The document summarizes hominid evolution and human origins. It outlines the major theories of human evolution such as Lamarckism, Darwinism, and the modern synthesis. The timeline of human evolution is also presented, beginning around 7 million years ago and progressing through key stages such as Homo erectus and Homo sapiens. Unique characteristics of modern humans like bipedalism and tool use are also discussed.

1. JIWAJI UNIVERSITY
CENTER FOR GENOMICS
MOLECULAR & HUMAN GENETICS
Akansha Chauhan
3rd Semester

2. HOMINID EVOLUTION

3. CONTENTS BRIEF
• Introduction
• Timeline of Human Evolution
• Theories of Human Evolution
• Stages of Human Evolution
• Homo sapiens characteristics

4. INTRODUCTION
• Hominid refers to the members of the human family homonidae which consists
of all the species from the point where the human line splits from the apes
towards present day humans.
• Hominid Evolution is the process by which human beings developed on Earth
from now-extinct primates.

5. TIMELINE OF THE HUMAN EVOLUTION
• Humans began to evolve about seven million years ago, and progressed
through four stages of evolution. Research shows that the first modern humans
appeared 200,000 years ago.
• Neanderthals were a separate species from humans. Although they had larger
brain capacity and interbred with humans, they eventually died out.
• A number of theories examine the relationship between environmental
conditions and human evolution.
• The main human adaptations have included bipedalism, larger brain size, and
reduced sexual dimorphism

6. THEORIES OF HUMAN EVOLUTION
• Main theories of human evolution:
I. Lamarckism:
II. Darwinism (Theory of Natural Selection):
III. Mutation Theory of Evolution:
IV. Neo-Darwinism or Modern Concept or Synthetic Theory of Evolution

7. LAMARCKISM
• Lamarck is best known for his Theory of Inheritance of Acquired Characteristics
If an organism changes during life in order to adapt to its environment, those
changes are passed on to its offspring. He said that change is made by what the
organisms want or need. For example, Lamarck believed that elephants all used
to have short trunks. When there was no food or water that they could reach
with their short trunks, they stretched their trunks to reach the water and
branches, and their offspring inherited long trunks.

8. Cambridge.org

9. DARWINISM
• Darwin defined evolution as "descent with modification," the idea that species
change over time, give rise to new species, and share a common ancestor.
• The mechanism that Darwin proposed for evolution is natural selection.
Because resources are limited in nature, organisms with heritable traits that
favor survival and reproduction will tend to leave more offspring than their
peers, causing the traits to increase in frequency over generations.
• Natural selection causes populations to become adapted, or increasingly well-
suited, to their environments over time. Natural selection depends on the
environment and requires existing heritable variation in a group.

10. DARWINISM vs LAMARCKISM
Reseachgate.com

11. MUTATION THEORY OF EVOLUTION
• Hugo de Vries (1848—1935), a Dutch botanist, one of the independent
rediscoveries of Mendelism, put forward his views regarding the formation of
new species in 1901. He also met some of the objections found in Darwin’s
theory.
• 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.

12. NEO DARWINISM(SYNTHETIC THEORY)
• Neo-Darwinism is an attempt to reconcile Mendelian genetics, which says that
organisms do not change with time, with Darwinism, which claims they do.
• Darwin actually knew very little about genetics. The great pioneer of that field
was Gregor Mendel, whose work was contemporary with Darwin's. Now the
theory of evolution incorporates Mendel's genetics into Darwin's framework; the
combined theory was called "neo-Darwinism." (The distinction from
"Darwinism" is often overlooked nowadays.)

13. STAGES OF HUMAN EVOLUTION
• Evolution involves the gradual changes from simple to more complex forms.
Humans are believed to have developed from simpler forms. The evolution is
hypothesized to have begun in the oceans billions of years ago. Darwin gave
the theory of evolution. In his book -The Origin of Species, Darwin has stated
that evolution has come through a series of natural selection. The theory
emphasized the following points:
• Natural Selection, variation
• Struggle To Exist, Survival of the Fittest
• Evolution is the outcome of the interaction between the following five
processes:
• Mutation
• Genetic Recombination, Chromosomal Abnormalities
• Reproductive isolation, Natural Selection

14. Humanorigin.si.edu

15. STAGES OF HUMAN EVOLUTION
Dryopethicus
• These are deemed to be the ancestors of both man and apes.
• They lived in China, Africa, Europe, and India.
• The genus Dryopethicus refers to the oak wood apes.
• When Dryopethicus was alive, the tropical lowlands which it inhabitated were
densely forwarded, so the members could have predominantly been
herbivores.

16. CONTINUED
Ramapethicus
• Their first remains were discovered from the Shivalik range in Punjab and later in
Africa and Saudi Arabia.
• They lived in open grasslands.
• Thickened tooth enamel, robust jaws, and shorter canines.
• Usage of hands for food and defence, and extrapolations of upright posture.

17. CONTINUED
Australopethicus
• The fossil of this genus was first discovered in 1924 in South Africa.
• They lived on the ground, used stones as weapons, and walked erect.
They were 4feet tall and weighed 60-80pounds.
Homo Sapiens Neanderthalensis
• The Homo Erectus evolved into Sapiens.
• During evolution, two sub-species of Homo Sapiens were identified- Homo
sapien Neanderthal and Homo sapiens sapiens. The cranial capacity of
Neanderthal grew from 1200 to 1600 cc.
• Some small hand axes had also been discovered.

18. CONTINUED
Homo Erectus
• The first fossil of Homo Erectus was found in Java in 1891. These were named as
Pithecanthropus Erectus.
• These were considered as the missing link between the man and apes.
• Another discovery made in China was the Peking man. This specimen had large
cranial capacities and is believed to have lived in communities.
• Homo erectus used tools comprising quartz. Tools made of bones and wood were
also discovered.
• There is evidence of collective huntings. There is also evidence of the use of fire.

19. CONTINUED
Homo Sapiens
• The remains of Homo Sapiens were first discovered in Europe and were named
Cro-Magnon.
• In these, the jaws are quite reduced, the modern man’s chin appeared, and the
skull was rounded.
• Their cranial capacity was about 1350 cc.
• They gathered food through hunting. Art first appeared during this time.
This is how evolution took place.

20. Brittanica.com

21. UNIQUE CHARACTERISTICS OF HOMO SAPIENS
• Four unique character define the genus homo:-
• Upright bipedal stance – standing upright and two footed, rather than four
footed.
• Opposable thumb : A thumb that can move across other four digits
• Enlarged cranium, Complex speech communication
• Other distinguishing characters are:
• Manufacture and use of complex tools
• Reduced jawbones and jaw muscles
• Shorter digestive tract

22. Humanorigin.si.edu

23. CONCLUSION
• Through this presentation I tried to explain different theories of Human
Evolution.
• Furthermore, I tried to gone through the gists of stages of Human Evolution
specifically looked for it’s characters and features.
• I concluded that Evolution is the lengthy process of change by which people
originated from ape-like ancestors. Scientific evidence shows that the physical
and behavioral traits shared by all people originated from apelike ancestors and
evolved over a period of approximately six million years ago.

24. REFERENCES
• Brittanica.com
• Humanorigin.si.edu
• Reseachgate.com
• Cambridge.org