Human Evolution
EVOLUTION is the slow and gradual
process of change over a long period of
time that has given rise to the diverse
organisms around us today.
• Anthropology
• Archeology
• Paleontology
Which picture represents each field
of study?
Becoming Human
• The Human Story
• http://www.becominghuman.org/node/intera
ctive-documentary
• The fossil record
• http://www.becominghuman.org/node/intera
ctive-documentary
What do we share in common
with other hominins?
• http://www.becominghuman.org/node/intera
ctive-documentary
• Australopithecus – bipedalism, use of hand
and feet
• Homo species- skeletal structure has
developed to be larger, larger brain, carnivores
Adaptation
• Structural, physiological or behavioral
characteristic that enhances the ability of the
organism to cope with its prevailing environment.
• In the case of humans adaptation to bipedalism
led to many other adaptations that effected many
aspects of the way they survived in their
environment e.g. the way they searched for food,
tools to bulid shelter, sexual practices….
Variation
The changes within a population.
Give an adaptation you were looking at in the hominin prac assignment.
What variations in this adaptation did you find?
Comparison of skulls
CHIMPANZEE
GORILLA
HUMAN
SKULL
Similarities Between Apes and Humans
– Opposable thumb ability to use
tools
– Share common genes, closest
relative is the chimpanzee
– Eyes in front of the head
– Position of foramen magnum
fairly low allowing to stand
upright
– Face flatter than most other
animals
– Similar dental structure with
canines
– Molar teeth used for grinding
food
Unique Features of a Human Skull
• Top of the skull (ie cranium) is smooth.
There is no anterior-posterior crest to
hold huge jaw muscles
• No protruding brow
• No protruding jaw or teeth (ie the teeth
are vertical)
• No protruding nose bone
• Teeth are arranged in a parabolic shape
rather than a narrow u shape
• Small canines and small incisors
• Foramen magnum (hole for the spine) is
positioned directly underneath the skull
not in the back of the skull
SKULL ORDER TIMELINE
Modern Man
Neanderthal
(32,000-150,000)
Cro magnon
( 100,000 )
Homo Erectus Pekinensis
Broken Hill
(200,000- 1.6 million)
Australopithicus Boisei
(1.3-2.5 million)
Australopithicus Africanus
(2.3 – 3 million)
Human Time line
• So oldest human is less than 3 million years old.
• Earth is 4600 million years old
• Take a look at the Table 7.1 on page 216 of your
books.
– In what era did the Earth begin to form?
– In what era did humans exist?
– When did the dinosaurs appear?
Other examples of timelines
Chart showing common
ancestors
Evidence for explaining theory
of evolution
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Fossil Evidence
Biogeography
Natural Selection
Comparative Anatomy
Comparative Embryology
DNA Hybridisation
Fossil evidence
www.albion-swords.com
faculty.evansville.edu
geography.berkeley.edu
Evidence that many of the species existed in the past can be see from the
fossilised remains of plants and animals that were trapped during the process of
rock formation.
Archaeopteryx – a missing link
Discovery of a transition between reptile and bird
Missing Link
Lucy - Australopithecus afarensis
3.2 million years old
More recent… Missing Link
"Sediba has more features related to toolmaking than...the hand that was used
originally used to define the 'handy man'
species, Homo habilis," says Tracy Kivell, a
researcher in the department of human
evolution at the Max Planck Institute in
Germany.
The cranium of the juvenile
skeleton of Australopithecus
sediba.
2 million years old
Read more:
http://www.time.com/time/health/article
/0,8599,2092438,00.html#ixzz1uPrhc5B7
Fossils
• How are they made?
• What type of fossils are there?
• Making Inferences
• Dating fossils
• Fossils and geological timescale
https://homininevolution.wikispaces.com/Fossils
Biogeography
• Clues to past evolution can be found in
the natural geographic distribution of
related species.
• Major isolated land areas and island
groups often evolved their own
distinct plant and animal communities
• 200 million years ago all the
continents were joined together in a
giant land mass called Pangea.
• 20 million years ago Pangea broke up
into 2 different land masses.
Gondwana included Antartica,
Australia, India, Africa and South
America
• 45 million years ago Antartica and
Australia seperated.
•
http://www.youtube.com./watch?v=NYbTNFN3NBo&featur
e=related
weblogs.madrimasd.org/.../2007/01/04.aspx
http://earthscience.wordpress.com/2007/04/13/day143-continental-drift-puzzle/
Natural Selection
What is the variation shown here?
Why do you think these variations exist? i.e. What are they adapted for?
Natural Selection
Example of Peppered Moths
In country the industrial
revolution has killed the
lichen and you can see
the light peppered
moth is easier to see.
Unpolluted woodlands
where white lichen still
around harder to see
then dark coloured moth.
Some controversy with this due to some fraud in Science but
new evidence has determined still an example of natural
selection
Natural Selection
• is the way or process that allows evolution or change to take place.
• It occurs because:
– Variation exists within any population of organisms.
– All organisms face a daily struggle to survive and reproduce, whether
it is to find mates, to seek shelter, to find food or to avoid predators.
– Those organisms with features that best suit their environment have
the best chance of survival and reproduction.
– Those organisms that are able to survive and reproduce pass on their
characteristics to their offspring.
– Over time, the population will become better suited to its
environment.
Natural Selection
• Mutation – a change in a characteristic (gene).
– Mutations can be beneficial, harmful, or neutral to the
organism.
– Mutations tend to occur in a steady state in nature.
• Fitness - describes how well an organism can
survive and reproduce in an environment.
• Survival of the fittest - The idea that species
adapt and change by natural selection with the
best suited mutations becoming dominant.
Artificial Selection
• Artificial Selection – the
selection by humans of
animals, plants, or other
organisms to breed
together.
– Artificial selection is also
known as selective
breeding.
– Breeders use artificial
selection to ensure the
continuation of desirable
traits and to develop new
varieties.
Breed- a variety of organism
created by artificial selection
Breeds are not considered
different species because
organisms of different breeds can
mate and produce fertile
offspring.
Lamarck versus Darwin
• See handout
Comparative anatomy
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•
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Comparative anatomy is the study of similarities and differences in the anatomy of organisms.
Homologous structures are similar in different species because the species have common
descent
Analogous structures are similar in different organisms because they evolved in a similar
environment. E.g. the torpedo body shape of porpoises and sharks.
Homologous structures
Analologous
structures
http://cas.bellarmine.edu/tietjen/Ec&Ev_Distance_learning/Evidence/evidence_pix.htm
http://www.citruscollege.edu/pic/46/0345l.jpg
Comparative Embryology
• Closely related organisms go through similar stages in their embryonic
development
• See figure 7.31 in text book. What do you notice about the embryos i.e.
what are the similarities?what are the differences?What is unusual?
nitro.biosci.arizona.edu/.../lect2.html
DNA hybridisation
•
All plants and animals
receive their specific
characteristics from
their parents by
inheriting particular
combinations of genes.
•
Modern technology is
able to use techniques
such as sequencing and
DNA of organism and
hybridisationof DNA as
tools in the
investigation of the
similarity
DNA hybridization generally refers
to a molecular biology technique
that measures the degree of
genetic similarity between pools of
DNA sequences. It is usually used to
determine the genetic distance
between two species. When
several species are compared that
way, the similarity values allow the
species to be arranged in a
phylogenic tree
Relationship between humans and their
close relatives using DNA hybridisation
techniques
Phylogenetic trees
Anthropology….
• is the scientific and humanistic study of
humankind.
• it looks at the human experience from a
holistic, cross-cultural perspective that
considers culture as well as biology, the past
as well as the present, and both small and
large societies.
• Example they would be interested in the
evolution of bipedalism.
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Paleontologist
• Paleontology is the study of fossils.
• A fossil is defined as any trace of a past life form.
Thus, although wood, bones, and shells are the
most common fossils, under certain conditions
soft tissues, tracks and trails, and even coprolites
(fossil feces) may be preserved as fossils.
• Paleontologists study fossils and attempt to use
them to reconstruct the history of the Earth and
the life on it.
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Archaeologists…
• study past cultures through artifacts, or items
which people have made, used or modified.
• investigate sites and artifacts to answer a
specific research question or to save cultural
resources from destruction, either from
human or natural forces.
• strive to investigate and preserve the finite
and fragile clues of former cultures in order
for us to understand our link to the past.
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