2. Some definitions of
Ecology:
Charles Elton
(1927)- wrote the
book “Animal
Ecology”. In this
book, he defined
ecology as “the
study of the
scientific natural
history”.
3. Eugene P. Odum
(1963)- defined
ecology as “the
study of the
structure and
function of
nature”.
Some definitions of
Ecology:
4. Andrewartha (1961)-
also gave a clear and
restrictive definition of
ecology: Ecology is
the scientific study
of the distribution
and abundance of
organisms.
Some definitions of
Ecology:
5. Charles J. Krebs (1985)-
gave a precise definition of
ecology based on the
modification of Andrewartha’s
definition: Ecology is the
scientific study of the
interactions that determine
the distribution and
abundance of organisms.
Some definitions of
Ecology:
6. Ecology
Is the scientific study of the interactions
between organisms and their environment.
The word ecology originated from two Greek
words; oikos and logos.
Oikos= “household”, “home” or “place to live”
Logos= “knowledge”, “study”
8. Human Ecology
Is an academic
discipline that deals
with the association
between humans and
their natural
environment.
9. The main task of human
ecology…
The investigation of human health condition
The research of dynamics of human health
condition in the process of historical and socio-
economical development
The determination of correlative dependence
between human diseases and environmental
pollution;
The investigation of the processes of human
health protection
11. 4 Main Theories of Evolution
Lamarckism or Theory of
Inheritance of Acquired characters
Darwinism or Theory of Natural
Selection
Mutation Theory of De Vries
Neo-Darwinism
12. 1. Lamarckism
Also called “theory of
inheritance of acquired
characters” and was proposed
by a great French naturalist,
Jean Baptiste de Lamarck in
1809 A.D. in his famous book
“Philosophic Zoologique”.
This theory is based on the
comparison between the
contemporary species of his
time to fossil records.
13. Summary of Four
Postulates of Lamarckism:
Living organisms or their component parts tend to
increase in size.
Production of new organ is resulted from a new need.
Continued use of organ makes it more developed,
while disuse of an organ results in degeneration.
Acquired characters developed by individuals during
their own lifetime are inheritable and accumulate over
a period of time resulting to a new species.
14. Criticism of Lamarckism:
A hard blow to Lamarckism came from a
German Biologist, August Weisman
who proposed the “Theory of
continuity of germplasm” in 1982 A.D.
this theory states that environmental
factors do affect only somatic cells and
not the germ cells.
15. Significance:
It was the first comprehensive theory of
biological evolution.
It stressed on adaptation to the
environment as primary product of
evolution.
16. 2. Darwinism
Also called Theory of Natural Selection
Charles Darwin (1809-1882 A.D.) an English
naturalist, was the most dominant figure among the
biologist of the 19th century. He made an extensive
study of nature for over 20 years, especially in 1831-
1836.
In 1858 A.D., Darwin was highly influenced by short
essay entitled “On the Tendency of Varieties to
Depart Indefinitely from the Original Types”
written by another naturalist, Alfred Russel Wallace
(1892-1913) who studied biodiversity on Malayan
archipelago and came to similar conclusions.
17. Darwin and Wallace’s views about evolution
were presented in the meeting of Linnean
Society of London by Lyell and Hooker on July
1, 1858. Darwin’s and Wallace’s work was jointly
published in “Proceeding of Linean Society of
London” in 1859. So it also called Darwin-
Wallace Theory.
Darwin explained his theory of evolution in book
entitled “On the Origin of Species by means of
Natural Selection”. It was published on the 24th
Nov., 1859. in this theory, Charles Darwin
proposed the concept of natural selection as the
mechanism of evolution.
18. Postulates of Darwinism:
Geometric increase
Limited food and space
Struggle for existence
Variations
Natural selection or survival of the
fittest
In heritance of useful variations
Speciation
19. 1. Geometric Increase
According to Darwinism, the populations
tend to multiply geometrically and the
reproductive power of living organisms
are much more than required to maintain
their number.
20. 2. Limited food and space
Darwinism states that through a
population tends to increase
geometrically, the food increases
only arithmetically.
21. 3. Struggle for existence
Due to rapid multiplication of populations but
limited in food and space, there starts and
everlasting competition between individuals
having similar requirements.
3 types of Struggle for Existence
1. Intraspecific- between the member of the same
species
2. Interspecific- between the members of different
species
3. Extra specific or environmental- between
living organism and adverse environmental
factors.
22. 4. Variations
Darwin stated that the variations are generally of two
types- continuous variations and discontinuous
variations.
Darwin proposed that living organisms tend to adapt to
changing environment due to useful continuous
variations (e.g., increased in speed, increased in water
conservation in plants) as these will have a competitive
advantage.
23. 5. Natural selection
Darwin stated that as many selects the individuals with
desired characters in artificial selection; nature selects
only those individuals out of the population which are
with useful continuous variations and are best adapted
to the environment while the less fit or unfit individuals
are rejected by it.
Darwin stated that if the man can produce such a large
number of new species/varieties with limited resources
and in short period of time by artificial selection, then
natural selection could account for this large
biodiversity by considerable modifications of species
with the help of unlimited resources available over
long span of time.
24. Darwin stated that discontinuous variations
appear suddenly and will mostly be harmful, so
are not selected by nature. He called them
“sports”. So the natural selection is an automatic
and self going process and keeps a check on
the animal population.
This sorting out of the individuals with useful
variations from a heterogeneous population by
the nature was called Natural selection by
Darwin and Survival of the fittest by Wallace. So
natural selection acts as a restrictive force
and not a creative force.
25. 6. Inheritance of useful
variations
Darwin believed that the selected
individuals pass their useful
continuous variations to their
offsprings so that they are born fit to
the changed environment.
26. 7. Speciation
According to Darwinism, useful variations
appear in every generation and are inherited
from one generation to another. So the useful
variations go on accumulating and after a
number of generations, the variations
become so prominent that the individual
turns into a new species. So according to
Darwinism, evolution is a gradual process
and speciation occurs by gradual changes in
the existing species.
27. Evidence in favour of
Darwinism:
There is a close parallelism between natural
selection and artificial selection.
The remarkable cases of resemblance e.g.
mimicry and protective coloration can be
achieved only by gradual changes occurring
simultaneously both in the model and the
mimic.
Correlation between position of nectaries in
the flowers and length of the proboscis of the
pollinating insect.
28. Evidence against Darwinism:
Darwinism is not able to explain:
1. The inheritance of small variations in those
organs which can be of use only when fully formed
e.g. wing of a bird. Such organs will be of no use
in incipient or underdeveloped stage.
2. Inheritance of vestigial organs.
3. Inheritance of over-specialized organs e.g.
antlers in deer and tusk in elephants
4. Presence of neuter flower and sterility of
hybrids.
29. 5. Did not differentiate between somatic and
germinal variations.
6. He did not explain the causes of the variations
and the mode of transmission of variations.
7. It was also refuted by Mendel’s laws of
inheritance which state that inheritance is
particulate
30. So, this theory explains only the
survival of the fittest but does not
explain the arrival of the fittest so
Darwin himself confessed, ”Natural
selection has been main but not
the exclusive means of
modification”.
31. 3. Mutation Theory of Evolution:
The mutation theory of evolution was proposed by a
Dutch Botanist, Hugo de Vries (1848-1935 A.D.),
in 1901 A.D. in his book entitled “Species and
Varieties, Their Origin by Mutation”.
He conducted his experiment on Oenothera
Lamarckiana in botanical gardens at Amsterdam.
The plants were allowed to self pollinate and next
generation was obtained. The plants of next
generation were again subjected to self pollination
to obtain second generations. Process was
repeated for a number of generations.
32. Evidences in favour of Mutation
Theory:
Appearance of a short-legged sheep variety, Ancon
Sheep, from long-legged parents in a single
generation in 1791 A.D.. It was first noticed in a ram by
an American farmer, Seth Wright.
33. Mutation theory can explain the origin
of new varieties or species by a single
gene mutation
It can explain the inheritance of
vestigial and over-specialized organs.
It can explain progressive as well as
retrogressive evolution.
34. Evidences against Mutation
theory:
.
Rate of mutation is very low, (one per million or one
per several million genes)
Oenothera lamarckiana is a hybrid plant and contains
anamolous type of chromosome behaviour.
Chromosomal numerical changes as reported by de
Vries are unstable.
Mutations are incapable of introducing new genes and
alleles into a gene pool.
35. 4. Neo-Darwinism or Modern
Concpet of Syntghetic Theory of
Evolution:
Modern or synthetic theory of evolution was
designated by Huxley (1942). It emphasizes the
importance of populations as the units of evolution
and the central role of natural selection.
The scientist who contributed to the outcome of Neo-
Darwimism were: J.S. Huxley, R.A. Fischer and
J.B.S. Haldane of England; and S. Wright, Ford, H.J.
Muller and T. Dobzhansky of America.
36. Summary Postulates of Neo-
Dawinsim:
1. Neo-Darwinism is a modification of the
original theory of Darwin to remove its short-
comings.
2. Instead of continuous variations, mutations
are believed to help form new species.
3. Variations accumulate in the gene pool and
not in the individuals.
4. Neo-Darwinism incorporates isolation as an
essential component of evolution.
37. What is the significance of
Environment in the Human
Natural History?
38. As the environment changes, the
organisms continuously change,
eventually causing to evolve into a
new species.
40. What is Geography?
Is the spatial study of the earth’s
surface.
From the two Greek words “geo” and
“graphein”
Geo= Earth
Graphein= to write
41. Two main areas of Geography:
Physical Geography
Human Geography
42. 1. Physical Geography
Is the spatial study of natural
phenomena that make up the
environment such as rivers, mountains,
landforms, weather, climate, soils,
plants, and any other physical aspects
of the earth’s surface.
43. The major forms of study within
physical geography include the
following:
Geomorphology- the study of the earth’s surface
Glaciology- the study of glaciers
Coastal geography- the study of the coastal regions
Climatology- the study of climates and climate
change
Biogeography- the study of the geographic patterns
of species distribution
44. Physical Landscape
Is the term used to describe the natural
terrain at any one place on the planet.
The natural forces of erosion, weather,
tectonic plate action, and water have
formed the earth’s physical features.
45. 2. Human Geography
Is the study of human activity and its
relationship to the earth’s surface.
Human geographers examine the
spatial distribution of human populations,
religions, languages, ethnicities, political
systems, economics, urban dynamics
and other components of human activity.
46. Cultural Landscape
Is the term used to describe those parts of the
earth’s surface that have been altered or
created by humans.
Urban Cultural Landscape- buildings, streets,
signs, parking lots, vehicles…
Rural Cultural Landscape- fields, orchards,
fences, barns, farm steads…
47. Basic concepts in Geography
Island- it is any piece of sub-
continental land that is
surrounded by water.
Peninsula- a body of land
surrounded by water on
three sides. Comes from the
Latin word “paene insula”
meaning “almost an
island”.
48. Strait- it is naturally
formed, narrow,
typically navigable
waterway that
connects two larger
bodies of water.
Isthmus- it is a narrow
strip of land connecting
two large land areas
otherwise separated
by sea.
49. Gulf- it is portion of the
ocean that penetrates
land.
Archipelago- a chain or
group of island that is
group together
50. Caldera- a bowl-
shaped circular
depression caused by
the destruction of the
peak of a volcano.
Desert- an area with a
little precipitation
51. Epicentre- the point
on the earth’s surface
directly above the
hypocentre, where
the energy of an
earthquake is first
released.
Erosion- forces that
shape the earth’s
surface. Includes
water, wind and ice.
52. Estuary- the end of a
river when it meets the
sea;
Geologic time- the
calendar of the earth’s
history since it’s birth
4.6 billion years ago…
53. Glacier- a large mass of
ice that moves over the
land, carving and
eroding surfaces as it
moves.
Globe- a spherical
model of the earth’s
surface that includes a
map of the earth.
54. Cartogram- a “map”
that is used to present
statistical information.
Cartography- the art
and science of making
maps.
55. Census- an
investigation or
count of a
population.
Demography- the
study of population
statistics and
trends, such as
births, deaths, and
disease.
56. Equator- zero
degree latitude
divides the earth
into the Northern
and Southern
hemispheres
Latitude- angular
degrees based on
the equator,
57. Longitude- angular
degrees based on the
Prime meridian
Map- a graphic
representation of the
earth’s surface.
58. Region- an area which is
marked common
characteristics
Prime meridian- zero
degrees longitude, also
known as the
Greenwhich meridian.
60. Ecological Footprint
Is a measure of human demand on
the earth’s ecosystems. It is a
standardized measure of demand
for natural capital that may be
contrasted with planet’s ecological
capacity to regenerate. It
represents the amount of
biologically productive land and
sea area necessary to supply the
resources a human population
consumes, and to assimilate
associated waste.
61. Understanding Ecological
Footprint
Ecological footprints helps in analyzing the
pressure on our planet and ecological
footprint analysis can be a useful tool to
educate people to manage our ecological
assets more wisely and take collective action
to make sure that a nation’s demand for
products and services remain within its
borders.
62. How does the ecological
footprint work?
The ecological footprint essentially measures
the supply and demand on nature. This
means that on the supply side, biocapacity
represents the natural productive land areas.
Theses includes forests, fisheries, pastures
and cropland. When left uninterrupted or
unexploited these areas have the capacity to
absorb almost all the waste produced by
humans particularly carbon emissions.
63. Negative Effects of
Ecological Footprint:
Carbon emissions
Lack of fresh air
Global warming
Increased environmental pollution
Depletion of natural resources
64. For some perspectives, some ecological footprints of
several countries are listed below. These values were
listed for the year 2017 in the Global Footprint
Network’s Open Data Platform:
The units for ecological footprints are global
hectares (gha)
United States: 8.0 gha/person
Russia: 5.5 gha/person
Switzerland: 4.5 gha/person
Japan: 4.7 gha/person
France: 4.6 gha/person
China: 3.7gha/person
Indonesia: 1.7gha/person
65. According to Global Footprint
Network, if everyone lived the lifestyle
of the average American US citizen
i.e. similar eating, transportation,
living, and consumption habits, we
need 5 planets to support ourselves.
66. Note that ecological footprints can be
counterbalance by biocapacity, which
refers to the ability of a biologically
productive area to continuously
generate renewable resources and
clean up its wastes. An area is
considered unsustainable if a land’s
ecological footprint is greater than its
biocapacity.
67. Simple steps to reduce your
ecological footprint:
Don’t drive when there is an alternative
Reduce energy use
Eat local, organic and in season foods
Eat less meat and dairy
Use less water
71. 1. Natural Ecosystems:
These ecosystems are capable of operating
and maintaining themselves without any
major interference by man.
a. Terrestrial Ecosystems: Forest, Grassland,
and desert
b. Aquatic Ecosystems: marine and fresh
water
72. 2. Artificial Ecosystem:
These are maintained by man. These
are manipulated by man for different
purposes, e.g., croplands, artificial lakes
and reservoirs, townships and cities.
73. Basic structure of an
Ecosystem:
Every ecosystem has non-living
(abiotic) and living (biotic)
components.
75. Biotic Components:
a. Autotrophic components (Producers)- this
component is mainly constituted by green
plants, algae and all photosynthetic organisms.
b. Heterotrophic component (Consumers-
the members of this component cannot make
their own food. They consume the matter built
by producers and are therefore called as
consumers.
76. c. Decomposers- heterotrophic
organisms chiefly bacteria and fungi that
breakdown the complex compounds of
dead protoplasm, and release simple
substances usable by the producers are
called decomposers or reducers.
Collectively we call them as micro
consumers.
78. Ecology can subdivided into
two:
Synecology (plant sociology/general
ecology)- Syn means together. Synecology is
the study of groups of organisms in relation to
biotic and abiotic factors.
Autecology (physiological ecology/
applied ecology)- Aut means self.
Autecology is concerned with the responses
of our individual organisms to temperature,
moisture, light, nutrients and other factors of
the environment.
80. Ecosystem
A geographic area where plants,
animals, and other organism as well
as weather and landscape, work
together to form a bubble of life.
Ecosystem contain biotic or living
components as well as abiotic or the
non-living components.
81. In nature, vegetation or plant
communities are changing from time to
time. In the same place, the
replacement of the old plant community
by a new plant community is called
vegetation succession. Similarly, an
ecosystem is replaced by another
ecosystem, which we call the
ecosystem evolution.
82. The history of earth is divided into
four great eons, starting 4,540
million years ago (mya) with the
formation of the planet. Each eon
saw the most significant changes
in earth’s composition. Climate
and life. It means abiotic and biotic
components.
83. Four Great Eons:
1. Hadean eon
2. Archean eon
3. Proterozoic eon
4. Phanerozoic eon
85. Hadean Eon (4540-4000 mya)
Represents the time before a reliable record
of life; it began with the formation of the
planet and ended 4.0 billion years ago.
The earth is formed out of debris around the
solar protoplanetary disk. There is no life.
Temperatures are extremely hot, with
frequent volcanic activity and hellish-looking
environments (hence the eon’s name, which
comes from Hades). The atmosphere is
nebular. Possible early oceans or bodies of
liquid water.
87. Archean (4000-2500 mya)
Prokaryote life, the first form of life,
emerges at the very beginning of this
eon, in a process known as
abiogenesis. The continents of Ur,
Vaalbara and Kenorland may have
existed around this time. The
atmosphere is composed of volcanic
and green house gases.
89. Proterozoic (2500-541 mya)
The name of this eon means “early life”. Eukaryotes,
a more complex form of life, emerge, including some
forms of multicellular organisms. Bacteria begin
producing oxygen, shaping the third and current
earth’s atmosphere. Plants, later animals and
possibly earlier forms of fungi form around this time.
The early and late phases of this eon mat have
undergone “Snowball Earth” periods, in which all of
the planet suffered below-zero temperatures. The
early continents of Columbia, Rodinia and Pannotia,
in that order may have existed in this eon.
91. Phanerozoic (541-present)
Complex life, including vertebrates, begin to dominate
the earth’s ocean in a process known as the Cambrian
Explosion. Pangaea forms and later dissolves into
Laurasia and Gondwana, which in turn dissolve in the
current continents. Gradually life expands to land and
familiar forms of plants, animals and fungi begin
appearing, including annelids, insects and reptiles,
hence the eon’s name which means “visible life”.
Several mass extinctions occur, among which birds,
the descendants of non-avian dinosaurs, and more
recently mammals emerge. Modern animals- including
humans-evolve at the most recent phases of this eon.
