace of commerce ; cinnamon is the
dried inner bark of a species of laurel ; cassia is a similar
species growing in China and the New World ; cloves are
the dried buds of a tree native to the Molucca Islands and
Southern India.

Medicinal plants are as widely dispersed as is the hu-
man race. The opium-poppy, native to tropical Asia, pos-
sibly to Egypt, has not migrated far from the place of its
birth. The cinchona, a native of South America, but now
cultivated in tropical Asia, yields quinine and a score of
derivatives. The various members of the night-shade
family ^ all yield powerful medicinal substances, among
them nux vomica, strychnine, belladonna, and gelsemium ;
they are found in both continents.

Rhubarb and ginseng are native to China, but are now
cultivated chiefly in the United States. The hemp that
yields cannabis indica, or hasheesh, comes from south-
em Asia. Coca is native to the Andes. Cascara seems to
be confined to tropical and sub-tropical America. Most
medicines widely used are derived from plants found in
tropical regions. Tobacco is native to America.

Plants used in the arts have followed man in his migra-
tions. Cotton ^° is the furze attached to the seeds of the


cotton plant. Flax and hemp are obtained from the bark
of flowering plants ; both came from the Old World —
probabl}' from Africa — but four-fifths of the world's prod-
uct is now grown in the United States. Jute and ramie
are native to Asia, but are now cultivated in America.
More valuable than either of these is pita, the fibre of the
wild pineapple, native to America ; and so also is hene-
quen, or " sisal hemp," the fibre of the agave.

The forestry of the world is distributed with a remarka-
ble degree of regularity. The pines and other conifers,
oaks, elms, maples, willows, chestnuts, and beeches, occupy
a belt between the 40tli and 55th parallels that crosses
both continents. The distribution of tropical forestry is
not so regular, from the fact that South America has a
flora peculiar to itself. The palm, banana, mahogany,
bamboo, and representatives of the pines continue through
both continents, however.

On both sides of the belts of forestry there are extensive
treeless areas. In some instances the areas are treeless
because they are deserts, but in others, such as the
prairies and plains of Russia and the United States, there
is a fertile soil and an adaptability of environment. In
many instances there are no trees because the seeds have
not been carried thither ; because the rivers and the wiuds,
flowing from regions that practically are deserts, carry no
seeds into the regions toward which they flow.

In the United States forestry thrives best in a giavdly
soil, but lives and increases in a sedentary, prairie soil.
In the Champlain period that followed the Glacial epoch,
the northern part of the United States was traversed by
streams that bore the seeds of various species. AVherever
the streams deposited gravel they also deposited seeds.
Hence this region was sooner or later covered with trees.
As a matter of fact, the timber-covered regions of tlie



northern United States are nearly identical with the area
covered by stream gravel and till.

Distribution of Animals.— The animal life of a region
constitutes its fauna. Of the various classes/' the mam-
mals represent the highest t^'pes of life, both with respect
to form and structui'e and also in the matter of intelligence.
All the forms of animal life possess the attribute of in-
stinct — the hereditary power of thought required in such
actions as tend to preserve and extend life. The higher

yi type of Antarctic life

forms, in addition, have the powers of reason. These
faculties have, doubtless, largely controlled the distribu-
tion of life.

In the dispersal of animal species the power of locomo-
tion has given a wonderful development to both instinct
and reason, and these have been controlled by the most
powerful motive that exists in connection with animate
life, namely — the sense of hunger.

As in the distribution of plants, there seem to be certain
centres from which animal species have migrated. But the
limits have been determined in a somewhat different way.



lu the case of plants the territory of a flora is mainly gov-
erned by environment ; in the case of animal life environ-
ment is an important matter, but the power of voluntary
locomotion has been the leading factor. The limits of a
fauua, therefore, are largely determined by its various
physiographic barriers.

In the map, page 318, it is seen that the North Amer-
ican and Eurasian regions have a very broad extent, and
are separated by marine barriers that are neither very
wide nor impassable. In the south, the regions are sur-
rounded by barriers that practically isolate them. For
example, South America is separated from North America
by the barriers of sea and climate. The African region has,
in addition to these barriers, a high mountain range on its
northern border ; the same is true of India, south of the
Himalayas ; Aiistralia is environed by the sea and also by
peculiarities of climate.

From this it may be inferred that the faunas of the two
northern regions are not greatly dissimilar. Such an infer-
ence is correct. In many instances the species are identi-
cal, and in others an order or a class has its representatives
in both continents. The southern regions, however, are
marked by strong contrasts.

The North American and Eurasian regions have in com-
mon many species of carnivorous, or flesh-eating animals.
Various species of wolf and bear are widely dispersed
through both regions, and the cat family is represented by
the panther and several species of wildcat. Many fur-
bearing animals — notably the lynx, otter, ermine, badger,
and sable- — are common to both regions, and so are species
of the deer family and mountain sheep.

The grizzly bear, caribou, bison, musk-ox and black
bear are peculiar to America ; the first named is foimd
only in the Rocky Mountain highlands. The reindeer,


camel,^- buffalo, and nearly all domestic animals are na-
tive to the Old World, but have been transplanted to the
American continent. The opossum, puma, bald eagle,
humming-bird and wild tui"key are native to the American
region; the chamois, ibex, fallow-deer and aurochs are
peculiar to the Old World.

The South American "Region is distinguished by a pro-
fusion of animal life. The monkeys of this region are a




species distinct from those of the OKI World. The camel '^
of the Old World is here replaced by the alpaca, vicufia,
llama, and guanaco — all distantly related to the camel.
The last named, however, is probably native to the South
American region.

The sloth, armadillo, ant-eater and peccary are peculiar
to this region, and so are the numerous parroquets, and a


host of insect life. The condor is the nearest approach
to the European vulture and the rliea to the ostrich.

The Ethiopian Region is conspicuous for the absence of
the species most common elsewhere. On the other hand,
the gorilla, lion, zebra, hippopotamus, giraife, ostrich, live-
toed elephant and many other characteristic species are
found nowhere else. In but one other region is the pygmy,
a dwarfed species of man, fomid.^*

The Oriental Eegion is the birthplace of most of the
domesticated animals. Among wild animals the tiger,
njongoose, cobra, and three-toed elephant are peculiar to
this region. The rhinoceros, jackal, and leopard are com-
mon to this region and that to the westward.

The Australian Eegion is marked by the most unusual
types of life on the face of the earth. Almost all its life-
forms are peculiar, and but few types found elsewhere
occur in this continent. Many of the species are marsu-
pials — that is, the female has a pouch or pocket in which
the immature young are carried. Many others, such as
the kangaroos, have enormously developed hinder legs.
As a rule, Australian species are similar to those of a
prior geological age.

The Bearing of Organic Life upon Physiography.
— In the foregoing paragraphs the effects of physiographic
forces upon life have been considered. The bearing of
life and its energy upon physiographic forms are just as
far-reaching and quite as important.

Life-forms have been and are now among the important
agents in rock formation. Some of the limestone basins
of the Mississippi Valley, all the infusorial earths, the
various fringing reefs, the barrier reefs, the atolls, and the
encircling reefs are the work of animal life. On even a
more extended scale are the chalk formations of Western
Europe, which are also the results of life.


In the broad areas of the tropical oceans the work of
organic life is of still gi-eater magnitude. The water of
these regions is swarming with life, and the skeletons
of the dead forms, together with other mineral constitu-
ents, are accumulating at the bottom. Wherever deep-sea

A type of the Auslralian region

dredging has been carried on, these accumulations have
been found.

But the secretion of the lime from the sea-water luis bad
still another effect. After the lime and other niin<rnl mat-
ter has been absorbed by the organism, the water is speci-
fically lighter, and, as a result, tht( change in the density
of the water has brought about a slow, but a none the less
certain circulation of water.


Vegetable life also is responsible for extensive areas of
rock formation. Under certain conditions, such as exces-
sive saturation, the leaves, twigs, and stems of plants accu-
mulate to considerable depths. If these accumulations be
covered by overtlowiug sediment, either tluviatile or ma-
rine, the wood-fibre, after long-continued pressure and par-
tial decomposition, is converted into coal.

In the United States more than 150,000 square miles of
territory are underlain by coal measures, and in the various
basins of Eurasia probably a greater area exists. The most
extensive formations of this character are found in the later
rocks of the Palaeozoic age, but coal is not confined to
any particular strata. Coal-making has been an incident
of every geological age. Diamond, graphite, anthracite,
bituminous coal, mineral pitch, petroleum, and natural gas
are all the results of organic life.

In preventing general surface erosion, vegetation has
also been an important factor. A surface covered Avith
grass or foliage resists the action of rain and winds alike.
Covered with vegetation a surface can withstand almost
any amount of wind and rain, but denuded of vegetation,
the surface is quickly scored by running water ; gullies
grow into ravines, and the latter deepen into impassable

It has been shown in another chapter that not only
is vegetation capable of converting a moderately dry region
into a swamp, but also that it may fill the swamp and after-
ward reconvert it into a dry region again. It may accom-
plish even more than this. A single species, such as the
Russian thistle, may exterminate every other species of
plant within a certain area.

As the native vegetation disappears so do the character-
istic animals, and, sooner or later, the entire flora and
fauna are changed. This changes also the character of


the soil ; and as the topography of a region is due more or
less to its characteristic vegetation, sooner or later this is

The very lowest forms of vegetable life, such as the
moulds, the bacilli, bacteria, and micrococci, perform an
important office also. These forms, commonly known as
disease-germs, may — and sometimes do — exterminate whole
species, both of animals and plants. In company with the
mosses and lichens they disintegrate and decompose the
hardest rocks and ciiimble them into soil. In warm, moist
regions exposed rock-cliffs and strata are much rarer than
in arid regions. Fresh surfaces of rock once exposed are
quickly covered with mosses, lichens, and the various pro-
tophytes. These, once established, require time only,
either to completel}^ disintegrate the rock, or else to cover
its surface to a considerable depth.

The common earthworm plays an important part also.
It thrives in moist earth, and a colony of these worms,
once bred in a given locality, continues to inhabit it mitil
the whole mass is changed to a rich, loamy soil, capable
of supporting a dense vegetation. Thus it is seen that the
lowly and often invisible forms of life become important
factors in the physiogTai^hy of a region.

QUESTIONS AND EXERCISES.— Make a list of the forest trees,
shrubs, and other wild plants growing in the neighborhood in which
you live.

Make a special study of any plant or " weed " regarded as useless or
baneful. If you cannot obtain the information you require, send a
specimen to the Department of Agriculture, Washington, D. C.

Follow the same directions with reference to the animal species, es-
pecially those injurious to vegetation, applying to the Department of
Agriculture for information you cannot obtain elsewhere.

Enumerate the articles of food and table furniture used at dinner, and
follow the route of each one from its native place to the table.

Mention the various uses to which maize or the corn plant is put-
grain, cob, and stalk.


In what ways does the wheat crop affect the habitability of the
United States ?

Name some of the chief causes of the destruction of forestry. Note
an instance in which the cultivation of the cotton plant has affected
the history of a people.

Describe instances in which the distribution of animals or of plants
has been effected by the agency of mankind.

Mill.— Realm of Nature, pp. 303-330.


• These are grouped in five sub-kingdoms, TJie protophytes are
the lowest form of vegetable life. They consist each of a single
cell or of groups of cells. In this sub-kingdom are included the
yeast plant, and other similar substances known as ferments, the
organisms that produce all the forms of "rotting" or putre-
faction, and the host of bacilli, bacteria, and micrococci (com-
monly known as "microbes") that are productive of disease and
various structural changes. The Thallophytes include the plants
in which there is little or no distinction between leaf and stem,
such as lichens and fungi. Nearly all the " sea- weeds " and the
vegetable "moulds " belong to this sub-kingdom.

Tlie bryophytts comprise the mosses and the liverworts. TJie
pteridojjhytes rank a little higher. They include the club-mosses,
horse-tail rushes, and true ferns. All the foregoing sub-kingdoms
are flowerless ; they reproduce by means of minute spores that
are borne in receptacles on some protected part of the plant. The
dust coming from a bursting puff-ball consists of spores, and these
have the reproductive properties of seeds or eggs. The phanero-
gams include all the species of grasses, shrubs, flowering plants
and forestry. Their growth, like that of certain lower forms, con-
sists of two parts, the roots and the aerial portion. They repro-
duce by means of flowers and seeds.

'This term is used here because, unfortunately, it is almost
universally employed in the science of geography. What really
has occurred to spread the species is a migration or a dispersal.


' This classification by regions or centres is practically the same
as that proposed by Professor Wallace, except that the names
Eurasian, i^orth American, and South American, are substitu-
ted for palcearctic, nearctic, and neotropical. This scheme has
been adopted because it is based strictly upon geographic laws.

* Buckwheat, for convenience, is included in this list. The
name is a corruption of " beech- wheat, " on account of the resem-
blance of the kernel to that of the beech-tree. It is said to have
been introduced into Europe by the Saracens, and in parts of
Europe it bears the name Saracen wheat. It probably came
from Manchuria.

^ To these should be added the beet, whiih is now extensively
cultivated for the purpose of sugar-manufacture. In tropical
America certain agaves, near relatives to the grasses, are the source
of not a little sugar.

^Tlie yam is found also in the East Indies, and it is a disputed
question whether or not the American species is a descendant of
that of India.

"This fruit is commonly but incorrectly known as a currant.
The latter is regarded as native to Eurasia, but Avild species are
certainly indigenous to western North America. The apple and
the plum, said to be native to Eurasia, are also found wild in
North America. The peach seems to have originated in Persia,
from which the name is derived.

"The fox grape, a wild fruit growing in Canada and tlie New
England States, was discovered and described by tlic Norse ex-
plorers who visited North America about A.D. 1000. Tlie culti-
vated species of America are mainly imported ; tlic Concord is an
improved wild species of America.

'' The potato, tomato, and tobacco are the most important Ameri-
can representatives of this family. The "jimson" (probably a
corruption of Jamestoirn) and other species of tlie datura stramo-
nium are found in all moist and warm regions of Nortli Aiiicrica.

'" Barbados and Sea-Island cotton are native to America.

"The classification of animals is somewhat more difllciilt tliaii
that of plants. The animal kingdom is divided into cigiit gn-at
branches f)r groups ; these are again dividi-d into<-iasscs and sub-
divided int(; the following orders :

Protozoans, the lowest forms of aniinai life, sucii as rhizopoils.
infusoria. Porifera, of wliicli the sponges are the <hicf Hpecies.


Ccelenterates, of which the coral-polyps, jelly-fish, and sea-
anemones are the best types. Echinoderms, represented by the
star-fishes, sea-urchins. Vermes, or true worms. Mollusks, or
shell-flsh, such as the oysters, clams, limpets, snails, and slugs.
Arthropods, including the types of lobsters, crabs, spiders, scor-
pions. Vertebrates, or animals having the back-bone.

Of these the first four inhabit the water ; the remainder include
both land and water animals. The vertebrates comprise various
classes of which the principal are mainmals, or warm-blooded
animals that suckle their young ; birds, mainly aerial in their
habits ; reptiles, including snakes, lizards, and turtles ; batra-
chians, represented by frogs and toads, smd Jishes — all aquatic in
their habits.

'■^ The factors that have governed the dispersal of animal
species cannot always be determined. It must be borne in mind
that dispersal began in prior geological times, when the condi-
tions of envii'onment were often different from those of the pres-
ent age. In the case of marine life, the limits to the territory of
species are bounded mainly by the temperature of the water.
The fauna of cold currents is materially different from that of
warm waters. Deep sea species are wholly different from surface
species also. The fish living at the bottom of the deeper parts of
the sea are mainly sharks, several new species of which were dis-
covered by the Prince of Monaco at a depth of two miles.

'^ The camel probably originated in America, but became ex-
tinct before the Glacial Epoch. In 1858 it was introduced into
the Basi-n Region of the United States and a few head still sur-
vive in the Gila Desert of Arizona. The popular distinction
between the camel and the dromedary is a very misleading and
an incorrect one. The latter term (from a Greek word, to run,)
first applied to a species remarkable for fleetness, afterward came
to include any camel trained to fleetness of movement.

"* There is some evidence of the existence of pygmies in Europe
during the neolithic period, and recent discoveries in Switzer-
land strongly confirm the evidence. Dr. E. M. Aaron has called
attention to the fact that the archaeological records of Cozumel,
an island east of Yucatan, bear evidence of the existence of a
pygmy race. The ruins of the diminutive store-houses that are
still found on the island, and the small human skulls lend credi-
bility to the theory of pygmy existence in America.


Man, though at the head of auimate creation so far as
the development of reasoning powers are concerned, from
a physiological stand-point is distinctly an animal, and is
closely related to other vertebrates.' The skeleton of a
man does not differ materially in structure from that of
a monkey, a bear, a dog, or a bat ; it does not differ very
greatly from that of a whale, a lizard, or a bird ; it closely
resembles that of the gorilla.

With respect to nutrition the resemblance is still
stronger. The digestive apparatus and the various
processes by which food is converted into blood, bone,
and flesh are the same in man as in other mammals.
The food, moreover, is practically the same — water, grain,
fruit, and the flesh of other animals. The organs by
which the blood is circulated are the same, and the proc-
esses involved in breathing do not differ in any essential

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Online LibraryJacques W. (Jacques Wardlaw) RedwayElementary physical geography : an outline of physiography → online text (page 22 of 25)