evolution and human evolution in detail

1. Evolution and Human evolution

2. ORIGIN OF UNIVERSE
THE BIG BANG
THEORY

3. Time begins
• The universe begins
~20 Billion years ago
• The universe begins
as the size of a single
atom
• The universe began as
a violent expansion
– All matter and space
were created from a
single point of pure
energy in an instant

4. Beginning of life
• About 4.5bya,The origin of our solar system took
place by the gaseous cloud due to this explosion
• This gaseous cloud collapsed and converted into
flat disc like structure called solar nebula
• Hot centre part become more hotter and
converted to sun.
• Now due to condensation of atoms and dust
particle moving around the sun formation of the
other planets took place.

5. ANCIENT THEORIES OF LIFE ORIGIN
1.THEORY OF SPECIAL CREATION
All the different forms of life - created by God.
1. HINDU CONCEPT :- Lord Brahma- created the living world in one
stroke. The first man was Manu and woman was Shraddha
2. CHRISTIAN & ISLAM BELIEF :- God created this universe, plants,
animals and human beings in about six days.
3 main postulates : –
• All different kinds of animals & plants were created at once.
• All organisms were created in the same form in which they exist
today.
• The earth is 4000 years old.
• It has no scientific basis.

6. 2. THEORY OF SPONTANEOUS GENERATION
• Living things originated spontaneously
from inanimate objects.
• It is also called abiogeniesis or biopoesis.
Supporters :-
Aristotle
Epicurus
Von Helmont
• They believed
» Insects arise from dew
» Fish & frog from mud
» Fly maggots from meat .
• Opposers
» Fransisco Redi
» Spallanzani
» Louis pasteur
• The opposers disproved this theory.

7. 3. Theory of Biogenesis
• By Harvey and Huxley
• Biogenesis is the production of new
living organisms or organelles
• ‘Omnis vivum ex ovo or vivo’ Latin for "all
life [is] from life
• That is, life does not spontaneously arise from
non-living material, which was the position held
by spontaneous generation
• This theory disproved the theory of abiogenesis by
two experiment
1.Francesco Redi Experiment 1668
2.Louis Pasteur 1862

9. • Also known as Naturalistic theory.
• Proposed independently by a Russian scientist, A.I.Oparin, in
1923 and an English scientist, J.B.S Haldane, in 1928.
• According to this theory, Life first arose from a collection of
chemical substances by a progressive series of reactions.
• 1st life originated in the water of ocean,so water is essential
for life origin
• Early Earth's surface and atmosphere – radically different
from today’s condition.
• The earth has originated 4.6bya,early earth had free atoms
carbon,hydrogen,nitrogen and oxygen.
• Due to presence of high temperature ,active Hydrogen
combined with all oxygen to form water that’s why, The
primitive earth's atmosphere -reducing type.
• Solar radiation, lightning ,heat of volcanic eruption must
have been the chief energy source for these chemical
reactions.
• Origin of Simple and complex organic compounds happened
and gradually accumulated in oceans and formed a
―hot primordial soup or hot dilute soup

10. In Cont’d
BIOLOGICAL EVOLUTION
• the organic and inorganic Macromolecules
aggregated and precipited in sea forming
organized colloid aggregates called coacervates
and were unable to reproduce
• They contain nucleic acid,lipid,polysaccharides
etc
• The coacervates were able to absorb and
assimilate organic compounds from the
environment in a way reminiscent of
metabolism.
• Oparin considered that the coacervates gave rise
to primitive cells or Eubionts
• Eubiont gave rise to Prokaryotes-cyanobacteria
2bya and these organism librate the oxygen by
photosynthesis
• Atmosphere has changed from reducing to
oxidising

12. THE MODERN THEORY OF EVOLUTION
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13. Lamarck’s Theory of Evolution
– Jean Baptiste de Lamarck believed that species
were not constant but that they changed, and that
new species evolved from preexisting species.
• He thought these changes were caused by
their need to adapt to changes in the
environment.
• His theory had two principles:
– Use and disuse
– Inheritance of acquired characteristics
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14. Use and Disuse
• The more a body part is used the stronger and
more developed it becomes. Parts that are not
used become weaker and less developed.
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15. Inheritance of Acquired
Characteristics
• Characteristics developed by
use could be passed on to
offspring.
• Lamarck said this was how
giraffes got their long necks:
by using them to stretch for
food their necks became
longer and that trait was
passed on to offspring. Over
time giraffe’s necks became
longer and longer.
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16. Weismann disproves Lamarck
• Weismann cut the tails
off mice and bred them
for over 20 generations.
Each time the mice
were born with tails.
• We now know that
traits are passed on by
genes which are not
affected by life
experiences.
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17. Charles Darwin
• Sailed on the HMS Beagle
as ship’s naturalist
• Collected and observed
specimens from South
America ,South africa and
the Galapagos Islands
• He thought that species
changed slowly over time.
• He influenced by two
books
–Principles of
population by Malthus
-Principles of
geoglogy by Charls Lyell
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18. Two key concept of Darwing theory
1. Natural selection
2. Branching Descent/Adaptive radiation

21. • He reasoned that because there is a struggle to
survive, those who are better adapted to the
environment (more fit) will survive to reproduce
and those not as well adapted (less fit) won’t.
• This he called natural selection because it is
nature that is selecting who survives.
• The idea of Natural selection first striked in A.R
Wallace, he wrote an essay and sent it to Darwin
• Wallace and Darwin jointly proposed the theory
of Natural selection

22. The Main Points of The Darwin-Wallace
Theory of Evolution:
• Overproduction – produce more offspring than
needed because only a few will survive.
• Competition – offspring must compete for food,
water, shelter so only a few survive.
• Variation – differences in individuals. Some may
affect the ability to compete.
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23. • ADAPTATIONS – because of variations some
individuals will be better adapted to survive and
reproduce than others. These individuals are the
most fit. An adaptation is any kind of inherited
trait that improves an organism’s chances of
survival.
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These beaks are
adaptations for
eating different
types of food.

24. • The more variations that exist in a species the
better that species chances of survival are if the
environment changes.
• A change in the environment does not cause the
variations – the variations must be present
before the environment changes in order to be
selected for.
• A selecting agent determines who survives.
• Natural selection – the environment selects
those best adapted to survive and reproduce:
survival of the fittest. These favorable traits will
be passed on.
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25. Types of Adaptations
• Structural – involve a part of the body
• Physiological – involve the metabolism
• Behavioral – involve actions
• Warning coloration – warns predators
• Camouflage – to blend in with environment
• Mimicry – copies something else
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26. Industrial Melanism – The Peppered
Moth
• The peppered moth-
Biston betularia in
England had been well
studied for a long time.
• The moth is mostly
white, but “peppered”
with dark specks.
• In 1845 a dark one-
Carbonaria form was
seen for the first time.
• By 1900, most of the
moths around the cities
were dark, while those in
the country were mostly
white. Why?
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27. Case Study: Antibiotic Resistance
• When penicillin is used on bacteria for the first time
99.99% of the bacteria die.
• The .01% of the bacteria that survive have an adaptive
variation that allowed them to survive penicillin.
• These bacteria multiply and their offspring will now be
resistant to penicillin.
• Each time penicillin is used on the bacteria, more and
more of them survive, until it is no longer effective.
• It is important to understand that the bacteria had the
variation before they were exposed to penicillin, and not
as a result of it.
• Penicillin is acting as the selecting agent.
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28. Adaptive Radiation/Branching Descent
(Divergent Evolution)
• The process by
which a species
evolves into a
number of
different species
each in a new
environment.
• Example: Darwin’s
finches: adapted to
trees or ground;
seeds or insects
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29. Darwin’s Finches
• Darwin believed that the
species on the Galapagos
Islands evolved from a
species that came from
the mainland.
• Each evolved to be
different due to different
environmental
conditions on each
island.
• Homologous organ are
the evidence for
Adaptive radiation
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30. Homology
• The similarity based on common origin, similar basic
plan of organization and embryonic development.
• Similarity in appearance and function is not necessary
• A homologous structure is an organ, system, or body
part that shares a common ancestry in multiple
organisms. Ex-

31. Criticism of Darwin
• Doesn’t explain the development of vestigial
organ.
• He wasn’t able to explain why few adapt in
population for harmful enviorment
• Doesn’t differentiate between Somatic and
germinal variation.
• He wasn’t able to explain Arrival of fittest.
• Lack of Heredity knowledge.

32. Mutation theory by Hugo De vries
•He is known chiefly for suggesting the concept of
genes, rediscovering the laws of heredity in the 1890s
while unaware of Gregor Mendel's work, for
introducing the term "mutation", and for developing
a mutation theory of evolution.
•According to him, new species are not
formed by continuous variations but by
sudden appearance of variations, which he
named as mutations. Hugo de Vries stated
that mutations are heritable and persist in
successive generations.
•He experiments on a plant Oenothera
lamarkiana

33. • Prominent features of the Mutation Theory
1. Mutations or discontinuous variations are the raw material of
evolution.
2. Mutations appear all of a sudden.
3. Unlike Darwin’s continuous variations or fluctuations, mutations do
not revolve around the mean or normal character of the species.
4. The same type of mutations can appear in a number of individuals
of a species.
5. All mutations are inheritable.
6.Useful mutations are selected by nature. Deadly mutations are
eliminated.
7. Buildup of differences produce new species. Sometimes a new
species is produced from a single mutation.
8. Evolution is a bumpy and discontinuous process.
9.Mutation theory can explain both progressive and retrogressive
(causing a return to an earlier and usually worse state) evolution

34. Evidence that support these modern
theories
1. Paleontological evidence
2. Morphological and Anatomical evidence