Download Multifactorial Traits - Study materials & Discussion

Human Evolution
BIO 2343
Oklahoma City Community College
Dennis Anderson
Animal Connection
• Humans share many
traits with animals
• We are most similar to
apes
– Same 206 bones
– All but 3 of 650
muscles the same
– DNA is 98% the same
– Same blood types
Albino Gorilla
2
Why are we so similar to apes?
• Modern apes and modern man share a
common ancestor who lived about 5 to 6
million years ago
3
Does the idea of human evolution
from animals contradict a belief
in God?
• Many scientists of all religious faiths
believe in both.
• Some people feel evolution contradicts the
literal interpretation of the Bible.
4
Earths Position in the Universe
• 400 years ago the
general public thought
that the earth was the
center of the universe
– Sun revolves around
the earth
– The earth does not
move
5
Galileo and Corpernicus
• Demonstrated scientific
evidence that the sun is at
the center of our solar
system and the earth
moves around the sun
6
Galileo and the Church
• Religious leaders felt
the heliocentral theory
(sun at the center) was
a direct contradiction
to the literal
interpretation of the
Bible
• Galileo found guilty of
heresy
7
Copernican System
(Heliocentral Theory)
• Did not destroy
peoples belief in God
• Public now accepts the
overwhelming
evidence for the
heliocentral theory
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Theory of Evolution
• Science has overwhelming evidence that all life is
constantly evolving
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Natural Selection
• One mechanism of evolution
• Main concepts of natural selection
–
–
–
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Overproduction of offspring
Inherited variation in offspring
Competition
Best adapted in a given environment survive
and reproduce to increase their kind
• They are naturally selected
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Overproduction of Offspring
• Elephants (very slow reproductive rate)
– If all the offspring of one elephant pair survive and all
their offspring survive then:
• 750 years = 19,000,000 elephants
• 1200 years = Enough elephants to cover the earth!
• Beetles
– A handful that weighs 10 mg each
– 82 weeks
• 61,000,000,000,000,000,000,000 ton
– The weight of the earth!
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Variation of Offspring
• Offspring of the same
parents are different
from each other
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Competition
• Since more individuals are born than can
survive for an extended period of time, they
compete for resources
– Food
– Living space
– Mates
13
Best adapted to a given environment
are selected to survive
• Brown bears
– Adapted to survive in
Oklahoma
• Polar bears
– Adapted to survive in
Alaska
14
Sequence of Human Evolution
• Hundreds of fossils
have been found
• Some of the major
fossils will be
discussed in this
presentation
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Australopithicus afarensis
•
•
•
•
•
3.5 million years ago
Nicknamed Lucy
Walked upright
Small brain
Skeleton human like
– Feet
– Pelvis
– Upright stance
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Comparative Anatomy
Lucy
Gorilla
Human
• Gorilla pelvis adapted for knuckle walking
• Human pelvis adapted for upright walking
• Lucy’s pelvis very similar to human pelvis
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Knuckle Walking
• Requires an elongated
pelvis and long arms
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Lucy’s pelvis allowed her to walk
like a human instead of an ape.
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Fossilized Footprints
• Footprints left when a
a pair of
Australopithecines
walked in the ash of a
recently erupted
volcano
20
Skull Anatomy
Lucy
Chimp
• Thick brow ridges like a chimpanzee
• Cranial capacity 400 cc. Chimp 350 cc.
• Teeth similar to human teeth
21
Lucy: A Transitional Fossil
• Transitional fossil shows
characteristics of two kinds
of animals
– Represent the transition from
one organism to another
• Ape characteristics
– Skull
– Cranial capacity
• Human characteristics
– Walked upright
– Feet
– Pelvis
22
Australophithicus africanus
• 2.8 million years ago
• Cranial capacity 460 cc
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Homo habilis
• Cranial capacity 630 cc
• Flatter face than
Australopithecines
• Used tools
– Nicknamed handy man
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Homo erectus
• 1.8 million to 35,000
years ago
• 1,000 cc cranial capacity
• Large brow ridges
• Sloping forehead
• More advanced tools than
H. habilis
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Homo erectus
• Skeleton very similar
to modern man
• Used fire
• Traveled
– Fossils found in Africa,
Europe, China,
Indonesia
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Homo neanderthalensis
• 135,000 to 25,000 years
ago
• Cranial capacity up to
1750 cc
– Larger than modern man
• No chin
• Sloping forehead
• Buried dead with tools and
flowers
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Homo sapiens
• 200,000 years ago to
present
– Photo is a skull
100,000 years old
• 1400 cc cranial
capacity
• Vertical forehead
• Pronounced chin
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Modern Homo sapiens
• Small front teeth
• Small brow ridges
• Rounded cranium
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Sequence of Human Evolution
One of several possibilities
Homo
neanderthalensis
Australopithicus
afarensis
Australopithicus
africanus
Common
ancestor
Homo
habilis
Homo
erectus
Homo
sapiens
Modern
apes
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Evolution of Skull
•
•
•
•
•
Cranial capacity increases for a larger brain
Face become flatter
Brow ridges become smaller
Forehead becomes higher
Chin develops
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Tools used to learn about our
evolutionary past
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•
•
•
Study of fossils
Comparing DNA
Comparing chromosomes
Comparing protein sequences
32
Paleontology
• Study of fossils
– Allows us to see
anatomical similarities
between us and
organisms that lived in
the past
– Allows us to see how
our ancestors have
changed over time
33
Comparing DNA
• Human DNA
compared to:
–
–
–
–
Chimpanzee 99% same
Gorilla 97.7% same
Orangutan 96.3% same
Another human 99.9%
same
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Comparing Chromosomes
• All apes have 48
chromosomes
• Chromosome bands
between human (H)
and chimpanzee (C)
99% the same
• Translocation of two
ape chromosomes
formed human
chromosome 2
35
Inversions
• Human and chimp
chromosomes
• Inversion between
p14.1 and q14.1
• 9 total inversions in
human vs. chimp
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Comparing Protein Sequences
• Many proteins in all of man are identical
• Organ transplants require similar proteins in
the donor and the recipient
– A sibling or parent is often the best source for
an organ transplant
37
Which would be the closest protein
match for an organ transplant?
Assuming all are alive and healthy.
• A persons father
• A persons great grandfather
• A persons 10th great grandfather
38
Molecular Clock
• The further you go back in time, the more
proteins (and DNA) are different.
• Differences in protein sequences and DNA
can be used to estimate time when two
species shared a common ancestor
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Related Organisms
• Close similarity of protein sequences
indicates close relationship
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Cytochrome C
• Protein used to release
energy from food
• 104 amino acids
• 20 of the amino acids
occupy the same position
in all eukaryotes
41
Comparison of Human Cytochrome C
• 100 amino acids different
in tuna fish
• 12 amino acids different
in a horse
• 8 amino acids different in
a kangaroo
• 1 amino acid different in
a monkey
• Identical to chimpanzee
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Mitochondrial DNA
• Only inherited from
mother
• Mutates faster than
nuclear DNA
– Lacks repair enzymes
43
Mitochondrial DNA
• Studied in several different human
populations
• Greatest diversity found in African
population
– Therefore the oldest population
• Molecular clock
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Mitochondrial Eve
• Mother of all humans
• She may have lived
about 200,000 years
ago in Africa
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Native American Origin
• Four Rare mtDNA
haplotypes are found in
Native Americans
• The same haplotypes are
found in Mongolia and
China
46
Mitochondrial DNA
• Four Rare mtDNA haplotypes are found in
Native Americans
• The same haplotypes are found in Mongolia
and China
47
Neanderthal Man
• Mitochondrial DNA
studies indicate he was
not a direct human
ancestor
• Contemporary species
with early Homo sapiens
• H. sapiens out competed
H. neaderthalensis
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Eugenics
• “Improvement” of the human race
• Attempt to direct human evolution
– Not allow unfit to reproduce
– By 1956 58,000 people in USA sterilized for
being feeblemindedness, criminality and
insanity
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American Eugenics Society
• Founded in 1923
• Lobbied for IQ tests of
immigrants
• Lobbied to not allow
immigrants from
countries not from
northern Europe
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Fitter Families Exhibit
• State fairs across the
nation
• Promoted eugenics
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Eugenics Champion
• Hitler wanted to
improve the human
race
• killed millions of
people in the name
eugenics
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The End
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