This document provides an overview of evolutionary evidence from biology class notes on a topic about evolutionary evidence. It discusses pre-Darwinian theories of evolution, Darwin's theory of evolution by natural selection, evidence from artificial selection experiments, the fossil record, homologous and vestigial structures as anatomical evidence, and the physical evolution of early humans including species like Homo habilis, Homo erectus, and Homo sapiens. The document is organized with headings and subheadings covering these various topics related to providing evidence for the theory of evolution.

1. DELHI PUBLIC SCHOOL,
RISALI, BHILAI, (C.G.)
(2014 – 2015)
Mockoul Ma’am
Name : -Priyam Mukherjee
Class / Sec : - X – D
Roll No. : - 33
Subject : - Biology
Topic : - Evolutionary Evidences
Teacher : - Bindu Mockoul Ma
‘am
1

2. INDEX
SR NO. CONTENTS PAGE
NO.
1. Face Page
01.
2. Index
02.
3. Evolution
04.
4. Pre-Darwinian Theories
05.
5. Inheritance of Acquired Characteristics
2

3. SR NO. CONTENTS PAGE NO.
3
8. Artificial Selection
11– 13.
9. Fossil Record
14– 17.
10. Bone Comparison
18.
11. Anatomical Evidence for Evolution
19 – 24.
- Homologous structures
- Analogous structures
- Vestigial structures
12. The Physical Evolutions of Humans

4. EVOLUTION
Evolution or organic evolution (Spenser, 1852)
is the development of newer types of
organisms from the pre-existing ones through
modification. Darwin (1859) has called
evolution to be descent with modifications.
Modification occur due to variations.
Variations develop during reproduction due to
errors in DNA copying and mutations, chance
separation of chromosomes during
gametogenesis, crossing over and chance
pairing of chromosomes. Variations taking
part in evolution are genetic variations.
Certain variations develop during life time of
an organism. They are called acquired
4

5. Pre-Darwinian Theories
• Idea of evolution did not originate Charles
Darwin
• Earliest references are from the Greeks; even
Darwin’s grandfather believed in the common
ancestry of all organisms
• Jean Baptiste Lamarck (French zoologist)
believed species were derived from preexisting
species
5

6. Inheritance of Acquired
Characteristics
• Widely accepted in early 1800s –
believed organisms develop new
organs or modify existing organs as
environmental problems present
themselves
• Organs change as the need arises
• Used giraffes as his explanation
6

7. Darwin’s Theories
• Summed up in 2 theories
• Descent with Modification: new forms appearing in
the fossil record are actually the modified
descendents of older species
• Inferred that All species had descended from one
or a few original types of life
• Accounted for biogeography: similar organisms
arise in the same geographic location
• Modern kangaroos evolved from now-extinct ancestor
7

8. Evidence of Natural Selection
Darwin collected a closely related group of 14 finch
species in the Galápagos Islands
•All were similar except for beak characteristics
•Darwin hypothesized that different beak shapes
were related to food gathering
•Darwin wrote “…one might really fancy that…
one species has been taken and modified for
different ends.” 8

9. Evidence of Natural Selection
Darwin’s finches 9

10. Evidence of Natural Selection
• Modern research has verified Darwin’s
selection hypothesis
• 3 conditions of natural selection
Variation must exist in the
population
This variation must lead to
differences among individuals
in reproductive success
Variation among individuals
must be genetically
transmitted to the next
10

11. Artificial Selection
Laboratory Experiments
•Drosophila melanogaster (fruit fly)
i. Selected fruit flies with many
bristles on abdomen
ii. Chose only those with most bristles
to reproduce
iii. 86 generations later: average
number of bristles had quadrupled
11

12. Artificial Selection
12

13. Artificial Selection
Agriculture
Corn looks very different from its ancestor 13

14. Fossil Record
Layers of rock contain fossils
new layers cover older ones
creates a record over time
fossils show a series of organisms have
lived on Earth
over a long period of time
14

15. Fossil Evidence of
Evolution
•Fossils document evolutionary
transition
•The oldest known bird fossil is the
Archaeopteryx
•It is intermediate between bird
and dinosaur
•Possesses some ancestral traits and
some traits of present day birds
•Archaeopteryx was first found in
15

16. Fossil Evidence of Evolution
Fossil of Archaeopt eryx 16

17. Fossil Evidence of Evolution
Recent discoveries
•Four-legged aquatic mammal
•Important link in the evolution of whales
and dolphins from land-dwelling, hoofed
ancestors
•Fossil snake with legs
•Tiktaalik: a species that bridged the gap
between fish and the first amphibian
•Oysters: small curved shells to large flat
shells 17

18. Compare the bones
• The same bones under the skin
● limbs that perform different functions are
built from the same bones
How could these
very different animals
have the
same bones?
18

19. Anatomical Evidence for
Evolution
•Homologous structures:
structures with different appearances and
functions that all derived from the same body
part in a common ancestor
•The bones in the forelimb of mammals are
homologous structures
•Different functions, same ancestor structure
19

20. Anatomical Evidence for
Evolution
Homology of the bones of the forelimb of mammals
20

21. Anatomical Evidence for Evolution
•Analogous structures : wing of an
insect, bird bat and pterosaur
• Strongest anatomical evidence supporting
evolution comes from comparisons of how
organisms develop.
• Early vertebrate embryos possess pharyngeal
pouches that develop into:
In humans: glands and ducts
In fish: gill slits 21

22. Anatomical Evidence for Evolution
Analogous structures :
22

23. Anatomical Evidence for
•Vestigial Evolution
structures:
have no apparent
function, but
resemble structures
their ancestors
possessed. Vestigial structures of a whale
23

24. Anatomical Evidence for
Evolution
Humans
Muscles for wiggling ears
Boa constrictors
Hip bones and rudimentary
hind legs
Manatees
Fingernails on their fins
Blind cave fish
Nonfunctional eyes
24

25. THE PHYSICAL EVOLUTION OF HUMANS
Evolution traces human development through several stages or species
from the first humanlike beings to modern humans. Although we still do
not know exactly when the evolution of humans and apes diverged or
who our common ancestor is, we do know that hominids (humanlike
creatures) began to appear over four million years ago.
Hominids are distinguished from apes most notably by their bipedalism
(their ability to walk on two feet) and by their larger brain size. All
hominids are members of the human family tree.
25

26. THE AUSTRALOPITHECINES
• Australopithecus
Anamensis
• Australopithecus Afarensis
• Australopithecus Africanus
26

27. IN SEARCH OF HOMO SAPIENS
• Homo Habilis :- 2.5 million years ago
• Homo Erectus :- 2 million years ago
• Homo Heidelbergensis :- 500 000 years
ago
27

28. Homo Sapiens
The species name, Homo Sapiens,
means “man who thinks”-an
appropriate title for the species that
formulated the spoken language and
developed more sophisticated tools.
The most ancient find was discovered
in Hungary in 1965, dating from about
450 000 to 400 000 years ago.
Other remains of Homo Sapiens have
been found in England, Germany, and
France. These bones date from
approximately 250 000 years ago, the
period between the third and fourth ice
ages.
There are two types of Homo Sapiens;
the Neanderthals, or Homo
Neanderthalis, and Modern Human, or
Homo Sapiens Sapiens.
28

29. THE MODERN HUMAN
About 40 000 years ago, modern humans moved into Europe armed
with the skills to make clothing, better shelters, and more efficient
hearths. Nineteenth-century scientists named these newcomers Cro-
Magnon people after the French rock-shelter where three anatomically
modern skeletons were discovered in 1868.
Cro-Magnons were Homo Sapiens who evolved in Africa and slowly
pushed their way into Europe. They developed the ability to endure
colder climates, even climates as cold as those found in Iceland or
Greenland.
Cro-Magnon people were about as tall as modern northwestern
Europeans. They also had many of the same facial and cranial
features as modern northwestern Europeans.
Eventually, their successors moved into Asia. About 30 000 years
ago, they crossed the Bering Strait after the retreat of the ice and
entered the Americas. Others reached Australia.
With this migration, our modern human ancestors spread throughout
29

30. http://www.pbs.org/wgbh/nova/beta/evolution/BIBLIOGRAPHY
• http://www.techapps.net/interactives/peppermoths.• 30

31. THANK YOU!!!!!