This document provides information about evolution from a class project. It defines evolution and discusses inherited versus acquired traits. It also summarizes Charles Darwin's theory of evolution by natural selection and his work. Key topics covered include evidence of evolution from homologous and analogous organs as well as fossils, and how complex organisms evolved in stages from simpler forms.

1. TOPIC-EVOLUTION
PREPARED BY-S.
ABHISHEK
GROUP MEMBERS-AKASH
RAJAT SAHOO-03
S.ABHISHEK-04
PRITHVI PATTANAIK
ARNAV PATTANAIK
CLASS-X’B’
GUIDED BY –
Mrs. S.TRIPATHY

2. EVOLUTION
The gradual changes taking place in living
organisms giving rise to
new organisms due to changes in their
genetic composition is called
evolution.

3. ACQUIRED and INHERITED TRAITS
a. Inherited traits :-
Inherited traits are traits in an organism due to changes in the
genetic composition and it can be passed from one generation to the
next and it results in evolution..
b. Acquired traits :-
Acquired traits are traits which are acquired by an organism
during its lifetime and it cannot be passed from one generation to the
next and it does not result in evolution.

4. DIFFERENCE BETWEEN ACQUIRED and
INHERITED TRAITS
ACQUIRED
INHERITED
TRAITS
TRAITS
i-These are somatic variations. i- These are genetic variations.
ii- Acquired traits develop due to the
effects of environmental factors, use
and disguise of organs and special
(conscious) efforts.
ii- Inherited traits develop due to
reshuffling of genetic material and
mutations.
iii- These traits develop throughout
the lifetime of an individual, and die
with death of that individual.
iii- these traits are transferred
(inherited) by the parents to their
offspring. These don’t die but are
passed on to the next generation.
iv- Example- Learning of dance,
music, etc. and muscular body of a
wrestler.
iv- Example- Attached or free earlobe
and curly hair.

5. CHARLES DARWIN
(1809-1882)
Charles Robert Darwin (1809-1882) at the age of 22
went around the world in a ship HMS Beagle. During
is journey he collected a number of fossil, flora and
fauna. He conducted various experiment and
formulated his hypothesis that evolution took place
due to natural selection. In 1858, by mutual
agreement, Darwin and Wallace presented a joint
paper on their theory. Darwin was an accomplished
naturalist and he also explained the role of
earthworms in soil fertility. Darwin didn’t notice
Mendel’s work as relevant to his.

6. CONCLUSIONS OF DARWIN’S THEORY
 All animals and plants have a natural tendency to
produce offspring
 The number of offspring is maintained at a constant
level.
 Struggle for existence.
 variation and Heredity.
 Survival of the fittest.
 Original of species.
 Inheritance of useful variations.

7. ORIGIN of LIFE on EARTH
A British scientist (he turned Indian citizen later) J.B.S. Haldane
(1929) and Russian scientist Oparin (1924) proposed the theory
of origin of life. This theory states that:
a) The lighter elements were present at atomic form.
b) As the temperature of earth decreased the lighter elements
combined to form the water, methane , ammonia, hydrogen
molecules (H2) and carbon dioxide.
c) All these molecules interacted in hot atmosphere of the earth
and formed sugar, amino acids, alcohol, fatty acids, etc.
d) By further interactions of these biochemicals, some complex
organic molecules were formed.
Later on an experiment was conducted by Stanley Miller and
Harold Urey in 1953 maintaining the similar atmospheric
conditions those were existed on early earth. At the end of the
experiment they found that 15% of the carbon converted to
simple carbon such as amino acids which form the proteins.

8. SPECIATION
Speciation is the formation of new species from pre-existing
species. A new species may be formed from the
populations occurring in different areas of distribution,
the process is called allotropic speciation. While when a
new species is formed from a fragment of population in
the same area due to mutation, it is called sympatric
speciation. Speciation also depends on type of evolution
i.e. micro-evolution and macro-evolution.

9. MICRO-EVOLUTION
Micro-evolution is the formation of a species due to
small but significant changes such as a change in gene
or gene mutation and gene recombination. For
example, if the group of beetles in an illustration we
have discussed earlier, splits into two populations and
don’t breed together can be called two species. It is
because they will develop some changes in genes for
pesticide resistance, high temperature tolerance etc.

10. MACRO-EVOLUTION
Macro-evolution is the development of different
genera and taxa. For such an evolution a part of
population should by a barrier so that the two sections
of a population cannot interbreed.

11. CLASSIFICATION
The arrangements of different organisms into groups
and subgroups based on their physiological,
biochemical and anatomical similarities and
dissimilarity is called classification. These similarity
and dissimilarity are the characteristics present in the
organisms. Characteristics are the details of physical
appearance, physiological and behavioristic features
of an organism. For example, the presence of four
limbs is a characteristics feature of human beings and
the process of photosynthesis is an important
character of green plants.

12. ANCESTRAL CHARACTERISTICS
There are some basic characteristics found in all
members of a large population . These characters
decide the fundamental differences among different
groups of organisms. For example, wings are found in
fish, forming two different groups of animals.

13. DERIVED CHARACTERISTICS
These are the characteristics developed due to the
evolutionary changes in ancestral or basic characteristics.
Derived characteristics determine the subgroups or
smaller groups of organisms. These characteristics help in
the classification of different organisms into smaller units
or groups. The presence of similar characteristics in
different organisms suggest their origin from the
common ancestor.

14. COMMON CHARACTERISTICS SHARED
BY MOST OF THE LIVING ORGANISMS
 Cell is the basic unit of life in all organisms.
 On the basis of presence or absence of well defined nucleus,
organisms can be divided into two groups- prokaryotes and
eukaryotes.
 The eukaryotes which have the cells with well defined
nucleus can be further divided into two groups – unicellular
and multicellular organisms based on whether they are
made up of a single cell or many cells.
 The multicellular organisms may have cellular level of
organisms or tissue level of organisms. The multicellular
organisms can also be classified based on whether they can
do photosynthesis or not .
 The multicellular organisms who can do photosynthesis are
called plants and those who cannot do so are called animals.
 The multicellular animals can be grouped on the basis of
presence or absence of skeletons inside the body.

15. Evidences of evolution
There are a number of common features in different
organisms which provide evidence to show
evolutionary relationship. The main
evidences of evolution are from the studyof:-
Homologous organs, Analogous organs and Fossils

16. Homologous organs
The organs which are similar in structure but different in
functions. Eg :- The fore limbs of amphibians, reptiles, birds, and
mammals have similar structures but different functions. Frog
(amphibian) uses its fore limb to raise the front of the body. Lizard
(reptile) uses its fore limb for walking and running. Birds fore
limbs are modified as wings for flying. Mammals use the fore
limbs for grasping, walking, running, swimming, flying etc. This
shows evolutionary relationship.

18. ANALOGOUS ORGANS
The organs which are different in structures
but similar in functions.
Eg :- The wings of butterfly, bird and bat have
different structures but similar functions. This
shows evolutionary relationship.

20. FOSSILS
The remains of organisms which lived long ago
are called Fossils . From the study of fossils
we can know their structures and the time
period in which they lived. The fossils of
complex and recent organisms are found
closer to the surface of the earth and the
fossils of simpler organisms are found deeper
inside the earth. The age of fossils can be
determined by Radio Carbon Dating. The study
of fossils show evolution of simpler forms into
complex forms and their evolutionary
relationship.

21. Tree trunk fossil Fish fossil (Knightia)
Ammonite – Invertebrate Trilobite – Invertebrate Dinosaur skull - Rajasaurus

22. TYPES OF FOSSILS
Trilobite- It is a Paleozoic arthropod with trilobed
dorsal plates, joint appendages and a pair of
antennae.
1. Ammonite – It is a spirally coiled shelled molluse
which underwent mass scale extinction along
with dinosaurs.
2. Rajasaurs- The Rajasaurs (dinosaurs) skull was
found only a few years ago in the Narmada Valley.

23. EVOLUTION by STAGES
Complex organisms and its organs developed from
simpler organisms gradually over generations.
i) Evolution of eyes :- The eyes of planaria are just eye
spots to detect light. It developed gradually into a
complex organ in higher animals.
ii) Evolution of feathers :- Feathers were first
developed in dinosaurs and used for protection from
cold. Later birds used them for flying.
iii) Evolution by artificial selection :- Humans cultivated
wild cabbage for over 2000 years and produced
different vegetables from it by artificial selection.
Eg :- Cabbage – by selecting short distance between
the leaves.
Cauliflower – by selecting sterile flowers.
Kale – by selecting large leaves
Kohlrabi – by selecting the swollen stem
Broccoli – by arresting flower growth

25. Embryology

26. Evolution should not be equated with progress
Evolution has not resulted in progress. Evolution has resulted in
the formation of several complex species from simpler species
due to variations, genetic drift and natural selection. This does not
mean that one species gets eliminated when new species are
formed or that the new species are better than the older species.
Species get eliminated only if they are not able to adapt to the
changes in the environment. Several species which could adapt to
the changes in the environment still continue to survive for
example bacteria. Human beings have not evolved from
chimpanzees. They had a common ancestor from which they
evolved separately. Human beings are not the pinnacle of
evolution but they are only one species among the several
evolving species.

27. Human evolution :- (Homo sapiens)
 There is a great diversity among human beings
in their form and features around the world.
Human beings evolved in Africa. Some of them
stayed there and others migrated to different
parts of the world. Then due to genetic variations
and the environmental changes in different
geographical regions they developed changes in
their forms and features.