IV. The Domain Eukarya
E. Fungi
F. Animals
G. Human Evolution
1. Overview:
Linnaean Classification
Hominidae
Pongidae
Hylobatidae
Apes = primates (grasping hands, binocular vision) with no tails
IV. The Domain Eukarya
E. Fungi
F. Animals
G. Human Evolution
1. Overview:
Phylogenetic Classification
Hylobatidae
Hominidae
IV. The Domain Eukarya
E. Fungi
F. Animals
G. Human Evolution
1. Overview:
1-4% difference
Hylobatidae
Hominidae
IV. The Domain Eukarya
E. Fungi
F. Animals
G. Human Evolution
1. Overview:
How can the small
genetic difference
account for the
dramatic
differences that
occur between
these species?
IV. The Domain Eukarya
E. Fungi
F. Animals
G. Human Evolution
1. Overview:
2. Patterns:
a. Morphological and Behavioral
Homo sapiens
Chimps, Gorillas
Larger Head/body ratio
smaller
Smaller jaw/head ratio
larger
Shorter limb/body ratio
longer
Less hair
more hair
Better learning
poorer learning
IV. The Domain Eukarya
E. Fungi
F. Animals
G. Human Evolution
1. Overview:
2. Patterns:
a. Morphological and Behavioral
Differences correlate with developmental differences
Juvenile Primate
Adult Primate
Larger Head/body ratio
smaller
Smaller jaw/head ratio
larger
Shorter limb/body ratio
longer
Less hair
more hair
Better learning
poorer learning
IV. The Domain Eukarya
E. Fungi
F. Animals
G. Human Evolution
1. Overview:
2. Patterns:
a. Morphological and Behavioral
Big head,
short limbs
Small head,
long limbs
IV. The Domain Eukarya
E. Fungi
F. Animals
G. Human Evolution
1. Overview:
2. Patterns:
a. Morphological and Behavioral
b. Genetic
Developmental genes can
have profound effects on
the final morphology of the
organism.
Human
Chimp
Primate Developmental Trajectory
IV. The Domain Eukarya
E. Fungi
F. Animals
G. Human Evolution
1. Overview:
2. Patterns:
a. Morphological and Behavioral
b. Genetic
What are some of these genetic differences?
The HAR1 RNA molecule.
- not a coding RNA; probably regulatory
- nearby genes associated with transcriptional regulation and neurodevelopment are
upregulated in humans.
- only 2 changes in sequence between chicks and chimps; 18 between chimps and humans.
“HAR” stands for “human accelerated region” – changing more rapidly than drift can explain.
why? Selection.
-Changes result in a profound change in RNA structure and, presumably, binding efficiency.
Beniaminov A, Westhof E, and Krol A. 2008.
Distinctive structures between chimpanzee and human in a brain noncoding RNA. RNA 14:1270-1275.
Beniaminov A et al. RNA 2008;14:1270-1275
IV. The Domain Eukarya
E. Fungi
F. Animals
G. Human Evolution
1. Overview:
2. Patterns:
a. Morphological and Behavioral
b. Genetic
c. Fossils
Chimpanzee
Human
Sahelanthropus tchadensis
Sahelanthropus tchadensis – discovered in Chad in 2001. Dates to 6-7 mya.
Only a skull. Is it on the human line? Is it bipedal? Probably not (foramen
magnum). Primitive traits, as a common ancestor might have.
Ardipithecus ramidus: 4.3-4.5 mya. Discovered in 1994 by Haile-Sailasse, Suwa,
and White, with the most complete fossils were not described until 2009.
Arboreal, but facultatively bipedal. Grasping toes.
IV. The Domain Eukarya
E. Fungi
F. Animals
G. Human Evolution
1. Overview:
2. Patterns:
a. Morphological and Behavioral
b. Genetic
c. Fossils
Sahelanthropus
tchadensis
Chimpanzee
Human
Homo sapiens
Competitive
contraction?
Radiation of Bipedal Hominids
Innovation:
Bipedality
Australopithecus afarensis: 2.8-3.9 mya. A femur discovered in 1973 by Donald
Johansson suggested an upright gait, confirmed by his discovery in 1974 of the ‘Lucy”
specimen. Also, the Laetoli prints (found by Mary Leakey) were probably made by A.
afarensis, and in 2006, a juvenile A. afaresis was found.
Kenyanthropus platyops: 3.2-3.5 mya – Discovered by Meave Leakey’s team
at Lake Turkana; most dispute it warrants another genus, and some even
include it in A. afarensis.
Australopithecus garhi: 2.5-2.6 mya; discovered by Asfaw and White in 1996, but the
skull below was discovered by Haile-Selasse in 1997. The tooth morphology is a bit
different from A. afarensis and A. africanus, being much larger than even the robust
forms. There are associated stone tools!
Australopithecus sebida: 1.9 mya, describe in 2010 by LE Berger; it has many
characteristics like A. africanus, but also similar to genus Homo.
Australopithecus africanus: 2-3 mya, discovered by Raymond Dart in South Africa
in 1924 – the ‘Taung child’. Then, in 1947, Robert Broom found a skull he
classified as Plesianthropus, but was grouped with A. africanus.
Paranthropus aethiopicus: 2.5-2.7 mya, discovered by Alan Walker and Richard
Leakey, the “black skull” is one of the most imposing hominid fossils there is!
Aside from the high cheekbones and the sagittal crest, it has similar proportions
to A. afarensis and is probably a direct descendant. It probably gave rise to the
“robust” lineage of Paranthropus.
Paranthropus boisei: 1.2-2.6 mya. Discovered by Mary Leakey in Olduvai Gorge in
1959, it was originally classified as Zinjanthropus and nicknamed “Zinj” or
“nutcracker man” because of the large grinding molars.
Paranthropus robustus: 1.2-2.0 mya. Discovered in South Africa in 1938 by
Robert Broom.
Competitive
contraction?
Radiation of Bipedal Hominids
Innovation:
Bipedality
Homo habilis: 1.4-2.3 mya, discovered by Louis and Mary Leakey, in association with
stone tools. “Handy man”. Longer arms and smaller brain than other members of the
genus.
Homo rudolphensis: 1.9 mya; Discovered by Richard and Meave Leakey’s team. Different
from H. habilis, yet a contemporary. Either may be ancestral to recent Homo.
Homo georgicus: 1.7 mya; the oldest hominid fossils found outside of Africa –
found in Dmanisi, Georgia, in 1999. Thought to be a potential intermediate
between H. habilis and H. ergaster/H. erectus.
Homo ergaster (H. erectus): 1.3-1.8 mya, the most complete
fossil hominid skeleton was discovered in 1984 by Alan
Walker who called it “Turkana Boy”. Some consider this
species intermediate to H. habilis and H. heidelbergensis/H.
sapiens, leaving H. erectus as a distinct Asian offshoot of the
main line to H. sapiens.
However, most paleontologists suggest that H. ergaster is the
African ancestor – even a chronospecies or population - of H.
erectus, which is ancestral to more recent Homo species.
Homo erectus: 0.2-1.8 mya; originating in Africa, but then leaving for Asia (Peking and
Java Man). Discovered in Java by Eugene Dubois in 1891. Certainly one of the most
successful hominid species in history; perhaps lasting as relictual species on islands in
Indonesia as:
Homo floresiensis: 94,000-13,000 years,
discovered by Mike Mormood on the island of
Flores. Shoulder anatomy is reminiscent of H.
erectus, but could be an allometeric function of
the small size (3 ft).
Homo cepranensis: 350,000-500,000 years old; discovered by Italo Biddittu in 1994
in Italy. It is just a skull cap, but seems to be intermediate between H. erectus and H.
heidelbergensis.
Homo antecessor: 800,000-1.2 mya;
fossils from 20 individuals found in
Spain in 1994-5; may be H.
heidelbergensis or an intermediate
between it and H. ergaster.
Homo heidelbergensis: 250-600,000 in
Europe and Africa; ancestral to H.
neaderthalensis and H. sapiens; may have
buried their dead.
Homo rhodesiensis: 125-300,000; may be H.
heidelbergensis or intermediate to it and H.
sapiens.
Homo neaderthalensis: 30,000-150,000; first
discovered in 1829. Descended from H.
heidelbergensis.
Homo sapiens idaltu: 160,000 – oldest
Homo sapiens fossil – found in Africa
in 2003… afar valley.
Competitive
contraction?
Radiation of Bipedal Hominids
Innovation:
Bipedality