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Definition of Evolution
 the process by which species arise and change
over time.
 The idea that all organisms have descended from
common ancestors
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Charles Darwin
Origin of Species, 1859
Decent with Modification
Natural Selection
Sexual selection
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Fossil Record
 tells the story of evolution
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Taxonomy
 Classifying organisms into groups
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Comparative Anatomy
 Homologous structures
 Intermediate forms
 Vestigial structures
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Comparative Embryology
 Early embryos of vertebrates are alike
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Molecular Biology –
 DNA, proteins
 mtDNA
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An organism becomes a fossil only if it dies
under the right conditions.
Majority of dead plants and animals are
consumed by other organisms and leave no
trace.
Dead organisms only leave a trace or imprint
if they are quickly buried in a bog or at the
bottom of a lake/ocean.
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Paleontologists find fossils
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Remains of humans were
preserved in fossils
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Bog is a wetland low in
nutrients, slightly acidic soil .
Mossy
Tollund Man. (Denmark)
Europe Iron age 2,400 ya
Buried in mud or at the bottom of a body of
water, the remains of the dead are protected
from scavengers, erosion and decay.
 Become buried deeply in successive layers of
mud
 Over time pressure from all these layers of
sediment turns the deepest layers into
sedimentary rock
 After millions of years geologic forces raise the
rock into mountains, canyons and reveal fossils
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Grand Canyon showing layers of rock.
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All organisms are grouped into hierarchies
based on their relationships.
Organisms of the same species can breed and
produce viable offspring
Major taxonomic levels - KPCOFGS
Common Name:
Human
Chimpanzee
Lion
Kingdom
Animalia
Animalia
Animalia
Phylum
Chordata
Chordata
Chordata
Class
Mammalia
Mammalia
Mammalia
Order
Primates
Primates
Carnivora
Family
Hominidae
Hominidae
Felidae
Genus
Homo
Pan
Panthera
Species
sapiens
troglodytes
leo
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Binomial nomenclature
Genus and species
Homo sapiens. Homo means “self” or “same”,
meaning “the same as me” — which, for you,
means “human”. Sapiens means “wise”.
Homo sapiens means “Wise human”.
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Species descended from a common ancestor
may evolve in different directions and still
keep some of the same characteristics
Evolutionary scientists compare the body
structures of organisms to find clues.
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Homologous Structures – similar structures
in two or more species that give evidence of a
common ancestor.
 Similar structure
 Same origin
 Different in function
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Compare legs of Human and Ape
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Intermediate forms – successive changes in
homologous bone structures provide
evidence of evolution.
Also called transitional forms
https://handfacts.wordpress.com/tag/evolution
/
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Comparing pelvis bones
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Vestigial Structures
 A part of an
organism with little
or no function that
reflects evolutionary
history
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Compare Embryo Development
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DNA, mtDNA, proteins
20 -20,000 genes in the Human Genome
Molecular geneticists have compared DNA
sequences of Humans and chimpanzees
98.8% identical
Humans are more closely related to African
apes than Asian apes (Immunological protein
analysis)
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DNA sequence
comparisons
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Mitochondrial DNA
 contains 37 genes
 Thirteen of these genes provide instructions for
making enzymes involved in oxidative
phosphorylation. Oxidative phosphorylation is a
process that uses oxygen and simple sugars to create
adenosine triphosphate (ATP), the cell's main energy
source.
 The remaining genes provide instructions for making
molecules called transfer RNA (tRNA) and ribosomal
RNA (rRNA)
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Mitochondrial DNA
Passed from mother to
all her children
Points of mutations are
a clear .
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Primatologists observe
our closest living
relatives, apes and
chimpanzees
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Sahelanthropus tchadensis
 Discovered in the Sahara Desert in 2001
 Between 6 – 7 million years old
 Considered oldest known hominid fossil
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Look up Rift Valley
Explain where it is
Explain why it is important to the study of
Human Evolution.
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As we have evolved Humans have
 Larger brains
 Walk bipedally
 Sparse body hair
 Nonopposable toes and longer feet
 Grasping flexible thumb
 Unspecialized teeth
 Arching backs
Australopithucus
afarensis
 Lucy
 Found in Ethiopia in 1974
 This the earliest species of
Australopithecus, l
 ived in about 4 million and
3 million years ago.
 brain was about the same
size as chimps
 3 feet, 70 lbs
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The researchers also found
that the model of
locomotion produced in
their simulations closely
matched a set of fossilized
footprints thought to have
been left by A. afarensis in
Laetoli, Tanzania, some 3.6
million years ago.
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They constructed the computer model using
a fossilised A. afarensis skeleton known as
"Lucy", recovered from Ethiopia in 1974. The
researchers then added virtual muscle to
their simulation and used genetic algorithms
to "evolve" the optimal walking movement
for the creature.
Australopithicus africanus
lived perhaps from 3
million to 1 million years
ago, and probably evolved
from A. afarensis
 had a rounder skull and
slightly larger brain
 Tooth and jaw design
suggest he chewed plant
foods, but might also have
scavenged meat from the
remains of carnivores'
kills.
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Neanderthal Man Fossils
found in Germany
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Homo neanderthalensis
More Neandertal skeletons
have been found than any
other ancient human
species.
They lived in Europe and
Southwest Asia from at least
130,000 -28,000 years ago.
May have evolved from
Homo heidelbergensis in
Southern Europe.
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protruding jaw,
receding forehead, and
weak chin.
The average Neanderthal
brain was slightly larger
than that of modern
humans, but this is
probably correlated with
larger body size in general.
May have been a different
species than Homo
sapiens.
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Homo heidelbergensis
(600,000 to 100,000
years ago)
The skulls of this
species share features
with modern Homo
sapiens.
brain was smaller than
most modern humans
Homo sapiens sapiens
Cro magnum man
Earliest modern man
Lived 35,000 ya
The body heavy and solid ,
muscular.
 Straight forehead with slight
browridges
 Cro-Magnons were the first
humans to have a prominent
chin.
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Neanderthal vs Cro-magnun
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Comparison of erectus, aferensis,
neanderthal
An evolutionary
comparison (from left
to right: Homo erectus,
1 million years old;
Australopithecus
afarensis, 2.5 million
years old; Homo
neanderthalensis,
100,000 – 32,000 years
old)