Evolution
Submitted By:
Zainab Batool
Bs 7th E01 F21
SESSION 2021-2023
Submitted To:
Prof. Dr. M Akbar Khan
Principles Of Paleontology
Institute Of
Zoology
University Of
Punjab

Content
Evolution
Lamarck’s Theory of Evolution
Darwin’s Theory of Evolution
Natural Selection
Artificial Selection
Evidence of Evolution
Misconceptions

What is Evolution
• It means that all living things on Earth are descended from a
common ancestor.
• The great diversity of organisms is the result of more than 3.5
billion years of evolution that has filled every available niche
with life forms.
• The millions of different species of plants, animals, and
micro-organisms that live on Earth today are related by
descent from common ancestors.

BILL NYE
Evolution is the
fundamental idea in all
of life science–in all of Biology

Lamarck's Theory
Organisms constantly strive to improve themselves
by changing.
Changes are adaptations to environment acquired
in an organism's lifetime.
A structure is modified or changed by use or
disuse.
The modification is inherited to the offspring.
Inheritance of acquired characteristics.

Lamarck’s View
The Development of long
necks in giraffes is an example of
Lamarck’s Theory of Evolution.
“Giraffes got their long necks by
striving to reach the leaves on the
tops of trees, so their babies were
born with long necks”

Charles Darwin (1809-1882)
He was an English Naturalist.
He travelled around the world
on his ship, the Beagle.
Studied species and fossils in
the Galapagos Islands and
around the world.
Why did some species survive
while others became extinct?
Natural selection Published
The Origin of Species in1859

Darwin’s Theory
Darwin's theory of evolution has four main parts:
Organisms have changed over time, and the ones
living today are different from those that lived in the
past.
 Change is gradual and slow, taking place over a
long time. This was supported by the fossil record.
 All organisms come from common ancestors by a
process of branching.
The mechanism of evolutionary change is natural
selection.

On The Galapagos Islands
 He studied different species of finches and the
slight variations in their beaks-
He noticed that the shapes of tortoise shells also
varied slightly from island to island.
He found fossils of animals that had recently
become extinct.
He kept a journal and collected fossils and
specimens for further study.

Darwin’s Finches
These are some of the finches that
Darwin studied on his voyage.
Though they are all finches, their
beaks distinguish them from one
another
Some finches developed short,
strong beaks that made it possible
for them to crack nuts.
 Some developed long, fine beaks to
reach insect larvae in tiny holes
 This is an example of how these
finches adapted to their environment
to survive (natural selection)

Natural Selection